DIY Solar Pool Heater

I did the same kind of construction for my solar pool heater, except that I made it out of 2 4x8 sheets. I live in Canada so not a lot of sun. Anyways, don't use plexiglass to cover the box becasue plexiglass turns yellow with UV rays. You need to use some other plastic that has UV Enhancer built in it. Check for "Plastic" in the telephone book to find a distributor.

#1 Alain on 2006-07-13 16:19

I'm in Canada too, but almost as far south as you can be and still be in Canada

With 4 times the surface area you must get great heating!

#1.1 Rob A on 2006-07-13 16:54

Rob, I cannot get the black irrogation hpose. Does 1/2 PVC pipe work? What lenght should I use. How about the 90º elbows?

Leo in Panama

#1.1.1 Leo on 2008-01-16 20:45

PVC, even painted black, is not a great absorber for solar heat. Rubber hose, or aluminum painted black, is better.

#1.1.1.1 Chuck on 2008-02-11 18:14

try mean green 1/2 inch times 200 feet.

#1.1.1.2 Anonymous on 2010-04-25 03:10

I just went to Home Depot and Lowe's, couldn't find that type of hose you were talking about. The stuff they had seemed too rigid, like hard plastic.

Is the material you speak of flexible? Is it rubber?

Gonna try Carter Lumber on monday.

#1.1.2 Tom Smith on 2008-07-06 01:00

I found a website hosexpress.com that has that food grade polyethylene tubing. $100.00 for 500 ft. of the 1/2" size.

#1.1.2.1 Tom Smith on 2008-07-06 16:38

Did not see any dark colored hoses for food grade

#1.1.2.1.1 D. Ryan on 2015-07-28 23:30

No luck at Carter Lumber, or Tractor Supply. Has anyone in the U.S.A. been able to find this polyethylene tubing?

#1.1.2.2 Tom Smith on 2008-07-06 20:09

I bought a 500ft roll from homedepot.com:
Toro Blue Stripe Drip 1/2 In. Hose, 500 Ft. Roll
Model 53616
$31.39/EA Each
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100031184&N=10000003+90401+527947
I put about 275 feet coiled on a 4x4 sheet of plywood.
I am right now refilling my pool after replacing the liner. It is about 80F outside. the water is about 74F without the heater, about 76F with the heater. I plan to divert one of the pool jets (I have an extra coupling that my vacuum hooks to) and use that for recirculating through the heater, once the pool is filled and the pump is back on.

#1.1.2.3 Johnny G on 2009-06-06 15:36

Just want to know how you drain this for winter storage.

#1.1.3 Deb Heitzman on 2008-09-04 13:37

Subject: How do I drain for winter?
If you install a tee with NPT 1/2 or 3/4 to install a boiler drain valve. Just hook up a short hose to the open faucet from an air compressor and the air will chase the water out the open end of the water filled coils.(caution; on a sunny day you may have some hot water spitting out as you drain it.)You may need to make up a short garden hose to a air compressor hose by fittings and hose clamps.

#1.1.3.1 Johnny H on 2011-05-08 14:58

If you use black polyethylene irrigation tubing, you don't need to worry about draining it for winter. Freezing will not damage polyethylene tubing. My solar panel has survived 3 Canadian winters without any problems. Before winter, I just disconnect the tubing from my PVC pool piping but I don't bother blowing it out.

#1.1.3.2 Ken on 2011-05-08 18:21

I have 48" x 30' above pool bought last year it was too cold to swim too many days with solar cover heated top 4 inches. I was told this pool hold nearly 10,000 gallon. How many feet of pipe do I need? A friend wants sell me a submersible pump don't buy it if won't work?
I want DIY to build heater with black pipe rolled up laying it flat on a stand on ground or on the roof. We have 18hrs direct sunlight most days all summer. Curious can I use submersible pump to move water through the black pipe?? Also how to drain it for winter in BC. Feed back asap Please

#1.1.3.2.1 Lois on 2016-02-13 06:15

R U Kiddin ME!!!
It took me hours to read through these posts, But because
of the time spent here it only took me 4 hours to complete this project. I can't believe that not only does it actually work very well it doesn't look ugly! I'll take some pics and close ups for you all to see what your advice produced. I'll also give you all the #'s pertaining to it. I'll put up a complete parts list used with prices and where i bought them from. Thanks to everyone here from me and my family. We are not only swimming in MAY!!! but my wife went in today! Temp @ 81 and rising. Thanks again I will post all info so as maybe help someone else do what i did.

#1.1.4 Frank on 2010-05-24 23:45

Hi Frank,

that is fantastic news that this is working for you. I have walked into Home Depot three times to pick up the parts to build this solar heater but I never know what to get to make all the connections so I end up walking out empty handed. If you could post the pics and parts #'s that would be a huge benefit for me. If you can not upload them to this site could you please zip them up and email them to me?

Thank you,
Kevin
kevin.ob@usa.net

#1.1.4.1 Kevin on 2010-05-25 13:18

Hi Kevin

Pics comming!!
As far as the parts go here's what I got.
I went online as it's only available online to home depot.
If you go to the very top of this thread post #9 you'll find a link to Home Depot and the Black 1/2 inch hose I and others have used. If you want you can just go to Home Depot.com and do a search for black hose and it's the only one that has a whopping 500ft for $31.00
I waited for it to come and when it did I went to Home Depot and bought the following:
2 10 ft lenghts of 2in PVC $6.00
1 4 way PVC T $2.60
2 Bags of Black UV resistant zip ties $7.50 per bag
4 End caps for the 2in PVC ( to keep out bees) $4.00
1 Can of Flat Black spray paint $4.95
Those are the materials to make the panel.
The rest are materials to plumb it in.
1 PVC T I have 1 1/2 hose going from my filter to my pool
so I bought a 1 1/2 PVC T with a 1 in coming off of it. I used
reducers going to my panel to get the line to 3/4 inch.
I bought a 4 ft piece of 3/4 PVC to connect to it. at the panel end I used a 3/4 shut of with another reducer to make it on the end of my hose that was 1/2in clamped the end and was done. on the other end of my panel I used a plastic male fitting and for the final 8 feet into the pool I bought 5/8inch heater hose for a car. Put it over the side and bungee corded it in place.
Itll al make sense when you see the pics!
Total cost to buy and make the panel and the plumbing fittings $88.00 or there abouts.
You should be able to make it from the pics but if you need instructions I will give it to you step by step.
Again it's real easy and there's lots of great info here.
Good Luck
I'll post the pics and temp Data shortly.

#1.1.4.1.1 Frank on 2010-05-30 02:12

Hi Frank,

Thanks for the info! Pics would be great.

Thanks for your help.

Kevin

#1.1.4.1.1.1 Kevin on 2010-05-31 19:34

Just wondering if you had any pics of your solar heater. Also what size of pool do you have?

Thanks Dan

#1.1.4.1.1.1.1 Dan on 2011-07-03 15:20

Since my hubby is utterly unqualified to build anything, ever, I am taking on this project for my family's swimming pleasure this summer. Like you Frank, I have spent a lot of time reading about how to do it but find myself overwhelmed when I go into the hardware store. Where to begin?

So I'm looking for your pictures and/or step-by-step construction instructions. I would like to get this project started (and finished) this weekend, if possible.

Thanks.

#1.1.4.1.1.2 Julie on 2010-06-04 21:05

Hi Frank,

Were you able to take any pics of the pool heater? Are you still happy with it?

Thank you,
Kevin

#1.1.4.1.1.3 Kevin on 2010-06-23 13:52

Hi Frank,

Can you send me a link to where your pictures are at? We are having a hard time with our pools staying cold. How much temperature raise did you end up seeing?

So the T that you put into your main pool hose going into the pool, has a 3/4" output to your heater... so I guess the water is just distributed then out the both sides of the T... correct?

Thanks!
Jeff

#1.1.4.1.1.4 Jeff Dressing on 2014-07-15 21:18

Frank can u pls send me your parts. List and your pics .thanks so much. Brenda

#1.1.4.2 Brenda on 2011-05-08 06:31

I have 48" x 30' above pool bought last year it was too cold to swim too many days with solar cover heated top 4 inches.
I was told this pool hold nearly 10,000 gallon.
How many feet of pipe, do I need?
I have friend want to sell me submersible pump for $60.
I don't want buy it is I can't use for pool
I want DIY to build pool heater like post above, with black pipe rolled up laying it flat on a stand on ground or on the roof.
We have 18hrs direct sunlight most days all summer.
Curious can I use submersible pump to move water through the black pipe?? Also how to drain it for winter in BC
Help Feed back Please ASAP

#1.1.5 Lois on 2016-02-13 06:29

I used Plexiglas and I sprayed a clear UV protector on the Plexiglas and it works great. no fade.

#1.2 Tim on 2009-06-19 22:48

I have a basic intex pool. I live in South GA, pretty good sun here but its not staying warm enought at night yet. What if i have a 100 foot black water hose i could attach to the outlet of the pump and just coil it on the ground in the sun all day. Do you think that would help heat the pool?

#1.3 paul on 2010-04-30 12:23

if your looking for the type of plastic to use as an owner of a Glass company and in the industry for over 35 years you are correct that Plexi glass will yellow. Use LEXAN instead it is the only "unbreakable" plastic for this. Plexiglass will break as well yellow. Hope this helps.Now if I can get my system to work which is 98% there i will be happy .

#1.4 Henry Kreutzer on 2010-05-04 11:56

I've heard some guy in Florida, USA has come up with a new type of floating water heater for pools and is working with some pool company in the US called smartpool (the web site is www.smartpool.com). I called the company up and they told me it's true but they will not oficially release the product until next year. They told me that the product relies entirely on solar energy and floats on the pool surface with no installation of anykind, you will be able to use it right out of the box.
I can't wait to see the product online, it's about time some came out with something like that!
If anyone else finds out more about it, please let me know!
John

#1.5 john beals on 2010-05-10 22:22

I too, live in Canada.....Pembroke, ON. actually. I'm interested in constructing the heater as you described, but I would like more info as to pipe size. Also, is the pipe you used just simple poly, plastic stuff available at home depot for example?
Great plans!
BTW, I couldn't get the pix to enlarge by clicking on them

Dennis

#2 Dennis on 2006-07-25 16:31

Hey Dennis -

The pipe is irrigarion pipe from Home Depot. It is fairy thin walled, so will kink if you bend it too sharply.

I changed the popups to be new pages, so hopefully that will work for you.

-Rob A>

#2.1 Rob A on 2006-07-26 03:26

Thank you very much. This seems to be a really great idea that can help me get my Canadian pool heated without paying as much as I used to for my gas heater.

I am trying to get a better sense of how to identify the irrigation pipe that farmers use. At first, it seemed to me to be just black garden hose. When I enlarged the photos I was able the read "20mm PE 75 PSI@23C Food grade, White stripe".

I believe I will be able to identify the pipe at Home Depot or a garden centre by finding black 1/2" pipe (20mm) that has a white stripe down it. Is this correct?

#2.1.1 Michael Newell on 2008-06-25 14:20

The tubing I have is the white strip polyethylene tubing from Home Depot. It's 1/2"PE food grade tubing and says 12 mm on it, not 20 mm which would be 3/4".

Polyethylene is strong and flexible and is not likely to be damaged from freezing.

#2.1.1.1 Ken on 2008-06-25 17:23

I found the direction to get "irrigation pipe" at Home Depot a bit frustrating. When I asked for it there, I was told that they didn't sell that. Later, I looked closer and found that the pipe shown in the pictures was labeled and I asked for that. Still, some Home Depot associates told me they did not sell that product. However, a buddy reassured me that they did sell it. I looked again and found it in abundance there. If you look for the product, "IPEX 018200
20mm (1/2") PE 75 PSI(White stripe) STD PIPE WITH THE STRIPE" you will find irrigation pipe. On my last trip to Home Depot, the associate even said, "Oh yah, ya mean irrigation pipe." I said, "Yah, that's it."

#2.1.1.1.1 Michael Newell on 2008-07-19 16:25

oops. Yah, you're right. 20mm would be about 3/4". 12mm is more like it. But the photo does show 20mm pipe. Interesting.

#2.1.1.1.2 Michael Newell on 2008-07-19 16:37

I found LDPE black polyethylene tubing resistant to sunlight and uv and also polyehylene flexible pipe nsf and not nsf listed that is not uv resistant. Since this will be in the sun all day on my roof heating water which would be better to use. I found them at usplastic.com.

#2.1.2 Mike on 2008-10-09 19:11

Hi Rob,

Great info!

I am going to try this. I am a blind persoon, so the pics won't help me. I was wondering if you could send me the step-by-step instructions mentioned somewhere herein? I am a bit confused as to where the T-adapter and the valve go.

Thanks for any help you can give.

Steve

#2.1.3 Steve S on 2010-07-24 13:02

I think your instructions for this solar heater are great. I have a 16ft by 48" Intex pool. I have constructed my panel and now ready to connect those hoses. Do you have step by step instructions on connecting the hoses you could email me. I think I have all the connectors. Thank you.

#2.1.4 Phyllis on 2014-05-31 12:39

I have folowed this model to develop my own. I am using 500 feet of 3/4" 75 psi piping. The water that comes out of the heater is 6-8 degrees F warmer than the water coming in. Since the flow is 6 1/2 liters per minute (measured)(so 390 liters per hour) and my pool contains 39,000 liters of water, I can expect to raise the water temp by about one degree per day (if it is sunny, of course!)
A link to pictures: http://www.cogev.com/gallery/Oka-pool

#3 Robert on 2006-07-31 12:58

Hi,

Im in Calgary and thinking about doing the same type of heater but using an old 7 or 8 ft satellite dish and painting it back, what do you think?

Brian

#4 Brian on 2006-08-13 03:07

That would be clever! My only worry would be the weight of all that water, and whether the dish frame would support it. Might need a support or two.

-Rob A>

#4.1 Rob A on 2006-08-19 20:13

Hi Brian,
I am in Calgary too, how did you do?

#4.2 Jon on 2008-08-14 20:36

This looks great! Thanks for sharing!

Instead of using plexi, what about covering the entire thing with either a black plastic sheet or black ground-cover fabric (you know, the stuff normally used to keep weeds from growing up in your garden).

It would hide the hose and maybe even conduct more heat.

#5 Rob C on 2006-08-19 18:31

That would help, but only a bit. The real need is to prevent wind from cooling the pipes. The ultimate would be to encapsulate the whole thing in some kind of epoxy to get a decent thermal mass. Ever notice how long it takes a south facing brick wall, or even a patio, to cool down on a summer night?

#5.1 Rob A on 2006-08-19 20:16

Hey I'm wondering would a plain old piece of glass work for that? I have a 4' x 8' piece of glass from replacing a picture window. Do you think if I made a 4'x8' solar assembly similar to yours it would work?

#6 Melissa on 2007-03-02 16:18

Just make sure it is tempered/safety glass. You wouldn't want any nasty accidents to happen.

I also went with 4x4 because built on a 4x8 it would be pretty heavy, and I roll it around the yard to drain at season's end (the one problem with a spiral).

Good luck and send us a link to a photo when it is complete!

-Rob A>

#6.1 Rob A on 2007-03-05 13:39

I have built a very simlar one with 2 - 100' rolls of 1/2" pipe coiled into each 4 x4 sheet- I have a large inground pool and use 4 of these boxes in series. At year end when I take them down I use a portable air compressor and blow the water out inplace of rolling them around -it works great as long as you are not standing in front of the other end....
I am thinking of using plexiglass to cover the boxes and to put them up on my pool shed roof (more sunlight) - any ideas or suggestions on how to mount them to the roof and and ideas on thickness of plexiglass that would work best here

#6.1.1 Jeff on 2008-06-28 01:27

Really great idea.

Just a few reflections of I wonder....

1. If the hose were smaller but longer, producing a slower flow, would the output temperature be greater?

2. If the backing on the frame was lined with a thin wall aluminum or copper coating, would there be a higher heat conduction and ability to hold the heat at a higher level on the piping?

#7 Kruise on 2007-03-26 07:57

If the hose were longer it would heat more (to a point). The heat gained would be relative to the length of time the water gets exposed. I achieve a similar effect by valving down the water to reduce the flow. The only real way to increase the heat conduction is to increase the surface of the pipe exposed to a hot mass. That means closing the panel over, so the hot air space can be better maintained, or filling the whole thing with a material that can act as a thermal mass. I might try filling the whole thing with clay to see how much more heat gain I get, but it would increase the mass significantly.

#7.1 Rob A on 2007-03-27 01:28

Hi mate,

Really inspired by your project here, going to make my own! Couple of questions you may be able to help with:

1. I've got a standard filter pump that came with the pool, do you think that will be enough to pump the water through all the pipe or do I need a pretty heavy duty pump?

2. Do I need special irrigation pipe or can I just use any old black pipe or even hose pipe painted black?

Thanks,
Ben.

#8 Ben on 2007-04-16 11:06

Hey Ben - All I use is the pump that came with my pool. It is a little on the large size, as the same pump can be used with a larger pool, so I didn't need to ad another pump. The key is the back-pressure. I have a gauge on my filter, and the there is not noticeable difference from no filter. might be the way I am plumbed.....I'll throw up a diagram in the next couple of days to show my plumbing.

-Rob A>

#8.1 Rob A on 2007-05-02 00:49

Hi,

I have a in ground pool and a propane heater that sits beside a 10 x 12 foot pool house. I am thinking of splicing the line just before the water heater and running a return line to the roof of my pool house, where I would construct some sort of PVC return unit covered in glass or PVC. My question is do you think that I should downsize the pipe gage coming off the water heater going up to the roof in order to maintain pressure (10 feet) ?

#9 Steven on 2007-04-27 20:10

Im looking to make somthing very similar, however instead of hooking the solar heater up to the filter system why not go to your local DIY shop and buy a solar fountain or pump and hook it up to that.

#10 Owen on 2007-04-28 09:49

Hi Owen - It would work perfectly well to add a second pump just for circulating heating, it would just use more electricity and cost additional dollars. The advantage might be that you could run the heating pump (small size, reduced flow) in the day, and run the filter pump at night, off peak, assuming your local power utility gives reduced hydro rates for off-peak use...

#10.1 Rob A on 2007-05-02 01:04

what about using a solar powered pump?

#10.1.1 Owen on 2007-05-09 18:52

We are trying this year (2009) to get our Bestway pool to warm up. It is unbearably cold.
Here is what we are trying:
1) to find suitable, inexpensive hose. Only hose so far is 69 cents a foot for pex, and over $1 for black poly - too much. So we are on the hunt.
2) We currently have 3 garden hoses on a frame beside the pool. It will run for 1-2 minutes hot, and then cool down.
3) We have chosen to put a sump pump (1/4 HP submersible) in the pool in a pail. It pumps water into the garden hoses, and then back to the pool. We have the heavy duty timer plugged in, and set to alternating 1/2 hour intervals (that's the shortest interval we could find on a timer so far). This means, during solar day (from about 10:00 - 4:00, our submersible will go on (if we've plugged it in), and will run for 30 minutes, shut off for 30 minutes, run, etc. We are happy with the heat it pumps out, but have to get a decent pool thermometer. We need more hose still.
4) Our bestway pool pump has a filter that needs daily rinsing apparently. I don't think I have the pump set up right, as the skimming is not working very well. I'm going out to check that after looking at Rob's INKSCAPE. I don't have a separate filter from the pump. I don't have a chorinator. I like the idea of running some type of cleaner through the garden hose so it doesn't get gunked up, but not sure if I'm going to stress. Any concerns there?
5) We are trying to figure out how many solar panels we need to power our whole system. We have a pool pump, a submersible for the heating system. We also have a well pump to feed our cistern. The cistern pumps to the house. So we have need for solar power for 4 pumps. Anybody?

#10.1.2 Northern Alberta on 2009-06-08 22:03

You don't need the timer just run the pump. It will pull any heat out of the pipe as long as the water is flowing. Letting it get hot sounds good but you are really loosing heat.

#10.1.2.1 Anonymous on 2009-07-15 21:58

I'm doing this soon, also. Thank you for having just what I was looking for when I googled..

I originally thought of running several hundred feet of 5/8" PVC/irrigation hose across the roof of my front porch that gets full sun all day. i figured the radiant heat from the shingles combined with the heat absorbed from the sun would work more efficiently than this spiral design. I've not yet began my project yet..

Any thoughts on radiant heat from the rooftop?

#11 jeremy on 2007-04-28 22:53

Jeremy - In my not-so-professional opinion, you should be able to benefit from the thermal mass provided by asphalt shingles, after all most commercial heaters are mounted on the roof to leverage the flat space, angle, and out-of the-way location. The only issue would be securing the hose in way that it doesn't slide or tear off, especially in high winds. And remember, adding things onto a permanent structure could be regulated by building codes in your area....

#11.1 Anonymous on 2007-05-02 01:43

Love the idea, will have to try it out! Just wondering, do you think clear tubing would work any better?

I'm also planning on using something clear to cover it (perhaps an acrylic sheet) since things like that tend to let light in but not heat out.

#12 Chris on 2007-04-29 22:18

Chris - I have been told that black pipes are the best to soak up the maximum heat. Covering the surface is a very good idea, as well, to prevent the wind from cooling the pipes, as you get a hot air pocket. If there are spaces between the pipes it would be best to have the background reflective, to bounce back any light that passed by the pipes and hopefully hit them the second time, rather than soaking into the background.

#12.1 Rob A on 2007-05-02 01:57

Rob - Love your work. Plan to replicate it as soon as I can. Could you post a diagram or explanation of your piping in and out of pump/heater/pool? I'm not sure I understand the bypass valve.

#13 George on 2007-05-01 12:05

AI think you can get more heating and put less stress on your pump - the sun is delivering energy to the tubing at the same rate whether you have high or low flow. You want as much of that heat to get into your pool as possible. So turn the flow up, not down. (Imagine if you were able to extract all of the heat from your pipes - they'd be cool to the touch. That would mean you were doing the best job of taking heat out of the collector and depositing it in the pool.) As long as you are drawing water out of the pool and putting it through the collector you want as much flow as possible. One caveat - insulate all the lines from the collector to the pool with those black pipe insulators you can get at the hardware store. And finally, the black pipe is absorbing the sun's radiated energy to conduct it into the water. Water is not as efficient at absorbing infrared light, so don't use clear tubing. OK, one more thought. Resistance to flow (and the work your pump has to do) is related to the length of the tubing. If you want a lot of tubing, consider reducing the resistance by breaking up the length into more than one circuit and connecting them in parallel in a manifold at the pump.

#14 Bob on 2007-05-01 13:36

Some good points there, Bob. Thanks for the clarification on clear pipe. A few responses.... As explained (now) I pass as much water through the heater as I can without causing too much back-pressure on the pump. Also, I didn't make a manifold/parallel pipe system as that requires a whole bunch of T's and glue (if using PVC) or solder (if using copper) any my point was to go as cheap as possible. (After all if I had the cash I would have just bought a unit, he, he).

#14.1 Rob A on 2007-05-02 02:30

Hey all

been reading all your coments and i think there all great I am going to try and make this at the weekend ready for the summer I live in the uk so dont get that much sun , I have brought 30 meters of black rubber 1/2 inch airline hose. will let you know how i get on. was thinking would it be better to cover the bOard in black rubber sheets AS rubber absorbs heat well instead of just painting it black ?

#14.1.1 Mark Southwell on 2008-05-01 22:14

Wow I can't believe it! I made one nearly exactly like this last year except mine is 4'x8' and my coil is actually a snaking back and forth instead of concentric coils. That way it drained pretty easily at the end of the summer. When I first hooked it up I got about a 18 degree F raise in water temperature inlet to output. However, I don't think it actually raised the pool temp more than a degree or two. Just too little flow volume. Mine is also not covered because I'm trying to keep it as dirt cheap as possible and the plexi is so expensive. However, this summer I'm going to try covering the entire thing with Saran Wrap and see if it makes a difference. Should be able to cover the entire 32 sft for a buck or two.

#15 Danny on 2007-05-01 16:28

Hey Danny - I was going to snake back and forth, but the pipe I used wasn't that flexible. So right on the draining issue. Even after blowing it out, I have to roll the whole thing around the yard several times to drain it

. Good thing I was 4x4 because I could never have rolled a 4x8 panel. Don't bother with Saran Wrap. I used some clear construction poly and even that go torn off by the wind is short order, so I think something more durable is necessary. Another suggestion made was to "fill" the areas around the pipes with concrete to make a large thermal mass....but then I'd never be able to move the thing.

#15.1 Rob A on 2007-05-02 02:37

i am having a really hard time finding irrigation hose i have purchased some 3/4 inside diameter pvc tubing but i was wondering if i returned that and went with a 1/2 inside diameter tubing instead. What was your inside or outside diameter of the tube and what store was it purchased at becuase i went to home depot and rona or revy and they i ask for irriegation tubing and all they show me is a tube with some holes in it.

thank you for all your effort on this and i apperciate your help.

#15.1.1 mike (Link) on 2007-05-18 14:39

What about using black beauty sand blasting media as a thermal mass. Ground black glass the consistency of coarse sand. Using it now works great.

#15.1.2 Mark on 2009-06-13 14:12

I'm in the UK where it's been 21c/70f every day for the last week, but it is often too cloudy for a solar heater to be productive.

I'm trying to figure out a cheap way of turning the pump on and off when the level of sun light drops, or when night falls. Solar powered pumps are expensive, and professional solar controllers are even more expensive.

I was considering using a small photovoltaic cell to measure the level of light, but then need to turn the mains powered (240v) pump on and off.

Has anyone got any suggestions or observations please.

#16 Tim Sneller (Link) on 2007-05-01 19:07

Hi Tim - Just search many of the home automation sites for controlling devices. The only issue here might be the pump pulls a pretty good current so you would need a heavy duty relay or contactor. BTW, I run my pump with a programmable block heater timer, so it only runs from 11:00 until 4:00. That is enough time to recirculate all my pool water, and is the best heating time. And remember, there is still solar radiation making it through on a cloudy day!

#16.1 Rob A on 2007-05-02 02:48

Thanks for the quick reply, Rob. I'm also in the UK and I'm finding it difficult to source a 'T' Valve to take water off the return hose from the filter to the pool. Anybody in the UK who knows where I might find one? The return hose is 1 1/4" diameter, and a black hose I've found is 1/2" diameter. I guess it would be out of the question to just compress all of the returning water into the one black hose? Would that put too much strain on the pump? (I don't know exactly what the capacity of the pump is, but it's between 500-2000 l/hour! A 12ft Intex Easy-Set pool)

#17 Chris on 2007-05-02 15:59

My pool has a clay paver surround. Due to orientation and where the people accumulate etc, one long side of the pool is rarely used. I have noticed during summer that you just can't walk on this side of the pool due to the heat in the pavers. Even with wet feet you can't go more than two meters, which explains why nobody uses it. Through the cooler months there is heat but not as much.

My questions for the group are:
1 - What are the ramifications of coiling the pipes directly on the pavers ? Will it work ? Do I need a black backing ? How can I contain the pipes to a shape and still utilise the heat of the pavers ?

2 - Also, I have noticed the pavers are noticably colder than the surrounds in the morning. Could this cause a problem, i.e. not retaining heat overnight.

3 - Is there anything I could cover the piping with so kids can still traverse the area without risk of accident.

#18 Dave on 2007-05-06 10:13

Clay pavers would make a great thermal mass for holding the heat. The trick is getting that heat into the water. Check out the link back in comment 3. He holds the coils together with twine and steel wires (on the roof of a shed, but the principle applies). As a note, the more of the paver surface that is covered by pipes, the less solar energy get to the pavers, and the cooler they will be. There should be a happy medium somewhere there, however.

#18.1 Rob A on 2007-05-16 17:49

But if it's difficult to empty (6.1: "...I roll it around the yard to drain at season's end (the one problem with a spiral)...") isn't it difficult to fill? Don't you get an airlock in the top of each spiral? Or is your pump strong enough to push all the air round the spiral?

#19 Ian on 2007-05-08 16:49

Hey, I use a shop-vac in reverse to blow the water out of my installation at the end of the year. Let it run 20 minutes or so. No water left in my system.

#19.1 Robert on 2007-05-24 14:01

Awesome idea! I used a shop vac to drain off my pool cover before opening for the season, but never thought to use it to blow out the coil!

#19.1.1 Rob A on 2007-05-24 14:42

Hi have you considered not using a pump, but simply using the natural convection currents caused by the heating and cooling of the water as well as water pressure to push the water round the solar heater and back into the pool.

#20 Owen on 2007-05-09 19:36

I tried using natural convection on mine and while it works, the flow is just too slow. It doesn't move enough water volume and so the net temp raise in the pool is pretty small. Of course, pumping it through the heater coil will increase the volume flow rate but will also decrease the heat absorbed by the water flowing through it. But the tradeoff is well worth it.

#20.1 Danny on 2007-05-16 17:18

I agree on that - It does work but is slow. The term I have seen used is "thermal siphoning" and it can generate extreme heat, but with low flow rates. I saw someone post about using a set of three 45ga; drums as heater tanks, thermal siphoning one from the other, and having the last dump into their pool (but I can't locate the site now).

#20.1.1 Rob A on 2007-05-16 17:25

Hi Rob:
I really appreciate people like you who take time to help others. Thanks,

.

Here's some back atcha.
Mass:
Sand is excellent for absorbing heat but does not pack very good and the heater would have to be horizontal ...so use Mud. Either make it a thick soup, pour it on and allow it to dry or, esp. if there is a young child, make it clay-like and smooth it into the grooves and up to the level of the frame with him/her. ... little kids luv the mud.
Pour sand over the top (after it is dried just a little bit) to improve the appearance, if you want.
IF, for some reason, you must move the sucker, soak it and then hose-off the mud and roll away.
Here, I can dig 18" - 24" and get all the clay-like dirt I want. Many places it is almost top-soil ... Think adobe homes.

Cover it:
6mil clear ( translucent ) plastic does not tear very easily. Home/hardware stores carry it, typically as an exterior window covering, ground cover, vapor barrier(attic), etc. Cheap ... relatively speaking. It should be stapled/tacked or clamped to the frame every 15cm(6") or so. It will last a year or two before becoming brittle and prbly need replacing.
(if it were me, i would wrap the plastic around the sides and staple it to the bottom or the sides. Or, if I had the time, just make a wood frame for it and attach that to the heater...)
If you buy by roll, e.g., from a Home Depot, other hardware/home store, etc., it will be cheaper and if stored inside(no freezing) will last for many years to be used to replace the cover on the solar heater. ( 10'x 25' Clear 6MIL Plastic Sheet: 24 buck$(US) online at Lowe's[not a rec' for Lowe's... just example] )

Maintenance/Draining:
First, The hose does not have to be 100% empty. You only need to make sure that there is no section which has a pocket that is full. ...a little frozen water inside won't hurt it as long as does not fill that section of hose. ...
If you feel uneasy, rolling that monster can still be stopped with a pump and anti-freeze. Blow-out the hose with air then cycle anti-freeze through it. Save the anti-freeze and use it next year, and next & ...
If really unsure, you can blow out the hose again to clear any full pocket. Even the little water that remains won't freeze.
It comes to mind that the pump you use for the pool might be having that service already to make it winter ready. If not then it could be and just include the solar heater.
Think submersible fish aquarium aquarium pump if you want to fix a anti-freeze recycling rig to do the job every year. ...
One thing: *keep all kids and pets away from the anti-freeze*! It is sweet tasting and either might drink it and die. It is very poisonous. Dogs luv it. ...

About the frame shape ... if you have to build another think hexagon or octagon. Pretty easily to build although a bit more time because you have to cut more to have equal length & mitered sides. ( Adding triangles to your current frame's sides might work to make an almost octagon ... )

...

Hope that increases your output and saves your back.

Thanks again for sharing.

C-ya

#21 Ric on 2007-05-11 16:19

Wow! Thank allot for all that feedback...It could be an entire article on its own! I tried using poly (vapour barrier) last year but it tore off in a wind storm. I had just used staples. This year I plan to use wood strips stapled down to "frame" it, which might help. I think I'll try blowing out the coil using an air compressor in the fall, too. That might be a simple way to clear the coils well enough for winter storage.

#21.1 Rob A on 2007-05-16 17:58

if you are skilled with brick work make a large cone shape from fire brick. the coil can be run around it from top to bottom on a collapsible tie system. it will hold heat well and collect it from all directions. then grab the bottom coil and lift all the others will fall into place and lie flat for storage. then make it a christmass tree for winter. think along the lines of those paper Chinese lanterns

#21.1.1 ns1 on 2009-10-15 18:43

if you put antifreeze use the RV type it wont hurt you

#21.2 Wayne on 2010-06-14 02:05

Polyethylene pipe can easily withstand freezing. There's no need to blow out your system or use anti-freeze to prevent it from freezing. I just disconnect the tubing on each side of the heating coil and let it freeze. I've gone through 2 winters so far without any problems.

#21.2.1 Ken on 2010-06-14 03:39

I've seen a couple of different mentions on this thread about creating a termal mass, absorbing heat from pavers, filling with mud/sand, covering with plastic to block the wind, etc. I don't want to insult anyone's intelligence (sincerely I don't) but I wanted to clarify a couple of things on how these work to help everybody improve the efficiency of your system.

The water is heated by only one source of heat... the hot pipe through which it flows. However, there are two sources of heat that causes that black pipe to get hot. You need to be careful that in the course of changing one heat source you don't affect the other. The first heat source is solar radiation. This is the direct "sunlight" radiating energy into the pipe. I say "sunlight" but it's really not mostly coming from visible light and will still have an effect on a cloudy day. Think of the pipe floating in the cold vacuum of outer space. It will still heat up if exposed to the sun, even though there is no termal mass around it. This is why astronaut suits are white (in part) to reflect as much of the solar radiation as possible as compared to darker colors. The second heat source, which is entirely separate and independent of the solar radiation, is direct conduction of heat from whatever material surrounds the tube. Think of putting the pipe in the oven where this is no solar radiation. It will, obviously, still absorb heat and get hot.

If your pipe coil is on a board, exposed to the air, with no clear plastic cover, the conduction heat transfer to the pipe will be minimal because the ambient air is only mildly warmer than the pipe and any wind will tend to cool it off. Painting the backer board black will help because it will absorb the solar radiation heat, and then conduct that heat to the pipe. So that's a little conduction heat. Covering the whole panel with a sheet of glass (or similar clear material) will help becuase it will help trap the hot air, causing the air to become somewhat "superheated" and increasing conducation to the pipe. However, any cover you put on the panel, even clear, will reduce the solar radiation to the pipe a little. A good, clear sheet of glass or plexi will improve conduction more than it will negatively impact radiation, but just beware that as it gets dirty, yellows with age, etc., the solar radiation impact becomes more severe.

If you were to paint the glass black, you would block all the radiation for example. This is exactly the same effect as burying the pipe in say 2" of black mud. If the pipe is completely buried you will eliminate direct solar radiation heating of the pipe. However, now the mud itself is heated from solar radiation and has the further benefit of having a greater "thermal mass" than what used to be air around the pipes meaning that it just doesn't cool off as easily. This is why the brick pavers stay hot into the evening, because they have a substantial thermal mass and don't cool easily and quickly like the ambient air does. So, surrounding the pipes with mud, or sand, or whatever, will increase the thermal mass around the pipe and improve conduction, but will eliminate radiation heat transfer. At northern lattitudes where solar radiation is reduced anyway, this is probably a good tradeoff. In Colorado where I live, and at high altitudes where the air is relatively thin and the solar radiation is particularly intense, this is a bad tradeoff.

There are a number of solutions to this. One, you could only bury the pipe half way, or maybe 2/3 deep. This would increase the thermal mass around them improving conduction but would leave a substantial surface area exposed directly to the sun for continued radiation benefits. Two, if you want to get really creative, you could bury them entirely but in a transparent material (I'm thinking gallons of clear epoxy) which would increase the termal mass around them but at the same time would not block much radiation. There are lots of other solutions I'm sure and again, depending on your geography, your normal air temperatures, or what you might use to bury the pipes in, the tradeoff may, or may not be worth it. Just beware as you make changes as to the effect you may have on both conduction heating as well as radiation heating since they are entirely independent of each other.

Danny

#22 Danny on 2007-05-16 18:06

Thanks for that most excellent clarification. In my case, as I was using plastic pipe. I packed the coils together as tight as possible to maximize the solar radiation exposure. I didn't need to paint the backing black, and probably would have done better painting it silver or white to reflect any solar radiation that passed by the pipes to reflect back. One issue with the plastic pipe is that is has pretty poor thermal conduction compared to metal, so relying on convection from a thermal mass wouldn't have worked well in my case.

#22.1 Rob A on 2007-05-16 18:37

My design is very similar to yours. Black plastic tubing attached to a plywood board. My tubing is spaced more loosely than yours and so I did paint the board black. 80% of my heating, if not more, comes from the solar radiation I'm sure. I'm hoping to make some tweaks this summer though. Pool goes up this weekend!

#22.1.1 Danny on 2007-05-16 19:08

What is the consensus on the colour of the backer board? Is it better to paint it flat black or to use a reflective colour?

Another question I have is how critical is the angle of the panel? If most of the heat is radiation onto the pipe surface, I would guess the angle wouldn't be too critical as long as the pipes aren't spaced so closely that they shield the adjacent pipes from the sun. In my case (small yard) , it would be nice if I could mount the panel vertically on my fence.

#22.2 Anonymous on 2007-10-15 01:38

I'd also like to point everybody to a great reference: The Integral Passive Solar Water Heater Book
http://www.builditsolar.com/Projects/WaterHeating/ISPWH/ispwh.htm that has allot of the theoretical basics as well as some great designs, many which could be applied to pool heating.

#23 Rob A on 2007-05-16 18:43

Thanks for this idea. I think your design is easy to construct and inexpensive. Having said that, I made one just like yours this weekend.

The only change I made was with the valve on the return line back to the pool.

I went to the pool store and bought a 3-way divertor valve. I don't have an inline chlorinator, so I was able to screw the 3-way divertor valve directly into the valve body assembly of the filter where the return line was connected before. Now the valve is connected direct, the return line is connected to the other side of the valve and the solar heater is connected to the 3rd outlet of the valve. With the valve handle I can have full flow to the pool, full flow to the heater or any combination which works most efficiently.

The only reason I was a bit reluctant on the "T" idea was that the water being returned to the pool from the filter would take the path of least resistence, hence how much water would never get to the heater. My thought was that diverting the water to the heater with a valve would be the ticket.

Aynways, that's my input and once again, thanks for the great idea.

Go Sens GO!!!

Yes, I'm in Ottawa

Gary

#23.1 Gary on 2007-05-20 12:00

Great idea Gary. I was planning on doing the same thing. I don't understand why you would pipe the solar heater directly to the pool instead of piping the solar heater to the return pipe. Estheticly it seems to me that it would look better.

#23.1.1 Ron on 2007-05-29 02:13

Would you be able to take a picture of your system. I don't quite understand the way your diverter valve is installed.

#23.1.2 ron on 2007-05-29 02:30

Wow! I realized I had an error in my diagram. I had shown a diverter valve which i did not use. The diagram now shows that I have a T (1 1/2" to 3/4") and then a 3/4" ball valve. Hope that clarifies things.

#23.1.2.1 Rob A on 2007-05-29 16:50

This would require a T valve for the rturn from the heater, correct?

#23.1.3 Jeromy on 2007-06-09 16:01

I did not tee in the return. I just have it pouring back into the pool. It can be seen clearly in the picture labeled "The Return". Because I am not valving the main line, I was worried a T return would just equalize the pressure and nothing would flow through the heater.

#23.1.3.1 Rob A on 2007-06-09 23:14

Hi guys. The problem is that your valve is at the wrong place. If your valve was on the main line (and not the heater line), you would be able to split the needed water into your heater, have a T return back in your main line without negative pressure issue. And it would look a lot cleaner...

#23.1.3.1.1 Pat V on 2009-05-26 18:18

How much heat do you add? I set up my pool this weekend along with my ipswh and took some measurements to determine how much heat I'm able to capture and add to the pool. I'm curious as to your calcuations of the same to see if I may want to make changes to the flow volume rate, or perhaps other adjustments like to a larger diameter tubing. Here are my calculations
Pool temp - 54 degrees (Farenheit)
Water temp out of the ipswh - 66 degrees
Flow rate - .833 gpm (6 minutes for 5 gallons)
Density of water 8.33 pounds per gallon
1 BTU equals the heat required to raise 1 pound of water 1 degree Farenheit.
It was a sunny day and pretty warm, about 70F. I took the measurements about 2 hours before my "solar noon".
If you run all that math...
12 degree F rise X (8.33 ppg * .833 gal per min) X 60 minutes
you come up with almost exactly 5,000 BTUs per hour added to the pool. Of course it would be more when I get closer to solar noon and even more when it's closer to the summer solstice, but how does that compare to what others are seeeing? Am I undershooting what's possible with these ipswh's?
Thanks,
Danny

#24 Danny on 2007-05-22 00:10

I had the time last weekend to do a few measurements. With "full" flow through the heater, I measures 10L in 28 seconds, and was seeing a temperature rise of 1.2 degrees C. I plugged the values in Excel, along with water density lookups, and thermal capacity lookups and determined I was getting 1.487kj/second. That converts to 5076 BTU/h, almost exactly the same as you. I then valved the flow through the heater down real low, and after allowing it to stabilize measured a temperature rise of 16 deg C (WOW!) at a tiny rate of 1L/35 seconds. That calculates as 1.901kj/second or 6487BTU/hour. The higher flow rate obviously wasn't maximizing my heat transfer. I'll retest later in the summer a a variety of flow rates, and hopefully get up a graph...

#24.1 Rob A on 2007-06-20 16:30

Rob

There's something not quite right about your calculation. the difference between 10litres in 28s raised by 1.2 degrees compared to 1Litre in 35seconds raised by 16 degrees is about 7% more energy for the low flow rate, not 28% (6487BTU versus 5076). And that 7% would be almost exactly cancelled out by a 0.1 degree low reading error in the temperature rise for the high flow rate

So the apparent difference may simply be experimental error.

The literature seems to suggest higher flow rate is better than low to avoid stagnation - as the flow rate is reduced (or the inlet temperature increases) there is a maximum temperature the heated water can get to (where the losses due to convection and conduction equal the gains from the solar energy) and slowing the flow rate further won't further increase the outlet water temperature. As you say, it will be interesting to get more than two points on the graph. But the energy transfer will be affected by the inlet temperature, so you need to record that too. And for very slow flow rates record the air temperature because that will largely determine the plateau temperature.

But, nice work!

HTH
Ian

#24.1.1 Ian on 2007-06-25 17:44

I would put more faith in the accuracy of the low flow reading, as it is much easier to measure a large temperature differential than a small one, as least with my equipment. It also looks like a math error. When I recalculate the 1.2 degree rise, I get 6091 btu/h. not the 5076 I had noted earlier. This makes the two reading effectively the same within range of experimental error. Thanks!

#24.1.1.1 Rob A on 2007-06-25 17:56

Intuitively I wouldn't really expect to see much difference between the high and low flow rates down to a point, all other things being equal. In either case, high or low flow rate, the inlet water temperature on an intensive sunshine day will be low relative to the energy absorbed by the IPSW. Therefore, in either flow rate case the IPSW should absorb all the solar energy available. Actually, not all available, but rather all the energy that it's capable of absorbing. Getting down into really slow flow rates we'll run into different effects like Ian suggests, but short of that my assumption is it ought to be relatively close. Slow flow rates do have the advantage of more accurate measurements both in terms of temperature change and duration of test. The other advantage of low flow rate is lower inlet pressure, and thus lower back pressure on the pump and longer pump life.

The big test that I wonder about, though, is 1/2" vs. 5/8" vs. 3/4" tubing. But I don't have the money to buy three different sets of tubing to test.

#24.1.1.1.1 Danny on 2007-06-25 18:33

Rob,
Can you post an Excel file spreadsheet on this blog? If so, I can send you one (though you probably already have one) that can accept either metric or English measurements and spit out BTUs per hour or other conversion like Joules per minute or whatever.

#24.1.1.1.2 Danny on 2007-06-25 18:37

is it necessary to attach the roof hose into the filter hose, can i just free pour the water thats in the pipe right into the pool, how dirty does the water get inside that hose, fill i be able to fill the hose with a garden hose, once i drain it into the pool, is there enough pressure,
thanks for your help, new at this
louis

#25 louis on 2007-05-25 00:03

Hi Louis - I'm not 100% sure what you are asking. Can you provide a bit more information?

#25.1 Rob A on 2007-05-29 16:56

I tried putting the hose on top of my shed because the felt on there would probably collect quite a bit of heat - but if you only have a filter from an intex 'easy set' pool like me, it won't be powerful enough to get up there! (As I found out today...)

I tried to get it going by siphoning but that doesn't work either. It's in circles, not in zig zags down, which would probably help but would be very difficult to mount without putting holes in the roof of my shed.

Tomorrow I'll be taking it back down again and mounting it on something at ground level, like Rob suggested, and like I should have done in the first place!

#26 Chris on 2007-05-30 00:27

Interesting thread and solution. I am looking at your idea of using a coil of black plastic to make an in-attic pool heater. I've been thinking about this for some time and with at least one commercial unit on the market, there has to be an easy diy solution here. Not being an engineer (but a good tinkerer) I am still working out the details. I am thinking of a six foot tall three foot in circumference coil of 3/4 flexible pipe-about 720 feet total with air space between the coils-with a fan to force the hot attic air (which I have an abundance of) through to help heat my 18X36 in-ground 27k gallon pool-which spends most of morning blocked fron the sun by trees in the east and the late afternoon blocked by the house in the west. The roof is the only ting on my property (exept for the trees) that gets full sun, so I could also help with the a/c by lowering the attic heat load. Any engineering thoughts on this would be appreciated. Oh, you might want to plumb your pipe to the bottom of the pool to help heat the whole pool-letting all of your solar heated water sit on the surface lets the heat dissipate without warming the rest of the water-remember heat rises.
Bob

#27 Bob M on 2007-06-03 18:56

I like your design Rob. But I am concerned that running the pool pump all day may be overkill to clean the pool and extremely expensive. My pump is 8.8 Amps, about 1100 W. Im thinking of using a much smaller pump to circulate the water just during the peek hours, has anyone tried this? can anyone suggest a pump?

thanks

Andrew

#28 A Mac on 2007-06-04 03:38

Well... I don't run my pump all day, as it is a full size pump as well. I only need to run the pump for about 3.5 hours to circulate all the water through the filter, so I have it on a block heater timer coming on at 11am and turning off at 3pm. This happens to line up with the best heating times as well. If I don't need the heat I just valve off the heating coil and change the timer to tun at night. I don't off-peak electricity rates where I live, but it makes me feel better

#28.1 Rob A on 2007-06-06 03:35

Having read through all the posts, one thing I haven't seen covered is the question of tubing size. If my math is correct, dropping to 1/2 inch tubing from 1 inch drops the surface area by half but only flows 1/4 the water volume. In theory four 1/2 inch tubes in parallel should provide twice the surface area for a given volume of water relative to using a single 1 inch tube.

So I guess the question is whether it's more cost/space efficient to have four parallel 1/2 tubes or two 1 inch tubes in series for a given heat output.

Any thoughts?

#29 Dale on 2007-06-05 14:32

Your math is all correct Dale. There is another factor though, that of the pump and the backpressure created by your choice of tubing. The more narrow the tube, and the longer the tube, the more pressure required from the pump to produce the desired flow rate. I used 1/2" tubing but my Intex pump is limited in that the max flow rate I can create through the heater is about 5 gal per 3 minutes. Too much back pressure. I would have been better off with 3/4" or 1" for sure, but then it's quite a bit more costly. Four 1/2" tubes in parallel would flow the same volume (given the same flow rate) as a single 1" but would have double the visible surface area as the 1". That's why I went with the 1/2". More surface area yields more heating. But more flow yields more heating too.

#29.1 Danny on 2007-06-06 01:55

Thanks Danny, that's what I thought. A bit of further math shows that it takes two 3/4 inch tubes to flow the same rate as one 1 inch tube, but has 50% more surface area. But using smaller hose means you end up with two or four times the amount of hose to get the same flow volume. The trade off is that you should get a greater percentage of the water flowing through a tube in contact with the surface. The other factor is the wall thickness of the tubing. I'm thinking that 1/2 inch irrigation tubing is going to be of thinner construction than 1 inch poly pipe. Wouldn't that aid in heat transfer? One last thing, I ran across a commercial product that looks almost identical to what we're trying to do: http://www.gullsolar.com/index.php?page=suncoil Unfortunately they don't provide any details of the pipe sized involved.

#29.1.1 Dale on 2007-06-06 15:34

My son counted 22 wraps of pipe in the picture on the website, the overall diameter is stated as 2m and the core diameter I reckon is 0.5m scaling from the OD, all of which makes the pipe about 34mm OD. Here in the UK I can find 32mm irrigation pipe for sale. The area of a 2m diameter circle is about 3 square metres. To make the same 3m2 projected area of a linear length of 32mm pipe, that makes it just under 100m length of pipe.

#29.1.1.1 Ian on 2007-06-09 08:14

Hello everyone, I come from Trenton FL

To start off, I went with 1/2" tube ( black ) about 500'. I have a easy set pool 18', and I run 2 pumps, one to filter the water and one just to run the solar.

Now my set up is I have 450' of hose on the roof of my house, the catch is the house is 12' up in the air so it's hard to pump that high up, but it does work. I am only getting about 2-3 gallons per minute out of it due to the tube size and length as well as pumping 12' up. I have the solar return just dropping right into the pool on the opposite side from the intake.

My results are as follows, on a normal partly sunny day about 85-90 degrees the pool was staying 78 degrees, after installing this the intake was 78 and the return from the solar was 112 ! this was taken with a digital thermometer.

I have run this now for 2 days from 11am to 4pm and the water in the pool is sitting at 83 degrees ! my goal is for the pool to be about 86, this is nice for the kids and wife, I myself would like it right where it is now.

I can't wait for a nice hot summer day with full sun to see what I can get from the solar return.

Just so you know all I did was lay the tube on the roof. I would have never come up with this idea if it wasn't for the people here, thanks alot !

Ice

#30 Icecreammann on 2007-06-06 14:12

Hi Ice, did you get it higher than 83 degrees?

Leo

#30.1 Leo on 2008-01-17 20:15

I havn't read anything in this blog about using differant size copper tubing painted black. Is the side wall of the copper tubing thiner than that of the irrigation tubing? And does the painting of the tubing insulate the pipe or will it get just as hot with no paint? I know that you wanted to keep it cheap but if anyone is going to build one and can invest in parts what parts would be used? Now the black paint everone speaks of, is it flat black or glossy black? Another question is, should there be a space between the mounting surface and the bottom side of the tubing? And the same idea of the mounting surface, should it be flat black or gloss black or a silver reflective surface or white surface? And should it be insulated from the plywood by means of styrofoam? So that the heat will not warm up the wood. I have heard of foil backed styrofoam sheets to insulate walls and attics and garage doors. What about two way mirrors as a top piece? will it let in light and keep in reflective light? And or heat? And in conclusion thank you for your ingenuity and patience

#31 tom on 2007-06-10 02:06

Great article, is there anyway to determine the weight of such a heater when it is full?
Also a couple of questions,
- Do you shut off the flow through the heater at night, cold or cloudy/rainy days to prevent the solar heater from becoming a radiator and cooling the pool?
- Have you tried blowing the heater out with air instead of rolling it around to empty the heater?

#32 Rob on 2007-06-11 19:02

The weight of the water in pounds is .03588 cubic inches. Cubic inches is = length of tube in inches pi * inside diameter in inches squared. So 500' of 1/2" tube, full of water, would weigh... .03588*(500*12)*pi*0.5^2 = 169 pounds of water.

#32.1 Danny on 2008-03-23 02:00

I believe there is an error in Danny's calculation. You can calculate the cross sectional area using the formula-
(PI x ID^2)/4. You then need to divide this area by 144 to convert from sq.in. to sq.ft. You then multiply the cross sectional area by the length of tubing in feet to get the total volume of the tubing in cubic feet. You then multiply the number of cubic feet by the 62.4 lb/cu.ft. So for 500 feet of 1/2" tubing, the weight of the water is-
(PI *0.5^2)/4/144*500*62.4 = 42.5 lb.

This is actually a pretty reasonable weight and shouldn't be too difficult to support

#32.1.1 Ken on 2008-05-26 00:28

Good catch. Cross sectional area is PI * radius^2 like you show, not the diameter squared like I mistakenly showed. The weight you calculated is exactly 1/4 what I had mistakenly calculated. Thanks.

#32.1.1.1 Anonymous on 2008-05-26 15:57

Great forum....Although I have taken all the facts in and the great results achieved, I decided to make a sort of copper pipe version.
I have made a 4ft square tray using wood sides and ply back. I have then placed a layer of 25mm polystierene in first, then covered with tin foil and finally a layer of unused black rubber pond liner. Onto this I have snaked 20mtr of 10mm soft copper tube painted matt black and cable tied through the backing and finally covered in some old greenhouse glass. I have connected to a small 12v pump.
All I need now is the sun to shine to see the results.
One remark about covering your panels.....can you not use the clear corrigated roofing type plastic sealed with the foam top and bottom .....and it is cheap.

If my panel does not acieve good results I will try the black plastic pipe to which most systems on the market use now.
Thanks for all the great reading.

#33 Alan on 2007-06-11 22:09

Getting into this game rather late, but how did the copper pipe go compared to plastic? I know its more money but won't copper conduct heat MUCH better than the plastic pipe or hose? Please let me know as I plan on building one of these units soon.
Thanks!
Paul

#33.1 Paul (Link) on 2010-05-31 19:58

Rob thanks for the post. I am going to be doing something a little bigger but you all gave me some real good ideas and I just want to thank you all. Rob maybe you can get a old glass window from an old screen type door. I may base my design around two windows like this if I can get them. Good luck

#34 jeff on 2007-06-15 18:06

That's a nice setup and you appear to be getting impressive results!

What size is your pool?

#35 Mathieu on 2007-06-20 13:24

It is a 18' pool, so it holds about 8000 gallons.

#35.1 Rob A on 2007-06-20 16:21

Rob,

Just built one almost exactly like yours. I included two pieces of 2X2 crossed over the middle of the tubing to hold it in place - made for very few straps to hold down the tubing and gives another area to attach poly sheeting. I used lath strips I ripped help hold down the sheeting, both front and back.

I wanted the tubing to be as pliable as possible, so I was working out in the sun. My fingers were getting fried by the time I finished coiling the tubing.

Thought for a while I wasn't going to get more than a trickle of a flow, but then I held my hand over the direct return line from the pump to the pool. That finally forced the tubing in the heater to fill and start a nice flow. Too bad the sun was down by the time I finished. Hopefully I'll get some data tomorrow on temperature rise and flow rate.

My pool is 15 x 30, so it has about 11,000 gals. Hopefully this will work and I'll be able to get my wife into the pool before late July. She needs about 86 degrees to be happy.

#36 Doug B on 2007-06-25 02:25

I have built one similar to yours, except I have the return line from the heater going into the return line to the pool.

I had to insert a ball valve into the return line to the pool between the heater intake and outlet.

I cut back on the flow through the return line to the pool by adjusting the ball valve. I also put in an on-off valve on the intake to the heater.

It works great thus far but I may make it larger (add another cell)

#37 Sportsbroker (Link) on 2007-06-29 14:25

Rob, great forum. Thanks for spreading this idea. It looks like a good one. Coincidently I decided on a similiar design. I'm already in the process of building it.

Right or wrong, I decided to use 1/2" tubing because of the thinner wall thickness and greater surface area to water ratio. I thought this was the way to go because I noticed the commercial products use small diameter tubing.

I have a 1 hp filter that sucks a lot of juice. I only run my filter 3 or 4 hours a day because of the high cost. I wanted to make use of the sun all day. So, I decided to use a dedicated smaller pump. I bought a cheap Intex pool when Menards had them on sale for $30.

I'm still experimenting with my design. I'm pumping through 200 ft. of irrigation hose now. I thought I'd keep adding 100' increments until I max out the pump. I have some alumuminum plates that I got for free. I will mount these and the hose on a 4 x 8 piece of plywood. I'm not sure if I will paint it yet or not.

This idea is probably not consistant with the concept of a simple design. But, my plan with the pump is to only pump when the water hot. I plan to turn the pump on only for short spurts to replace the hot water with colder. I thought this would save on electricity and pump wear. I plan to accomplish this with a temperature switch connected in line with the tube. Does anyone have an opinion about this idea?

I am really stuck trying to find a cost effective temperature switch that is weather proof and can switch 110V. Can anyone help? Thanks! Tim

#38 Tim W on 2007-07-01 04:22

Tim, did it work with the pvc pipe. You painted it black? How about the elbows? Please give more detailed info if you can

Leo

#38.1 Leo on 2008-01-16 20:56

Hello i have made a solar pool heater out of a 8 ft satellite dish with 800 ft 1 inch poly drip pipe. It heats my 14,000 gallon pool very well, i use a 1/2 hp pump to circulate the water. On average here in Spokane Washington my pool maintains 80 deg f from April- early October with no outside heat source ( ie: heat pump ) I will try to post pice soon if time.

Tight Lines and Fast Bites

Aloha
Keoni

#39 Manaakua on 2007-08-09 23:50

Rob, great Idea to which I copied almost to the tee. A few points of change I made though..some good, some bad.

I have an easy set pool 16 ft circular by 42 inch deep. I live near Lake Simcoe, Ontario, Canada.

I decided to use 1/2 (inner Dia) black garden hose (200 ft) and coiled it like you. Results ...not a good conductor of heat..the water coming out of the return line is most likely the same as going into the heater. I think I'll be changing this to the 1/2 inch pvc piping soon.

For the backing of my box I picked up some shingles at the Restore and tacked them on...THEY GET HOT ! I've realized I've wasted two days testing this and wasting that heat from the shingles.

Back to the hardware store for the 1/2 pvc. And like most of you, I'm doing this so my wife is happy ...even though she's nagging about the location and the look of it ;-)

#40 Rick on 2007-08-13 17:55

Hi Rob,

This is a great article and given me a lot of enthusiasm to get one going myself, thought about it for a while but never actually did anything as I thought it wouldn't work. I have a question though. Where I live although it gets really hot my pool is totally shaded and even in the very hot months I don't use the pool that much as it is a bit too cold. My question is this.
Would your system work with pipes of the following size and length?
0.8 of an inch thick diameter and 50feet of pipe?

I don't have a way of measuring the pressure on the pump, is there a fail safe way to ensure I don't burn it out?

#41 George on 2007-09-18 09:48

Hey George. I can't say if it would work (or not) because it would really depend on the size of the pump and the induced back-pressure of your existing piping. The important thing about my piping arrangement is that you can not strain the pump because there is no restriction on the outlet. The water is allowed to find its own balance between the flow through the heater and the original flow into the pool.

#41.1 Rob A on 2007-09-20 17:15

Hi Rob,
Well I tried my idea and it seems to work, the wter is warmer in the outlet, now just need a couple of nice hot days to see the difference it makes, if at all. Been raining and not so great since the day after I did it. One question though. What did you find had the best results, high flow rate or a low flow rate there by allowing the water to get hotter in the pipe before going into the pool?

#41.1.1 George on 2007-09-25 13:50

Hello All,
To put a slight twist on the solar heater, has anyone tried of running pipe in the attic and heating the water using the hot air there simply by conduction? If so, did it work and how well? Cheers!

#42 Ryan on 2007-09-20 17:00

Ryan, while there is a company that makes a pool heater that draws it's heat from the attic using what is essentially a big radiator (http://www.solarattic.com/pools.htm), I have concerns about simply running cold water piping through my attic space for two reasons. First and most obvious is possible leakage from the piping. The second reason is condensation. Pool water is likely to be much cooler than the air space and on humid days would be susceptible to sweating. The solarattic radiator has a catch pan under it for condensation to drain and also uses a fan to maximize the heat transfer. A simple tubing arrangement wouldn't have the benefit of either.

#42.1 Dale on 2007-09-22 16:51

After reading and contemplating all summer, I finally constructed something similar. I bought two 500ft rolls of 1/2 inch irrigation tubing and cut each roll in half. I now have four collectors with 250ft of tubing running in parallel. Flow is via a small pump rated at 360GPH, though under under near free flow conditions it may flow slightly higher. Temp rise so far has been about 4F, though I've yet to test it under full sun, as it's been partly cloudy the past few days. I'm hoping that in the spring when the sun is more intense I'll see a greater temp gain.

#43 Dale on 2007-09-24 21:48

Great input on this idea. I have done something similar for a few years to heat my 21' round pool. I have used black rubber hose atop my metal shed and pumped it with a pond pump on a timer. I get 6-8 degree hotter water coming out the end of hose. Next year I will try some of these ideas to improve the temp.

One thing people need to remember is that you can loose many degrees of heat over night when it gets cooler, so I try to always keep my solar pool blanket on at night.

I have never drained any water out of the hose over the winter and perhaps the rubber expands enough to avoid bursting the hose. It gets very cold here in St. Louis MO.

Would filling the tray half way with black colored concrete increases the thermal mass? Heavy yes..but if it works it works.

#44 Debbie on 2007-09-27 15:40

here is a thought all, make a box with reflective pannels and install marine waste bags, there made of black rubber, they have both inlet and out let and will hold about 25 gals more then your pipe would, that way it would heat more volume...what do ya think?

#44.1 Randy (Link) on 2007-10-02 17:12

Hello I wanted to introduce our company to you. Come check out our solar pool heaters on our website: http://www.solarattic.com

To watch an ABC News report on our heaters just click on the link below. It may take a minute to upload just click on the picture of the PCS2 to watch report.

http://www.tampabays10.com/news/local/article.aspx?storyid=60345

Have A Happy Thanksgiving

SIncerely, James Kantorowicz

Vice President of Sales & Marketing
SolarAttic, Incorporated.
15548 95th Circle NE
Elk River, MN 55330
763-441-3440

#45 James Kantorowicz (Link) on 2007-11-21 18:02

to all trying to use plastic piping.There is a new product out now for supply lines for your homes domestic water lines. It's call pex piping and they sell it at the home depot for about $30.00 for 100' roll of 5/8" od.If you can't find it at the home depot any of your local plumbing suppy houses should carry it.It doesn't come in black you'll have to paint it yourself.Another thing about covering your piping in a box.Try calling or visiting a window store or glass supplier.Maybe even a local handyman who replaces windows.These people will have some double pain low e windows or doors that where replaced in someones house.they will give you the glass for free. place the glass on top of your box wala thermal heater.

#46 zeppie420 on 2008-01-14 04:35

the problem is if you use thermal windows the heat will not get to the pipe, black box is great and timmer Idea I love, you can even buy a valave that opens and closes by the temp you set...that way no timmer needed

#46.1 Randy on 2008-01-16 20:18

Good day,

What is the consensus of the length of hose. I have heard that when coiled it should account for about half the surface area of your pool, is this necessary or would 100 feet do the job? I am sure also the flow rate has an impact.

My sinario:
If you wanted the water coming out of the pipe to be about 5 - 10 degrees celcius hotter than the pool water and a flow rate of about 3 gallons per minute what sort of length would you say would work, 100 foot, 200 foot, 500 foot, or is it more of a case of start with 100 foot and keep adding until the temperatur is where one wants it? The thing is I don't want to start and end up having 100's and 100's of feet of pipe?

Can someone lend a hand on this?

#47 George on 2008-01-21 10:55

Hi George - the best thing by far is to keep a solar cover on your pool. Nothing keeps in heat like a cover.

As a rule of thumb, I am guessing you divide your gallons by 10 to get the footage for the 1/2" pipe. Examples - 3,000 gallon above ground pool, use 300 feet. 25,000 gallon pool, use 2,500 feet.

I also have heard that you really should branch off the tubing into parrallel runs if you get more than 1000 foot on any one run. This will make it easier for your pump. But depending on the size of your pump you may want to do more or less.

I have just ordered 3000 ft of 1/2" for my 25,000 gallon pool. I'll let everyone know how I make out by late summer.

#47.1 Anonymous on 2008-02-19 12:54

I'm trying to build some coils like this in Australia using 13mm LDPE pipe which is around $12 for 50m.

I saw a commerical US system using the same idea.

http://www.gullsolar.com/index.php?page=suncoil

They are using .84-.94 inch tubing, and I estimate 4000 inches / 90 m of tube per ring using their water volume figures.

#48 Ian on 2008-01-24 10:45

Hmmmmm, I wonder why the Sun Coil website says: The Sun Coil does not require draining to protect it from freezing?

#48.1 brent on 2008-02-15 15:45

I'm thinking about coiling 1,000 feet of black irrigation hose in an old Honda Civic parked next to my 12,000 gallon in-ground pool. That car gets so hot with the windows rolled up...

Besides the obvious fact that it looks like an old car parked next to the pool, the upside is it just looks like and old car parked next to the pool

#49 jeremy on 2008-02-27 01:57

I see your picture at the top with the heater in the sun it is in more shade than actual sun. Do you normally leave it as is and as the day goes it gets more sun?

Do you get much warmth by the outlet in overcast weather, for how many months is the warming helpful, I would imagine not in winter?

#50 George on 2008-02-28 10:21

Good day,

I was wondering if anyone had tried connecting to the heating pipe to the outlet of the pool? I would prefer to do it this way as I do not want to cut into the existing filter setup. Otherwise do you think a small solar water fountain pump would do the trick. Can some one advise?

#51 John on 2008-03-20 11:34

I read with interest about your DIY spiral pool heater. You need a way to reduce the price of the frame and holding clamps and to make the fabrication easier. I made a frame of crossed 2 x 3 inch spruce, radial spokes of 2 x 3’s (see the photos) and the centre strengthened with an octagonal box cover screwed on the back. It is then painted black. Galvanized roofing nails are used to hold the spirals in place. They have large heads, are galvenized against rust and can be used between spirals. This is a 4 ½ foot diameter spiral containing 200 feet of ½ inch poly hose (Home Depot). The inner circle diameter is 12 inches and garden hose connectors at the ends allow connection to a garden hose. It is fed by a “T” connection at the filter when the pool pump is running, or a 1/6 horsepower submersible pump at other times. At initial start-up in the spring I lay the unit down so the pump can fill it with water, then prop it against the side of the house. In the fall, I lay it flat and blow the water out with an air pump. Care has to be taken so the frame doesn’t break.
Initially, I made several 100 foot spirals, which I put in series around the pool in the concrete deck. They worked fine but looked ugly when people came over. The large panels give the best square footage for space taken.
It seems to work well, but thermal measurements will be made this summer. He cost is ¼ the price of commercial panels. Several of these units will be needed for our in-ground pool, so I will soon be building a 7 foot diameter unit. I will keep you informed.

If you email me your email adress, I can send some photos.

#52 Brian Clarke on 2008-03-22 02:58

This is an update that Brian emailed me...
I used ½ inch tubing to get the smallest spiral possible in the centre without kinking. I will try a transparent cover this summer to see if efficiency can be improved. The cost of a cover, filling the spirals with concrete, etc. may better be spent on more simple heaters.

The faster the water flows, the more efficient the system, as less heat re-radiates from the panels and connecting hoses. Someone asked for a good pump to use when the main (1 HP) pump is not being used. I bought a 1/6 HP, 115 volt submersible pump (Simer Model 2305-03) from Canadian Tire (about $65) to clear my pool cover in the spring. This works very well as a solar heater pump.

With regards to paralleling several spirals not lying flat: If air gets into a spiral, it may be difficult to start water flow. If several spirals are paralleled, water is likely to take the path of least resistance, the spiral flowing easiest, and no water may flow through the other spirals. If spirals are coupled into a large return hose, you may never discover that water is not flowing in some spirals. I let the return hose pour into the pool. Friends enjoy the warm water pouring over them.

http://www.silent9.com/blog/uploads/Misc/Spiralcloseupa.serendipityThumb.jpg

http://www.silent9.com/blog/uploads/Misc/Spirala.serendipityThumb.jpg

#52.1 Rob A (Link) on 2008-03-25 18:09

I have finally built and tested a 7 foot diameter spiral panel using 500 feet of ½ inch vinyl irrigation hose and 2 x 3 spruce studs, pre-drilled for 1 ½ inch shingle nails, 7/8 inches apart. Disks of ¾ inch plywood front and back (1 foot diameter) provide support for the frame at its centre and a guide for the inner spiral. Two “spokes” were made 4 inches longer to act as legs and the frame was sprayed black. I used garden hose connectors on the ends so I could connect to it with garden hoses. Irrigation hose connectors have a different thread! Total cost of the 7 foot diameter panel was $93 + tax.
It weighs 60 lbs empty and 117 lbs full of water, so it should be moved empty.
Its performance was measured lying flat beside the pool in full noon sunlight, fed with water from a “T” in the return line from the filter to the pool. 7 litres of water per minute pass through the panel, raised in temperature by 10 degrees F, from 69 F to 79 F. I calculate this to be 154 BTUs/minute or 2.7 Kw.
Because it is not convenient to permanently keep the spiral beside the pool, I have mounted it vertically against the side if the house (see photo). I am in the photo to give it scale.
For those who want to mount the spirals to plywood.... have you seen the price of plywood lately? And the paint to cover it? You could probably build another panel for the price of the plywood!
The next step is to cover the surface with a transparent cover and re-test. If the day is warm, it may not cause a great improvement. If air gets trapped inside a vertical spiral panel, you may have to push it out with water pressure from an outside tap.

http://www.silent9.com/blog/uploads/Misc/Spiralclose.serendipityThumb.jpg

http://www.silent9.com/blog/uploads/Misc/Panel7fta.serendipityThumb.jpg

Brian Clarke.

#52.1.1 Brian Clarke on 2008-06-08 00:35

Hi Brian, I'm going to try and build a system like yours, and have one question: if you were to do it again, would you still use the shingle nails, another type of nail/screw, or would efficiency be improved by wrapping the coils tightly together?
thanks,
david

#52.1.1.1 DavidP on 2010-03-23 06:58

Hi, David:
I built a smaller panel using thinner galvanized nails with smaller heads and found no problems but I have not compared efficiencies. Thicker shingle nails allow wind gusts to pass through easier and allow some sun to get to grass or hedges behind.
I am currently building another 7 foot diameter panel which will stand a few feet in front of a hedge. I have added a brace across the bottom legs to stop them from spreading. I still think simple is best! I will send photos and results this summer.
Instead of using expensive spray paint, I found some cheap mis-mixed dark grey paint in the hardware store.
Brian Clarke

#52.1.1.1.1 Brian Clarke on 2010-04-17 16:31

Yes I did, I got the water temp up to 94 in the hot months. which in my mind was way to hot. So I started running the pump less and less till I ended up with 88.

it was just 500 ft of 1/2 hose laid on the roof of my house, pushed up 13 feet by a standard pool pump.

The flow wasn't great maybe 3 gpm but it was enough to warm the pool up a few degrees a day.

I did note that at one time the water coming out topped 122 which is hot enough to burn so I had to place that near the bottom of the pool so it would mix quickly with the colder water.

#53 Ice on 2008-03-31 02:16

I can't believe I found your site! This is exactly what I was going to do for my 15,000 ga. above ground pool. Great ideas from all! A few observations / comments / questions...

Not alot of mention of pool covers here. They are probably the single most important element in retaining the heat gains, especially at night. Any thoughts on best covers for heat retention?

I have to agree also with the idea of not valving the outlet to pool/heater as it does restrict flow. Getting the pipe size and restriction calculations would work better, allowing the water to flow directily to pool, or through heater according to resistance. (Especially if the return for the heater has it's own outlet directly to the pool).

One thing I find interesting about all of these designs, especially the "attic heater," is the balance you have to have to use these heaters. I am in Nor Cal, and when it is hot for a number of days, the pool actually "overheats!" (Without any heater!) So when you have the best solar heat or attic heat available, is when you least need it....just food for thought.

Last...Has anyone here experimented with "pump heat capture?" I worked for a company years ago that was using pump heat capture to heat their spas. They were actually able to pull between 1100 to 1500 watts worth of heat just from the pump running. It was as simple as a manifold, or coils wraped around the motor of the pump (models with motor exposed) that water flowed through all the time. I think the coil size would have to be in the area of half inch, and should probably be metal to avoid the potential of melting or fire. It worked amazingly well, and may even be commercially available. The great side effect is that it actually helps with pump cooling, especially when the pump is in a hot area.

#54 Kurt G on 2008-04-27 23:24

This is a great idea. I'm looking at doing same but snaking the hose on top of south facing garage roof. My small 15 ft. pool didn't come with pump and only small filter. Any idea what size pump I would need to lift the water about 12 feet high. How far could I hae the pump from the pool?

#54.1 greg on 2008-05-11 21:10

What size pool do you have using this solar pool heater?

#55 Hebert on 2008-05-25 21:34

I have an intex 800 g/h filter pump. Will this be enough to push the water? I would use black garden hose as it heats up better I think or do you think the irrigation would be better? Also, how do you adjust the hose connect to the sixe of the pump hose?
Thanks

#56 Dave C on 2008-05-28 17:07

Has anybody tested if it is better to mount the coil on a plywood sheet or if it is as effective without the plywood such as with Brian Clarke's version?

I like the idea of building it without the plywood to reduce the cost and weight. However, it seems to me it might work better with the plywood which might help reflect the sun back onto the tubing and may also reduce the effect of wind blowing through the coil.

#57 Ken on 2008-05-29 01:18

These are some great ideas guys. Some really good system ideas here I must say.

But I have a question. I'm not really that keen on having the return of the heater coil hanging over the edge of the pool. Do you think there would be any problems associated with connecting the end of the heater coil back to the same return line that goes into the pool? Looking at Rob
s pics as reference, I'd be basically putting 2 tees in the line between Rob's clorinator and the pool return. Would there be any possibility of the water not circulating correctly like that?

#58 Chris on 2008-05-30 02:51

Chris - It should work, but would probably reduce the flow The only concern would be the amount of back-pressure preventing the water from flowing through the coil.

#58.1 Rob A on 2008-05-30 15:01

It will work installing the 2 tees the way you suggested, however, you may also need to install a valve on the return line between the 2 tees, which could be throttled to force more flow through the heater loop.

You could try it without the valve first. If the tubes on the collector are warm, it means you don't have enough flow. The advantage of using a hose over the edge of the pool is that it's easier to monitor the temperature and flow in the heater loop. I'm going to use the hose over the edge initially and once I know how it's performing, I plan to plumb it into the return line.

#58.2 Ken on 2008-05-30 15:07

Ben, Instead of Plexiglass try either clear or black plastic sheet held down with thin wood strips. Cheaper than plex. and would be able to see if it helps to cover the heater with out major expense. Two layers with wood strips between would provide an air space as insulation.

#59 JK on 2008-06-01 02:41

Hi.

Just a thought. Why not cover the coils in black Tar? It's cheap and it will take in all the heat.

#60 Joseph on 2008-06-01 17:58

Rob, when you were coiling up the tubing, did you start from the centre of the coil or from the outside?

I'm getting ready to build a similar collector with 300 foot of tubing. I thought it would be easier to start at the centre and work outwards. I'm not 100% sure what the final diameter of the coil will be so I'm thinking of building it on spokes like Brian Clarke's design. Once I've finished wrapping the tubing, I thought I would cut off the spokes an inch or so past the edge of the tubing.

#61 Ken on 2008-06-02 02:46

I started at the outside. Initially I started at the center but found the hose kinked when I tried too tight a radius. Working out to in let me go until I started to kink the cable. That is where I stopped and drilled the hole out the back and installed an "L".

#61.1 Rob A on 2008-06-02 03:06

Rob, Hows your heater working?I'm going to make one just like yours this weekend.How big is your pool?Do you have a cover on it now?

#61.1.1 Rick on 2008-06-02 20:02

To be honest, I have been tied up this spring and not yet opened the pool. I always leave the solar blanket on it, however, when not in use as most heat is lost due to evaporation.

#61.1.1.1 Rob A on 2008-06-02 23:38

Am really interested in having a go at this. I live in the UK. Anyone know of a supplier of cheap rubber hose or anything else suitable? Ive found cheap PVC hose but one of the comments mentions this is not as efficient. Ta

#62 Mike on 2008-06-11 18:30

Rob, much of the 3C temperature rise that you described in your initial post must have been from the sun heating the pool directly, not from the solar heater. Assuming an output of 6091 BTU/hr for 6 hours, the solar heater would raise the temperature of your 18' pool by 1C. It's possible you ran it longer than 6 hours, however I assume the output you calculated was a peak output, and it would've been less for much of the day.

I tested my new solar heater yesterday and I was a little disappointed with the performance. My heater has 250 feet of 1/2" poly tubing installed on spokes similar to Bob Clarke's. At noon, I calculated it was operating at just over 3,000 BTU/hour. I live in Eastern Ontario so I'm north of where you live, so it's possible the sun isn't as strong here. The temperature of my 18' pool rose about 3C yesterday, but I calculate the solar heater contributed less than 0.5C of the temperature rise. I really don't need the heat this time of year, as my pool is already above 80F, however I was wondering if it would help much in the late summer and early fall when I need the heater to help extend the swimming season.

#63 Ken on 2008-06-13 12:25

Could very well be, Ken. I know the rule of thumb for commercial panels is >50% of the pool's surface area. My little coil is no where near that. But every bit helps, in my opinion.

#63.1 Rob A on 2008-06-13 14:21

If you look back at 52.1.1 you will see that my $93, 7 foot diameter spiral panel (500 feet of half inch vinyl tubing) provided 154 BTU/minute (9270 BTU/hr) of power in Ottawa, Canada at noon. According to this, the power from your 250 foot panel should be 4635 BTU/hr not 3000 BTU/hour. The spirals pick up ambient heat as well as direct radiation from the sun so I hope your power picks up as outdoor temperature increases.
The equation I use is:
Power (BTU/min) = flow (litres/minute) x temp rise (deg. F) x 2.207
Multiply by 60 to get BTU/hr.
Although this will not raise your pool temperature as quickly as a $2000 gas heater, once it is built, the heat is free and the capital cost is only about $100 per 7 foot panel. Don’t forget your pool cover every night.
Brian Clarke

#63.2 Brian Clarke on 2008-06-16 21:22

I own a tanning salon, if you contact a salon owner in your area, see if you can have some of their used acrylics when they get ready to throw them out. the acrylics will let UV pass through without yellowing. I change my acrylics once per year and the only thing wrong with them is that they filter out more UVB and UVA than they should. heat still transfers fine.

#64 Jeff North on 2008-06-14 05:10

Hey Rob,
Looking at post #37--It seems more versatile and sensible to run the output of the heater back into the inlet for the pool with a valve between the input and output of the heater. I don't understand how your setup works--how can you get any flow through your heater with just a "T" and nothing to force water through the heater?

Also, would a manifold with several 1/2" parallel runs be better than a continuous series run?

Thanks to everyone for making this a very informative blog.

#65 Sam on 2008-06-15 15:47

Sam-

If you just tee the heater return back in, then you will get virtually no flow through the heater, as the pressure at both ends is almost balanced. The only way to ix this is to then add a valve in the main line between the heater inlet and outlet that can be used to force the water through the heater. Doing that would need 3 valves (heater inlet, outlet, and main line) as I wanted to be able to valve off the panel outside heating hours so it doesn't act as a radiator and cool the pool. Since the valves were the most expensive single component I tried to limit it to the one.

And yes, a manifold would be ideal. If you had enough parallel runs all the water could run through the heater, or heaters (just like commercial systems work).

#65.1 RobA on 2008-06-16 15:52

Thanks, Rob.

My post wasn't clear enough. I meant for the first valve to be in the main line between the input and output of the heater to control flow through the heater. A second valve would be in the input of the heater, thereby allowing me to "turn off" the heater. Sound like it would work?
Thanks,
Sam

#65.1.1 Sam on 2008-06-17 01:39

Hi, I am thinking about the manifold system solar heater. It seems like it would be a lot more expensive with all the connections, as well as worrying about leaks. But I noticed you thought it would be better. Perhaps you could explain why you think so.

I am also concerned about back pressure as stated in one of your posts. Going from what is it 1 1/4 line from the pool to 3/4, and in the instance of the manifold sysyem down to 1/2, what kinds of problems might I have.

What about a system that had a black holding tank of some sort, to reduce size of system, and back pressure concerns.

I have read the whole page and there are a lot of great ideas, I will be trying some form of solar heater.

Thanks

Tom Smith-Ohio

#65.1.2 Tom Smith on 2008-07-05 22:03

First off, my thanks to Rob for starting this thread. My wife tracked down this blog/forum so I could build her a pool heater. We bought our 18'x48" metal frame pool two years ago. This will be it's third season. She never uses the pool as it stays too cold. The pool is in the shade of a big Black Walnut tree until 2pm. The pool is where it is as it is next to the shed with power and was already bordered by a fence and shed wall meaning I only needed to add two more fence sides to be by-law compliant. Plus it is in a great spot to view from our back covered porch.

We read this blog from top to bottom and it was great getting different peoples perspectives on their versions of do it yourself solar pool heaters. I loved the design that Bob Clarke has posted and I went with it.

I went to Home Depot bought what I though I would need and got to it. It took me three days on and off to put it together and install it.

My final design is 2 6' spokes with 300' of 3/4" hose on each. Plus another ~100' to and from their final operating location. So all in all about 700' of hose.

I have a porch roof off my bungalow that has a very low pitch and gets the sun from 9am to 8pm this time of year (mid-June) and is South-East facing. The roof is about 15' up from the pool and a run of about 25' from the pool to the base of the house. To push the water up to the roof I bought a Flotec Pool Pump model FPC6131 1HP. I use the original pool pump that came with the pool to drive the filter and chlorinator. I have a 1-1/4" T connector to split to the two pumps. I put a back flow restrictor on the pipe to the older pool pump for fear the new pump might be so powerful it would suck from the filter. Seeing it in operation now I doubt it would but everything is working great so I'll leave it as is. The heater pump draws in at 1-1/4" and pumps to the heater line at 3/4". The heater line drains in to the pool separately. Acording to the pump manual, with the distance and height I am getting ~38.5 GPM moving through the heater coils. The flow seems decent enough.

At 11am today the intake temperature was 20C (68F) and the return from the heater coils on the roof in full sun was 24C (75F). I hope the combination of the black hose and radiated heat from the black asphalt roof shingles really kicks up the ambient pool temperature so my wife actually makes use of the pool she bought. My kids will love it regardless. I would like to see the pool sustain a minimum of 27C (80F) and not exceed 32C (90F). The heat pump is set to run the entire time that sun is on the coils.

I will follow up with my findings in a few weeks once I gather some more results. Currently I don't have a solar cover...on this list of things to buy.

#66 Heath on 2008-06-15 18:19

Heath, I’m not sure it makes much sense having such a large pump for your solar heating system. I can understand using a separate, small pump for your heating system if you want to run it longer than what you need to operate your pool filter. For example, my 1 HP pool pump turns over the water in my 18 foot pool in about 3 hours. I want to run my solar heating system for approximately 8 hours per day and I don’t want to waste power running my 1 HP pump that long. If I were to do that, I would probably be further ahead just putting the energy into an electric heater to heat the water directly. I have a small pump from a simple set pool that I use for my solar heating system. With about 300 feet of ¾” tubing, it puts out about 4.2 LPM (1.1 GPM) and only uses about 0.68 amps, compared to 11.8 amps for my 1 HP pool pump.

I don’t have a curve for your pump, however I doubt it’s capable of pumping 38.5 GPM through 700 feet of ¾” tubing. The head loss through 700’ of ¾” tubing at 38.5 GPM would be in the order of 1600 feet, which goes to show it would be virtually impossible to pass that amount through a ¾” tube. I would guesstimate you are probably getting about 5 or 6 GPM through your heating system, which would result in a head loss of approx. 50 feet. The height of the roof has nothing to do with the head that the pump is operating at. The pump does need to generate sufficient head to get the water up to the roof in the first place, however once it is operating, the height of the roof is irrelevant. For roof installations, it's a good idea to install a check valve in the pump discharge line to prevent the water from draining out of the heater coils.

Since your line from your solar collector drains directly into the pool, I would suggest you measure the flow rate by timing how long it takes to fill a container of a known volume. Once you know your flow rate and the temperature gain through the collector, it’s relatively simple to calculate the output of your solar collector.

#66.1 Ken on 2008-06-17 00:21

Hi I was wondering if you are going to be selling these solar pool heaters?

#67 Debbie on 2008-06-21 02:45

I'm not planning on selling them. There is a similar commercial product - suncoil mentioned previously in the comments.

#67.1 Rob A on 2008-06-21 12:27

I found another manufacturer of a solar panel with the same basic design as Rob's. It's the G.A.M.E. AquaQuick solar pool heater. From the pictures, it looks like they use larger diameter black flex hose and a plexi-glass (?) cover. I first noticed them for sale on Sear's Canada website (http://www.sears.ca/product/game-solar-pool-heater/06690030?ptag=1) but found additional information on the following website-
http://www.qualityinflatables.com/game-aquaquik-solar-pool-heater.html

It seems quite small (23"x23") so I'm a little skeptical about the claimed performance (2500 BTU/hr)

#67.1.1 Ken on 2010-05-11 03:09

Thank you very much. This seems to be a really great idea that can help me get my Canadian pool heated without paying as much as I used to for my gas heater. I am trying to get a better sense of how to identify the irrigation pipe that farmers use. At first, it seemed to me to be just black garden hose. When I enlarged the photos I was able the read "20mm PE 75 PSI@23C Food grade, White stripe". I believe I will be able to identify the pipe at Home Depot or a garden centre by finding black 1/2" pipe (20mm) that has a white stripe down it. Is this correct?

#68 Michael Newell on 2008-06-21 16:36

Very insightful and interesting thread.I did a similar installation a couple of years ago and was very happy with the outcome.I constructed a 3' x 8' wood panel with two 100 foot coils of 1/2 inch poly pipe basically kept in a circular pattern on a flat black plywood surface.I made a glazed panel with plexiglas which can be quite expensive if you use the good durable product.An alternative is using a strong poly plastic you can frame in but you'll probably replace it each pool season from weather damage,etc.I had no idea just how hot it can get inside a glazed panel(up to 150 degrees C).It can be quite dangerous when you first turn your solar panel on.For now I simply run the solar loop into the pool and will eventually run it through a waterfall instead.But make sure kids don't put their hands under the solar pipe outlet when it first comes out.It is scalding hot and needs to circulate through the loops to reach the desired temperature.Using a thermometer at the outlet,it maintains about a 4 to 6 degree temperature difference from the actual pool temperature.We live in Southern Ontario and averaged 86 to 90 degrees for the pool.This is way to hot personally but I seemed to be the minority,lol.I followed the advice of having at least half the square surface of the pool done in my solar glazed panel and it worked very well.Others have already stated about using a shop vac or air compressor to blow the lines out for winter.Another alternative is RV anti-freeze which can be used over and over as well.My pool is an inground 14 x 28 rectangle.I have a 1hp Hayward pump which easily handles the solar loop which is on a self supporting rack at about a 30 degree angle facing southwest(best scenario I had).
This was a very interesting thread and there are many links to solar heating for pools with tons of information and advice which was also stated here.This is definitely a very inexpensive and yet efficient way to heat your pool.Like the experts say though,it is very important to use a solar blanket along with your solar panel.70% percent of heat loss is through evaporation and this jumps to 300% for every 10 kp/h wind.Plus you'll maintain your chemicals longer and not waste as much.

#69 Den on 2008-06-21 19:21

This has been a great read - I haven't found so many useful comments/suggestions anywhere else.

The background to my interest
I have an Intex 15'x36" (12,400 liters) frame pool in the UK. Now, some will know that the UK doesn't see too many bright blue skies or temperatures above 25°C - so heating these pools is essential. I therefore purchased a 3KW Intex pool heater, and boy is it rubbish (the manual indicates that it will [may!] provide a 1°C temperature increase in 7.5 hours [or 1°F in 4.5 hours]). At current electricity rates that's £2.32 ($4.56) - I haven't used it much, but that could cost £40-£60 a month if I want to use the pool frequently. Ouch.

The solution inspired by this blog
The Intex filter pump that came with the pool has a flow rating of 800gph/3000lph and so I wanted to develop a solar collector that could handle that flow rather than diverting the flow (my rationale was to reduce costs as UK prices for the smallest thing seem high). Obviously I figured that the spiral couldn't take that flow, so I thought about running thinner pipes in parallel. I had room for a small panel to sit on top of my heating oil tank. I purchased 100 meters of 4mm hydroponic irrigation tubing and cut it into 1.5m lengths. Then I purchased 32mm black plastic plumbing pipe (which is non flexible) for the feed (top of the panel) and collector (bottom of the panel) and drilled 67 5.5mm holes into each (the outer dimension of the 4mm pipe is 6mm). Each 4mm pipe was fitted into its corresponding holes in the top and bottom 32mm pipes. This is all fitted into a 80cm x 170cm box lined with thin stainless metal sheeting and covered with a single sheet of corrugated plastic roofing.

The BTU/hr rating
I have just measured it's BTU rating on a fairly cool summers day (average this year. Ha.). The pool temperature was 26°C and the temperature of the water leaving the panel was 27°C. The flow rate is 43lpm now that the pump has to get the water up to the hight of the panel (190cm). This gave me a BTU/hr rating of 10249! Now I haven't got a digital thermometer so those temperature readings are give or take a little. For fun I tested the Intex 3KW heater. It gave an increase of (roughly) 0.75°C with an slightly higher flow rate of 50lph as it was lower than the panel. This gave me a BTU/hr rating of 8938.

I wish I had access to a digital thermometer for more accurate readings, but as all of us here, I want to keep this project as cheap as I can. Oh, so how much did this cost to build? About £50 ($98) - things sure are pricey over here. (the 4mm irrigation hose was £30).

#70 Paul on 2008-06-24 13:54

That's an interesting way of constructing a solar collector and you appear to be getting great performance from only 100 m of 4 mm tubing. I was thinking of using a similar header arrangement, however I thought I would have to use tees to connect to the header and they took up too much room and drove up the cost too much. Too bad I've already built my spiral style collector as your collector looks promising.

Did you glue the 4 mm tubing to the 32 mm headers, or is it just a friction fit?

What are the overall dimensions of your collector?

The reduced flow through the collector is due to the friction in the 4 mm tubing, not the height of the collector. Your pump does have to develop sufficient head to initially fill the collector, but once it's operating, the height of the panel is irrelevant.

If you want to more accurately measure the performance of the collector, you could consider reducing the flow through the collector by throttling a valve on the discharge side of the pump (don't throttle valves on the suction side). A reduced flow rate will raise the temperature gain achieved by the collector. It won't increase the performance of the collector, however, it will reduce the margin of error in your temperature measurements. I realize in normal operation, you want the full flow as you will be filtering your pool at the same time, however, you might want to try a reduced flow to test the performance of your collector.

#70.1 Ken on 2008-06-24 23:01

Hi Ken, I did initially try using the threaded barbed joiners, but as you correctly assumed, a full set would have increased the cost quite a lot, and they reduce the internal diameter to about 2.5mm and therefore increase the friction/reduce the flow.

With my mark 1 model I simply had the 4mm tubing fitted with friction, but that led to minor leaks which was OK as it wasn't boxed or covered so the water just drained off. My second (and current) version is boxed and covered, so I have used PVA glue just to seal those minor leaks - so far there has not been a drop of condensation inside, so none of the joins have failed yet.

The overall dimentions of the collector are 80cm wide x 170cm tall with the box depth of 10cm.

I have just found a digital thermometer on eBay that is quite good value, so I'll see if my bid wins.

I may still make a couple of modifications. Currently the 4mm tubing is not pinned down to the metal lining of the box, and therefore just rests down on it. The idea behind this was that the shiny metal would reflect more of the suns rays back onto the tubing - thereby maximizing the surface area of the tubing. I now wonder if painting the metal lining black and pinning the tubing down may increase the efficiency.

During the next tests on a windless day I may also remove the corrugated plastic cover to see how that affects the efficiency - although we're having quite a cool early summer here, so I'm assuming that for the most part it is more efficient to keep the cool air away from the pipes by keeping the cover on.

#70.1.1 Paul on 2008-06-25 06:58

Paul your system looks really interesting. Could you post pictures of it. Also could you provide details of where you got your hose and pies from with prices. This would be a big help.

#70.1.1.1 Mike on 2008-06-26 14:23

Hi Mike, sure, I'll try to send a picture of it set-up to Rob and see if he'll post them for me.

I'm now heading for stage two of the solar collector obsession - I want to improve this to work for my domestic hot water. This will involve using a 12V pump, a 5 or 10W photovoltaic panel, and silicone tubing instead of PVC. It'ss take me a while though

The 4mm PVC tubing came from cityirrigation.co.uk @ £12 per 50M roll Shipping was £7.50, so £31.50 for 100M. The 32mm black pipe was simply waste pipe from B&Q - £1.88 for 3M plus about 90pence for each connector (6 used on my setup)...

#70.1.1.1.1 Paul on 2008-06-26 14:37

Mike, here's a couple of links to pictures of it and the set-up. The first picture shows the collector which I still need to paint :), and teh second shows its basic connection to the pool. The top feed fits onto the inline Intex heater (which never gets used, but it's just there anyway) and the bottom connection goes straight back into the pool.

http://www.paulphilpot.com/images/pp_solar_collector.jpg

http://www.paulphilpot.com/images/pp_solar_collector2.jpg

#70.1.1.1.1.1 Paul on 2008-06-27 09:59

I tried wood heat. I took an old window air conditioner apart and took the evaporator and put an inlet and outlet on it. I used water hose to run the water to and from the pool since the wood burner is inside my garage. I used a battery operated bilge pump from my boat to push the water.

The idea was to put the evaporator inside the wood burning stove and heat the water. The set up will work if the pump can force the water enough. Mine was not big enough. I was only going to use this at the beginning of the season to heat the pool and then use the solar panel to help keep it there. I will be building a solar panle next week. What a great web site!!!! Thanks!!

#71 Tim Wilson on 2008-06-25 06:37

Hi there,

I see one or two mentions of connecting your solar heater to the outflow of the pool. Can this be done in any safe way? My reason is one day should I sell my house I don't want to have to replace pipes by the pump and all that and don't want to buyers to think it looks like there were problems or something? My outflow back into the pool is about 1inch. If I fit a Y to the outlet with the 2 out parts been half inch each and the bottom of the Y been 1 inch to conenct to the outflow and from the one side of the Y let the water go into the pool and the other side of the Y go through the solar panel that will sit along side the pool. Will this work or cause too much pressue on the pipe. What are your thoughts. As I said I am not keen on cutting into the filter setup for fear of making a mistake and don't want to have to buy an aditional pump if I can help it.

Please can you help advise and let me know what you think?

Thanks

#72 John on 2008-06-25 11:44

Good day,
My pool is approximately 15,000L. To heat the pool at any decent rate and to a nice temperature what would you recommend as the flow rate and what should the outlet heated water be roughly to make a difference?

If I can raise the water coming out compaired to the pool water by 7C and have a flow rate of 600L per hour would I be on the right track or is this too slow or too cold?

Please can you help me calculate a good flow rate and temperature for the outlet. I have more than enough space to add additional piping so if it means having 1,000ft so be it, but don't want to over kill at the same time.

#73 Johan on 2008-06-26 11:25

If your collector raises the temperature by 7C at a flow rate of 10 LPM, you would raise the temperature of a 15,000 L pool by 1.7C per day if you ran your heater for 6 hours per day. In reality, you will find that the output of your collector will vary throughout the day (highest near noon and lower in early morning and late afternoon), so it may be difficult to maintain the 7C temperature rise throughout the day.

Based on the performance that others on this site have obtained, you will need to have approximately 1000' feet of 1/2" tubing to obtain 10C temperature rise at 10 LPM. However, this would probably be at peak output, so you may need more tubing if you wish to average this output for the whole day.

#73.1 Ken on 2008-06-26 14:04

My previous post should have read-

Based on the performance that others on this site have obtained, you will need to have approximately 1000' feet of 1/2" tubing to obtain _7C_ (not 10C) temperature rise at 10 LPM.

#73.1.1 Anonymous on 2008-06-26 14:32

What if I the flow rate is slower and the water coming out is much hotter, say 12C? I did a very simple test and can get the water coming out to be between 10C and 14C hotter than the pool depending on the time but the flow rate was low, only about 4LPM? Would this have about as much effect as a higher flow rate at a slightly lower temp?

#73.1.1.1 Johan on 2008-06-27 13:02

Hi Johan-

I did a quick test and found the total heat transferred into the pool was almost the same regardless of the water flow. I think that at the extreme end, if the flow was too slow you would start to loose any additional heat gained, decreasing the efficiency. The term used is *convective heat transfer*. Someone else might have a better idea.

#73.1.1.1.1 Rob A on 2008-06-27 13:24

Just a guess here, but the metal lining within my collector is actually quite cool to the touch when the water is pumping through it at 47lpm. I made an assumption that any heat that is left withing the collector is wasted heat. Therefore if I reduced the flow on mine, I would possibly leave heat within the collector...

#73.1.1.1.1.1 Paul on 2008-06-27 13:39

So if the flow is at least in the region of about 500L per hour and the heat coming out is about 10C hotter than the pool water it should definitely help make a difference then?

#73.1.1.1.1.2 Johan on 2008-06-30 11:18

I am interested in finding out if anyone has built a floating solar heater that is placed in the pool and connected to the discharge port in the pool itself? I'm thinking that the most efficient way of gathering heat from a 4'x4' coil of hose would be to actually have the hose in the water (or at least floating in a box on the water). Also, the head required to pump through an in-pool heater would be less that a rooftop mounted setup.

Adding drain valves at strategic locations would help empty the panel for easy removal from the pool.

Your input is greatly appreciated.

#74 Kevin on 2008-06-30 19:49

Does anyone have input on this idea?

#74.1 kevin on 2008-07-07 13:21

Excellent forum!

We are in north Italy and have a pool 5x10m with approx 80000 litres. My idea for heating it is:
Lay down polystyrene boards for insulation.
Cover with alum foil to reflect IR
Lay down hose coil to about 50% surface area of pool
Cover with glass or plexiglass.

Now, for aesthetic reasons we'd really like to use a dark green hosepipe, but I know the best for heat absorption is black. Would we lose a huge amount of efficiency?

Also, since the idea is that the water constantly takes the heat from the hose, I'm not convinced that insulation is strictly necessary.

Anyone know a cheap source of solar water pumps in Europe. Anything new tech in Italy costs a bomb!

Steve

#75 Steve on 2008-07-02 11:22

Fantastic idea! I'm thinking to give it a go too.

In my situation, it's not convenient to tap into the existing pump / filter line due to the location. So I thought about getting a solar powered pump to circulate the water through the heater.

I intend to position the heater on the pool deck, i.e. just above the pool water level, just dropping the heater intake and outtake pipes into the pool.

Would I be correct in thinking that once the heating coil is charged with water (say using the water pressure from a garden hose) would a small pump on the outlet side of the coil be sufficient? What size? I hope that a siphon effect would help the water flow once it's moving, right?

Also, if I did need to drain the coil (I'm in Sydney, Australia - so not much chance of freezing), would the small pump on the outlet side do the job of pulling the water out of the coil (remembering to pick the inlet pipe out of the pool!)

Any comments or advice would be greatly appreciated.

#76 Andy on 2008-07-03 02:09

Andy, you don't need a very large pump to use with your solar collector. I use a small pump that puts out about 4.5 LPM through 300 feet of 1/2" tubing. My temperature gain maxes out at about 3C.

From a pumping standpoint, it's better to have your pump on the inlet side of the collector. Pumps work better and last longer with more suction head.

You might have trouble maintaining prime if you drop your intake hose into the pool, unless you have a foot valve on the end of the inlet hose.

#76.1 Ken on 2008-07-03 13:11

Thanks Ken.

Just to check my understanding of what you've said...

Would I really have a problem maintaining prime if the intake and outlet pipe ends were in the pool?

Is your pump solar powered? I read that solar powered pumps need a 'maximiser' (some kind of capacitor device?) to get the pump started. Any advice on that?

How big is your pipe coil panel to give the 3C gain? And in what kind of climate is that happening?

Thanks

#76.1.1 Andy on 2008-07-03 22:49

You may be OK maintaining prime if you keep the inlet and outlet pipes submerged in the pool, however you may lose prime if you have any minor leaks in your system. Try it without a foot valve first. You can always add one later if you have problems.

My pipe coil is about 4.5 feet in diameter with about 300 feet of tubing. I have it mounted on spokes, not a plywood panel. You can see photos of one similar to mine made by Brian Clarke in Post 52.1. He also provides some performance figures in his post. Although we live fairly close to each other in Eastern Ontario, he seems to be getting better performance. My tubing is wrapped tightly together and is held onto the spokes with 8 pieces of angle aluminum. Brian's tubing is held onto the spokes with roofing nails, which maintain a small space between the adjacent tubes. My theory is that this is more efficient as it allows the sun to reach further down the sides of the tubing than with my collector.

My pump isn't solar powered. I use an Intex pump from an old Simple Set pool. The pump nameplate rates the motor at 0.68 Amps (at 120V), so it doesn't use much power (about 80 watts).

#76.1.1.1 Ken on 2008-07-04 02:33

I bought 100m of LDPE 19mm tubing (for A$53) at the weekend. I just laid it next to my pool, without fully uncoiling it. I hooked it up to a pond pump that I already have - rated at 750 l/h.

I just wanted to test the overall concept of what kind of flow rate I'd get and whether I could detect any temperature increase.

We're just about mid-winter here, but the sun was shining for a few hours. It was about 18 deg C air temperature. Before I hooked up the water pump, I left the pipe exposed to the sun for a couple of hours and it did feel surprisingly hot!

With the pump hooked up, I measured the flow rate at about 3.5 l/m, and the temperature differential was about 2 deg C.

Considering this was mid-winter, for only a couple of hours, with the pipe hardly uncoiled... I'm encouraged by this result.

Now I need to consider that in the summer I should be able to increase the flow rate - which means I'll need a solar pump rated at over 1000 l/h... which gets expensive (probably A$700 with panel).

But I'm happy to invest that money now that I can see the concept working in my situation.

Thanks for the idea and tips.

#76.1.1.1.1 Andy on 2008-07-06 23:02

Hi Andy. Im also in sydney and wanted to contact you in regards to your project

#76.1.1.1.1.1 adnan on 2008-10-16 00:25

Anyone have any advice on a pool heater for a 8' Easy Set pool. I'll be using the OE pump. Planning on using 200' 1/2" irrigation hose and two valves. The outlet of the heater will be tied back into the discharge line with one valve between the T's of the inlet ond outlet of the heater. will 200' of hos be enough for this small pool?

#77 Cassey on 2008-07-09 20:26

200' of 1/2" tubing should work great for an 8' easy set pool. I'm not sure of the exact volume of your pool but I would guess it would be order of 700 gallons. Based on the performance that others on this site have achieved, you should expect to average about 0.5 F per hour increase (or better) in the temperature of your pool when the sun is shining. Of course your performance may vary, as it depends a lot on your location.

#77.1 Ken on 2008-07-10 02:09

Ken, would you happen to have info on where I can get the food grade flexible hosing spoken of in Rob's illustrations? I'm from the northeast Ohio area and have not been able to find it. All the home depot in my area has is rigid black coils of hose/pipe.

I emailed Rob the other day but have yet to hear from him.

#77.1.1 Tom Smith on 2008-07-10 13:34

I got mine from Home Depot in Canada which is where Rob also got his (see post 2.1).

It's possible it's the same stuff that you refer to as "rigid black coils of hose/pipe". The tubing is polyethylene. Higher pressure polyethylene tubing has a thicker wall and is more rigid, although it can still be coiled, although not as tightly. The tubing that Rob has been referring to is only rated for 75 psi and is fairly thin walled, which makes it more flexible.

#77.1.1.1 Anonymous on 2008-07-10 14:56

Many thanks to everyone for the postings here. It's been very useful as I decide if/how to make a solar water heater. Here are a few questions:

- Does anyone have any insights about how effective the Sunheater by SmartPool is (http://www.smartpool.com/website/sunheater/s601.htm)?
- Can a non-glazed system get hotter than the ambient air?
- How much more effective would a glazed system in which hose was put in a black box with a glass cover be than thye hose without the box and glass?
- Does anyone have insights into how effective a system in which water was run over corrugated roofing vs the hose based systems discussed in most of these threads (see #4 in http://www.builditsolar.com/Projects/PoolHeating/DIY/SimplePoolHeat.htm).

As further background, I have a 15x30 inground pool in the Northeast that is currently unheated.

Thanks,
JP

#78 JP on 2008-07-10 00:28

Hi rob

how do i put pictures with my comments , i have made one simalar to your one and wanted to show it on this site , see what you think ??

#79 Mark southwell on 2008-07-20 09:52

Here are Mark's photos and email:

I have made my own version of this , by using 2 x four foot square ply , with 1/2 inch rubber airline hose coiled on it , and clear perspex front cover , the water is pumped round the pipe by a normal UK central heating boiler pump (100 watts) , I have included a inline tap to slow the water , on a hot day the water is almost boiling coming out of the pipe.

http://www.silent9.com/blog/uploads/Misc/DSCF0164.serendipityThumb.jpg

http://www.silent9.com/blog/uploads/Misc/DSC00255.serendipityThumb.JPG

http://www.silent9.com/blog/uploads/Misc/DSC00254.serendipityThumb.JPG

http://www.silent9.com/blog/uploads/Misc/DSC00256.serendipityThumb.JPG

#79.1 Rob A on 2008-07-21 00:30

How much hose have you coiled? What sort of flow rate do you have, ie litres per minute, what size pool do you have and what is the temperature rise?

#79.1.1 Bobb on 2008-07-21 11:09

Im going to also now try to add a on of timer to my pump , two mins on and two mins off , this should allow the water to rise in tempreture in the pipe more

#79.1.2 Mark on 2009-04-12 21:59

Mark,
It's actually not a good idea to start and stop your pump that frequently. Motors are usually only designed to start a few times an hour. The motor will overheat if you exceed the number of starts per hour that it is designed for.

Also, there is no advantage to allow the water in the tubing to heat up. A steady flow will more efficiently transfer the energy collected by tubing to the water in your pool. If you allow the water in the tubing to rise above the ambient temperature, you will actually be losing energy that the tubing has collected to the surrounding air. It's actually better if the7AEU tubing feels cool to the touch. If it is feeling warm near the outlet, it means you should actually have higher flow.

#79.1.2.1 Ken on 2009-04-13 02:38

Yea but maybe its just me but it seems that the water starts of boiling hot but after 5 mins has cooled down and is almost cold coming out , maybe its the hose im using 1/2 rubber airline hose maybe its to thick ?

#79.1.2.1.1 mark on 2009-04-13 07:39

When the water has been sitting in the hose before you start the pump, it will be very hot, however the heat doesn't get into the pool until you start the flow.

Once you have flow it will obviously cool the tubing. If the tubing feels cool, that tells you that all of the solar energy is being transferred to the water. If the tubing remains warm, it means you have insufficient flow and you will be losing heat from the tubing into the air.

Think of it this way- The output of your solar heater is a function of the area of your panel and the intensity of the sun. Increasing the temperature of the water by reducing the flow (or with intermittent flow) will not increase the output of the solar heater. Rather it will reduce the efficiency as explained above.

#79.1.2.1.1.1 Ken on 2009-04-13 17:47

You are absolutely correct Mark. I worked in an oil refinery for 30 years and am familiar with heat transfer.
Thomas

#79.1.2.1.1.2 Anonymous on 2009-05-12 19:24

Hi Mark,

I'm about to build one of these in the UK and I was planning to use a central heating pump as well. Your photo looks like you have a valve on either side of the pump. Is that correct. If so, which side do you use to slow down the flow? How did you go about priming it the first time. Are you geting much rise in water temp with yours? Thanks.

Thom Box

#79.2 Thom Box on 2008-08-01 10:44

Hey there , there is a valve on the output side of the centeral heating pump , it must be on the output as if you put it on the input it will stress the pump , i use a hose pipe to prime the pump , i have used around 50 metres if airline hose .

#79.2.1 Mark on 2008-08-01 19:50

Hi Mark
This looks like a great system and it seems you are very pleased with its performance. I'd be pleased to have any further details regarding materials and suppliers used if you are prepared to share them. A simple diagram for this novice would be great too!
ATB
John

#79.3 John on 2009-04-12 21:07

wow it was the simples way i ever saw the simples water heater. thanks for the information and the sharing idea. i'll try to implement it and i will share this info to my fellows. please give me permition to share it.

#80 Eko Prasetyo on 2008-07-21 04:19

GREAT SITE!!!

I see you make reference to rougly 100 feet of hose per 1,000 gallons of water for heating, at what flow rate would this be? Also if I may ask, where I live we use meters and liters, what is the guide in this, about 10 meters per 1,500 liters?

#81 David on 2008-07-22 11:22

The output of the heater will be virtually the same regardless of the flow rate. You just need to make sure the water coming out of the heater isn't too hot or that the tubes are cool to the touch. If this is not the case, you may need a faster flow rate. My collector has 275' of 1/2" tubing and it works fine with a flow rate of about 4.5 litres per minute- typically heats the water up about 3C.

100 feet of tubing per 1000 gallons of water is the equivalent of 10 metres of tubing per 1240 litres of water.

#82 Ken on 2008-07-22 13:18

Can anyone give any advice or links for a pump to run a solar heater. Thanks!

#83 Cassey on 2008-07-24 00:35

First of all, you should see if your existing pool pump could be used to circulate water through your solar collector. If you presently run your pool pump/filter for 6 hours or more per day, it should work well to use with your solar collector. If your pool pump is oversized, like my 1 HP pool pump (turns pool over in about 3 hours), then you might want to consider having a dedicated pump for your solar heater. If you plan to use your pool pump, you probably don't want to run the entire flow through the collector as the tubing will restrict the flow too much. I would suggest connecting it the way Rob has connected his.

If you plan to use a dedicated pump for your solar heater, you don't need a very large pump. I use a pump from an old simple set pool. It pushes about 4.5 litres per minute (1.2 GPM) through my solar collector, which is uses about 275 feet of 1/2" tubing. It heats the water up about 6 degrees F, which I think is fine. For my size of heater, I don't think you need a pump much larger than what I have. If you have more tubing, you may want a higher flow rate to reduce the temperature rise through the collector. Of course the larger the pump, the more energy it will use, which will reduce the efficiency of your system. My pump only uses about 0.68 amps (80 watts). Also, you don't need a very high head pump if you keep the flow rate down. The head loss through 200' of 1/2" tubing is about 4 feet at 1 GPM. At 2 GPM, the head loss is about 8'. Unless you have a high head pump, it's unlikely you'll get much more than 5 GPM through 200' of 1/2" tubing regardless of the size of the pump (head loss would be about 47 feet).

#83.1 Anonymous on 2008-07-25 14:22

I have a simple set pool pump but I cant get it to pump water to the hight of the pool edge. 4' What is your setup? is the pump above or below the level of the pool. can you post a picture?

thanks

Andrew

#83.1.1 andrew Macklin on 2008-07-26 02:26

If you have trouble pumping water through the spiral you may have an air lock in your spiral heater. Use your house water pressure to get water flowing through the spiral then switch to the pump. The height of the pump should not matter.

Brian Clarke

#83.1.1.1 Brian Clarke on 2008-07-26 15:27

I've now got my pipe (90m of 19mm LDPE irrigation pipe) mounted on a sheet (2.4m x 1.2m) of formwork.

I've temporarily hooked it up to a pond pump which I manually switch on and off. I'm getting a trickle but even in mid winter here in Sydney I'm getting a 10 deg C rise in temperature).

I've gone off the idea of using a solar powered pump due to the cost. So I intend to either use my existing pond pump or even buy a higher rated pump. The higher flow and higher temperature rise as we get closer to summer should show some good overall results.

But now I'd like to switch the pump on only when the sun shines.

Does anyone have a suggestion how I can do this? I guess I need a sensor that can be adjusted to turn on a power circuit when the sun is shining and off when the sun goes down.

Any assistance would be appreciated.

#83.1.2 Andy on 2008-08-12 07:08

I have my pump on a timer...on and off every 1/2 hour...thru 1" black hose coiled on garage roof...able to raise pool temp at least 5 degrees on a hot day.

#84 mike on 2008-08-18 01:06

You'd get even better performance if you left your pump running continuously during the hours of the day when the sun is the hottest, instead of turning it on and off every 30 minutes.

#84.1 Ken on 2008-08-18 02:48

Good day,

This looks amazing. I haven't had time to read all the postings people have done so I am sorry if I ask something that has already been asked. I live in South Africa and get a lot of sun pretty much all year round especially in summer. My question is this. I have a pool of about 16,000 liters. If I can have the flow rate at about 600 liters an hour, 10 liters per minute, and the temperature of the water coming out of the pipe ranges from a low of 5 degress celcius hotter to a hight of 10 degrees celcius would this suffice? The "heater" would run from about 9am to 4pm.

Thanks

#85 Gregg on 2008-08-20 11:34

At 600 litres/hour and an average temperature rise of 7.5C, you would raise the temperature of your 16,000 litre pool by about 2C in 7 hours. I don't know how hot your sun is in SA, but I would guess you would need quite a long length of tubing to obtain a 7.5C temperature rise.

Whether or not it would be sufficient depends on a number of factors-

-How cold does it get at night. Where I live here in Canada, it's starting to cool off to about 10C at night. I find that it's getting hard to get the temperature of the pool to recover during the day. Of course any heat input will help extend my swimming season.

- Do you use a solar cover? I've found on a sunny day, most of the temperature rise is attributable to the solar cover. My solar heater consists of just under 300' of 1/2" tubing. I calculate that it raises the temperature of the pool by about 0.5C a day, whereas the solar cover can raise the temperature by about 3C. If you don't use a solar cover, you'll lose a lot of heat from evaporation and also from the cooler night temperatures.

- Do you get a lot of sunny days? A solar heater or solar cover won't produce much heat on a cloudy day. I find the pool temperature plummets on cloudy days, even in the middle of summer when the air temperature is high.

The most bang for your rand is a solar cover. I use a clear solar cover which I understand is the most effective.

#85.1 Ken on 2008-08-20 13:38

Hi Ken,

Thanks for the info. The main months I am tageting are October to end of April and I get a lot of sunny days where I am in South Africa. The night temperatures during this time are in mid teens to 20's, would that make a big difference and cause the pool to get a lot colder?

Winter time, now, my pool sits at about 12 degrees celcius which is very cold but wouldn't swim now so as I said the main time I am targeting is Ocotber to end April, the nice hot months and I would probably diconnect and store my "heater" in the winter months.

Regarding the solar cover I am not too keen on one as it becomes an effort to take off and store and then put back every time I swim, but if my "heater" doesn't help enough I will look at one, just thought for a bit of simple easy heat the "heater" would be the best option.

Thanks.

#85.1.1 Gregg on 2008-08-21 10:02

Greg, using a solar heater without a solar cover is like heating your house and leaving the windows and doors open. Also the biggest source of heat loss in the summer is through evaporation, which can be prevented by using a solar cover or any other type of cover for that matter.

A solar cover is going to be a lot cheaper to buy than a solar heater with the output you specified. Also a solar cover doesn't use any energy other than your own to operate. I find that with a solar cover, I don't really need to operate my solar heater in the summer as the temperature of my pool reaches the mid 80sF (30C). I'm hoping the solar heater will help to extend the swimming season in the late summer.

I have an 18' above ground pool. It takes a couple of minutes to remove the cover and to replace it. I don't actually remove the cover totally. I pull it back and drape it over the side on one half of the pool. You can purchase reels to make it easier to install and remove the solar cover. A cheaper option are solar cover saddles that fit along the outside of the pool- see this link:
http://www.inyopools.com/Products/00100001005541.htm

#85.1.1.1 Ken on 2008-08-21 20:28

Hi Ken,

Thanks for the info. I think I am going to give just my heater a go as my pool is an in ground figure 8 so it is a "funny" shape and to just pile the blanket on the side of the pool when no in use will look shocking. Thank you for your info. If my pool still doesn't get as hot as I hope then I will do the blanket thing, but for now I think I am going to go with the "heater", it is neater and no effort once it is made.

Thanks

#85.1.1.1.1 Gregg on 2008-08-22 10:32

WOW! I have just spent a couple of hours reading through these posts... and I didn't even get through all of them!

We are in the process of installing a pool and definitely want to use solar power to heat it. We have looked at buying solar pool heaters, but they are quite expensive when comparing them to the price to build one ourselves!

We are putting in a 14x28, 8' deep end rectangle (~15,000 gallons) and my question is, how much pipe would I need to heat a pool this size? We would probably go with the spiral type that Brian Clark demonstrated, but mounted on our roof.

Sorry if this has already been discussed, I tried to read them all before posting... but I'm afraid I don't have time!

Thanks for your help!

#86 Paula on 2008-08-27 16:09

Just wanted to say thanks for taking the time to put instructions and pictures for the panel you built. I built one using 300' 1/2" irrigation pipe on a 4'x8' sheet of plywood. I had some leftover black roofing shingles in the garage, so i put them in between the tubing and the plywood. I run water through it for about 6 hours a day and we always put our solar cover on at night so we will keep the heat we get during the day. We live in Maryland. Our neighbors are starting to close their pools because they are getting too cold while ours is 81 degrees today! I built it about a month ago and in one week brought our temp from 74* to 80*. That's for a 22,000 gallon in ground pool. So thanks again for taking the time to pass the info along!!

#87 jimmy on 2008-09-15 23:41

I just installed the system as described however i did not box the sides. I placed the system on a 10 hour sun facing point. My entry and return pipes is 30 meters respectively. there is no hot water on the return. what am i doing wrong?

#88 kool_kruzer on 2008-09-17 04:58

Good day,

Let me start off by saying this is briliant and definitely worth a try. I am not nocking this is any way or fork just asking if any one knows of other sites / blogs that have postings of pool heating for the DIY'er? Never hurts to get a second opinion or look at someone elses design and see what they did differently. Anyone have any other sites / blogs they know of?

Thanks

#89 George O on 2008-09-26 09:30

Good day,

This is brilliant. Been building one for myself but I have a problem. The pipe keeps on kinking when it bends too much near the corners. Do you think putting the pipe in hot water to mold it into the bend and then putting cold water on it to make it hard again will help?

#90 Peter on 2008-10-03 11:24

I've read down through this whole blog. A great read and I will definitely be doing something very similar for my pool.

Can someone please confirm that I've found the correct type of pipe. Here is a link from a local supplier here in Ireland;

http://www.corkplastics.ie/products/Water_pipe_fittings/Polyethylene_pipe/product.htm

Also! While browsing online for methods to heat pools, I came across a youtube link for a guy using a lense to heat a body of water. The lense is useless to heat the water itself as its transparent, but when he focused the lense on black object in the pool the object did heat up quite quickly. This is similar to how the solar pool covers work.
So if I put a large black rubber mat at the bottom of the pool would it improve the performance of the solar cover?

#90.1 John O'B on 2009-03-23 15:58

John O'B

The pipe should be black, the cheapest is usually described as LDPE irrigation pipe, must be UV resistant (or I suppose it'll rot and leak after a few weeks/months).

From a heating perspective the bottom of your pool would ideally be painted black, but I think this would be difficult to keep clean and would actually be a serious safety hazard; for example you wouldn't see something resting on it, like a glass bottle - or a body - so definitely isn't recommended.

Yes a lens - or perhaps a mirror - could focus sunlight onto a removable black mat or panel at the bottom of the pool (at least, not close to the surface, so there is convection to spread the heat) which would definitely aid transfer of heat into the water, but it would be an interesting project in optics and mechanisms to keep the converging light rays incident onto the black target, particularly as they are diffracted (or is it refracted?) as they pass from air to water. And you would have to be careful that bathers don't get into the focus of the lens/mirror or you would be reinventing the idea of a pool-side barbecue! The lens/mirror would have to be quite large too; imagine that if you would need 4 square metres of solar panel to heat your pool then the lens/mirror would have to be a similar sort of area to capture the same amount of heat, give or take a bit for better efficiency.

Your solar cover doesn't really focus sunlight, it does two things: firstly and easily most important it insulates the surface of the water so heat loss due to air conduction/convection is reduced. Secondly it can absorb some heat from the sun and conduct it into the water, but as this heat is conducted into the top layer of water which has nowhere to convect to (the warmer water wants to rise but has nowhere to go) this heat probably doesn't transfer very far into the main body of water so I suspect that the value of this effect is minimal.

HTH
Ian

#90.1.1 Ian on 2009-03-23 17:32

Thanks Ian,

I wasn't suggesting to use a lense as that would be way too difficult to set up and keep focused on the bottom of the pool.
I simply meant that the principle seemed sound and that a black mat on the pool floor should attract heat naturally anyway. Same as the panel heater does. But obviously being totally submerged would transfer the heat simultaniously as its being absorbed.
Every little bit helps when trying to heat the pool.
I just presumed that the solar cover acted like a type of plastic lense by focusing the light energy into the pool, as well as preventing evaporation and insulating the pool surface.

Also! Laying a couple of sheets of lino or plastic on the ground with some insulation material such as rockwool in between, and then the pool placed on top of this might help to reduce heat loss into the ground.
Just thinking out loud, really. But as I said above. Every little bit helps.

#91 John O'B on 2009-03-24 11:43

I am hoping for a more effective hose so that I can use a shorter hose. I am thinking of using a braided stainless steel 3/8" or 1/2" flexible hose. Would it be significantly more effective than the irrigation hose? (It does, obviously, cost much more than the irrigation hose.) The steel hose wall is not thin. If I paint it black, what kind of paint do I use? Or perhaps I can thinly coat it with rubber somehow?

I would also like to get input on how to improve the background. A thin sheet of aluminum painted black would be one of the most effective? Would painted aluminum foil be sufficient?

(I plan to cover my shallow solar box with plexiglass.)

#92 Inventive on 2009-04-03 10:43

I have been reading about diy solar heaters for pools for two days now... I still don't know what is best for the price: black piping, coloplast, etc, etc. But something that I have not found that originally thought of was this...

What about clear piping with either black behind it or a mirror behind it? Has anyone tried this? I figure this way I could put two or more layers of pvc piping to save space, the uv rays actually go through the water (I know nothing about science, would this actually help), and I could reflect the rays with a mirror to go through the water again.

Is this just a dumb idea or could it work?

#93 Joe on 2009-04-08 23:41

Interesting idea but I would guess that black or mirror behind would not heat nearly as much as black hose.

#93.1 Inventive on 2009-04-10 00:27

What about the Aquaquik Solar pool heater?
Would this be effective with less effort?

#94 Dan on 2009-04-14 23:13

I'd recommend you avoid the Aquaquik Solar pool heater. I purchased two of these before I built my own solar heater. Both of the Aquaquik Solar pool heaters burst at the seams. If you read the reviews on Amazon.com you'll find many people complaining of this.

#94.1 thelber on 2009-06-22 15:57

going to try making a panel was thinking of 15mm copper tubing spread over a 6x4 panel sprayed matt black with reflective backing [stuff you put behind rad] covered with 6mm toughned glass, a sealed unit stuck behind fence facing true south with seprate pump, want to try and fit a thermastate to turn pump on when temperture is high enough to benifit it will act like a big radiater so should heat up ok im finding the copper piping cheaper than hose or on par depending what i go for cheapist is underfloor heating pipe but is clear so going for copper my m8 going to solder it all up for me as he loves doing things like that

#95 dave on 2009-04-15 21:43

anyone know the best source in th UK for the type of hose needed. Excellant blog.

#96 Tony on 2009-04-24 11:15

I am using black 1/2 airline rubber hose which does not seem to be keeping the water hot for long , would a clear pvc braided hose a bit thinner retain more heat and work better ?

#97 Mark southwell on 2009-04-25 13:49

thanks for posting this (and thanks all for the additional comments)

As so many others have commented, I don't want to run my 1HP main pump 'unnecessarily' to take advantage of the solar heating. Ideally, I'd like to drive this with a solar powered pump... has anyone had success with this?

All the best from Ottawa

TIA

Al

#98 al caughey on 2009-04-26 03:26

Thanks to all for the great info. I am definitely going to build one. My question is "has anyone tried black 5/8" rubber garden hose?"( I saw Mark Southall's post regarding airline hose). I was in Sears and saw that they had it on sale, $31 for 100'. Anyone think that this would work well as I am having trouble locating the irrigation hose?

I have also noticed some talk of having a chrome or silver painted back board, I wanted to try this and wondered if anyone had experimented with it?

Thanks in advance.

Jeremy

#99 jeremy on 2009-04-29 19:31

Coincidentally, my name is also Jeremy and I did just that last year. I bought 7 100' Craftsman hoses from Sears at $30 each. 600' of them are laid atop my southern-facing roof. On a clear hot day, the water was 80F going in and 100F+ when it came out of the hose.

Mine just lays across the asphalt shingles with nothing covering it, although you can watch a thermometer fluctuate as clouds cover the sun or a light breeze cools the hoses..

I tried this a few years ago with 600 feet of PVC pipe painted black but the couplings/elbows kept expanding/contracting/leaking. I decided to spend a few hundred bucks on water hoses instead of fighting with PVC again. Besides, it's hard to beat the LIFETIME WARRANTY Sears offers on their Craftsman hoses.

#99.1 (another) jeremy on 2009-05-02 19:41

What pump do you use to circulate the water through the hoses? do you have any kind of manifold or is it one straight run? where does the water discharge on the return? And finally, did you try this with the 7 hoses coiled up with any success?
Thank you.
Thank you to all that have left comments...quite a wealth of information.
I wish all of you a summer filled with eye massages at your pools!

#99.1.1 jay on 2009-05-06 06:04

I just use my dual speed 1HP motor on my 23 year old Hayward Super Pump. Set to 'high' speed and it sends the water up to the roof and through the hose and back down and out above a return jet in the shallow end. 'Low' speed doesn't quite have the power to send it up to the roof.

I T'd (3-way PVC adapter) the return line with a 1.5"-3/4" PVC reducer and a ball valve and PVC male water hose adapter. Everything you need for this is in the plumbing isle at your local hardware store/Lowes/Home Depot.

I stick the return line down just above a return jet so the force of the jet sends the hot water out to the rest of the pool.

I want to try coiling the hose up in big spirals but it's really hard to get the hose to lay the way I want it. I just have long 20' runs like this:
___________________
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(__________________
___________________)
(__________________)
__________________)
(__________________..etc

#99.1.1.1 (another jeremy on 2009-05-18 22:20

I used regular 5/8 black rubber hose. It works fine. I also used a 4 x 8 piece of Styrofoam with silver backing for my background. You can get these at any Lowes or Home Depot. Space the hose out between your coils with 1'' wood blocks or what ever and let the sun reflect at angles back to the sides of your hose. This will increase the efficiency.

#99.2 Richard Lawton on 2009-05-27 19:24

I've been having a devil of a time finding the right low density polyethylene pipe that I've seen described here in the forum. Not one of the plumbing suppliers or lumberyards knows about it. They all carry the black well pipe rated at about 125 psi but i know that's way too inflexible for this purpose. I did find a company on the web that sells polyethylene irrigation pipe with a 5/8 inch diameter. In talking to them on the phone he told me that it was indeed UV resistant but is not recommend for high pressure situations, he thought up to 40 psi would be fine. It's made by Toro Ag, is black and he thought flexible enough to spiral to a 12 inch diameter at best. This sounds like the right stuff but before i plunk down the cash would appreciate any comments from anyone as to whether or not you think this would do the trick. Thanks!

#100 Pat on 2009-05-19 20:17

Hi Pat, and all. Pat, the pipe is for iragation systems. I have seen it at Menards.

#100.1 Les on 2009-05-28 04:52

Thanks for the reply Les. I did some more research and decided to go with Drip Rite out of California...a 500 foot roll of ldpe irrigation pipe, UV treated, 5/8 inch diameter. With 500 feet I can do 2 panels and since the roll is coming from California to Maine the freight is much more economical with the big roll. My plan at this point is to make 2 separate panels, one facing a bit towards southeast and the other more west for the afternoon sun and will run only one at a time. My pool resides in a large 32 x 48 greenhouse and one of the panels will be inside and one outside so it should be interesting to see how the two compare. I'll keep the group posted as to the progress.

#100.1.1 Pat on 2009-05-28 11:45

great design. made small changes. added 1/16" thick plexi over the coil supported at the the edge and across the middle with 3/4 square stock. also because of the panels position relative to the location of my pool pump it wasn't practical to use it. instead i combined a 12 volt continuous duty in-line water pump connected to a deep cycle marine battery, kept topped up by a solar panel. even on a cloudy day the water is warm coming out . also i'm using 1/2 inch hose all around including the line delivering to the pool and the pick-up. also rigged a funnel to the pickup hose and it really improved the start up flow. will post pictures as soon as i take them . glad i found the site. THANKS.

#101 peter (Link) on 2009-05-22 17:08

Got an email request from Al C:

"Peter... for those of us who are ignorant... can you provide a little more detail about the pump/battery/panel combination?

I want to build something like this and want to drive it from the sun (like you are doing).

Sorry to be a bother but much appreciated."

#101.1 Rob A on 2009-05-23 17:14

well, the collector is basically the same as the one at the top of the page except i added some 3/4 inch stock across the middle of the box, because i could only find 24x48 inch panels of plexi and i had to use 2 pieces. i used 1/2 inch black pipe from HD and then connected it to 2 pieces of 1/2 inch garden hose for the intake and output of the pump. i modified a plastic funnel (used a heat gun to soften the plastic to widen the throat and give it a bead around the opening for a nice tight fit in the intake hose.) to increase the efficiency of the intake. for power (i live in canada) i went to the local canadian tire and bought a 12 volt inline utility pump (they can be found on the net,make sure it's for
"continuous duty",designed to run for hours at a time.) and a 12 volt 15 watt output solar panel. then i picked up a 850 cold cranking amp deep cycle/starting battery for the primary power. didnt ufeel the need to use a regulator for the solar panel to the battery since it doesnt have a huge output and i dont run it long enough to drain the battery plus "hey i live in Canada, summer's ain't been the hot here lately. the rest is basic electrical. connect the panel to the battery connect the battery to the pump and away she goes. hope this helps. if not let me know.

#102 peter (Link) on 2009-05-23 23:10

one thing i just discovered by accident. DON'T take the intake or the output hose out of the pool. I just made that mistake attaching some bitrious fishing weights to the intake to keep it pointed at the bottom, and just like basic plumbing (air behind water) the water in the collector siphoned out into the pool and the pump would'nt prime. If that happens to anyone just force feed the intake with the garden hose. Once you get it going with the hose submerse
it in the pool. when the system is full of water it will stay that way so long as both line stay submerged. you CAN take the output out of the pool while the system is running with no ill effect but to save yourself the pain in the behind of having get out the garden hose, leave both ends submerged. that it was important for you to know this little bit.

#103 peter (Link) on 2009-05-24 21:00

additional note to my solar powered solar pool heater. got tired of turning the pump on and off manually. found an inexpensive 12 volt timer on line at Hometech solutions, model 6030. easy to hook up using a 12volt 30 amp 5pin auto relay to handle the cuurent draw of the pump. just followed directions for setting up the timer, set it for 15 mins. it is a 50/50 timer so it will turn on and off in equal amounts. using 2 timers would allow for selectable on off times (10 on 30 0ff) but that required buying 2 timers. did'nt want to invest that much. but other than that the system works great. i connected it after the on/off switch so it can be switched off at night or cool cloudy days, but it's a lot easier than walking around the far side of the pool to switch it manually.

#103.1 peter on 2009-06-17 15:32

another suggestion. if anyone is considering building a 12 volt powered system and knows someone into electronic hobbies there is a website,"uk.geocities.com/ronj_1217/rt2s.html" that shows a diy repeating timer circuit one could build that has independantly selectable on/off time controls. very cool.

#103.1.1 peter on 2009-06-18 12:51

Why would you want to turn the pump on and off every 15 minutes or so?

You'll transfer much more energy to the pool if you run it constantly while the sun is up.

#103.1.2 Ken on 2009-06-18 14:10

no actually it doesn't. after about 10 minutes or so the water coming out is about the same temperature as the water going in. remember the poly used for the pipe is by it's nature an insulator, not a very good conductor for transfer of heat. so leaving it run 15/15minutes on/off gives the water a chance to heat up in the collector and gives the 12 volt solar panel (remember it's only a 15 watt model) a chance to pump some juice back into the battery. I want the batt to last all season long on the one charge. the pump draws about 14 amps so the battery would'nt last long running the pump continuosly during sunny periods.

#103.1.2.1 peter on 2009-06-18 16:07

Peter, others on this forum can explain better in scientific terms, but leaving the system to run will transfer more heat than turning it off and on repeatedly.

My system currently yields 2-3 degrees increase in water temp while running. It's not much but that constant 2-3 deg will transfer a LOT more heat than if I turned it on and off to get a larger, momentary increase.

The warmer your piping/water is, the less heat it is absorbing. I hope someone who knows the BTUs and math formulas can explain it betterFPVH

#103.1.2.1.1 Tim Ellis on 2009-06-19 00:50

one added note . today june 19th, it's cloudy and cool. just did a little test. pool temp. 22.2 deg C. heater on, output temp jumped to 25.3 C. for about 2 minutes than slowly began to fall to 22.4 C. the same holds true on hot sunny days except it takes about 10 t0 15 minutes for the temp to drop to near ambient pool temp. I have considered installing a valve to slow the flow of water cominng out of the pump but determined that would put undo strain on the pump motor. so again thanks for the opinions and suggestions but seems to be working very well as is. only problem,yesyerday i forgot to put the blanket on and it lost about 5 degrees C since it's been cloudy and raining since yesterday morning. Oh Well!!!

#103.1.2.1.1.1 peter on 2009-06-19 15:29

Your solar heater will be much more efficient if you run water through it continuously. The same amount of solar energy hits the tubing regardless of whether the water is flowing through the tubing or not. However, if you have continuous flow, almost all of the energy absorbed by the tubing is transferred to the pool. If you have intermittent flow, you will get a larger temperature rise when the flow is stopped, however you will lose a lot of the energy to the surrounding air.

If the limiting factor is the size of your electrical solar panel, and you don't want to increase it's size, you would be better off having a smaller pump that draws less current than the continuous output of your electrical solar panel.

#103.1.2.1.2 Ken on 2009-06-19 03:42

i would be happy to connect a larger solar panel or a smaller pump. a panel able to run the exsiting pump is in the neighborhood of $700.00 (no thank you) and a lower amp pumps (80$ and up)are only designed to run intermittently not continuously. I have measured the water temp going in and coming out after 10 minutes running and there is about a 1/2 to 1 degree difference compared to the 145 degree jump if it's left off for 15mins. or so. my panel is exactly the same as the one in the photo @ the top of the page. Now if i was to substitute the poly pipe for stainless steel then the results would be different. stainless is an excellent heat conductor but as i wrote before the poly is by it's molecular nature an insulator not a conductor. also a minor factor is the noise of the pump. I have managed to muffle it but it is a bit annoying hearing the whine of the impeller so intermittent operation is more tolerable. I am considering building an insulated enclosure that will use phase inversion sound amplification cancel the noise of the pump but i think after the $ i've spent so far (350.00)give or take. that will be a project for next year. and to let everyone know in 2 days of sunny weather water temp has jumped almost 10 degrees f. between the heater and the brown liner i had installed last year so i think for what the results i'm getting "as is" i'll leave well enough alone thanks!

#103.1.2.1.2.1 peter on 2009-06-19 14:32

~what about using new aftermarket auto radiators? they are black aluminum finned and I believe copper cored? and would be easy to plumb together.they are made to transfer heat and cost about $60 ( for a dodge caravan 3.0 engine, smaller sizes are cheaper)delivered on ebay...anyhow just thinking it would work pretty good.....Wayne

#104 Wayne on 2009-05-27 07:26

not a good idea if it's copper cored since the copper will leach into the chloronated water amd cause disclouration, but to be sure ask a reputable pool service department person.

#104.1 peter (Link) on 2009-05-27 13:49

Can anyone tell me if you can just "t" back into the return to avoid having the hose hanging over the side of the pool?

#105 Henry on 2009-05-27 15:50

First off kick butt idea. I'm just about done building mine. Ran out of clamps last night and I need another 100 feet of hose but this should work great.

Henery,

I come out of my filter have a T then a Valve then another T then the pool.

With the Valve in the middle of the Ts I can control how much flow I have going through the heater with out it reverting to taking the path of least resistance. Also, this way I don't have a hose hanging in my pool. The water just returns right into the same line that has always gone to the pool. In theory I'm pretty sure this should work but I won't know for sure until this weekend when I get it done and hooked up.

I also found some think plastic (clear). The stuff you would hang over windows or doorways if you were painting or texturing a room. Hopefully this will reduce heat loss through convection. I don't know how much UV heat I'll lose with the plastic but I bet the trade off is worth it.

#105.1 Eric on 2009-05-28 16:03

As an introduction into another idea I have, below you will find a redneck pool heater that I found just too funny as well as effective.

"I've also built something similar to the "redneck pool heater". In my case I took a old car radiator (aluminum) and placed it over my fire pit. Nearly 100% of the heat produced by the fire was transferred to the core area, with the top side of the core being cool to the touch. The hardest part was keeping the fire burning all day! I think if I was burning wood pellets instead of scrap lumber I might have had better luck. "

Ok, so after reading that I got an idea. Most of us are probably aware how hot the pump motors get running all day out in the heat. There is an awful lot of electricity being turned into heat. My idea was to make a little well insulated box clam shell with some clamps to seal it up. Place the pump motor in it with the fan blowing through a small motorcycle oil cooler.

Stupid?

#105.1.1 Eric on 2009-05-28 20:10

Rob, great site! I'm building something very similar to yours, but where did you get the 1 1/2 to 1/2 (or 3/4) Tee?

I cant find anything like that, and it's delaying my project

#106 Tim on 2009-05-29 02:00

I just finished fabricating my heater. I found a GREAT little pump at Harbor Freight for $ 40. and used PVC connections to run hose from the inlet and outlet ports. Overall, I have a total of $ 134 in parts (Black rubber hose was at HF also!) and about 6 hours of time...All the connections (T valves, adapters, etc) are available at Lowes or Home Depot...FYI do NOT use CPVC (commercial grade) stick with the regular white pvc...easy to use and glue!

#106.1 John T on 2009-06-03 22:22

Quick Question,

Some people seem to want to feel hot (or at least wamer) water coming out of the heater.

Now it seems to me that all your doing with this is turning photons into heat. If that's the case it shouldn't matter how fast the water is going. As a matter of fact the more water the better so your not losing that energy as radiant heat and sucking it all into the water and out into the pool. Correct?

In short the cooler you can keep the pipes in your heater the more efficiently you are transferring the heat to the water, right?

#107 Eric on 2009-05-29 21:48

great site and thread!!! tons of info but I am unsure of what I would need for my pool. I have an 18x36 21,500 gal pool in southern NH, that has been stuck at 67degrees for the past 45days. I would like to use a separate pump if possible to run the system. What should i use for a pump and how many coils and length of coils should i use?

I will post pics of my pool setup in regards to house and garage location vs pool.

#108 justin on 2009-06-02 22:32

Great info here. I have a decent sized inground pool and have been looking at solar. I'm going to give it whirl, but perhaps with some modifications to try to enhance the efficiency of the heater after reading design of solar water heaters.

I am thinking of covering a fairly tight circle of 1/2" PEX hose with a metal plate (prob aluminum) and filling in the gaps between the two with silicon caulk to maximize the heat transmission. I'm also going to glaze the collector. Why isn't glazing in this situation a good idea? Couldn't we get away with much less hose and fewer "modules" and get the same desired temp rise, especially if the ambient temperature is relatively low? The additional cost for my modifications and labor will be reasonably small if I can get additional use of the pool without needing to use my natural gas heater.

#109 Bob on 2009-06-03 01:32

I like this idea and am starting this weekend. The whole idea of slowing the water down does not make sense to me though. I am no science guy by any means but if you are covering the unit with something so the wind doesn't pick up the heat and take it away, wouldn't you want to take as much of the heat and get it into the pool as fast as you can before the wind gets it. There has to be one of those formulas that I wrote on my hand in science class for this.

#110 Henry Bruinink on 2009-06-05 12:38

I'm with you. Why not use 1 1/2 inch hose to match what's on the pool already? Won't the water flow nicely with the existing pump (1hp w/sand filter)? My idea would be to coil the 1 1/2" tubing (black) and cover with a sheet of black Tar paper (or would that melt the hose?), connect between the filter & return, wouldn't this work also? I don't think it would tax the pump either. I have an 18' above ground pool.

Jump in here & tell me if you think this would work or expand on my idea! I appreciate the feedback. Thanks,
Dawn

#110.1 Dawn on 2009-06-10 14:05

Dawn, the reason you don't want to use 1 1/2 inch piping is because there is a lot more "water in the midde" of the pipe that isnt exposed to the heated plastic outsides of the pipe.

I just finished my first system, which is still a bit un-finished. You can see what I did in these pictures. The pipe (3 lengths of 1/2" black) cost $11 each at Home Depot. All the fittings were sourced at Home Depot too. I have a total of about $50 in the system so far.

It's just a small 12' pop-up pool, but on a full-sun day it warms the pool up about 5 degrees.

http://s66.photobucket.com/albums/h266/tim126/pool/

#110.1.1 Tim Ellis on 2009-06-11 16:55

Tim, I can't even log into photobucket, I have an account but my computer won't let me, not a secure site. Can you send me the pictures? what kind of hose did you use? 1/2" seems so small, won't that kill my pump or no? (kinda like stuffing 10 lbs of crap in a 5lb bag!) You know more about it than I do!
Thanks.

Dawn

#110.2 Dawn on 2009-06-11 20:01

Try going to the pictures directly

http://i66.photobucket.com/albums/h266/tim126/pool/IMG_6752.jpg

http://i66.photobucket.com/albums/h266/tim126/pool/IMG_6753.jpg

http://i66.photobucket.com/albums/h266/tim126/pool/IMG_6754.jpg

http://i66.photobucket.com/albums/h266/tim126/pool/IMG_6757.jpg

#110.2.1 Tim Ellis on 2009-06-11 22:16

I am in the process of setting up 2 collectors for an 18 ft round 52in pool with each collector having 250 ft 1/2 in black pipe. I want to use a dedicated pump, would a small pond pump be too small, could I hook the 2 collectors together and run the water through both and then out or should I keep them seperate and run a manifold with 2 separate lines to both and then out, I would lay on my deck and have a 4ft run up to the top of the pool for the pump as well. Would a small set pump be better. Any feedback would be great. Yesterday will re topping the pool for the season, the tap water was 14 degrees I hooked the water to 200 feet of piping and ran the water slowly and the water going into the pool was 22 degrees, I know the increse won,t be as good circulated the pool water but even a 4 degree increase would make me happy. Any comments would greatly help out. Sandra

#111 sandra on 2009-06-07 18:03

I just hooked up a solar coil almost identical to the one Rob built at the very beginning of this post. And before I go any further, I want to thank Rob and all the contributors for all the excellent information here. Talk about standing on the shoulders of giants!
My situation is a bit different and in a nutshell here are the facts:
I have a 15x30 above ground pool enclosed in a 32 x 48 foot greenhouse so I have no problems with wind cooling things down. 11,000 gallons or about 91,740 pounds of water. My coil has about 180 feet of 1/2" black pipe on a solid back plumbed just like Robs, insulated from the outlet to the pool.
First day of use I set the flow rate at about 6 liters/minute (1.585 gal/minute) and was getting about a 5 degree F rise in temp at the outlet.
What I'd like to have someone double check here for me is what kind of BTU output I received per hour. My calculation comes up with approx. 3950 BTUs per hour and with 91740 pounds of water I would need about 23 hours to bring up the temp. 1 degree F. Does that sound right?
In actuality I ran the coil from 7 AM to 4 PM. I live in Maine, had good sun all day long. The temperature outside went from 58 F to a high of 72. The temp. in the greenhouse went from 70 F to over 100 F (and the 100 temp was from 11AM to 4PM) Yes!...it gets very hot in the greenhouse. The pool temp. went from 72F to 78F at the end of the day at 4PM so I had a significant rise in pool temp, but I'm figuring that most of that came from the hot temps in the greenhouse and of course the sun blazing down on the surface of the pool. Unless I'm missing something, it looks like the solar coil is not contributing much to the rise in temp. But being no whiz at physics I'd love to have someone straighten me out on this. Any help would be greatly appreciated.

#112 Pat on 2009-06-14 16:24

Your BTU calculations are right on. On a sunny day, the sun on the pool will contribute much more to the temperature rise than the solar heater will, unless of course you have a very large solar heater.

My heater has 275 feet of 1/2"black poly tubing and it also contributes a relatively small amount to the temperature rise of my 18 foot AG pool. I believe a good solar cover is the best bang for your buck as it helps to heat up the water on sunny days and keeps heat in by reducing evaporation and insulating the surface of the water.

#112.1 Ken on 2009-06-15 01:49

Thanks Ken...that's what I thought, but I figure any heat I add is doing some good. The greenhouse really does help a lot as it captures so much heat when the sun is shining plus it has the added bonus of keeping out the black flies and mosquitos.

I may look into parabolic trough heaters since I could run a couple of 20 foot runs along the south side of the pool. Any thoughts on these? They sound good but haven't been able to find any data as how many BTUs they generate. Thanks again for the reply.

#112.1.1 Pat on 2009-06-15 13:05

Hello All.

First off; a big thanks to those who have contributed with great info that inspired me to build my own solar heater.

I'll give the details of the heater I made, then I have a question for those who are in the know.

Pool =20x40 inground 9' deep end
Location = Lindsay (Southern) Ontario Canada

Set up
Two 8'x8' panels made from 1/2" plywood painted flat black and framed with 2x4s.
620' of 1/2 poly pipe coiled tightly in each panel and panels are installed horizontaly on top of my pool shed roof.
Both panels are covered with 6mm poly vapor barrier.
One faces slightly east and the other slightly west. They both catch some good sunshine between 11am and 7 pm.
Thermometers installed inside both panels read approx 120 degrees when the sun is shining bright.
Circulation is provided by teeing into the output of the 1hp pool pump before the sand filter with a ball valve to turn heater on and off.
Temp increase of water is approx 10 degrees after it has gone through the heater
Flow rate (with valve wide open) is 5 litres per minute.

My question is, "at 5 litres per minute, is the solar heaters' flow rate enough to really change the temp of the pool water in any substantial way"? My pool has approximatly 130,000 litres of water in it, and I don' think that a 5 lpm flow rate is going to do anything. I will probably install a 3 way valve in order to force more water through the solar panel and increase my flow rate, but thought I would ask the opinions of others who have already made and experimented with their own heaters.

Thanks in advance for any help! It will be much appreciated!

James Cadigan

#113 James Cadigan on 2009-06-15 02:49

Hi James...I wondered the same thing with my setup (see post #112) and using your figures here's what I've come up with. At 130,000 Liters you have about 34,342 gallons of water and at 8.33 pounds per gallon that comes out to 286,068 pounds of water you're trying to heat. Referring back to post #24 by Danny, and remembering that it takes 1 BTU to raise 1 pound of water 1 degree F, you will need to provide 286,068 BTUs to raise the temperature of your pool just 1 degree F. Using the temperature rise you gave and your flow rate converted to gal/minute and then plugging it into the formula:

(10 degree F rise)*(1.32 gal/minute flow) (8.33 pounds/gal) (60 minutes) = 6,597 BTUs per hour

Doing the math, you would need approximately 43 hours of production from your coil to raise the temp of your pool 1 degree F.
I've discovered that a nice sunny day shining on the pool is much more effective at raising the temp of the pool, although every little bit helps in my opinion. And to underscore what several people have said, a pool cover helps a lot in keeping what heat you've gained. I'm investigating parabolic troughs to see if they might be feasible in producing more BTUs as the surface area of sunshine collected and concentrated is greater than i'm getting with my coil. Hope this helps.

#113.1 Pat on 2009-06-23 01:17

Hi I have had a solar panel installation fitted for my swimming pool and I notice that they have had a flow switch fitted on it to stop the power from the solar panels destroying the plastic pipe work if the main filtration pump fails. Can the solar panels really heat the fluid up to these temperatures and can your DIY solar pools heat to a similar temperature and if so do you have flow switches installed?

#114 annie (Link) on 2009-06-16 11:30

For anyone using a dedicated pump, what are you using? I have looked at pond pumps, most don,t want chlorinated water, some are to large and very expensive, some small pool pumps may do but I,m not sure if they will do. I think the combination of my solar blanket which does heat well but not quite enough along with a small pump circulated the water through the collectors will be better than keeping the water all circulating throughout the whole pool, thus not using the solar blanket to the best use. Anyone have any ideas. I thought I did pick up a good one, a transfer pump with garden hose attachment but you had to prime each time and then I would not be able to eventually hook to a timer. Sandy

#115 sandra on 2009-06-17 19:24

sandra, if your using a transfer pump,one that takes garden hose (which is what i am using) make sure you leave each hose (input and output) submerged. (see my previous post #103) my pump is a 12volt model for draining ponds , rv'ing etc. i live in canada and picked it up at canadian tire on sale for 59 bucks. its connected to an 850 cca deepcycle/cranking marine battery kept topped up by a 12 volt 15 watt solar panel. the 12 volt timer was 25 bucks and easy to wire up to system using a 30 amp 12volt automotive 5pin relay to handle the amp draw of the pump.
as long as you keep both hoses in the pool water pressure should keep the system primed. and the timer can run everything unattended. good luck.

#115.1 peter on 2009-06-18 01:10

After spending several days reading this thread I got some great ideas and decided to build my own solar heater. It's around 7 feet in diameter.

I wanted to try to stay away from wood and metal since this will be outside and I want it to last as long as possible.

For the frame I made an x brace out of pvc pipe and then got zip ties (uv safe) to attach the black pipe to the x frame.

I went with 200 feet of 1 1/4 inch pipe which is larger than most people use but I was concerned with making sure I didn't put to much pressure on my pool pump.

Here's a link to a picture of the finished product:
http://www.twitpic.com/83f5j

Depending on how well this works I may look into getting a smaller pump to run just the solar.

Thanks everyone for giving me some great ideas.

#116 thelber on 2009-06-22 15:32

Thanks for such a great write up for a very near free pool heater.

Also I have a few suggestion for you to add to your system that should really benefit your system in 3 ways. If you were to find a way to take the hose right after the shut off valve and first go to a hose that is somehow coiled around the pump motor then out to your solar heater setup you will first cool the pump motor which should allow it to run its best and start the heating process on your sloar heater system by absorbing the heat from the motor. And lastly i know you have stated in your original post the you intend on doing something with the return hose, Can i suggest if you havent done the job yet to possibly think about just tee'n it back into the system coming off a short length of hose right away from the return inlet. This will do the obvious without having to worry about another hose in your pool that can get knocked loose during play. I hope this makes sense and if it was already covered sorry for the re post.
Also if this was already brought up and then shot down Could someone please direct me to the info as to why? Im always willing to learn.

#117 Rick Gonzales on 2009-06-23 03:26

One thing that has not really been brought up...

I use a solar cover and the top 1' of the pool is always the warmest. My skimmer pulls in this warmer water and that is what will run through my hose.

Wouldn't this affect how much heat the water in the hose can absorb (if it's already warm)? Would it be better if I was pumping the colder water (from the bottom of the pool) through the solar heating coils?

Thanks for the information here...very informative. It has generated my interest in building one this weekend.

#118 Eric on 2009-06-24 15:14

I have 2 heater coils with approx 400' 1/2 inch tubing mounted on my roof. The intake for the heater is off the return hose from the filter pump to the pool (Intex pump that came with the pool). If I close the pool return, the pump will continue to put water thru the heater (tho sometimes gives the low flow rate error). But if I open the pool return, the heater flow drops to a trickle, then stops.

Overnight, I seem to get an airlock that needs to be flushed out each morning which makes it useless to have the whole thing on a timer.

Anyone have any suggestions to avoid the constant air lock problem? And the problem with the heater flow crapping out when the pool return is open?

Thanks.

#119 Susan on 2009-06-29 19:42

Hi , awesome page , lots of great ideas and thoughts . Here's what i am doing , it's basically the same as Rob's but bigger . I plan on using 2 4x8 sheets of plywood framed in 2x4's and covered in black ashphalt shingles. I'm not sure how much pipe it will take to fill this area coiled but i have a buddy in a plumbing supply store who has got me 900 ft of half inch black water pipe for about .21cents a foot , i'm thinking this will be plenty of pipe based on Rob using 200 ft for quarter the area . I have a 3 way diverter from my pool guy for 15 .00 and will put that in between the filter and the pool with return hanging in front of the jet. I plan to cover framework with uv resistant plexiglass . Does anyone see any problems with this ? Please respond if you do it would be greatly appreciated. I'll let you all know how it goes . I mainly stuck with Rob's idea and used a few more from the posts.
Thks
Gavin

#120 Gavin Leggate on 2009-07-08 17:53

If you are working with a 4x8 frame, I'd suggest making 2 parallel coils, so the flow will be half in each (and parallel the two panels, possibly). Having the parallel paths will allow most (possibly all) of the water flow through the heaters, maximizing the heat transfer.

#120.1 Rob A on 2009-07-22 12:58

I have an Intex 15'x 48" above ground pool. Would like to construct one of these to heat the pool. What kind of fitting do I use to go from the 1 1/2" hose to the black irragation hose? Do I have to use the ball valve or is there something else I could look for? Wandered around plumbing section at Menards for about an hour today, but couldn't find anything that would do the trick.

Thanks.

#120.1.1 Rebecca on 2009-07-29 02:14

Hi Rebecca,
Go to Home Depot or Lowe's an tell the plumbing guys what you want to do. I had the same questions....but when I went, they helped me put together the following: 1 1/4" ball valve, 1.25" to 1" reducer, 1" to 3/4" reducer, 3/4" to 1/2" reducer, then a grey threaded PVC piece that goes into the 1/2 " irrigation hose. To go out, you simply do the opposite. Buy enough teflon tape to cover all of the reductions. Email ccrawford58@rochester.rr.com if you have questions.
Chad

#120.1.1.1 Chad on 2011-06-07 20:34

I live in Tadoussac Quebec, which has a very short summer. This year I installed my own homemade solar pool heater. My installation has the following improvements, I beleive compared to those I have seen here. It's 1/2inch black PVC hose ( 0,07Cents per foot) aproximately 300 feet coiled in two inline spirals laid on a 4X8 plywood sheet with 2x4 framing all around. The sides and the bottom however are aluminium paper in order to reflect back the sun rays towards the piping, instead of absorbing the rays, which is what a flat black paint will do. Plus, I've covered boxed the spirals with a 4X8 sheet of Lexan 1/8'' to create a greenhouse effect. It's mounted on the roof angled around 35 degrees south. I use a 1/4 HP inline gear pump (120v) to circulate the water. If I stop the flow for 15 minutes, I've measured à 30 degrees Celcius plus differential! One time I stopped the water for about 45 minutes, when I started the flow again, the hose melted and balooned and burst at several spots! Do not repeat! he he! It's quite the oven and works great! Total cost; 135$ canadian. It's great!

#121 Vincent G on 2009-07-10 00:11

Will a 2' by 20' sunheater work with a intex 2000 gallon per hour filter pump.

Does it depend on the size of the tubing in the sunheater, can't tell from the picture
http://smartpool.com/website/sunheater220.html

I would be placing it right beside the pool.

#122 Nick on 2009-07-10 22:55

Should have asked if the answer is no, could i run a small dedicated pump to drive the sunheaters, a small intex pump maybe?.

What size pump would be needed to run a 4' X 20' panel?

#122.1 Nick on 2009-07-11 01:27

I live in Calgary and I run 1000' of 1/2 inch poly I bought from the sprinkler warehouse. It cost about 100$ to get here including shipping. I built it similar to the one at this guys website http://www.sunfree.net/id27.htm. (Plans are on http://www.sunfree.net/HTMLobj-568/ONE.pdf). I put all the hose on the ground where it gets alot of sun. I tried putting it on the roof but got sick of the hoses constantly kinking up after a strong wind. My pump also had trouble pumping it up the roof, and with the slant in the roof it was alot of up-down flow of the water in the hose. Now that its on the ground it flows quite nice. I have played around with the flow of water quite a bit, not quite sure where the sweetspot is. I believe that pumping water through the pipes as fast as possible to be the best results during peak hours.

I also use a cover and a solar heater.

I run the solar system usually during the day when its sunny. I have noticed temperatures at least 10-20 degrees F higher coming out of the hoses when it is forced through the pipes. Its working quite well. I am going to try putting black or reflective material under the poly pipe and cover it with clear plastic and see if its any better

Right now my pool is at 80 deg F, and its been sunny for a few days. I had trouble keeping it up above 72 for a while there because of the poor weather. I may try insulating the pool with bubble wrap, i heard that helps.

#123 Marc on 2009-07-21 20:53

Hi Mark.
I am wondering if you tried using a timer rather than full flow.
I have 4 coils on my shed roof totalling 1300 feet of 1/2 ipex white stripe pipe the shed sees sun all day.
I have teed off after the filter side of my filter pump and run a 3.3 gpm 120 volt RV pump to pump the water through the heater coils.
The pool filter pump and the RV pump are connected to 2 cascaded digital timers that allow for 40 on/off events.
The timed events are 5 minutes on and 5 minutes off during the day.
I used the timers with the thought that a longer dwell time would heat the water to a higher temperature and the pump running at 3.3 gpm every 5 minutes would pass more water than lower flow all the time.
I have not tried running the pump all the time.
I cannot valve down the RV pump which pumps at 45psi.
The water does come out much warmer than it goes in even after only 5 minutes of dwell time in the pipe.
Your thoughts??

#123.1 andy on 2009-07-27 17:27

hey Andy,

I know it seems counter intuitive but the colder you can keep your pipes the more efficiently you're transferring the Sun energy into the water. Cold water conducts the heat better than hot water does.

Don't think of it as warm and cold, think of it as energy and the lack of. It doesn't matter that the water doesn't feel warm coming out, your still transferring that energy into the pool.

#123.1.1 Eric on 2009-07-27 20:10

I am not sure you have answered my question.

Will my present set up as described heat my pool better than running the pump full time or on a 5 minute rotation?

Thanks

#123.1.1.1 andy on 2009-07-28 02:55

Andy, From reading the previous comments your would get a better overall heating result from running constantly.

#123.1.1.1.1 Tom on 2010-07-05 11:25

Just made a similar panel myself. I used 200' of 1/2" polydrip line coiled on a 4x4 piece of plywood. I checked it last sunday and running about 1 gal/minute I was getting a 5 F higher temp on the outlet. That works out to about 40 BTUs per minute or the equivalent of a 700 watt heater. I'm building a second one, using the other half of the plywood sheet and hope to get it hooked up this afternoon. We are in for some hot days ahead so I hope to take advantage of it.

#124 mark on 2009-07-22 17:57

update - I got the other panel installed and at 3 pm on a sunny day I am getting a 12-14 degree F bump at about 1.5 gal/minute.

#124.1 mark on 2009-07-31 19:31

Mark, I'm blown away by your results, pretty unreal, sadly I made a very valiant attempt to create one panel and my intex pump, 1000 gal/hour couldn't push 200' of poly, period.

What kind of pump do you have and what part of the country do you live, wondering if your weather is any better than edmonton.

Just curious, I ended up buying a solar panel with glass evacuated tubes, wse47 unit from saskatoon.

#124.1.1 John on 2009-08-08 14:19

I have a 30' round abouve ground pool. Any suggestions on how wide and long of pipe I would need?

#125 Craig on 2009-08-10 00:33

for solar pool heat, i built a 22' x22' roof over my pool equipment angled at 30 degrees, on this i installed 8 2' x 20' plastic panels sold on ebay as solar pool heaters the first year they heated my 15' x 30' inground at an increase of 8 degrees a day supplied by my filter pump 9am untill 4pm,,,, the second year the panels started leaking,,,now i have 65 1 1/2 x 1/2 t's glued into a manifold running verticaly on both sides connected by 65 20' 1/2" pvc horizontally all painted flat black,, now i get temp rise of 12 degrees a day,, i have reached 92 degrees pool water in december with a cover ,,location northern fl.

#126 john on 2009-09-04 10:24

Good day,

I would like to know. I have a 15,000 liter pool. I would like to know how to calculate if my system will be effective or not. If my system can return water that is 4 degrees hotter than the pool water and at a rate of 1,000 liters per hour for 6 hours per day, would it be effectice? Is there a calcualtion I could use so I can guage the temperature increase I could expect based on liters warmed liters returned to pool per hour and depending on how many degreess hotter this water is than the pool water?

#127 Anonymous on 2009-09-07 11:25

Well in 6 hours, you would put 6000 litres of heated water into the pool. That would raise the pool temperature by-
(6000/15000)x 4 degrees = 1.6 degrees

Please note that even without a solar heater, the sun will probably warm your pool more than your solar heater will, especially if you have a solar cover.

#127.1 Ken on 2009-09-07 15:58

This was a very smart invention and I think that you can apply it to larger pools as well, with a larger garden hose. But as I read here: http://www.squidoo.com/diysolarpoolheater the main thing you should tink of first is to get a good cover for your pool, because it's basically radiating heat all the time. the surrounding air will cool this instantly if you don't have a good cover.

You can do these covers yourself as well and I think a lot of guides exists on the internet. You can always checkout doityourself.com forum for advice.

#128 David on 2009-09-16 09:06

Your system looks fantastic and definitely worth a try. My only problem is I do not have enough space near my pool that is in the sun and would like to mount it on my house roof. I am not worried about the plumbing of the system into the filter, but am concerned at how I would attach it to the roof. I have cement roof tiles, similar to the spanish half round ones and I am not sure how to attached the panel to the roof. I am not keen on drilling into the beams under the tiles to fix the panel in place and where I live I get a lot of wind, over 20 miles per hour on a regular basis so for it to be free standing / luying on the roof I am sure it will fall off, also the roof is at about 20 degree angle. Please can someone help me / advise me?

#129 Ross on 2009-11-24 11:25

Hi am from Kyoto, Japan

Here using solar cell as heating system is increasing popular. I think this technology will work well if we live in equator region.

I have solar heater for pool of my community that have 4 4x8 sheets. I will use your article as guide when my solar pool heater get trouble.

Thank you.

#130 Solar pool Holic (Link) on 2009-12-23 22:09

Rob et al,

Thank you all for the awesome information posed here over the last several years! I have been pondering this type of design for a while now, and now that I see others have been making it happen I now have my winter project.

I have an Intex 12'x24'x48" above ground pool that got very little use this last summer because it was unseasonably cold last summer and I want to make sure that doesn't happen again. I live in SW Michigan.

There are a lot of really "hot" design concepts posted here, and I will probably use the one that started it all (Rob's), but through this entire thread (I spent 2 days reading), I never got a definitive answer to the questions on the hose array (plywood) backing from the experts- just questions like mine.

Should it be black plywood, or reflective material of some sort? It would seem to me that sunlight that passes through the gaps between hose coils would be better reflected back to the hoses for re-absorption than for heating some random background medium for ambient (convection) re-admission.

Am I on track here Rob, or off on a tangent?

By the way, I will become an active participant in this blog and return to everyone the results of my success- I just need to wait for the Michigan winter to subside first...

Thank you all!!!

#131 Trey on 2009-12-30 06:30

We're just gathering the parts to make a 4' square panel. We're using 4mm ID irrigation pipe. 10 runs from/to manifolds that input/output on 13mm tubing.
Spiral is being built into the underside of a plastic pallet. This will mean that it already has the base and walls. Top will be enclosed with clear plastic sheeting initially.
Pumped via solar panel and pump.

Anyway, has anyone who's used this type of tubing experimented with gently rubbing the gloss finish off the tubing? Would this help with absorption at all? Enough to warrant doing it to aprox 450 feet of the stuff?

#132 Jonny Bendo (Link) on 2010-03-03 15:07

Any chance you found a suitable solar panel and pump for your project? That was what I was hoping for too but wasn't sure what would work without spending an arm and a leg.

#132.1 Jeff on 2010-04-02 11:37

No... not yet.
I've got bigger issues with the pool at the moment... the concrete walls have delaminated (sigh)

In the meantime, I've acquired a small collection of cast off solar panels and hope to use them to either drive the pump directly or charge a battery which drives the pump.

Anyone have thoughts on that?

First, however, I need to get a pool which actually needs heating. (Fortunately, last summer was a good year not to have a pool... hopefully this year'll be warmer and sunnier)

Al

#132.1.1 alc on 2010-04-02 19:16

I finally have my solar pool heater hooked up and running successfully. Thanks for everyone's ideas and comments.

On mine I used a few hundred feet of the black irrigation tubing inside the insulated box. I'm powering it by an 8 watt solar pump (with battery) with a 2m water max lift and 800 l/h flow. It didn't have enough power to push the water through the tubing initially, but that wasn't a problem since I could just use the hose to start it off. Now whenever it's sunny we just go out and turn the pump on and let it flow. It appears to have a decent 5 degree F difference which seems good to me for being completely free after the initial costs.

My only concern is the condensation that forms under the glass that is caulked in on top of my box. Is this normal or do I need to seal this better? Any ideas? Thanks...

#132.1.1.1 Jeff on 2010-06-30 12:43

I've finished building two units similar to Brian's (#52)
Now I need to add a pump, and I need some help. I'd like to avoid using the main pool pump as it only runs for a couple hours in the winter for filtration, but I want the solar system to run for 7 hours.
Can anyone suggest a suitable pump given the following data:
1. drawing water from the pool thru 1/2" irrigation pipe
2. need to pump to the top of the first coil at 8'
3. need to push through appx. 800' of 1/2" irrigation pipe before returning to the pool.

#133 DavidP on 2010-03-26 18:13

OK....I am going to takle this soon.

Questions.

Question #1

Garden Hose vs. PVC ?

Black Gardent Hose $35 for 100 ft
PVC $17 for 100 ft

Would people agree or disagree with my statements?

Hose more expensive but seems more durable and thicker which would hold more heat. It also seems easier to work with.

Question #2

I plan to make 4-6 100 ft coils. What size pump should I get? 340 gpm enough? too much? does it matter?

Question #3

What is the best thickness of PVC? it seems like 1/2 inch is most popular.

Thank you for your time.

Lee

#134 Lee on 2010-04-05 17:00

First of all, the tubing most people use is irrigation poly which is polyethylene, not PVC. I personally prefer poly tubing but see no reason why black garden hose wouldn't work. The garden hose would be easier to work with although I doubt it would be more durable than poly.

With regards to flow rate, you don't need a lot- 1 or 2 GPM is sufficient. Any more and the friction loss through your piping will be get high. For example, the friction loss through 600 feet of 1/2" diameter pipe is approximately 24 feet. The friction loss at 2 GPM would be 87 feet so the friction loss increases dramatically with an increase in flow.

If you plan on using a dedicated pump for your solar heating system, I would recommend you buy a small pump with an approximate capacity of 1 GPM at 30 feet of head.

If you want to reduce the friction loss through the tubing, you could install the panels in parallel instead of in series. This would significantly reduce the friction loss in the system, or it would allow you to increase the total flow while maintaining a lower friction loss.

I don't know if the thickness of the tubing is really that critical. Most people use irrigation tubing which has a pretty thin wall thickness. You have to be careful not to kink it while installing it but once it's installed the wall thickness isn't an issue.

#134.1 Ken on 2010-04-05 18:31

I have a question. Could you not fill in the gaps for the configuration the Brian did with black roofing tar. Would this help the pipes get hotter?

#134.1.1 David on 2010-04-06 00:00

A correction to my previous post-

I meant to say the friction loss through 600 feet of 1/2" diameter pipe is approximately 24 feet at 1 GPM (I left out the 1 GPM).

#134.1.2 Ken on 2010-04-06 20:11

If a small pump would do could a solar fountain/pond pump work. The largest I see around are 8 Watts with the following specs:
Water Intake: maximum intake 2 gallons per minute
Water lift Max: 2m Water flow max: 800L/h

Would this be a possibility or just not be powerful enough to push the water through the entire hose?

If not, does anyone have any links to good pumps that are ideal for this project? I have a 1/6 HP pump used to remove water off the cover. Solar just seems ideal since it can run as long as there's sun without worrying about the electric usage.

Any input is appreciated

#134.1.3 Jeff on 2010-04-08 20:22

It would probably work, but to know for sure, you would need some additional information such as tubing diameter and total length. You would also need to have the pump curve. It's most likely the max. specified flow rate for the pump is at zero or minimal lift and the max lift is at zero or minimal flow.

The friction loss in 100 feet of 1/2" tubing at a flow rate of 0.5 GPM is only about 1.2 feet so it's quite possible you might achieve that flow rate with that pump. The only way to know for sure is to look at the pump curve. The longer the tubing, the lower the flow rate will be.

If the pump can only produce a maximum 2 m lift, you may have difficulty filling the solar panel if it is mounted above the pool. This is really not a problem as you can use a hose from your domestic water system, or your regular pool pump to initially fill the line. As long as the discharge end of the tubing is always submerged, the line will remain full, even when the pump is off.

I like the idea of a solar pump as it will automatically shut off when it is cloudy, unlike an electric powered pump. Although a higher flow rate may allow the solar heating system to operate more efficiently (less energy loss to the ambient air), it should still operate quite well at a flow rate in the order of 0.5 GPM, even though you may notice the temperature of the water entering the pool is quite warm.

#134.1.3.1 Ken on 2010-04-09 02:41

FYI...
I saw that several posters asked about the black pipe to use for a solar heater.
See below web address form the manufacturer.

http://www.ipexhomerite.com/Content/Common/7_0_Retailer_Locator/index.asp?results=1

If the link does not work go to .
http://www.ipexhomerite.com
Go to the home page after selecting your language and click on irrigation.
A retailer locator is available to find the pipe in your area.

The pipe I used is made in Canada by Ipex.
It is a thin wall polyethylene pipe.
It is used in lawn sprinkler systems and farm plumbing.
It is often called, Ipex white stripe.
I use 3/4 and 1/2 inch in my setup which is not complete yet.
I bought the pipe form Home Depot. It comes in 100 foot rolls and cost about $20 per roll.
I hope this helps.
Big A

#134.2 Big A on 2010-05-25 13:53

Hi Ken, I built a solar pool heater with two 4'x8'sheets of plywood for the base and appx. 700' of 1/2 irrigation tubing. the pump I'm using has the name Pacific Hydrostar on the box. Here is a link
http://www.harborfreight.com/cpi/ctaf/Category.taf?f=bylogo&logourl=Pacific%20Hydrostar.gif&brand=Pacific%20Hydrostar
I'm using the 1" clear water pump, cost $39.95, ITEM #01479
I'd like to use a solar pump in the future, but can't figure it out yet...
This pump puts out about 2.5 gallons per minute after going up to eight ft or so, then thru the 700' of tubing. Hope this helps

#135 DavidP on 2010-04-09 00:27

The first thing you need to do to assist in selecting a suitable pump is to produce a system head curve for your solar heating system. A system head curve shows the pressure (head) required to push the water though your solar heating system for a range of flow rates. You can either calculate the head loss in your system for a number of flow rates, or if you already have a system in place, you can measure the pressure required to produce various flow rates in your system. You then plot these points with flow rate on the horizontal axis and pressure (in feet) on the vertical axis. This is your system head curve. (This is a simplistic description on producing a system head curve so you may want to do a bit more research on it).

When you're evaluating pumps, make sure you get a pump curve for the pumps you are evaluating. Plot the pump curve on top of the system head curve you have produced. The point where the pump curve intersects the system head curve is the point where the pump will operate in your system (flow and head). Make sure this operating point is within the recommended operating range of the pump, and as close as possible to the pump's best efficiency point.

If you are considering a solar pump, I would recommend keeping the flow rate as low as possible, to keep the power requirements low. Flow rates in the order of 1 to 2 GPM should be adequate although you could probably get by with lower or higher flow rates.

#135.1 Ken on 2010-04-09 03:26

I'd like to cover my spiral coil of 1/2" irrigation tube attached to 4'x8'x3/4" sheet of plywood to keep the wind from stealing heat. Is there a consensus here on the best material for the price?

#136 DavidP on 2010-04-12 19:25

I just went and bought some heavy window plastic. I think it's the stuff you'd use on the outside of your house if you were gong to plastic your windows that way.

You only get about a season out of it, but it's cheap and I just use duct tape to hold it on.

It definitely keeps the wind from wicking away the heat. I've heard Plexiglas isn't a good option because it's opaque to ultraviolet light.

Anyway, that's just my cheap solution.

#136.1 Eric on 2010-04-12 21:45

Good Eric, thank you. Do you think it would effect efficiency if the clear plastic laid on top of the spiral coil. Else I could attach 2'x4's to the sides of the plywood and attach the plastic to it.

#137 DavidP on 2010-04-13 03:00

I'm not sure how you designed yours but mine looks pretty much identical to Rob's.

The only thing I changed was I put about a 5" (or so) long 2x4 in the middle of the coils with a bit of Styrofoam pool matting (the same kind of stuff you put under a Pergo floor) to cover the end. That way after you've stretched the plastic over your heater, the middle is higher than the sides. It keeps the rain from ponding on it. The Styrofoam matting is just to keep the sharp edges of the 2x4 from ripping through my plastic covering.

I just cut the piece so it's a little bigger than the rig, then just run a strip half on the plastic and half on the outside 2x4s. It works great and looks fine too. Make sure you get your plastic tight. If the wind blows and it's flopping around it won't last long.

You'll get about a season out of the plastic, before it gets brittle and rips. I just redo it every spring.

#137.1 Eric on 2010-04-13 18:52

Can you post some pictures

#137.1.1 DavidP on 2010-04-13 23:13

Hello Everyone,
I just spent 2 days reading the above and learned a lot. I am in the Algarve, southern Portugal with an annual average of 3000 sunshine hours the Algarve is one of Europe’s sunniest places (sunnier even than California). The summer months will see 12 hours of sunshine per day on average and almost no rain.
My pool is 10x5m and will have 40m2 for creating the solar panels.
During my research on the net I found a solar powered pump but what was interesting was the fact that the speed of the pump was by the power of the sun, so the temperature of the water would be optimalized. But I did loose the link and can not find it. Does any one have some link or information on this pump.
Thank you very much and I wish a nice future for this site.
Ludwig

#138 Ludwig on 2010-04-14 10:31

i biult one this morning it is not fancy but i am hoping it wil do the job. if i can figuire out how to upload pics i will put it on

#139 scooter on 2010-04-22 18:32

Right, 10 runs of 6mm dia irrigation tubing in a 10 way spiral on a 5' x 4' pallet works a treat.

Controller circuit will be a relay activated by a heat differential circuit. If the pool is cooler than the panel, the pump flows. Cost £6 and required little modification.

We're seeing around 250 litres an hour and on an OK-ish day of sunlight (in uk) was increasing output water temp by 2.5 degrees after we'd given it time to stabilise. Once panel is covered and days are warmer, I think this will be sufficient along with the solar cover.

#140 Jonny Bendo (Link) on 2010-04-26 16:18

Hi Jonny,
could you please break down the parts needed for a heat differential circuit and how it would be incorporated into the system?

#140.1 DavidP on 2010-04-26 16:59

Hi guys,

I am going to install this solar heater for my above ground pool. My connections are all hoses. Can someone tell me please what size Tee I will need?

Thank you,
Kevin

#141 Kevin on 2010-04-28 18:41

Hi

Have been reading all the excellent ideas here and keen to try my first go.
Living in the UK I am concerned that the payback time for a system would be too long. Ive tried to make a heater with stuff I have in my shed. Ive adapted a trickle down heater design from here http://www.jc-solarhomes.com/solar_thermal_roof.htm . Basically ive made a 16 x 4 panel on the south facing roof of my shed from black plastic damp proof membrane sheet and a couple of pipes. I have the DPC sheet folded over and battened down to make two layers on the roof with a 1“ pipe running inside it along the ridge. This pipe has lots of holes in it and the pool pump pushes water up through. The water trickles through the DPC layers and is collected by rainwater troughing at the bottom of the shed roof to go back in to the pool.
Its still a bit early to put my 21 x 12 x 4 oval above ground pool up yet. I have tested the system with a bin full of water on a sunny day of about 16 degrees c and the relatively small quantity of water got quite warm. My thinking is any heating (even a degree C or two) for little or no cost is worth a go. I was wondering if anybody else has had a go at something similar?
Mike

#142 Mike Steadman (Link) on 2010-05-03 19:04

Nice going. You should be praised for your efforts. My company SOLARHOT manufactures Solar Water Heating Systems would have loved to be of service to you.

We manufacture solar water heating to suit many purposes including domestic, pool heating and commercial uses.

Keep up to Good Work!

#143 SolarhotUSA (Link) on 2010-05-04 09:13

Anyone have any suggestions on inexpensive pumps to use? I am not sure I want to hook up to my already install poop pump just yet.

Thanks

#144 Wes on 2010-05-14 18:19

Good Day all:
I have a question.
I have a roof top solar pipe heater fpor my kids pool.
It uses just over 1200 feet of 1/2 inch black poly irrigation pipe from Home Depot.
It is plumbed into my return line after the sand filter.
There is a three way valve after the filter that allows the water to go back to the pool or through the solar pipe heater.
When the valve is turned to only go to the pool the pressure is around 10psi and lots of flow.
When the valve is set for solar heater the pressure rises to over 15 psi.
The problem is the pump dpoes not appear to be strong enough as the water does not come back out of the solar return end of the pipe.
There are 4 coils of poly pipe connected to one another and then back to the pool via a seperate line.
The coils are on my shed roof which is about 10 feet off the ground.
The shed is about 50 feet from the pool.
Is my pump too small.........
Thanks in advance

#145 Big A on 2010-05-24 21:17

First of all, you don't want to run your pool pump directly through your tubing. The amount of flow you will get through your tubing will be very small compared to the size of your pump. This means it will operate at a high head (pressure) using lots of energy and will also wreck your pump. You're better off using a smaller pump. If you want to use your pool pump, position your 3 way valve so most of the flow is going through the filter and a small amount (1 or 2 GPM) is going to the solar heater.

As far as your problem about getting no flow through your solar heater, with 15 psi discharge pressure, you should have adequate pressure to get the water up to the roof. I suspect air in the coils is blocking the flow. Did you leave any outlets on the downstream side of the coils to bleed the air off when you initially fill the coils? I installed a tee with a plug that I can remove to bleed off the air. Works fine.

#145.1 Ken on 2010-05-25 14:08

Ken - In my system I use a diversion valve to control the amount of water that flows though the tubing to avoid the issues with excessive back-pressure and potential pump damage. I don't think a separate pump is necessary. It may be more economical to run a separate, smaller pump, however.

#145.1.1 Rob A (Link) on 2010-05-25 14:51

Hi Ken:
I tried a bizarre trial using a garden hose and faucet.
I connected my garden hose up to my solar heater.
My municipal water supply is about 30 psi.
I ran it through the soalr pipe and bled out all the air.
I was very surprised at how hot the water got.
With the faucet on full it pushes water through the system at about 5 gpm.
I disonnected from the garden hose and reconnected to the pool pump and it did not work.
I broke down and bought a pony pump and plumbed it into the lines.
It is a water wizard model 360 utility pump.
Rated at 360 gph with zero feet of head.
It works and delivers about 3 gpm through the system.
The tempature rise is immense.
Just checked. water going in at 72 and coming out at 85 after 15 minutes.
The pony pump is only rated for 15 minute conitinuous run time so I shut it down.
Does any one know of a small continuous use pump??
Also how do I calculate my feet of head?
I have 1200 feet of 1/2 inch poly in 4 coils.
There is an additional 120 feet of 3/4 poly horizontally fixed to my fence for delivery and return to the solar coils.
The coils are on my shed roof about 9 feet above the pump.
How many feet of head is this??
Thanks in advance!

#145.1.2 Big A on 2010-05-25 21:21

For a closed system where you are pumping out of your pool and returning it through a submerged line, the height of your roof is irrelevant in the calculation of the total head. The head that your pump has to overcome is simply the friction in your piping.

You can either calculate the head loss based on a given flow, or you can measure it with a pressure gauge. Here is an online calculator you can use-
http://www.tasonline.co.za/toolbox/pipe/velfirc.htm
Make sure you measure the actual inside diameter of your tubing. You'll have to calculate the head loss separately for the 3/4" pipe and the 1/2" pipe. You'll also have to consider if your coils are installed in series or in parallel. Based on your flow rate, I assume your coils are installed in parallel. Ignoring fitting losses, I calculated your head loss to be about 24 feet.

If you have a pump curve, you can use the pump curve to determine the head. Using the pump curve for your pump, it appears your head is about 30 feet. Here is the pump curve-
http://www.lgpc.com/ProductFiles/SpecSheets/995178.pdf The fitting losses would probably account for the 6 foot difference (24 s 30).

Even though the pump is only rated for intermittent duty, assuming it didn't cost too much, I would just run it continuously.

#145.1.2.1 Ken on 2010-05-26 14:01

Hi Ken:
I read your reply and then considered the friction loss of the 1200 feet of 1/2 inch pipe.
I did some reading and research.
I learned 1200 feet of 1/2 pipe was alot of resistance to over come.
The problem was the entire system, all 4 coils, were connected in parallel.
The water was fed into the center of the first coil and out of the outside of the coil , then into the center of the second coil and so on through each coil and out of the outside of the 4th coil and back to the pool.
I then devised a solution.
I added poly pipe to the in feed line, added tees and a reducer to it.
The tees allow each coil to have a dedicated line going into the center of each of the 3 coils and the reducer ends that line at the 4 th coil.
The out put lines from the outside of the coils are connected in the same fashion and return to the pool.
I purged the lines with the municipal water from my garden hose and then reconnected my pony pump and swithched it on.
Holy crap!!
I had incredible flow and pressure!!
I then disconnected the pony pump and used only the pool pump and found that I had way more flow and pressure without the pony pump.
I closed the diverter valve from the pool pump so that all the water from the pool pump was running through the solar coils.
The pressure guage was reading 15 psi as it did before but the flow shot water across the pool and the heated water form the coils was reduced to the same temperature as the pool water in very short amount of time.
I reset the diverter to all lines open and found that the water returning from the solar coils was still much higher than the flow of the previous setup.
I am now down to the single pump arrangement I wanted and need a sunny day to find the right position of the diverter valve to keep the water temperature and flow just right.
I may even add a timer to the setup to save electricity.

The theory is that each of the 4 coils now recieve water equally and return in the same fashion via the manifold I created with pipe that feeds each branch (solar coil)
The original parallel arangement meant that the first coil had to feed the second coil and those 2 coils had to feed the third coil and so on.
WAY TOO MUCH RESISTANCE.
By adding the manifold I dropped the resistance down to what a single coil, of 300 feet, would have.
What a simple fix from what seemed like a huge problem.

Thanks to all for making me think.
Big A

#145.1.2.1.1 Big A on 2010-06-01 13:59

Rob-
As I mentioned in my post, if you don't plan on using a smaller pump, you should use the diverter valve to divert only the amount of flow needed for the solar heater (say 1 to 2 GPM), with the remainder of the flow being returned to the pool.

As far as economics, if your pool pump is properly sized, using your pool pump to circulate the flow through the solar heater may be the most economical solution. In my case, my 1 HP pump is grossly oversized for my 18 foot above ground pool. It will turn over the pool in about 3 hours, so it doesn't make sense to run my pump all day just so I can use my solar heater. Instead, I use an old pump from an Intex pool I used to own which draws about 60 watts and produces about 4 litres/minute.

If you need to filter for 8 to 10 hours per day, it may make sense to use your pool pump to circulate the water through your heater, otherwise you're wasting energy.

Actually, when I'm home, I often use the pool pump to circulate the water through the heater for the 3 hours it takes to turn over my pool while filtering. The rest of the time, I use the smaller pump.

#146 Ken on 2010-05-25 16:27

I have a questions about connecting the irrigation hose to the pool hosing--the pool hosing is much wider than the irrigation hose--what do you use to connect the two different sized hoses? thanks

#147 Lisa on 2010-05-25 18:35

If you want a little extra sun directed towards the heater line the base of the plywood under the pipe with either roofing felt aka tar paper, or eaves guard aka ice and water shield. Any home improvment store will carry some, best thing to do however is see if they ahve any scraps as you will not need a whole roll(it can be expensive). Add another layer over the pipe to help keep the heat coming!

#148 Brent on 2010-05-25 19:55

Hello everyone ... I really enjoyed all the info in this blog ... I was in the planing and priceing stage when I ran across this tho ... http://inyopools.com/Products/11300013056425.htm ... There are other places that sell the same product but this was the cheepest I found (153.53 after shipping) ... Prolly $50 more than I would have in buliding my own minus the time and aggravation ... Seemed like a good deal to me so I thought I'd pass it along

#149 Mark on 2010-05-30 22:59

Everything i have seen tells me they leak in like 1 week so be carfull

#149.1 Hammy on 2010-06-11 19:06

Well I hope not .... Seems rather soild ... Didn't come with what was needed to directly hook it to both the filter and the return hose ... Emailed tho and the parts needed should be here shortly ... I'll update and give a review of it all after I get it up and running for a while

#149.1.1 Mark on 2010-06-11 20:06

I have put together a similar system, but not getting the output I wanted. I have 300' of black rubber hose on my garage roof, hooked-up to an Intex 1000 GPH pump. I'm only getting a small flow entering the pool. Granted, it's quite warm, but not much volumn.\

Do I need a bigger pump? Any help would be appreciated.

#150 Frank C, on 2010-05-31 23:45

How much flow are you actually getting? Even though your pump may be rated at 1000 GPH, that may be at a very low head. I have an Intex pump rated at 610 GPH. I'm getting about 1 GPM through 300' of 1/2" poly tubing.

The other thing you may need to check is whether or not there is air trapped in the tubing on your roof. It helps if you have a point where you can bleed off the air on top of the roof. It also helps if you can put a larger flow through the system using your pool pump, or from a garden hose, to flush the air out. Make sure the outlet from your solar heater is submerged at all times so you don't have to "prime" the line each time you use it.

#151 Ken on 2010-06-01 02:00

Hey Ken, I'm up to 3/4 GPM after adding 200' of the good black hose. Still very much disappointed with the output. I'm going to try it with a different pump.

My brother has a Hayward pool pump from his old pool he's going to give me. I'll see if that works. If not I'll try a different pump. Not sure why the output is so low.

#151.1 Frank C. on 2010-06-09 22:51

Hey Ken, I'm getting 1/2GPM right now. Another problem is that when I shut the pump off, it won't start again unless I use a garden hose to get the water flowing first. I have both in & out ends always under water.

I'm thinking my problem is the cheap hose I used on the intake & outlet ends. Looking at the hose laying on the roof (the cheap ones) they get flat when in the sun. I picked-up 200 more feet of the good black rubber hose. I'll attach them instead of using the cheap hose. Hopefully, that will do the trick. If not I plan to get one of those Pony pumps. Any thoughts?

#152 Frank C, on 2010-06-05 12:53

Hey Ken, I just hooped-up a different pump. What a difference that made. I didn't measure the output yet, but it's much more than before.
I installed an old 1 hp pool pump. Before installing it to the roof hose I tested to see how much water would get pushed. It was a huge amount through a 1 1/2" pool hose. I put in a splitter with a shut off valve. Nor I'm getting a full stream from the diverted 1 1/2" hose, and a full flow from the roof. I may hook-up a fountain with the overflow.
I will probably add a few more hundred feet to the roof. I'm all excited about the prospects of a warm pool.

#152.1 Frank C, on 2010-06-19 13:39

I am a maintenance manager at a small apartment complex and have been looking for a viable way to do exactly this. only ramping it up for a commercial grade 30,000 gallon pool at my property. any one have any numbers on the estimated BTU's you get from any of these systems? assuming full sun (Im in Colorado and we get a good deal of sunny days.) say btu's/ft?
Just wondering how much pipe I need for 30,000 gallons?

#153 Daryn S. on 2010-06-20 04:34

I measured the flow & temperature today. I'm getting 3 gal per min @ 85 degrees. The air temp was in the low 70s when I took the water temperature. The pool was 76 degrees about 9am & by 4:30pm it was up to 82 degrees.

I am so pleased with this roof heater. I now have 700 feet of 5/8" black rubber hose. This winter I plan to mount it all on plywood with spacing between the hose. Right now it's just wound tight.

#153.1 Frank C. on 2010-06-23 04:21

Hi All, I'm getting small bubbles coming from the roof outlet, and once in a while a couple of large ones. I don't see any water leaking from any of my connections. Any ideas. Could I have air coming in, but no water leaking out?

#153.1.1 Frank C. on 2010-06-26 03:07

If the leaky connections are located on the roof, water will not come out of the leaking connections but air may be sucked in. This is because the piping is acting as a siphon. This means that anywhere above the hydraulic gradeline, the pressure in the piping will be negative.

#154 Ken on 2010-06-26 12:28

ok , I went to Lowes today looking for the "T" and pipes .....I'm confused here...my pool pipe has an inside diameter of 1 1/2 and they don't sell any plastic pipe with an outside diameter of 1 1/2" and none of the T's pvc or anything else with a diameter of 1 1/2"...I see in the picture that you used a grey colored T which I did not see at lowes ..does that have an outside diameter of 1 1/2" ?

#155 Wayne on 2010-07-02 01:01

Spent a lot of hours on sites - this is by far the best!!

Would it work to place the tubing as pictured in a solar oven? The sheet with tubing basically becomes the
bottom of the solar oven. I landed on this site http://www.re-energy.ca/t_solarheat.shtml and took the link to build your own solar oven. (They have a pdf file with really detailed instructions for construction) Thoughts? Comments? Live in central Alberta water is a tad on the cold side - want to get something built.

By the way if the person who was asking about the liquid solar cover wants the URL I will post it just have to find it. They're little bags in the shape of a fish that you cut the fin off of - then toss it into the pool and it regulates release of the chemical itself. They say the chemicals are all safe (in case you swallow the liquid) but then .. I personally would think twice about it and check it out.

#156 Anne on 2010-07-10 08:01

Meant to add some additional thoughts for comment. I realize that one would have to take into account that you don't want to melt the tubing - informations says that done properly a solar oven can get up to 350 Fahrenheit (200 Celsius). What temperature can the black tubing withstand? I thought the other option would be to run some copper tube across the oven bottom just like in a real oven then fit your hoses to the the ends outside the box. I know some people run copper tubes over barbecues or fire pits but this can be a hassle (need wood or propane always at hand). Has anyone on this forum ever built a solar oven or give some comment back - either way any comments would be welcomed.

#156.1 Anne on 2010-07-10 17:10

By using this method, do I need to run my pool pump continuosly? I think this is an obvious question though lol.

#157 Geo on 2010-08-18 14:49

Guys, I had a few questions in regards to building my solar coil heater. Application is on 12'x24'x52'' Intex above ground pool. Plan on everything you discussed above with following changes;

1. Coil (250') is to be mounted flush on roof. We are in San Diego CA and the roof is always 90F, even on cloudy days.

2. Given the head pressure of 1/2" tubing going up 20ft to the roof I'm going to have to buy a hi-pressure, low volume elec. booster pump so as to not blow out the main pump and save on electricity. Check valve between booster pump and roof so when pump shuts off water doesn't fall back towards pool.

3. The booster pump will take a suction off the pump inlet as this is lowest point (4 ft.) below the pool level and should provide constant inlet pressure to the booster pump so priming is never needed.

4. The booster pump to be mounted on a timer, booster pump comes on for 30-45 minutes, push hot water to pool
and refreshes with cold water from pool to coil. Pump comes on every 1.5 hrs. from say 11am to 5pm.

Now questions:

a. Can I tie the heater return line into the main pool pump discharge piping so it doesn't look ugly hanging over the top of pool? Will the small amount of return flow be able to overcome 3ft of 2" piping going from main pump to outlet pool jet (jet is right at pool water level)?

b. What kind of automatic air bleeder valve can I put into the coil on the roof? I know with 20 ' of tubing going to a roof I will have air lock if I don't have a bleeder. Auto store??? Have not seen anything at Home Depot.

Appreciate any ideas or support.

R/
David
david.oakey@gmail.com

#158 David (Link) on 2010-09-10 21:12

After reviewing some of the posts in here it appears several people are sucessfully using their main pool pump to feed their roof solar coils. I am starting to re-think whether the booster pump is needed at all. I do NOT want to put too much stress on my pump but I do have two of the Intex 2500gph pumps, original is back in it's box, as it was replaced for free by warranty as timer is broken, example: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220457124680&rvr_id=138344976171&crlp=1_263602_263622&UA=WVI8&GUID=02f06dee12b0a0aad3d674d6ffe0f3d2&itemid=220457124680&ff4=263602_263622
So I suppose I could test with the pump with the broken timer so if it gets ruined no $$$ loss to me but isn't 2500 gph way too much. Even taking into effect 18' lift to roof with 500' 1/2 poly?

#158.1 David on 2010-09-11 22:43

The 2500 gph pump is way too large to use as a dedicated pump for the solar heating system. For one thing, you'll be wasting a lot of energy- 1/2 HP is a lot of power to use for a solar system. You might as well use a 1/2 HP electric heater to heat your pool. Secondly, with 500 feet of 1/2" poly, the flow is going to be a lot less than 2500 gph. That would probably not be good for the pump as it is not a good idea to operate a pump that far off it's best efficiency point.

I use a small pump from an old Intex pool. It only uses 65 watts and produces about 1.5 GPM. Works fine through 350 feet of 1/2" poly.

BTW, the height of the roof is irrelevant as long as the discharge from the solar heating loop is submerged i.e. doesn't just drop into the pool. You might have to use your pool pump or a hose connected to your domestic water system to initially fill the line, but once it's filled, the solar system pump doesn't have to lift the water to the roof. The force of the water returning from the roof to the pool offsets the force required to lift it up to the roof (siphoning effect). That means you should be able to get by with a much smaller pump as the pump only has to overcome the friction in the poly tubing.

Just remember to have a means of bleeding the air out of the solar heater when you are initially filling it. I have a plug which I can remove to bleed out the air.

#159 Ken on 2010-09-12 12:39

Ken, thanks for taking the time to reply. So if I go with your design and use the main pool pump, tee'd off the pump discharge, or clorinator line. Then I adjust the ball valve so 80% of the flow goes to the pool how does the water not go the easiest path of resistance? I mean if the water can simply go to the pool why or how would it flow through restictive 500' of .5" poly tube to a roof 20' above?

#159.1 David on 2010-09-12 17:33

I don't believe I said to use the main pool pump but if you do, you need to have a valve on the pump discharge line, between the tee supplying the solar heater and where the return line from the solar heater tees back into the pool piping. You would need to throttle that valve to achieve the desired flow through the solar heater.

I would only recommend using the main pool pump for the solar heater if you normally run the pump for the same length of time you want to operate the solar heater. If you're running the pool pump only for the purpose of supplying the solar heater, you're wasting a lot of energy and you'd be better of using a smaller dedicated pump for the solar heater.

#159.1.1 Ken on 2010-09-12 21:09

Ken,
After reviewing some pictures on various websites of roof mounted coils I was thinking about winding the coil directly to the roof WITHOUT the wooden frame.
This would:

1. Allow full transfer of roof shingle heat (100%) to the coil through direct conduction. Combined with the heat of the sun on the coils this may be 150% more effective than wood frame models.
2. Limit “wicking” loss of heat due to wind carrying away heat. (wind between roof and the wooden frame/ wind catching heat off coil since the coil is no longer flush with the roof)
3. No time or money spent making the wooden frame.

Guy on one of the pool forums said his heat index increased remarkably by doing this.
One thing would be having to figure out way to hold down coil without having the wooden frame. Maybe some zip ties screwed into the roof or combination of zip ties and PVC hold downs screwed to the roof. Either way pretty easy to do.

#159.1.1.1 David on 2010-09-17 00:01

Sorry to be a bother but I keep getting ideas in my head.

I also thought, instead of just hanging the return line over into the pool how about installing a small PVC eductor, like this one:
http://www.millerplastics.com/eductors.html
Eductor to be tied into your pump's return line going back into the pool. This will greatly enhance the collector's flow (your pool pumps flow thru the eductor creates 15-20" of vacuum in the coil return line).

See explanation:
http://www.primetechrkg.com/images/tme.jpg

Even if your collector gets completely air bound the eductor will suck it out automatically aiding in collector flow and less burden (static head) to the pool pump.
We had huge, 500 to 2,000 gpm eductors in the Ship's engineering plants in my Navy days. They will suck up anything, water, air, oil, small people. Even swallow and pulverize 2x4 boards (yes I tried that)....or suck your hand off your arm if your not careful.

#159.1.1.1.1 David on 2010-09-17 17:52

When filled with water, isn't that system really heavy? I mean, i dont know if this could be placed in a rooftop or something..

Sorry for the poor english,

Victor

ps: great ideia man!

#160 Victor on 2010-12-27 16:23

The weight of the panel is really not that substantial. The water in 300 feet of 3/4" tubing weighs about 10 lbs. 300 feet of tubing probably weighs another 10 to 20 pounds so the total weight of the panel would only be about 20 to 30 pounds. The loading on the roof would only be about 3 or 4 pounds per sq ft. For comparison, a typical design snow load in Canada is 50 pounds per sq ft.

#160.1 Ken on 2010-12-27 23:06

I'm in Australia and about half way through constructing a tubular monster to heat our inground 8000gallon pool. I'm using 0.5" irrig pipe wound into 4ft spirals, each contains approx 200ft of tube.

So far, 5 coils are sitting on the paving around the pool, and supplying a 2 degree C (35F) rise in full sun at ~5 gall/min flowrate, very encouraging indeed.

Eventually 10 of these will be sitting on the colourbond garage roof, fed by a parallel feeder/return made from 2.5" pvc pipe.

The pump is a 0.5hp QB60 from Ebay (a chinese clone) and it works fantastic supplying 600gallons/h at very good pressure, running extremely quiet as well.

And for $50 you can't go wrong!

#161 David on 2011-01-01 00:33

I don't know if it's been covered in the previous comments, but you DON'T want to restrict the flow through the hose to maximize the temperature of the output water. You want to set your diverter valve to allow for maximum flow through the use without restricting throughput. Usually about 3/4 of the speed water would come out of the hose if it were connected to a faucet.

The reason for this is that by raising the temp of the water in the pipe, you reduce the overall heat collected. Don't confuse "heat" with "temp". It's better to raise 10 gallons per minute by 2 degrees than 1 gallon per minute by 10 degrees. The larger the difference between the water temp and the solar air temp the more heat is collected.

It does seem like it would be a bit of work to get the water flushed at the end of the season. Do you blow it out with compressed air?

#162 Chris Chubb on 2011-01-12 17:12

If you use polyethylene, which is what irrigation tubing is, you don't have to worry about blowing out the water before winter. Polyethylene is flexible so it can handle the expansion that occurs when water freezes. I blew out my tubing the first year I had it but haven't bothered since then, without any detrimental effects.

#163 Ken on 2011-01-12 22:53

When you discuss water freezing in polyethylene tubing, is there a difference between low density and high density poly as far as freezing water is concerned?

I would think the low density would be more flexible and less inclined to turn brittle and break when water is frozen inside.

Is the Home Depot tubing low or high density?

#163.1 bill on 2012-01-28 09:56

I don't know if Home Depot tubing is high or low density, but I used Home Depot tubing and it has frozen for several winters without any adverse effects.

I do know that high density polyethylene can withstand freezing (from IPEX brochures), but I don't know if high or low density polyethylene is better when it comes to freezing.

#163.1.1 Ken on 2012-01-28 19:35

Thanks for sharing this!

Here in Belgium we haven't the nicest weather, last year I bought a Intex pool (6000L) and only used it a few times!(the temp. was between 20 and 26°C, only by standing in the sun)
Becouse we were freezing in water of 20°C, I'm going to try making a solar heater this year (in store the cheapest is around 160€, wich is to expensive for me...)

I tought of creating a black painted box ('greenhouse') from a panel (1X1,5meters/40x60") and 5cm (2") high sides, covered with a PMMA (plexiglass/acryl) plate on it to reduce the airmovement inside the box...
Into the box I should place a black painted garden hose, I estimate 20-25 meters.
All that will be attached to my original pool pump (after the filter) with a T junction...

The questions I have:
- Do I need a valve (and where?) for adjusting the water inlet? The original pipe (one side of the T junction) is wider (I think 8cm/3") than the garden hose (2cm/1", other side of the T junction) -> Is the water going to flow into the garden hose, and have enough pressure to get throug the 50meters of garden hose?? (from the T junction to the heater and to the pool, the heater will be placed in the sun about 10meters from the pool)

- I have read that UV light pass through PMMA glass -> So produces it less or more heat inside my 'greenhouse'?

- I've also read that PMMA glass discolour by UV light, making it will have a white or yellow shine -> Is this still going to work if it isn't translucent?

Thats all at the moment...
(And please forgive me for my english)

#164 Jeroen on 2011-01-19 03:14

Last summer I installed two 500' coils on the roof last summer and on average got an 8 degree return in pool temp for a 12x24 above ground Intex. Never got over 72 degrees, but it was a cold summer here in Southern California. I have a new plan (in addition to the coils) and can scan attach the free-hand diagram if needed.
So how about if I use the existing solar coil inlet (connected off the main pool pump outlet to the auxiliary 1HP "coil" pump, to a 40', 1.5" underground PVC pipe going to the crawlspace under the house, where, an 80 gallon auxiliary water heater would be placed (right next to the existing house water heater) I then fabricate all appropriate gas connections and then run the water heater outlet PVC line back to the existing coil return line (pool pump return)
*note coil will be isolated by ball valves in this mode.
So when Mother Nature is not working with me I can AUGEMENT the solar energy with a natural gas heat source. No different than the $3000 professional gas heaters used for underground pools but 1/6th the cost. Natural gas is cheap and if the water heater was set for say 110 degrees, 80 gallons of 110 degree water would definitely raise the water temp of a small 8000+ gallon pool that is say 72 degrees. The water heater is designed for a pressurized water system so an inlet check valve and spring loaded pressure unloading outlet valve is required. Water heaters take time to heat the water in it so I would run this for say 15-20 minutes daily to cycle the hot water out, refill with cold pool then shut it down. The gas expense should be negligible, as it is used sparingly and the pilot light is pennies on the dollar. Estimated cost of entire system (with a used water heater $250-300).

This should augment the solar coils nicely, especially when I put up the pool again this summer and fill it with frigid water off the hose tap.

Your thoughts?

#165 David Oakey on 2011-03-09 19:48

I'm surprised that you live in Southern California and can't get your pool over 72F ... maybe I read your post incorrectly. I'm on the east coast of Canada and with nothing other than the sun and a pool cover (on almost every night) my pool is at 78-82F from July 1 to the last week of August.

I'm looking for the options that will allow me to heat my 24 foot round AG pool so that I can get better use out of it in Mid-May, June and September. In those months we will range from 70 to 75.

It is May 3 and the pool was just opened yesterday. The water temp is 53F but we also just added 18" of municipal water to the pool from its winter level. Once my chemicals are balanced I'll throw the cover on and over a week probably get the temp up to 67 or 68F. I'd like to have a way to take that 68 to 78 in May and early June when the evenings are still cool., and replace what I lose in late August and early September when the evenings are cool again.

I like the coils but they aren't the prettiest setup ... and the esthetics are more important to my wife than the temperature is. The more coils I have to build the uglier it seems to get.

With all the time and effort that you put into this I'm wondering if simply buying the $200 Sungrabber kits isn't just as simple an alternative. It would take the guessing out of it all and you get it sized correctly for your pool size.

#165.1 Steve R on 2011-05-03 16:32

The hot water heater should work OK, but the cost of the gas needed to heat the water may be more than you expect.

You could raise the temperature of the pool much quicker if you just ran the water continuously through the heater until it reaches the desired temperature. The gas burner would operate continuously. Even though the water temperature coming out of the heater may not be very high, you would still be adding energy continuously to the water. You won't gain anything by waiting for the water in the heater to warm up.

As far as I'm aware, most hot water heaters don't need a minimum pressure to operate. It's simply water in- water out. You'll have less line loss which will equate to higher flow if you can get away without a spring loaded valve.

#166 Ken on 2011-03-10 00:58

Can someone give advice or answer the questions in #164 please?
Thanks!

#167 Jeroen on 2011-03-12 23:07

Will this pump work..??
http://www.sears.ca/product/algreen-306-gph-statuary-pump/671-000872127-91504

Type of pool: Intex 18x48"
Location: Northeastern NS
Pump available now: Saltwater system chlorinator... http://cgi.ebay.ca/INTEX-Krystal-Clear-Saltwater-System-Pool-Chlorinator-/230591806741?pt=LH_DefaultDomain_0&hash=item35b057bd15

OR will the pump/chlorinator that we have now work?

We would install the solar panels on the ground, not on the roof. Too much wind here, and I would be the one to have to install. No thanks

We generally run our filter/chlorinator at night, would be thrilled if we could run the solar and filter all at the same time during the day.

But if the other additional sears pump will work better, and easier to install without having to adjust existing hose fittings, that's fine.

TIA!!

#168 Mary on 2011-03-20 21:40

Guys, thanx for sharing good ideas

I have question about length of hose for one coil.
What is maximum length of hose (for given diameter and flow rate) to transfer heat efficiently?
I guess if hose reaches certain length the coil will not gather and transfer more heat.

#169 Sart on 2011-06-22 07:16

Just in the process of building my solar pool heater and neeed some answers to a few grey areas .

1. Can you Tee your return water from your solar heater back into the main pool return line?

2. What kind of pump could you use if you didnt want to utilize your pool pump.

#170 Dan on 2011-07-04 01:29

ALL VERY CLEAVER AND INTERESTING GUYS BUT MOST IMPORTANTLY REMEMBER THAT YOUR BLACK SURFACE AREA OF THE PIPE IS THE EXACT SAME AS PLACING A BLACK PLASTIC SHEET OF THAT SIZE IN YOUR POOL.

MATT BLACK ABSORBS HEAT WITH MIN REFLECTION.

CALL ME PROFESSOR MARSDEN HA HA

#171 Mark on 2011-09-14 14:40

Prof. HaHa... I'm not sure that your assertion is quite true.

I gather from your proposed solution, you would have to remove the sheet of plastic from the pool when you wanted to swim (which sounds inconvenient to me)

I keep my 'system' very simple... in addition to my solar blanket, I coil the hose on an unused area of my concrete pool deck and have a small submersible pump attached to a timer which pushes the water through the hoses. Consequently, I'm able to gather heat from the sunlight striking the hose and also the thermal mass in the concrete. This means that the water coming out of my hoses is still warm for quite some time after the sun goes down... I doubt that your solution provides the same benefits.

One down side to my current solution is that the timer comes on (and stays on) whether or not the sun is shining... so on grey days, I could actually be cooling the pool.

In the future (when I'm rich and famous... or at least the former), I'd like to replace my current 1/4HP AC pump(? maybe 1/6HP - I can't remember) with a DC model powered by a PV panel. The thought process being if there is enough sunlight striking the panel to drive the pump then there should also be enough energy to heat the water and conversely, when it's cloudy, the pump stops running. If anyone has any suggestions on this front, I'd like to hear them (a good source for cheap & reliable DC pumps in particular)

#171.1 al c on 2011-09-14 15:36

I used zip ties on pvc pipe to make roll up black poly shades for the sunny sides of my pool. I just used open end pvc on the bottoms for the poly to give it some weight.

After 3 days I have gain 2 degrees with just 2 each 8 foot poly shades of black. I have room for one more, I am not 100% on this solution, but do think it helps. It takes about 10 second to roll them up out of the way.

Cheers, Bob in TX

#171.1.1 Bob on 2011-10-12 01:19

From Oct 9 to 17, the pool made it to 80 degrees with 3 10x4 foot black poly shades in the water. The avg temp was 66 to 86 with just morning sun about 4 hours of sun on 10% of the pool surface.

Tonight it will be in the 40's degree range, so the expearment might be over for the year. Bob in TX

#171.1.1.1 Bob on 2011-10-18 20:27

I haven't made one of these yet, but I have some of the same questions regarding using a standalone pump powered by a PV solar panel.

Ideally, I'd like to stick it on my roof because that's the only part of my property that gets sun all day, but I'm not sure that a DC water pump powered exclusively by solar will be powerful enough to lift the water up to the roof height. Because of the layout of my property, the roof area will be approximately 20 feet higher than the surface of the pool.

Does anyone have any specific suggestions for solar powered water pumps?

Also, I saw someone online suggest using a 5/8 or 3/4 inch lead-free garden hose (preferably black) instead of the poly drip tubing. Is this a good idea? Larger diameter should equal higher flow rates, everything else being equal.

#171.1.2 Krick (Link) on 2013-05-30 21:40

Krick,
The height of the roof is really irrelevant. You may have to use a hose to initially fill the tubing but once it's filled, the pump does not have to overcome the height of roof. The pump only has to generate sufficient pressure to overcome the friction in the line.

#171.1.2.1 Ken on 2013-05-31 15:05

Ok hi everyone, long read to get to the bottom, I lasted about 3/4 of the way down. Im in New Zealand and have a 30 thousand litre pool. The temp at present sits between 22'C and 25'C. I would like to raise it by approx 3'C. This set up is pretty much what my husband and I had in mind. I have a couple of questions, my friends have there solar system set up professionally and I hear a timer on it, does this mean that when it gets up too temp its then pumped back into the pool. From the reading above it seems to me that this isnt done, as the waters moving through the solar panals all the time!! Is this right and if so is it as efective as haveing a thermastate and only moving it when it gets up to a certain temperature??

I was also wondering if running the PVC pipes over laid bricks (believe me we have many in Christchurch New Zealand at the mo from all the fallen buildings) as this holds the heat well into the night. Whats the peoples thoughts please??

#172 Saskia on 2011-12-29 00:30

Hi there, i am from chch as well. i have installed a solar system, our temp of the pool is about 26 degrees and slowly climbing, we have got about 100m of irrigation pipe hooked up to a sheet of ply that circulates while the pump runs, The water coming back to the pool is constantly 2-3 degrees warmer. When the pump starts the hottest that the water has been is 44 degrees, but that usually only lasts up to 5 mins. If you give me your email address, i will send some photos through, Cheers Daniel

#172.1 Daniel on 2012-01-23 00:11

I have gotten many great ideas from this site. Thank you.

An FYI I plan to do a scale CAD drawing with a complete bill of materials and cut bill. If anyone wants this contact me and I will be more than happy to provide this.

#173 Aaron (Link) on 2012-01-04 04:20

you cannot use ant kind of plastic pipe to gather heat, plastic is a insolator to get max heat transfer use copper . conductivity of copper is 350 ,alumminum is 180 black poly pipe is between 12 and 16,this should be a nobrainer. if you make a half inch copper manifold 4x 10 feet with 10 foot lenths of half inch that manifold will have approx 300 feet of pipe this would equal 4000 feet of plastic with the same heat output

#174 ja. merv on 2012-02-18 15:08

I used to work for Home Depot in New York, I've built several of these as store demonstartions. I have found some problems.
First the 1/2 hose works fine if you use a second pump only for the colector. the pool pump can't handle the extra load, plus algie grows in the pipe.
second, use no less then 1" pipe if you use the circulator.
third. the pipe bends easily if you heat it with a heat gun, to about any shape you want.
If uou are lucky enoungh to know someone with an old big satellite dish, they want to get rid of, coil the pipe in that and tie it down with wire ties to the mesh. if the steering part still works even better to face the sun.

I live in the south now (retired) I made one with 2 window well covers bolted back to back, and a coil of 3/4 undergrpund irrigation hose, the coil needed is much smaller down here, sits under that, works quit well, as I have to use a seperate small pump just for that, usually late in teh season or in early spring.

#175 Steve on 2013-04-02 23:11

Me it work great
cloudy day 2hrs and 1.5 degrees i imagine when
it's sunny. the secret is to close the arrival valve for the eater so the water temp can rise slowly se the next adress for getting the valve frome the pool to the eater. It cost me around 70$ at rona and the pool shop for every thing.

http://www.youtube.com/watch?v=tFcuDkqsntA

Sa marche bien
journée nuageuse en 2 hres j'ai gagnée 1.5 degrés
j'imagine par une journée ensoleillée.
Le secret c'est de bien réglée la valve d'arrivé d'eau pour
le chauffe eau voir le lien suivant pour les valve entre le chauffe eau et la piscine c'est facile a faire sa ma coûté environ 70$ chez rona et magasin piscine.

http://www.youtube.com/watch?v=tFcuDkqsntA

#176 Étienne (Link) on 2013-06-29 13:20

What a great article.. I'm going to build a solar system for my 16x27 above ground pool Approx 14k gallons. I plan to use 800 feet of 1/2 inch black PVC and run in on my sunroof roof its about 12 feet off the ground, I plan on running the piping down the corner and then underground to the filter system where both intake and return will be plumbed from the return-side of the filter and using valves to control the flow and turn it off at night to not lose heat, I run my pump 24/7. My goal is a 15-20 degree increase basically 70'2 to 90's and extend my swim season. I plan on using the 1 HP pump that i use with with filter and not adding an additional pump unless it's required. Any thoughts or ideas would be very helpful and gratefully appreciated

#177 Jason Allen on 2014-05-05 20:19

That's a nice system, have thought about such a thing myself. It is no help to run the water slow thru the system to let it heat up. It will actually absorb heat faster if the water is cool because the difference between the pipe temperature and water is greater. Even though the water won't feel warm, it will be picking up heat faster.
Ron

#178 Ron on 2014-06-21 17:18

I am intending to install a pool heater on the adjacent existing south facing downward slope with the base of the panel some 1 metre below the bottom of pool level and top some 0.4 metre below the pool inlet for the hot water produced which in turn is 0.6m, below the surface of the pool.
Will natural gravitation of the solar heated water be sufficient to work satisfactorily without a pump.
Also where leaving a pool blanket on a sunny day when the pool is not in use, is this beneficial to the heat gain or should it always be removed on such a day.

#178.1 Peter Nunn on 2015-02-03 11:14

Thank you for the great post! I have been researching solar pool options in the Sacramento area!

#179 Michele Smith (Link) on 2015-04-29 21:40

Has anyone made one out of copper 1/2 refrigeration coil? If you used a joiner you could easily use 250' on a 4' x 4' plywood sheet. This would equate to approximately 6250' of poly pipe if we go by the stats posted in reply # 174.

My thought is to do one 4 x 4 panel with 250' but the issue of chlorinated water corroding the copper in a salt water pool is a concern. I am going to back my panel with aluminum cladding, attach the copper pipe and paint it all black. Had in mind to attach inline water temp sensors to the inlet and outputs to see what my rough gains are.

Any help, comments or ideas would be greatly appreciated

#180 Mark on 2015-06-22 16:17

I live in southern central Australia and have got a lot of info from this site.
My plan is to have 4 coiled 100' lengths of 1/2" polyethylene irrigation pipe mounted of a wooden cross. Will hold pipe down with nails bent over as this will also give a 1/8" separation of pipe on the coils. To reduce friction the coils wil be hooked up in parallel to 2" manifolds and run the same size pipe back to a low volume pump that will operate continuously.

The aim is to extend the swimming season from 3 to 6 months.

My 10,000 gallon in ground fibreglass pool is slightly uphill of my pump shed by about 3' and the pool has a dedicated heating inlet and outlet pipe halfway between top and bottom of water level. QED the pump will always be primed.

Can any people see why this would be an issue before I start building it please. Kudos to community input.

#181 David Leach on 2016-02-23 11:45

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