Instructables
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How to build a solar pool water heater.
 
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Step 1: What you will need

Picture of What you will need
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When you live in Canada, you need to turn up the heat in your pool all summer long if you want to use it.

First off, you need a location to install the heater. Preferably, if you live in the northern hemisphere, a southern exposition. The location should have as much sunlight as possible all day.

That said in terms of supply and tools , you will need:

L shape metal rods (or wood it you prefer)
2 x 64 inch 1 1/4 inch diameter copper pipes
3-4 rolls of 1/4 inch copper pipes.
Tin solder
Sandpaper
Soldering paste
Welding torch (bernzomatic, plumbers stuff)
Pipe cutter
Chalk line
Automatic punch
Pencil
Measuring tape
Broom stick
Acetone or other cleaner that can remove soldering paste
Plumbers tape

Step 2: Making a frame to hold the pipes

I think you could probably builds the frame out of wood or other material. I decided to build this with L shape steel rod.
Cut the rods to length to make a rectangle. on the shorter side , I made some notch with a hole saw, so the pipe will fit in. Weld the rectangle together. If you don't have a welder, or access to one. You could also drill and bolt the part together. I used some rubber to isolate the steel frame from the coper to prevent metal reactions.



Step 3: Drill the manifolds

Picture of Drill the manifolds
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Drill 1/4 inch holes in a straight line into the 1 1/4 inch pipe to make two manifolds. I made holes every other inch for a total of 63. In order to make a straight line, I used a chalk line.
insert the pipes onto the frame so you can evaluate where to start and stop drilling holes.
This way you will not have any holes where the manifold pipe will attache to the frame.

I have evaluated the 63 1/4 pipes will have more then 3 times the diameter of the 1 1/4 " pipe. this is to make sure the water will slow down a bit in the smaller pipes.
By slowing down the water a bit , It helps with the heat exchange...

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Lynxspring (author) 10 months ago

Ben,

I suggest you add a box around it to close it, with a glass overhead... as well as a reflective plate on the bottom.

I was able to harvest more energy from it.

I also added an anode in the pool to prevent the copper from corrosion

A friend of mine made the same thing from PVC... it is about 75% as effective
He made it with small PVC tubes just like my design...Keeping the small tubes gives off more surface contact...

If this is on a roof, I suggest using CPVC as it has a higher resistemce to heat

If you leave it out in the sun while it is not working... PVC start to fail faster

Good luck and have fun!

reddog923962 years ago
Why does it enter through the bottom? To slow the water flow?
KD7CAO5 years ago
Overall this was a nicely done instructable. I do however have a few comments. 1. The steel frame is welded, but copper is either brazed or soldered (you were soldering). 2. PVC or CPVC would be much cheaper, last longer, and is easier to work with. 3. You really need to have either a reflective surface under the tubing or a flat black. Reflective surface will allow the tubing to receive the light a second time, flat black will absorb the light and provide some radiant heat. 4. You would be better off using a small pump that is separate from your circulator, unless you run your circulator continuously.
regarding: http://www.instructables.com/id/Pool-Solar-water-heater/step16/Swiming-2nd-week-of-May/


Wouldn't the system have ben more efficient has the plumbing been ran in series rather than parallel? Thank you.

gjlyon@hotmail.com
PVC is cheaper, BUT you will not get the heat transfer that you get with copper. Still the best bet for transfer of heat energy. Great Idea.
Thanks for pointing out the proper word usage, English is not my first language... (I'm in Canada and mostly use french ) we use the word "souder" the equivalent of soldering I guess. There's not really any welding equivalent, as we use the same word "Souder" for both. I do understand the difference. I will change the words in the instructable. Thanks
Interestingly enough "souder" is used to explain how the word "solder" is to be pronounced, in English.
PKM static5 years ago
Only Americanglish- in the UK we pronounce the L in solder, so it sounds like smoulder without the M.
static PKM5 years ago
Ah, English. I'm an amateur radio operator. While listening to an Aussie and a Kiwi give a Texan a bad time about his drawl, the Aussie remarked to the Kiwi, it's those Limeys who really talk funny. ;)
You telling me that we Aussies talk funny? I think you're wrong. It's the Kiwi's that talk funny, Not us!
Didn't say that you Aussies talk funny, just that one Aussie, and one Kiwi where in agreement that the Limeys talk funny.
Lol, Yeah, Some Aussies do talk funny, But not too many. Yeah, the Limeys talk funny!
cShellPro2 years ago
This project looks really complicated and time consuming.
Wouldn't it be better to simply lay black plastic pipes
in sleeves inside the box?
toastdore5 years ago
Salut Richard, Tu a raison pour la température au Canada (Québec) moi ja l'ai fait il y a 4 ans, avec des tuyaus d' ABS et de la colle ABS 4 pieds par 20 pied et ca marche!!!! moi j'ai une 18 pieds et mon eau est entre 80º & 86º Merci Christian
heat pool.jpg
 You will get a more uniform flow through the vertical pipes if the manifold pipes (top and bottom) have the inlet and outlet at opposite ends (one left, other right).

Other wise the greatest vertical flow is closest to the connections.
jack17 avid0g3 years ago
You got a really useful blog I have been here reading for about an hour. I am a newbie and your success is very much an inspiration for me.

Water heater installers
thats a lot of copper the watter will turn green i have a propane heater curently and it has much less copper piping and a have a large pool and it still turned green i dont know what can be done about it but just my point
unless you have sulfuric acid in your pool, its not the copper. HCl, the standard ph balancing acid for pools does NOTHING to copper.
Lynxspring (author)  snowluck23453 years ago
it's been running for 3 years, without any water discoloration, and the units is not corroded any any way... Our PH and chlorine is always fine and tested almost daily...
Typically the bluish-green color comes from having a low PH. The acidic water eats away at the copper. This causes copper leaching into the water.
Are you sure it was the copper turning the pool green??
I made a pool heater basically identical to this one, but I use it as a fire pit grill. (Yes, water flows through the copper pipes and yes, it is still good for cooking on.) My pool has never had a problem (until I miss a couple days of checking chemical levels... lol)
I have never heard of this from anyone before. Even copper that is left in a pool of water will not relese the oxide without scrubbing on it. I would think someone likely played a prank and food colored your pool.
i have no neibors i live in the middle of nowhere no one put foord coloring in my pool the heat and water being pumed through actualy put it into the watter we used the copper treatment in our pool and it cleared up in a day i dont remeber what te treatment was this was 2 years ago
Last I checked, algae turns pools green. ;-) The treatment that was most likely used was a pool shock. Basically a lot of chlorine and the like used to clean out any nasties.
thats what ithoght but alge stuff didn't work and ph was fine it was copper
That's really strange... I didn't know copper could affect water that drastically. Well, you learn something new every day.
scram13 years ago
great article !! I built two of these for an above ground pool back in the 90's, and they worked ok..I used a separate pump for heating..As-far-as Algae goes, it has been my experience that first the PH must be correct, and then the Chlorine levels..Easy to maintain, but once things get out of hand, it can be a real bear to fix !! Here's a couple of other heating methods for your pools: Install a heat exchanger in your attic space of your house..A radiator in reverse...Blow the hot air in the attic space across or through a heat exchanger, and warm the water in your pool....Another one is ( and this is complicated but another real good energy saver) to modify your home air conditioning condenser..All of you know that water is probably the best mover of heat and cold, so instead of blowing hot air across a coil as in your air cond. condenser, use a tube-in-tube heatexchanger and cool the condenser with pool water..It's so much more efficient that air !! check it out.
l8nite5 years ago
disturbed, Sorry but I have to disagree with you, copper will actually prohibit algae growth, a copper wire stretched over a roof prone to moss growth will prevent growth and kill any spores, copper nails driven in the base of a tree will kill it and the marine industry has used copper plate and copper based paint to prevent marine growth on boats for centurys. Warm water will encourage algae especially with plenty of sunlight, I would suggest you check the other chemical balances and perhaps add an ultraviolet light system
shortw l8nite4 years ago
Copper will also kill parasites in water. I used to work in a tropical fish store and 2 copper pennies ( the old real copper pennies) added in a 10 gallon fish tank will prevent eek ( white spots on fresh and salt water fish) and limit if not kill all the plant life and algae.
To much copper and it will kill bacteria or fish in water.
Copper is also used in killing roots ( root killer= copper sulfate). I have never seen green water in a open or closed h2o system that was caused by copper tubing.
As far as I know there is no chemical that would treat copper in the water, thats why if you treat your fish tank with copper you have to replace the water.
A diatom filter system is the best you can have, but it will not filter copper out of the water.
If the water turned green this test may /should show if you have copper in the water. Take 2 stainless steel rods, hook up a wire to each rod and connect a 9 Volt battery to it and hang the 2 stainless steel rods in the water for about 1 hour without touching each other. If the one( - pole) of the rods looks like copper you have copper in the water.
Calorie l8nite5 years ago
word...
t.rohner l8nite5 years ago
Have you ever tried to kill a tree with ONE copper nail? (Say a foot diameter trunk) You will need MANY copper nails...and lots of time. Mythbusters will try it one day.
GusGrass4 years ago
I like it best of the design I have found.
Will try PVC and make it larger.
Will Drill the headers and Glue the smaller pipes directly in drolled Holes.
Might use a lathe to taper and sholder them slightly for a better fit to the headers??

Love the Corragated Roof Idea...
Been all around looking for that solution.

123award4 years ago
Great job. I built a 3 solar panel boxed unit this summer. I wanted to use copper however 1 1/2 inch t's- 1/2 inch where about $15.00. So I went with pvc. I wish I had of thought about drilling the 1 1/2 inch pipe. Like your design I am using the manually 3 way value from the pool pump. On sunny days I see a 3 to four degree difference between the water temp from panels to pool. You would greatly increase the your temp by boxing your unit. Thank you for sharing your design.
That a good idea! You should write an simple instructable on it.
Mikey85674 years ago
I have built one of these also but I built it more in a boxed enclosure (much like a solar panel) by doing this you can cover the coil ( I used soft fexable 3/4 inch copper, much like what is used in A/C systems. No solder joints except the fitting ends) to protect it during storms and the winters. The the coil was supported in the box by standoffs and I also painted the entire inside with black paint to increse the heat asorbed. Basicly built a hot box. I've seen the same thing made out of PVC for the coil but it dosn't work as well as copper. Just a thought for ya on how to improve the heat absorbitaion and protect your investment. And a plus there is no way for water or wind to get to the coils, that would in turn cool them off. Like the Instructable!
matt8inc4 years ago
Great idea. I have taken alot of your ideas but used normal pvc hose pipe instead of copper pipe. I am trying the very poor council estate way using tin foil as a storer of heat behind the piping painted black mat. Folding the foil up around 5 times. Using 50m of pipe and taken into account the idea of using a sepearate pump. Do you think it would be a good idea to cover with glass. I was thinking maybe the reflection bounces light of but on the other hand keeps heat in.
jaketeater5 years ago
PVC can be used in solar heaters.  There are limitations, but if cost is a factor PVC is worth a look.  

I built one - check it out - 
www.teaters.com/modules.php

Lynxspring (author)  jaketeater5 years ago
It will work, but the reason for using a metal, was to make it more compact. since copper is a better conductor, the heater was much smaller.  (only takes up 4' x 2' )  Taking into consideration our lattitude, and the time we have the sun out on the heater. We are able to heat up a pool. it's only about efficiency.

Lynxspring (author) 5 years ago
UPDATE
summer is over... no pool discoloration...I added a small pipe on the top collector, with a cap. Makes it easier to empty the thing and add a bit of pool antifreeze before winter.
I used a shopvac to blow some air into the system to flush it out.

I will build a second module for next summer, and add it to the first one...
Adding a black metal backing or closing the sides did not make any significant difference.
Great information!  Did you know it's also possible to use ageothermal heat pump to warm a pool?  Solar can only cool waterover 50 degrees, but geothermal can heat even the coldest ofwater.  For more information see Geothermal Experts
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