Looking for advice on heating above ground pool

[Nico]

hi, i am looking for some advice on a self build solar hot water heater for my above ground swimming pool. I live in Normandy, France, i have a 40m2 30 degree south facing roof that i was going to mount some insulated timber frames containing black 13mm hose in 100m lengths, covered with polycarbonate. I have a 300w wind turbine and a 150w solar panel rigged up to a bank of deep cycle 12v batteries, through a charge controller. I aim to use 2 12v self priming pumps to produce a flow of 5l per minute through the 4-600m of pipe, hoping that this will create enough heat to reduce the use of my mains powered heat exchanger. The pool is 50m3, and i want to continuosly run the pumps for approx 8 hours per day. The total maximum pumped height is 3m, and pipe length can be varied. I was looking at shurflo 8000 series pumps, but dont know if this will do the job, any ideas are most gratefully received

[sdold]

Hi Nico, and welcome to Solar Panel Talk. If you make additional posts, you might not be able to see them until the forum administrator has "approved" you for posting. Please be patient, it usually only takes a few hours.

Steve

[J.P.M.]

1.) To maintain pool water temp. for the least financial input, get and use a pool cover before an add on solar water heater. Unbeatable for cost effectiveness, much easier than solar heating and so more sensible as a first measure. A pool cover will also reduce the required size of any stand alone solar pool water heater.

2.) See builditsoalr.com for ideas on DIY soalr pool water heaters. Some are good, others are best described as redneck engineering.

3.) Consider solar panels made for pool heating, Fafco, etc. Much more efficient and reliable and easier to plumb. Aesthetics are usually better as well.

4.) First guess at solar pool heater size might be ~ 50 % of pool area as a start and work up in area as needs dictate. DIY arrangements will take more area approx. inversely proportional to efficiency penalty over made for purpose commercial pool panels.

[Nico]

1.) To maintain pool water temp. for the least financial input, get and use a pool cover before an add on solar water heater. Unbeatable for cost effectiveness, much easier than solar heating and so more sensible as a first measure. A pool cover will also reduce the required size of any stand alone solar pool water heater.

2.) See builditsoalr.com for ideas on DIY soalr pool water heaters. Some are good, others are best described as redneck engineering.

3.) Consider solar panels made for pool heating, Fafco, etc. Much more efficient and reliable and easier to plumb. Aesthetics are usually better as well.

4.) First guess at solar pool heater size might be ~ 50 % of pool area as a start and work up in area as needs dictate. DIY arrangements will take more area approx. inversely proportional to efficiency penalty over made for purpose commercial pool panels.

Thanks J.P.M, in response, i have a solar pool cober and have insulated sides and beneath, although i believe these two are not particulatily productive.
i have seen the prefab products as i have a distribution agreement with a french pool manufacturer, even at cost these seem expensive. 10 ft from the pool is the south facing roof of an outbuilding, newly reinforced and perfect for the job, atleast as big as the pool, i just hoped, rather than running my pool pump constantly (mains) i could utilise the regular sea breeze and some solar back up to run water through 4-600m of black hose to heat the pool in the day. I understand the build, its the water pumps and battery bank i am struggling with. There is loads of info on the www for systems using mains power pumps, but little on 12v. I can get the parts for 1/3rd cost of thr equivalent branded heaters, i already have a turbine etc, just wanted 6o harness mother nature in totallity. Any help is really gratefully received, as i said loads of info on systems pumped from mains power or by filter pump, little on a 12v dc system ? apologies not a usual emoji user

[Nico]

Other option would be to run solar electric panels amd a turbine plus inverter to run pump and heat exchanger, at 12.5kw plus pump, i guess this would mean quite a lot of batteries and solar cells etc? I have a 300w turbine, i have room for more!

[J.P.M.]

Other option would be to run solar electric panels amd a turbine plus inverter to run pump and heat exchanger, at 12.5kw plus pump, i guess this would mean quite a lot of batteries and solar cells etc? I have a 300w turbine, i have room for more!

Generating electricity and then using it to heat pool water is about the most unproductive and wasteful use of electricity I can think of (except maybe those old kitchen tools that used to electrocute hot dogs).

Powering a pump - sure - great application. But the amount of energy necessary to keep pool water warm is a couple of orders of magnitude or more than what's required to run a pump.

Sounds like you're unfamiliar with heat loads, the best ways to meet them, or the idea of matching the quality of the energy source to the task (the load).

Heating water is a dumb, high entropy job best done by dumb flat plate solar thermal collectors or natural gas. Electricity is a low entropy energy source. It takes a lot of energy to get it to that low entropy/high energy/high versatility and high energy quality state. That's why the same amount of energy supplied via electricity usually costs 2 to 3 times what the same amount of energy supplied via burning of fossil fuels costs.

[Nico]

Hi, thanks, I realise that trying to generate electricity to heat the water is too much, I just need advice on a good constant flow self priming pump and the maximum amount of pipe I can pump the water through, thanks again

[J.P.M.]

Hi, thanks, I realise that trying to generate electricity to heat the water is too much, I just need advice on a good constant flow self priming pump and the maximum amount of pipe I can pump the water through, thanks again

Because I don't know the specifics of the application such as piping, array size or flow arrangements etc, and because of that, anything I suggest would be based on incomplete information, I don't make equipment recommendations.

I'd suggest getting the preliminary design done, including design flow rates and resulting head loss estimates and then consult pump curves among possible pump candidates for pump selection. Then iterate the design as necessary.

[LucMan]

A common practice for solar pool heating is to utilize the existing line voltage pool filter pump circulating the water through the panels. A 5 lpm pump is not going to do any thing for you. Solar pool heaters work on a very small delta T, and usually a high volume of water pumped through the panels because of the high resistance of the tubes and line length.
An average pump would 1.5 HP with a capacity of around 1000 gph (3800 liters per hr.)

[aabuin]

Hi,

For what it's worth, I have been researching this topic and I tried to gather all the good tidbits of information into my new system. We recently moved into a house with a large old pool without a heater, live in a sunny area (not hot, though). Solar sounded like the way to go.

I have a cover, limited the length of tubing per panel, connected them in parallel, covered them with plexiglass, added corrugated metal, etc etc...

Here is a video I made, along with the performance calculations: https://www.youtube.com/watch?v=9Fz4pJNP3v8

I hope it helps!

Thanks all

Alex

[sdold]

Here is a video I made, along with the performance calculations: https://www.youtube.com/watch?v=9Fz4pJNP3v8

Hi Alex, it might take a few hours or possibly a day or two for your account to be fully approved for posting. In the meantime I approved this post. Nice video, and welcome to the forum.