How to cheaply heat pool?

[Pskhaat]

Despite the fact that it is still 109F out, our pool is getting too cold to swim in and we've got 2.5 more months of this heat hell.

Heating the pool with my natural gas heater is a ridiculous cost to us. Just outrageously expensive and not even close to worth it. Not inclined to poach electricity from the neighbor. I was considering hooking up a heat exchanger to the AC evaporator but that's big $ too. But we do have lots of sun, sun and more sun.

How about a small array of black ABS piping sitting out in the blazing sun and running pool water through it with low-volume pump?

Any other cheap ideas how to heat the pool?

 

[NorCal Cruiser]

Do you use a pool cover?

Energy Savers: Swimming Pool Covers

 

[Pskhaat]

So yes we have used a cover in the past. The problem is that if the cover is on during the day then we are insulating it from warming it from the sun which just reverses the situation. Otherwise we'll need to go out frequently to cover/decover.

 

[NorCal Cruiser]

Even though a cover blocks some solar energy it should still heat the pool. The main energy loss is due to evaporation. The cover should keep water from evaporating out of the pool which will make the pool warmer.

Swimming pools lose energy in a variety of ways, but evaporation is by far the largest source of energy loss. Evaporating water requires tremendous amounts of energy. It only takes 1 Btu (British thermal unit) to raise 1 pound of water 1 degree, but each pound of 80ºF water that evaporates takes a whopping 1,048 Btu of heat out of the pool.
This pie chart shows outdoor pool energy loss characteristics: there's a 70% energy loss from evaporation, 20% from radiation to sky, and 10% to ground and other.

The evaporation rate from an outdoor pool varies depending on the pool's temperature, air temperature and humidity, and the wind speed at the pool surface. The higher the pool temperature and wind speed and the lower the humidity, the greater the evaporation rate. In windy areas, you can add a windbreak—trees, shrubs, or a fence—to reduce evaporation. The windbreak needs to be high enough and close enough to the pool that it doesn't create turbulence over the pool, which will increase evaporation. You also don't want the windbreak to shade the pool from the sun, which helps heat it.

 

[FJ40_owner]

I run irragation tubing back and forth accross my roof and feed that supply into a home brewed solar panel. It runs on a Taco pump and a bulb stat set to 85 degrees OSA.

On a hot day I get about 20 degrees.

 

[LandCruiserPhil]

Even though a cover blocks some solar energy it should still heat the pool. The main energy loss is due to evaporation. The cover should keep water from evaporating out of the pool which will make the pool warmer.

100% correct

 

[Pskhaat]

It runs on a Taco pump and a bulb stat set to 85 degrees OSA.
.

Can yopu explain some more. What is a taco pump and what is your homemade panel?

 

[-Spike-]

Solar pool covers can make the pool so hot you won't want to be in it- in November around these parts. Maybe what you had wasn't designed to heat the water so much as keep dust out.

 

[FJ40_owner]

Can yopu explain some more. What is a taco pump and what is your homemade panel?

Taco is a brand name pump, like Grunfos. They make all kinds of pumps for pools, fountains, boilers etc.

The bulb stat is like a Honeywell T675a-xxxx. It senses temperature and makes and breaks at the setpoint on the scale. I have it installed on the roof to sense when the roof temp is above 85 degrees. This contact pulls in a contactor and starts the pump.

The home brewed panel is two water headers, large diameter pipe connected by capillary tubes of smaller diameter plastic tubing and covered by glass.

 

[tltaylor22]

In your area a solar heater or solar cover is ideal. Like the system FJ40_owner is talking about with a large header and footer pipe and a series of capillary pipes connecting the two, home made or purchased. You can also get a cheap cover that is basically like heavy duty blu bubble wrap. It stops the evaporation and still allows the UV light into the pool, thus heating the water under the cover. Do a quick google search on solar heating covers for pools. There's a ton of stuff out there in many different price ranges. I work in the spa industry and we have people wanting to hook up solar hot water heaters all the time to thier spas. In your area, the biggest problem is keeping spas cool enough in the summer.

 

[Pskhaat]

My neighbors have very warm pools, mine is cold. No idea why, mine is consistently deeper, darker and I loose less to evaporation (as we've compared). We think it is due to the wind down this "greenbelt" (not really green) where we are vs. other homes.

 

[-Spike-]

Deeper would contribute to colder. The wind should make it evaporate more.

The blue bubble wrap style covers are the ones I've seen heat the pool beyond hot. Is that what you had?

Is it possible water is being added to your pool that you aren't accounting for? Automatic level control or something? How's your water bill?

 

[stayalert]

Empty it and Paint it dark blue or black? An outdoor wood fired boiler would do the job nicely as well but would be some $....I talked to a farmer earlier this Summer who also sells fire wood he said his son hooked up his outdoor wood boiler to the outdoor pool and it was like 80 degrees all Winter.....In Vermont that's pretty remarkable.....I guess it helps if your dad sells firewood