Finally got my shop/gameroom/carport building up and started talking to family members about how the driveway should shaped etc.. It’s 174 feet to the road and will meet the front of the carport slab that’s 50 feet wide. After paying $700 to fill the propane tank to heat the pool (primarily) and water in the shop bath, I got to thinking about the possibility of implanting loops of pex water line in the concrete to pump pool water through during the cold months to heat the pool. We have mild winters in Cent. TX and I’ve noticed warm concrete in the past during winter. Has anyone ever seen or done such a thing?
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I used to install pools, mostly vinyl liner in-ground types. All but one of the companies I subbed from used 1 1/2" black poly pipe to plumb those pools. I found that laying a 50' roll of that stuff on any dry surface and running water through it with a standard pool pump would raise the temperature a few degrees.
Of course it had to be sunny. Obviously a 100' roll would raise the temperature more. So, on a sunny day, using a 100' roll, you could raise the pool's temperature about five-six degrees while running the filter for eight hours.
Poly pipe is very inexpensive. So, if this idea appeals to you, I'll be glad to get into more detail about how to make it work well.
I'd check out motherearthnews - You can build a cheap solar water heater for under a hundred bucks that would work a lot better. Basically a black container to heat water, that would absorb better than plain concrete. You can get water temps of up to 180 degrees if done properly, which is better than you would get from your concrete slab
Try the link below,
http://www.google.com/search?q=build+solar+water+heater+site%3Amotherearthnews.com
Go with Nater's route. I've installed several heated sidewalks and driveways for commercial buildings here in Michigan to keep main entrances and such clear of snow in the winter. This type of slab will dramatically increase the cost of install even before you consider if it would be worth using to heat pool water on the return run.
I also know these slabs are not as durable and we have had problems with them. The increased cost also comes from several factors; 1. is the equipment needed and material just for the piping. 2. The concrete generally needs to be thicker to compensate for all the "hollow" tubes running through it or a stronger mix. 3. Is the labor, it's very critical and tricky to get the piping in right while pouring the slab. Even when the lines are charged while concrete is placed they want to float up in the mix. So the slab needs to be poured with sand chairs, and road mesh and than just about every 6" of pipe needs to be tied down or an additional rebar matt laid on top of the piping to weight it. However it's also a fine line between having the piping just below the surface to be effective and not popping out after it's been bull floated. Than there is the consideration of when the slab cracks and where and that it dosen't end up rupturing the water lines inside it.
Far, far, simpler, effective, and cheaper to install an additional water heater.
it's experimental, but we've seen people pull 120 degree water out of a darkish slab driveway piped for snowmelt in august, in Massacheusetts, on an overcast day.
I suspect there is lots of energy to be had. Pipe isn't necessarily that expensive. use a heat exchanger or, in our case we piped the pool liner (gunite) itself to heat the pool "radiantly".
I can't say it's foolproof or definitely a great idea, but people are playing with it and you can get significant heat from it.
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