Impromptu redneck pool heater

[duanebe]

This isn't a permanent fixture... but thought some of you might get a chuckle out of this...

Cleaning up a bunch of stuff around the yard after pool construction... including several pallets, some old firewood... and I had an old piece of stainless pipe that I had once used to heat domestic water from my wood furnace, so I threw it into the pool water loop and tried to capture some BTU's while burning my yard waste...

Water was running through my solar loop before it hit the fire... I suspect the solar was collecting more heat than the fire, but I was getting a 4 degree rise at 8gpm. I figured that was pretty decent for "free" heat. Day was warm (27 degrees), pool started at 15 degrees in the AM, was 18 degrees by suppertime.. 30,000 gallons. I'm happy with that for a single day gain. I really need a heat pump, but budget is going into concrete deck right now.

 

[CJadamec]

Heat is heat and if you already had the stuff kicking around why not. Those domestic hot water coils can transfer a good amount of BTUs if the delta T is high enough. Just be careful about the outlet temp of the water, with an unregulated fire the potential exits to make the water leaving the coil hot enough to hurt people and damage plastic plumbing/pool parts. PVC is only rated to handling up to about 140F past that it becomes very soft and mushy.

 

[duanebe]

At 8gpm, the water coming into the pool was still only 21 degrees celsius at the highest... very safe temps... I wish it were higher! The delta in the coil was pretty huge... which is why I get a lot of black creosote buildup on the coil.

 

[CJadamec]

As long as there is water flow thru the coil the temps won't be bad its just the "I've watched too many safety videos mentality I get." Recognizing the risks and being aware of what can go wrong is a major step in doing things safely.

The black soot on the coil will dramatically cut the heat transfer down. It should basically be resting in the coals to get as much into the coil as possible. Oh and if you can get air forced or drawn up under the fire and through the coal bed you will get a much hotter fire.

Now you got me wondering if I can modify my maple sap evaporator for pool heat... That thing eats wood like mice eat peanut butter tho.

 

[duanebe]

I wouldn't trust anyone other than myself to try to operate this... even though it is very simple.... you are right, it could get dangerous very quickly.

The soot/creosote definitely reduces effectiveness... no practical way to keep it clean, and this is just a temporary setup that I will use while cleaning up the wooden/paper based yard waste.

If I ever do build something like this to operate more permanently, it would need a firebox so that the heat gets directed towards the coil... I'm likely losing 85% of the heat from the fire that doesn't even hit the coil.

Just a fun distraction at this point.... and it gives me incentive to find "all that burns" around the yard... things are tidying up quickly ;-)