Homemade wood heater

[Rumbleehockey03]

All this social distance free time I had made me want to get the pool warmed up for cheap. After some youtubeing I made a heater out of a 55gal drum, copper coil, and my winter cover sump pump. I’m Getting about 20 degree rise at 3gpm and have calculated that I should get about 10 degrees if I run it for a week for 8ish hours per day...I’ll take it.
I should’ve put the coil on the outside and ordered some firebox insulation to caver it. I will probably got the plumbing store tomorrow for some more copper to add some outside coils to up my heat exchange.
Overall, seems to be working well for about $100 invested.

 

[ajw22]

You should make a combo wood pool heater and pizza oven. Maybe a smoker also?

 

[Rumbleehockey03]

You should make a combo wood pool heater and pizza oven. Maybe a smoker also?

That’s honestly a completely doable idea and would justify me spending more money on it since it would be double-duty. I also will be in the market soon for a new smoker???

 

[Donldson]

Pretty interesting! One thing: if you possibly can try to increase the GPM. The larger the difference between the input and output temperature, the less efficient it is. Any increase in GPM you get will get more out of the system.

 

[JoyfulNoise]

An old radiator from a car would help. The copper coils would be more efficient with some metal fins sweated to them.

 

[JoyfulNoise]

Or even an old air conditioner heat exchanger.

 

[JoyfulNoise]

At the very least, wrap some fiberglass insulation around the drum, you’re definitely radiating a huge amount of heat away.

 

[JoyfulNoise]

Also, make sure you’re sucking water from the skimmer into the heater and then returning it to the bottom of the pool. Convective mixing will help ensure good heat distribution.

 

[Rumbleehockey03]

Also, make sure you’re sucking water from the skimmer into the heater and then returning it to the bottom of the pool. Convective mixing will help ensure good heat distribution.

I’m actually pulling from around 2’ deep in the pool and returning hot to the skimmer to mix. The return eye is pointed as far down as I can get it.

 

[Rumbleehockey03]

Pretty interesting! One thing: if you possibly can try to increase the GPM. The larger the difference between the input and output temperature, the less efficient it is. Any increase in GPM you get will get more out of the system.

I’m trying to avoid buying a better pump but still want to add some outer coils to the barrel. I could possibly split the inside/outside to provide parallel paths and might could get up towards 4-5gpm that way. I have a friend who is a plumber so can get that split made pretty easily. My intake and outlet hoses are 5/8”

 

[PoolGate]

How much wood does it use?

 

[JoyfulNoise]

Here’s a good resource -

Firewood BTU Charts - BTU of Firewood Cord

Firewood BTU charts for energy content and weight per cord for common firewood types and species.

worldforestindustries.com

 

[JoyfulNoise]

If you can wrap a coil of copper around the outside of the drum, I would send water there first to pre-heat it before sending water into the combustion chamber. That will cut down on the temperature differential between the input and output of the combustion chamber. The best heat transfer will happen if the outer copper coil is brazed to the drum body; intimate contact is required for good heat transfer. Placing a fiberglass blanket on the drum, or wrapping the outside with fiberglass, will help to slow radiative and connective heat losses which are huge in your current setup. Most of the heat from the wood is going out the exhaust or radiating away to the surrounding air.

That’s a fun setup. Perfect science experiment for kids that stuck home from school ...

 

[AndyTN]

 

[Newdude]

My inner Manchild and Redneck is LOVIN this. Thanks Rumblee !!