Thread: DIY heat pump??
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Old 09-20-2008, 04:49 PM   #3 (permalink)
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Originally Posted by SuperTrooper View Post
The problem is heat pumps are very inefficient in cold environments. The heat expelled from the condenser was originally absorbed from the air passing over the evaporator. In a cold environment there is very little heat to be absorbed by the evaporator, therefore little heat is produced.

Your window A/C unit was designed to do one thing: cool. There are larger wall mount units that do both heating and cooling, but the efficiency numbers for the heating cycle are much lower than the cooling cycle.
But today, it's in the 50s
I'm thinking today would be the perfect kind of day for a mild-heat pump system. Scavenge what heat is left of the summer!

My backyard borders on a little swamp, and 70 yards back is a small lake (~ 100,000 sq feet). It's surface is 2 below the bottom of my back yard. This means the water table in the lower part of the backyard is only about 2 feet down..

So, I have a giant source of 54 to 58 degree water/coolant in the ground out back.

All I have to do is plant a really big heat exchanger about 5 feet underground. Closed-loop type sounds like the best.

This morning, I ran the cold water tap for a long time before making my
breakfast drink. It didn't feel cold, so I measured it. 62 degrees!
It was room temperature! (The hotwater system was off & cold).

Anyways, that should take care of the problem of cold weather..?.

Just have to build the right kind of heat exchanger to couple into a modded AC unit.?.

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