DIY heat pump??

[Xringer]

I've been thinking about hacking an old 6,000 BTU AC and, I also have an old
de-humidifier that I could hack up.

But, I don't want to release any refrigerant into the air.
I've seen some affordable vacuum pumps for removing air from heatpump systems (preparation for R-410A),
but have not seen any cheap refrigerant recovery hardware.
The smaller units are in the $500 range.


That's interesting about the propane. I guess one could make his own
heat exchangers etc if he had the compressor..

I would really like to try making an HP hotwater heater for use in the summertime. (Air to water HP).

[franklinh]

I turned around my 5000btu window AC. The problems you encounter is that it won't turn on the compressor below 64 degrees. I had to open up the control panel and short the thermostat so that it would turn on no matter what the temperature. It was able to produce a useful amount of heat and I estimate that it produced the same amount of heat as a 3000 watt space heater. I tested by comparing how fast it could raise the temperature in my room compared with a 1500 watt resistance heater. The AC could heat up the room about twice as fast under the same conditions. This is when outside temp is around 55 degrees. Output heat is about 80 degrees. Input power is about 400 watts. The AC has an ERR rating of 9.7 and it appeared to be multiplying the power input by 7.5.

The next problem you will notice is that the coils freeze up on the outside. This is especially a problem in the morning when the morning dew. Then when you turn off the AC, all of this melts and flows back into the interior where you have the AC hanging in the room. You have to put a bucket to catch the water. When you turn on the AC, a stream of water comes out the bottom from the coils defrosting. This isn't so much a problem in the evening, but a big problem in the morning. The longest you could run this before it froze up is about 30 minutes. It could increase the temp in my room about 5 degrees during that time.

To cycle the AC, I hooked it up to an appliance timer. The smallest increment it can be set to is half an hour. I had it turn on during the night to keep the room warm.

I need to figure out how to redirect the melt water from the coils to the outside instead of the inside and figure out how to time the cycles so that it has time to defrost. Other than that, it seems to have converted my cheap $130 window air conditioner into a 3000 watt heater that only runs on 400 watts. Pretty neat ....

[Xringer]

Here's a link to some heat pump stuff that's been going on..

Geothermal & Heat Pumps - EcoRenovator
I've been using Sanyo Air Source heat pumps for a few years now..
They work real good until it gets real cold.. like 8deg F..

[Christ]

Anyone on here ever actually rebuilt a window or whole-home AC unit to act as a heat pump with a reversing valve?