Dxgshpwh (ground source heat pump water heater)

[AC_Hacker]

Originally Posted by MEMPHIS91

Here is where the change happened. I could not get 30 feet of 1/4 refrigeration copper to coil in the tank without going to the top. This really was a problem because I had planned on simply brazing on an old hacked element base and continuing to screw the coil in. So I just uncoiled the tubing and and ran in it the bottom element hole and got it to coil at the bottom.

I used teflon tape and joint compound with a 36" aluminum pipe wrench to put it all together. I will finish the back half tonight. Idea is to braze the coil through a 1 inch bass cap then tighten the union down. I'll post more picture at the right size from now on.

Very interesting approach, all around. Brilliant to use an inspection cam to see what's going on, thanks for the pic!

And your solution to the problem of twisting the copper tubing, by using a pipe union is just awesome.

Great stuff!

Best,

-AC

[jeff5may]

Pictures have been showing up ok on my smartphone. HTC evo 4g running android 4.0.3, on WiFi only.

[MEMPHIS91]

Got to all brazed up last night. Its held house pressure with no leaks all night.

[Daox]

The project seems to be coming along great.

[AC_Hacker]

It's going to be really interesting to see how the earth works part of the project goes.

I don't know how easy it is to dig where you are, but we have had reports from other Mississippians who reported that boreholes were not a huge problem.

I hope that part goes well for you.

-AC

[MEMPHIS91]

Thanks so much for all the replies.
Randen
Somehow I totally missed your post, thank you for your insight. Very encouraging to know you think it is going to work so well. I got to play with the compressor some today it was pulling 2.13 amps on 120 volts with R290 and 17 psi on the low side. So you estimate looks very accurate.

Starting to plot out where everything is going to go. The bucket is the compressor housing and the compression coupling is the hole. I'm going to just put the paving stone back over the hole when I'm done filling it with the pea gravel.
Question, should I wrap the tubing coming back from the hole around the compressor a few times? I think I could gain some heat and also keep the compressor cool. Also should I insulate the housing for the compressor?

This is the updated drill head, as you can see it is going to be 3.5 inchs instead of 2.

[randen]

MEMPHIS91

Good point yes wrap the compressor with evaporator tube. These little rotor type compressors liberate a lot of heat while operating. You could wrap it from mid way up to the top where most of the heat is generated. Maybe after returning from the ground loop to the compressor wrap for additional heat. Good thought!!!!

I wouldn't recommend insulating though. Any trapped heat could overheat the compressors windings burning out the motor. Leave it naked with only the copper tubing wraps.

Randen

Looks really good I like the tank/HX coupling solution!!

[MEMPHIS91]

Originally Posted by randen

MEMPHIS91

Good point yes wrap the compressor with evaporator tube. These little rotor type compressors liberate a lot of heat while operating. You could wrap it from mid way up to the top where most of the heat is generated. Maybe after returning from the ground loop to the compressor wrap for additional heat. Good thought!!!!

I wouldn't recommend insulating though. Any trapped heat could overheat the compressors windings burning out the motor. Leave it naked with only the copper tubing wraps.

Randen

Looks really good I like the tank/HX coupling solution!!

Yes that was exactly what I was thinking, good point about wrapping only the top half. Ok ill just make a cover with plenty of holes in it, and maybe one with less holes for the winter months that I can just swap out.

[jeff5may]

Your brass cap adapter is an awesome idea! Coupled with a common union it's ingenious. Common parts, simple construction methods, I love it!

This adapter idea would make it much easier for the average garage hacker to build one of these energy-savvy devices. I hope you start a trend with this piece of magic.

[AC_Hacker]

Originally Posted by MEMPHIS91

Question, should I wrap the tubing coming back from the hole around the compressor a few times? I think I could gain some heat and also keep the compressor cool. Also should I insulate the housing for the compressor?

I think that it is a very good question about wrapping the compressor. The refrigerant will absorb a lot of heat in it's trip through the compressor (that keeps the compressor cool enough so it will not burn out), and the absorbed heat goes into your heat pump's out-put (hot water tank).

If you are going to use the cap tube that came with your A/C, it will be designed for the anticipated running environment of that air conditioner, using R22, and the condenser coils and evaporator coils that your unit came with.

When you hack a unit, you are violating the original design in so many ways! Vlad, a real refrigeration tech, was absolutely beside himself when he first heard what we were doing... until he tried it for himself. It's kind of a miracle that after all these reckless mods, the new machines not only work, but work so well.

It will be very interesting to see how wrapping the compressor in copper tubing will influence ultimate COP. Seems like it should be a good idea. Even without wrapping the compressor, which sounds like a good idea, I think that your COP is going to be very favorable, better than an air-source conversion. Your concept has very many features that favor high efficiency: ground source (conduction beats convection), direct expansion (no heat exchangers, each taking it's 10% toll), no pumps, no defrost cycles, no hassle with freezing conditions.

Because you are heating a tank of water, it will be very easy to do an accurate assessment of COP.

You really are on the cutting edge here.

Best,

-AC

P.S.: Awesome drill bit you have there... DIY?