[pick1e]

Hey all, thanks for sharing all this information. I found this thread searching for info on fixing up air conditioners I've only been able to read up through the first dozen pages so far though.

I too am headed down the DIY GSHP path. I think my project should be easy to accomplish. I have a 1 car detached garage that I would like to heat a little bit. I'm not living in it, it's just a workshop, so I'd just like to keep it from freezing in winter, maybe 45 degrees or so would be good, and raise it up to 60 or so when I'm working out there. I hope to use a window air conditioner unit and a water ground loop.

I have some questions though. What's the deal with straight down and up loops in PEX tubing? What kind of flowrate are you using? I would rather dig less holes and use some copper tubing, but I guess I'm curious if that's worth it, maybe the thermal transfer rate in the soil is the limiting factor? I mean suppose you buried the same size loop of copper instead of PEX in the same hole, would you still be limited to the same amount of heat gain?

I'm not a HVAC guy but I do have an engineering background so I know the thermo basics. I borrowed a heat transfer book from a friend (mine is long gone) and am trying to figure how much tubing I need... But I don't know the temps of the in and out water until I rig up a test I guess. Any insight here? What is a reasonable temperature of a cold evaporator? I could use that as a theoretical for max heat gain I suppose. I didn't know if I could use the ground temp as the theoretical exit temperature though. Do you guys with working systems see the exiting water reach ground temp or still slightly below?

I guess a big and most immediate question I have for you HVAC gurus (the answer to which could through a big monkey wrench into my plans) is can I extend the tubes leading to the evaporator coil? My plan was to literally add a few feet so that I could just hang the coil in a tub of water kept warm by the ground loop.

Thanks for any insight