i would of done it a long time ago but i dont have a back hoe handy
and i dont like diging by hand
how deep are u going ?
I'm not 100% sure of the trench length yet because it'll depend on how wide the trench is and how much I overlap the coil loops. The longer and less overlap the better for cooling but I don't know if that will be necessary with less than 1000w of heat going into the loop.
The plan is to do two passes in the hole, with a couple feet (maybe 18", I don't have data to support either option!) of dirt separating the layers. The warm water will go down into that top layer and exit colder from the bottom return one. The length and density of the coils will most likely come down to how easy or hard the excavating goes on the big day.
Here's the link to the ground temperature probe results from Maryland. The guy who didn't isn't sure if his probes at the bottom of the tube are insulated from the others enough because the temperatures are higher than the prevailing wisdom says they should be. Also his long term data isn't collecting correctly unfortunately. I'm going to try and set up a 1-wire system like he did so there will plenty of hard data on this projects results.
Condensation will become a problem at some point. The 1-wire controller pc could be programmed to monitor humidity and turn on de-humidifier (with drain valve) in the summer. The automation capabilities are quite amazing.