The 300% rain that we received here in Tennessee this summer finally dried out enough where I was able to finish burying the cooltubes out into the forest. It turned out to be fairly labor intensive the way I did it as I was unable to use a machine to bury the tubes directly. The clearing I had made in the forest for the ditch was fairly well surrounded by trees making it impossible to get my backhoe in there. Also, the ditch was only 3-4' deep which required me to be very particular about getting the fill directly in contact with the tubes just right to maximize heat the transfer from the tubes to the earth.
There is no "industry standard" as yet for the installation of this system. I had to take into consideration the soil type, topography, available equipment, and budget to design my earth air heat exchange system based on the knowledge available to me at the time. I put the tubes 3-4' underground and had them exit the ground horizontally to maximize drainage. The fall in elevation from where they exit the house is 15' which made me decide use a solid, non perforated pipe as any water due to condensation would drain out of the downhill end eliminating the need for a perforated pipe. I did not want to use perforated pipe as the holes are an entry point for underground moisture. With the solid pipe making any condensation drain out only at the end of the pipe, there is no need for gravel in the ditch around the tubes. The dry-ish crumbly clay I packed around the tubes has much more surface area than gravel maximizing the contact with and heat exchange from the air through the wall of the tubes and into the earth.
Dirt has .1R value per 1 inch. I buried 2" of white beadboard insulation (the cheap stuff) on top of the 6" of dirt on top of the tubes. So the math: 2" of insulation at 5R value per inch= 10 Rvalue/.1 Rvalue per inch of dirt = 100"/12 = 8.3'+3'deep burial = 11.3' deep
Part of the plan here is to have a small dairy operation to reduce or eliminate feed costs to the birds and hogs. My animals can get what they need off pasture to survive but to be productive, they need protein and mineral supplementation. Cows or other ruminant animals more efficiently convert grasses and forage to protein, minerals, and other nutrients in the form of meat and milk, and manure. These animals fill a niche here at the farm.
Dexters make the best fit here. They are easy to find on Craigslist, not far away, and produce good quality milk and meat. You can have a 40% larger herd due to both smaller size and foraging efficiency. You can also breed them with Jerseys to produce other breeds with more milk such as the Belfair or breed to an Angus or Simmental to get better beef.
I found a guy who had Dexter registered calves and bred heifers for sale. We had a 3hour round trip to get them and they had to be rounded up and put on the trailer. We bought all 3 heifer calves and got 1 of each color.