In my travels on the internet, I tried to find an industry standard working model for installing a ground coupled heat exchanger that I could copy and found that it doesn't exist. Everyone seems to have a different opinion on how this system should operate which led me to the conclusion that the design is very site specific.
In my situation, I have a hot, humid climate that I most need to mitigate, a limited budget, a bulldozer, fairly easy to dig clay subsoil, much slope in all directions (both away from the house and towards), all connected to a home which will be off grid and will not have the power required to run a dehumidifier at night.
I went with 6" non perforated corrugated flexible pipe and chose to bury them 170' from the house. From various studies, you get diminishing returns after 130' so this should be adequate. There is 20' of drop from the house so I am not concerned with the pipes not draining properly. I used corrugated because in the flat walled pipe, the air separates into layers and a slow moving layer forms on the inner surface of the pipe and the hot, humid air flows through that layer of slower moving air directly into the home. The goal of this system is to have as much of the air as possible come into contact with the inner surface of the pipe which is directly in contact with the ground to create the greatest amount of heat and humidity transfer so a bumpy inner wall over distance helps this process .