We are finally breaking ground on the shop. LOTS of delays. I don't want to get too hung up on "required btus" because I already own a 2 stage ClimateMaster 5T T27 unit, and target temps can sometimes be "better than what is going on outside"..... There will also be supplemental heating so this is not the only means of heat and the heat strips will be disabled. What we have is is a septic system that will be placed about 300ft from the building. I am installing my geo tubing directly under the septic lines. Some might offer concerns here but I did a lot of work in this area and there is no way one will cause issue with the other. I was originally going to go deep on this but right now, I need to target a more reasonable depth and design. Thinking 4ft but I need to run more numbers. I am in the middle of KS. What I need to do is run tubing out to the field, then return. The lateral runs will probably be 4x 125ft or so. I will probably make them 3ft wide. I want to make a straight run out there, run coils in each trench, then return, possibly in a separate trench. I would like to figure out a design for this, optimally without connections in the field and only using continuous pipe. Thermal conductivity of this area should be well optimized by the continuous wetting of the sewer, and the 5T unit will likely operate at the low setting of 3.25T most of the time, so if 5T is demanded, it would not need to be continuous because the shop is perfectly fine at 78F and reduced humidity, which is what running on low will provide. I am mostly trying to figure out how to move fluid between the EWT and LWT lines in the ground. How much separation? Also, these lines will have to be in the middle of my rock driveway. I am totally conflicted if I want to bed them with concrete, flowable fill, sand, nothing, etc. Concrete should eliminate potential breaks, but if an issue occurs, repair becomes a nightmare.