Tennman
Minister of Fire
Buzz, Be great to share what your CE comes up with in the underground sticky. This question comes up fairly often and usually the answer is based on a successful experience from the kind pros who help folks out here for free. Most likely your friend has some type of table to tell him compressive psi as a function of depth.
As I recall all the pre-foamed underground products use the polyurethane so the insulation properties are the same as the in trench approach. That makes foam thickness essentially the only factor in which process provides the best insulation. My barn to house underground run is ~140-150' (add maybe another 50-60' in root cellar and boiler barn). If our underground run had been 30-50' probably would have gone with Thermopex or Logstor. During long periods of idling with the pump running (only energy loss is line leakage) I've seen less than a 3 degF (actually ~2 deg) temp loss for the ~350' round trip including through the water to air HX. No question which method is the most thermal efficient, but having the plastic protector adds some value. For really long runs like ours the extra foam thickness translates into less wood usage not sure how much. But I CAN tell you first hand about the energy loss from a bad underground! Looking forward to hearing what you learn from your CE buddy. Best wishes, take your time. Gotta go make money.
As I recall all the pre-foamed underground products use the polyurethane so the insulation properties are the same as the in trench approach. That makes foam thickness essentially the only factor in which process provides the best insulation. My barn to house underground run is ~140-150' (add maybe another 50-60' in root cellar and boiler barn). If our underground run had been 30-50' probably would have gone with Thermopex or Logstor. During long periods of idling with the pump running (only energy loss is line leakage) I've seen less than a 3 degF (actually ~2 deg) temp loss for the ~350' round trip including through the water to air HX. No question which method is the most thermal efficient, but having the plastic protector adds some value. For really long runs like ours the extra foam thickness translates into less wood usage not sure how much. But I CAN tell you first hand about the energy loss from a bad underground! Looking forward to hearing what you learn from your CE buddy. Best wishes, take your time. Gotta go make money.
