How deep trench of the horizontal loop when install closed loop geothermal system?
You may need to get out what is the soil temp after coldest winter passed, if very low, the deeper, the better. Shallow loops need to place more longer pipes. Normally trenches deeper than 1.5m, and length for several thousand m, with a backhoe or chain trencher, then pipe laid in the trench and backfilled. A typical horizontal ground loop will be 30-50m long for each KW of heating and cooling.