Ground Loop Heat Pump Directions

A heat pump is a device that uses compression and expansion to draw thermal energy from a cold environment and use it to warm another environment. In the simplest sense, heat pumps are air conditioners in reverse. Heat pumps can only raise the temperature by 30 degrees Fahrenheit, so standard heat pumps, which use the outside air as the cold environment, are impractical in cold climates. Placing the cold environment coils underground, where the temperature stays between 50-60 degrees year round, can allow you to use a heat pump in colder climates.

Shovel/ backhoe tractor
High pressure stainless steel tubing
Radiant heat exchanger
Duct tape
Refrigerant filling port
Compressor
Expansion port
Solder
Blow torch
Refrigerant

Instructions

- 1
  Dig a hole adjacent to the building using the heat pump. The hole needs to be about 1/2 the footprint of the building and 2 feet deeper than the local frost line. The frost lines vary from 3-5 feet in most of the continental US.
- 2
  Lay out the stainless steel tubing along the bottom of the hole in a zig-zag manner. Parallel lines of tubing should be kept about 2 feet apart from each other. The ends should both be close to the building where you are going to run the lines in to the ventilation system.
- 3
  Run the tubing into the building and to the ventilation system then back fill the hole, covering the tubing, with dirt.
- 4
  Place the heat exchanger in front of the ventilation fan, so that air blown by the fan will blow easily through the coils of the heat exchanger then down the duct work to the building's vents. There should be no gaps in the ventilation system, so duct tape should be wrapped around the joints to make sure the system is air tight.
- 5
  Connect one of the ends of the stainless steel tubing to refrigerant filling port then connect the other side of the port to the compressor's input.
- 6
  Use a small length of tubing to connect the output of the compressor and the input of the heat exchanger.
- 7
  Connect the input of the expansion port to the output of the heat exchanger then connect the free end of the tubing to the output of the expansion port. This will completely seal the refrigerant loop of the heat exchanger.
- 8
  Solder each joint in the refrigerant loop closed using the solder and blow torch. This is to prevent leaks when the system is pressurized. If you used only pressure-lock joints through the entire system, you should not solder the joints, because these joints will self seal when the pressure is increased.
- 9
  Fill the refrigerant loop with refrigerant at the filling port.

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