DIY: Ground Water Heat Pump

A heat pump is a heating system that uses compression and expansion to draw thermal energy from a cool environment and deposit it in a warm environment. These systems are common in subtropical climates where the temperature may get low in the winter, but seldom falls below 40 degrees Fahrenheit, since heat pumps can only raise the temperature 30 degrees above the cold environment. A heat pump which uses ground water as the cold environment, could be used in more temperate climates, since the ground temperature is stable between 50 to 60 degrees no matter the air temperature.

2 Ground water wells; one with a pump and the other without a pump
Liquid-liquid heat exchanger
High-pressure tubing
Expansion port
Refrigerant filling port
Compressor
Radiant heat exchanger
Refrigerant

Instructions

- 1
  Connect each water well to the liquid-liquid heat exchanger using high pressure tubing. Use the larger volume side of the heat exchanger. The well with the pump should be connected to the input side while the output side should be connected to the well without a pump. This will allow water to flow from the pump, to the heat exchanger then back under ground, preventing destruction of the local ground water supply.
- 2
  Screw the expansion port onto the smaller volume input of the heat exchanger then run tubing from the expansion port and the heat exchanger's output to the building's ventilation system. Typically the heat exchanger is located in a semi-heated area, such as a crawl space or small shed. This prevents excessive heat loss to the environment.
- 3
  Screw the filling port onto the tubing running directly to the heat exchanger; connect the other side the port to the compressor's input.
- 4
  Insert the radiant heat exchanger in front of the ventilation system's fan. There should be an air tight seal between the fan, the heat exchanger and the duct work.
- 5
  Connect the tubing running to the expansion port to the output of the radiant heat exchanger; connect a short segment of tubing between the output of the compressor and the input of the heat exchanger. This will complete the refrigerant loop.
- 6
  Fill the refrigerant loop with refrigerant at the filling port. The compressor will pressurize the refrigerant, heating it up. The warmth will be dumped to the building via the radiant heat exchanger. The refrigerant will be allowed to depressurize, cooling it well below the ground water's temperature. The water warms the refrigerant which then repeats the cycle. To activate the system, the ground water pump, the compressor and the fan all need to be turned on.

Energy Saver Electrical Heaters

Renewable Energy Systems in Wisconsin

Energy Efficient Homes