Geothermal heat pump
What it is
There are two main types of heat pumps connected by ductwork: air-to-air and ground-source or geothermal.
A dual-source heat pump combines an ASHP with a geothermal heat pump.
Its parts
- Compressor
- Because the compressor for a ground-source heat pump is located inside the home, it is subject to much less wear and tear than the outdoor compressor fan of an air-source heat pump. As a result, ground-source heat pumps last longer and maintain their efficiency better than air-source heat pumps. System life is estimated at 25 years for the inside components and 50+ years for the ground loop (DOE 2012).
- There are two broad categories of compressors: positive displacement and dynamic.
- Expansion valve
- If overfeeding of the expansion valve causes intermittent flooding of liquid into the suction line, the compressor may be damaged.
- Liquid refrigerant enters the expansion valve, is reduced in pressure and temperature at the valve port, and enters the evaporator at point A as a mixture of saturated liquid and vapor.
- Air handler
- upflow air handler for a traditional heat pump has an electric resistance auxiliary heating element located at the top of the unit (circled in red).
- Auxiliary heat
- In the case of typical electric resistance auxiliary heat, the heat pump can continue to contribute simultaneous to the auxiliary heat.
Related pages
- Glossary: Geothermal heat pump
Its entry, and the guide's pages that use it.
- Heat pumps
How a heat pump heats and cools, and how it copes with Chicago cold
Sources
- U.S. Department of Energy. Heat Pump Systems.
- U.S. Department of Energy. Consumer Guide to Geothermal Heat Pumps.
- U.S. Department of Energy. Ground-Source Heat Pumps.
- ASHRAE. ASHRAE Handbook—Compressors.
- ASHRAE. ASHRAE Handbook—Refrigerant Control Devices.
- U.S. Department of Energy. Cold Climate Heat Pump Sizing and Selection.