Heat pumps can seem a bit mysterious to the average homeowner. How can the same system provide both warm and cold air? And how can it provide more usable energy (in the form of heat) than it consumes in electrical energy?
A quick look at the anatomy of a heat pump system can help provide some answers. Here are the main parts of a heat pump:
- Compressor – The literal pump in a “heat pump,” though it actually pumps refrigerant.
- Refrigerant – A pressurized liquid with a very low boiling point. It can only boil when the pressure is released, though.
- Expansion valve – A valve that allows the refrigerant to expand, thereby lowering its pressure. The compressor supplies pressure, while the expansion valve releases pressure.
- Indoor coil – The part of the system that is inside the house, and either heats or cools the air.
- Outdoor coil – The part of the system outside the house. It also either heats or cools the air, though that air is quickly dissipated into the great outdoors. In the case of a geothermal system, the outdoor coil exchanges heat with the ground instead of the air.
- Fans – Used to blow air over the coils (and throughout the house, in the case of the indoor coil).
- Electric resistance coil – A heater that provides additional warmth during very cold weather. A dual-fuel system uses gas instead of electricity as a backup heat source.
When your home needs to be cooled, the compressor pressurizes the refrigerant in the outdoor coil, while the expansion valve lowers the pressure as the refrigerant then travels to the indoor coil. The lower pressure in the indoor coil allows the refrigerant to boil, which absorbs heat from the indoor air. The higher pressure in the outdoor coil causes the refrigerant to condense back to a liquid, releasing that heat in the process. For heating, the process is reversed; the outdoor coil absorbs heat, and the indoor coil releases heat.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about heat pumps and other HVAC topics, visit our website.
Glasco Heating & Air Conditioning services South Windsor, Connecticut and the surrounding areas.
|Heat Pump image via Shutterstock|