Anatomy Of A Heat Pump: How This Unique System Does Such An Efficient Job
Heat pump systems are both simple and complex. Simple, because a single system provides both heating and cooling without requiring a separate air conditioner and furnace. Complex, because the ability to both heat and cool requires the system to have a lot of different parts.
To help you understand the basics of how a heat pump works, here is an anatomy of its major parts.
- Coils – A heat pump system has two radiator-like coils: one inside the house, and one outside. The coils are connected by two lengths of tubing, turning the system into one long, serpentine loop.
- Refrigerant – The substance that flows through the loop, refrigerant is naturally a gas, but condenses to a liquid when highly pressurized.
- Fans – Each coil has a fan to move air through the coil. This air is either heated or cooled by the coils.
- Compressor – The literal “pump” which pushes the refrigerant through the loop and pressurizes it in the process, the compressor can pump in either direction to reverse the flow of coolant.
- Expansion valve – This device releases the pressure that the compressor creates. Like the compressor, it can work in either direction. So, one half of the system is always pressurized, and one half is not. Whether the indoor coil or the outdoor coil is the pressurized half depends on whether the system is heating or cooling the house. The low-pressure coil cools the air as the refrigerant evaporates into a gas. The high-pressure coil heats the air as the refrigerant condenses back into a liquid.
- Electric resistance heater – This is a backup heat source used only when the temperature is at or below freezing.
A geothermal (or ground-source) system has the same parts, but adds an underground geothermal loop to exchange heat with the ground.
Together, these parts make the heat pump an energy-efficient way to heat and cool your home. The refrigerant simply carries heat into or out of the house; doing so requires much less energy than actually creating 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.
Air-Tro Inc. services the greater Los Angeles area as well as the metro areas of Riverside and San Bernardino County.