How Heat Pumps Cool

There are several cooling system options to choose from! One of them is the heat pump.  But how does it work? To cool your home, heat pumps transfer heat from the air inside the home to the outside of your home. To perform this function, a heat pump works like a central air conditioning system. It has three main components: a compressor, a condenser, and an evaporator coil. These parts are responsible for converting the working chemical known as a refrigerant (R410A) from a gas to a liquid and then back again. The air handler (indoor unit), which contains the evaporator coil, removes undesired indoor warmth and humidity from the air. The heat pump (outdoor unit), which contains the condenser and compressor, releases the heat that the indoor unit captured.

The Cooling Cycle

The cycle of cooling begins when the refrigerant arrives at the compressor as a cool, low-pressure gas. The compressor then squeezes the refrigerant and packs the molecules of the refrigerant closer together, causing them to increase in temperature. The refrigerant leaves the compressor as hot, high-pressure gas and flows into the condenser. In the condensing coil, the refrigerant releases its heat. A fan draws outdoor air in through louvers surrounding the outdoor cabinet and blows air across the hot coil. As the air blows across the coil, it transfers the heat to the outside air.  Additionally, cooling the refrigerant inside the coil.

Once the refrigerant leaves the condenser coil, its temperature is much cooler. Also, it has changed from a gas to a liquid. The refrigerant then flows indoors through the tubing and passes through a small opening in the expansion valve. In this valve, the refrigerant expands and the liquid’s pressure drops, and it becomes a low-temperature, low-pressure liquid that flows into the evaporator coil. Once here, it evaporates and absorbs heat from the return air, which blows over the indoor coil due to a fan. At the same time, moisture in the air is removed as it condenses on the indoor coil. As it makes contact with the indoor coil, humidity is removed from the air. Then, it collects in a pan at the bottom of the coil. Finally, it flows to a drain or pumps to a drainage receptacle. The result? Your home is comfortable even when there are sweltering temperatures outside!

How Heat Pumps Heat

When an air-source heat pump is heating your home, the cooling cycle is reversed. In the outdoor unit, the heat pump evaporates a low-temperature refrigerant. As the liquid evaporates, it absorbs heat from the outside air. A heat pump can do this because heat exists in all air even down to absolute zero (-460 F or -273 c). Even cold winter air contains heat.

After the gas is compressed in the outdoor unit’s compressor, it passes into the indoor coil and condenses; this releases heat to the inside of the house. The pressure changes caused by the compressor and the expansion valve then allow the gas to evaporate at a low temperature outside and condense at a higher temperature indoors. All this work lets you come home to a warm, comfy house, even where it's crisp and cold outdoors.

O'Brien Service Company

Call O'Briens for all of your HVAC needs! For more information on heat pumps, click these links:  heating installation, why do heat pumps have defrost systems?, and which system is better to heat my home?

 

For more information on heat pumps, click here to visit Trane's website.

"We have a heat pump. There was a sour odor coming from the vents when the heat would come on. We called O'Brien's and they sent Chris H. as our service technician. He resolved the problem immediately by cleaning our system. He then went outside and checked everything there and then cleaned the outdoor unit completely including the concrete slab that it sits on. I've never had a technician so absolutely conscientious about being careful, clean, and thorough. I will recommend O'Brien's and Chris any day of the week. I have called and asked that Chris be our regular technician in the future." -Kurt M. (Rocky Point 28457)