What Is a Heat Pump, and How Does It Work?

Purchasing appliances for your home is stressful if you don’t know what to expect. With all the product names, functions, and prices to deal with, remembering all the details is daunting.

One overlooked product that is integral to providing comfort in your home is the heat pump. For those who aren’t familiar, a heat pump is a machine that transfers heat from one location to the next.

There are a few different types of heat pumps. Here is your guide on what a heat pump is and how it works.

Know the Different Types of Heat Pumps

Heat pumps work both indoors and outdoors. They don’t generate heat—they move it from place to place.

An air source heat pump pushes air from inside your home to outside. Ground source heat pumps, also known as geothermal heat pumps, transfer the heat from indoor air to the ground outside your home. Since air source heat pumps are the most common type for home use, they will be our focus for this piece.

Outdoor units possess a fan and a coil. The fan blows air from outside over the coil, and the coil will either work as a condenser (for cooling) or an evaporator (for heating).

Indoor heat pumps, sometimes referred to as air handler units, also have a coil and fan, but for the opposite reasons as outdoor units. This means that the coil of an indoor unit will work as an evaporator for cooling and a condenser for heating because the fan moves air across the coil and throughout the vents in your home.

Be Aware of the Components That Make up a Heat Pump System

Now that you know the basic components of both indoor and outdoor units, you need to learn about the other pieces in the system. Refrigerant is the material that either absorbs or pushes away heat while it circulates in the heat pump. The refrigerant receives pressure from a compressor so it can flow freely throughout the system.

When refrigerant flow needs a reversal, the reversing valve allows the system to function the same but in the opposite direction for easy switching between heating and cooling. An expansion valve’s purpose is to make sure the flow of refrigerant remains consistent. Expansion valves also reduce pressure and decrease the temperature in the system by regulating the amount of refrigerant passing through, functioning as a metering device.

Learn How a Heat Pump Works in Cooling Mode

Heat pumps in cooling mode are almost functionally identical to air conditioners because they don’t create heat; they circulate it. If you’ve been looking for air conditioning filters online, you should learn more about the physical property of heat.

Heat energy naturally moves to areas with low temperature and pressure. Heat pumps use this physical property for efficiency by putting heat in cool, low-pressure environments for a natural transfer of energy.

When a heat pump is operating in cooling mode, it follows the same path every time. First, the liquid refrigerant goes through an expansion device. The indoor coil’s expansion device works as an evaporator during cooling mode. Then, indoor air travels across the coils. The refrigerant absorbs heat energy at this point.

This process results in cool air that blows all over the house. The liquid refrigerant heats up when it absorbs heat energy, causing it to evaporate. Now, as a gas, the refrigerant will go through the compressor. While the compressor pressurizes the gas, the refrigerant heats up even more due to the physical property of compressed gas. This hot gas then goes through the system, where it reaches the coil. Then, the coil pushes the compressed gas outdoors.

The outdoor unit’s fan then moves outside air across its coils, which serves as a condenser during cooling. The heat from the compressed gas refrigerant transfers into the air outside because outdoor air is cooler, and heat transfers to cooler locations naturally.

As the heat travels outside, the refrigerant goes back into a liquid state as it cools from the condenser. Eventually, the refrigerant, currently in a state of warm liquid, pumps through the system until it reaches the indoor unit’s expansion valve.

Once the refrigerant reaches the expansion valve, it cools significantly due to the reduction in pressure. Now that the refrigerant is back in a chill liquid state, it’s ready for the system to pump it back to the indoor unit’s evaporator coil to begin another cycle.

Review How a Heat Pump Works in Heat Mode

The operation procedure of heating mode is comparable to cooling mode, but the refrigerant flows in the reverse order because of the reversing valve. This means heat energy goes inside the home because the outside air is the heat source due to the flow reversal.

The role of the outside coil switches from condenser to evaporator, and the indoor coil turns into a condenser. The physics stay the same as the outdoor unit absorbs heat energy and turns it into cold gas with the cool liquid refrigerant. The cold gas turns back into a hot gas with pressurization.

Next, the hot gas passes cool air in the indoor unit, heats the air, and condenses the gas into a warm liquid. The pressure of the warm fluid reduces significantly when it returns to the outdoor unit, which turns it back into a cool liquid. Finally, the cycle is complete and ready to begin again.

Take a Final Look at Everything

Heat pumps are so versatile because they work as efficient cooling and heating systems. The reversing valve is critical because it changes the flow of refrigerant for heating or cooling.

The system blows air over the evaporator coil, transfers heat from the air to the refrigerant, and circulates the heated refrigerant to the condenser coil. At this point, the heat escapes because the fan blows air across the coil.

This entire process allows heat to travel from one place to another. With all of this knowledge at your disposal, you can finally answer the question of what is a heat pump, and how does it work?


What Is a Heat Pump, and How Does It Work?

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