January 10, 2021

If you own a heat pump for your home or building, then trying to learn the basics of how they work becomes a necessity. Don’t get us wrong, you could always hire us for help. But since it’s a device you plan to use with the changing weather, it’s still wise to decipher how heat pumps work. Yet, learning how a heat pump works is not that complicated, and all it takes is to start with the basics.

Heat Pump Basics

Simply put, a heat pump guarantees you an all-in-one device that acts as a cooling and heating appliance for your home’s air conditioning. Initially, how the heat pump works is thanks to the device’s primary components — the outdoor heat pump and the indoor air handler. Both these are responsible for alternating the heat pump so they can function under both weather conditions.

During summer, the pump compressor absorbs heat from inside the home while also expelling it outdoors, much like how an air conditioner works. The winter is a similar mechanism but reversed to extract the heat from outside and into the indoors. Each heat pump will depend on the play tool since they are adaptable and come with different mechanisms.

First, the best heat pumps available at McGowan's Heating & Air Conditioning can source heat from the ground, water or air. With air as a source, the pumps get heat from the outdoor atmosphere to the indoors, while the cooling season has the pump working in reverse.

Likewise, ground-sourced heat pumps use the thermal energy present underground to heat your indoors or your home. The story is different from water-source heat pumps, which draw heat from augmenting your domestic hot water supply heat into your living spaces.

In any case, learning how heat pumps work sets you on a course of knowing the physics behind the devices. Our NATE-certified pump experts at McGowan's Heating & Air Conditioning recognize the need to understand the types of heat pumps available to act as an efficient air conditioner. While the system best for your indoor heating may depend on several factors, air-source heat pumps are among our best bets available for our Jacksonville, FL, customers.

Our next section acts as a step-by-step guide of the heat pump-working principle behind the models at McGowan's Heating & Air Conditioning. In comparison, there are variants of heat pumps, and the following steps are the most basic ways of looking at how heat pumps work.

How Does a Heat Pump Work?

Step 1: Heating Cycle

The heating cycle sets off your heat pump by taking heat from the outdoors and pumping it indoors. The mechanism first has the liquid refrigerant changing into a vapor mixture after passing an expansion device component. Afterward, the low-pressure liquid or vapor mixture finds its way into the outdoor coil component, which acts as an evaporator. The liquid refrigerant then absorbs the outdoor heat, boils and changes it to become a low-temperature vapor while inside the coil.

Inside, the vapor continues to pass through a reversing valve straight to an accumulator, which traps any liquid component remaining as part of the moisture. Fast forward, and the vapor heads to the compressor, which reduces its volume while increasing the pressure, causing it to heat up.

With the gas now hot, the reversing valves carry it to the indoor coil, which acts as a condenser. Later on, the heat from the hot gas is released into the indoor air, while the refrigerant condenses back into a liquid. The liquid heads over to the expansion device to ensure a repeat of the cycle for ambient indoor temperature.

In contrast, the heat pump’s ability to transfer heat from the outdoor to inside depends more on the outside temperature for effectiveness. With each drop in temperature outside, the heat pump also loses the ability to absorb the heat present.

Step 2: Cooling Cycle

The cooling cycle also runs in a similar way, although here, the above is reversed to provide the indoors with a cooling effect during summer. As such, the heat pump works to take out the heat from the indoors and expels it to the outside atmosphere.

First, the liquid refrigerant would have to pass through the expansion device, like in the heating cycle. Inside, the refrigerant changes to a liquid-vapor mixture, which transfers to the indoor coil for possible evaporation before moving on. The liquid refrigerant would then absorb the heat from indoors, boil and evaporate into a low-temperature vapor.

Once a vapor, the mixture passes through a reversing valve and heads on to the accumulator to collect remaining liquid droplets. Afterward, the refined steam goes to the compressor, which reduces the volume, causing enough pressure to heat it.

Finally, the hot gas product goes through the reversing valve straight to an outdoor coil, a final condenser. Here, the heat from the hot gas gets out to the outdoor air while the refrigerant condenses back into a liquid. After the reverse, the liquid refrigerant heads back to the expansion device, and the cycle repeats itself.

Apart from expelling air, the cooling cycle also has the heat pump dehumidifying the indoor air to remove the excess moisture or humidity present. For this, the heat pump has the air moisture pass through the indoor coil, which is a condensing surface. The air moisture then condenses inside the loop, collects in a pan at the end of the loop and later drains into the house drain.

Step 3: Defrost Cycle

When frost conditions occur, heat pump problems become common enough for a defrost cycle to be in place. The cycle is necessary to drop possible machine defects from such frigid conditions. It happens that frost conditions will have the outdoor temperature below or near freezing, which works against the heat pump mechanism. When on, the heat pump working on the heating mode will have air moisture condense and freeze inside the outdoor coil even before inside. Such frost buildup means the refrigerant receives less heat transfer due to less efficiency with the coil.

As such, a switch to the defrost mode will go a long way to cut potential heat pump problems.

The defrost mode sets on the reversing valve, which switches the heat pump into a cooling mode. The mode attempts to melt the frost present by sending hot gas into the outdoor coil in place. The outdoor fan is also shut off to prevent the loss of heat needed to melt the frost buildup.

Meanwhile, the heat pump continues to cool the ductwork’s air rather than warming it for distribution indoors.

The defrost mode is rarely put to use and would need monitoring of the refrigerant pressure, airflow, coil, air temperature and stress for possible changes. These aspects determine whether to start a defrost cycle since doing so unnecessarily may alter your pump’s seasonal performance and cause heat pump problems.

Get on Board With the Pros

Although there are complexities to how a heat pump works, you can be confident that professional help could be handy for anyone. At McGowan's Heating & Air Conditioning, we believe in lending that helping hand in offering our NATE-certified technicians’ expertise on all-things heat pumps. If you are in greater Northeast Florida, Jacksonville or Daytona Beach, call McGowan's Heating & Air Conditioning for our heat pump services to offer sound advice, competitive rates, repair, installation or maintenance. We also offer a full range of cooling services, too.

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