Most people don’t wonder how their AC system cools their home. They just kick back and enjoy the cooling comfort that it offers. If you are curious, however, then you’ll love learning about the refrigeration cycle and the essential role it plays for your AC.
Let’s clear up a common misconception, first. Air conditioners don’t make cold air – at least not in the way you think. Instead, air conditioning is all about subtraction. In this case, ACs subtract the latent heat found in the air before said air passes on to the rest of your home. The end result is air that feels significantly cooler compared to the air that enters the AC.
So, how does your AC absorb latent heat? It all comes down to the refrigerant circulating inside the unit. Your AC needs a flexible and efficient way to absorb, move and release latent heat. Fortunately, refrigerant answers that call. It can change from a liquid to a vapor and back at high and low pressures, depending on where it is in the refrigerant cycle.
These changes are essential for capturing, moving and releasing latent heat at the right points during AC operation. Next, we’ll take a closer look at the refrigerant cycle itself and the components that make it happen.
The Refrigerant Cycle in Action
At the start of the refrigerant cycle, hot, low-pressure vapor enters the compressor, where it’s compressed into a hot, high-pressure vapor. The compressor also helps push the refrigerant along throughout the entire cycle.
In this state, the vapor flows into the condenser where it cools down and condenses into a high-pressure liquid. As the condenser fan blows air over the coil, the refrigerant also sheds latent heat, preparing it for the next stage in the refrigerant cycle.
Next, the refrigerant moves through an expansion valve. This component restricts the amount of refrigerant that enters the evaporator, which in turn helps it transition from a high-pressure liquid to a low-pressure vapor. When you think about it, it acts almost like an aerosol can spray nozzle.
Now a low-pressure liquid, the refrigerant moves into the evaporator, where it absorbs latent heat captured from the air blown through the coil by the AC blower fan. The low pressures combined with the heat absorption causes the refrigerant to boil off into a vapor state, preparing it for its journey back through the compressor. Only vapor is allowed to pass through the compressor, which is why it’s important for refrigerant to be in its vapor form before it reaches the compressor.
As the refrigerant removes heat from the surrounding air, the blower fan moves that air out of the AC, either through a series of ducts or directly out of the air handler itself. The end result is cool, comfortable air you can enjoy.