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How Does an Air Conditioner Work: The Refrigeration Cycle Explained

Air Conditioning System

Although many people believe that air conditioners create cold air to cool down your home during the hot summer days, in fact, what it does is remove the heat from your home instead. As the heat is sent outside, your home gets cooler.

Air Conditioning System

The Refrigeration Cycle

The air conditioner operates thanks to a thermodynamic cycle known as the refrigeration cycle. The basic principle behind is that the air conditioner absorbs or releases heat by changing the pressure and state of the refrigerant. The refrigerant is often referred to and better known as Freon, although this is a trademarked brand of The Chemours Company. The refrigerant is used to absorb the heat from your home and expel it outside. So in order to work properly, you always have to check if the refrigerant levels are enough to keep the AC unit. If you’re not comfortable messing around the air conditioner, you can always have it checked by a reputable company dealing with AC repair and maintenance like Hughes Air Heating & Cooling. Most air conditioning systems use an air-source split system. We’ll explain what this means. The air-source part refers to the fact that the heat from your home is expelled outside and into the air. There are other different air conditioning systems that pass the heat into water or into the ground. The split system refers to the fact that the AC operates using two units, one located in your home and one located outside. The outside unit is usually located on the side of your house or building, while the inside unit is located in a room inside your home. The steps of the refrigeration cycle are the following:

Air Flows over the Coils

Air Conditioning System

As the air flows over the coils, the heat gets absorbed by the refrigerant found inside the coils. The air that passes through the coils gets colder by approximately 20 degrees. The process uses the 2nd law of thermodynamics, which states that heat passes from a warmer body to a cooler one spontaneously. After the heat is absorbed, the refrigerant changes its state into vapor from its original liquid state. The gas is then sent to the compressor.

The Warm Refrigerant Gas is compressed

Air Conditioning System

The refrigerant remains cool even after absorbing the hot indoor air. The warm gas enters the compressor, found in the inside unit, where its temperature and pressure are increased. The system does this as the refrigerant temperature needs to be hotter than the outdoor temperature, so heat could pass to a cooler body, which in this case is the air.

Hot Refrigerant is sent to the Condenser Coils

The pressurized, hot refrigerant gas is sent to the condenser coils. There it is exposed to outdoor air which draws the heat out of the refrigerant. This way the heat is released into the outdoor air. When the outdoor air cools the refrigerant to a certain level it condenses back into its liquid form and is pumped inside the AC.

The Refrigerant Needs to Cool

The refrigerant is still hot even after it leaves the outdoor unit. Before the refrigerant can absorb more heat it needs to cool down. To do this, the system expands the refrigerant to increase its volume and help it cool faster and depressurize. To be able to absorb indoor heat again, the refrigerant needs to be cooler than the indoor air. Once it is, it goes back to the evaporator coil, and the cycle begins again.