How Do Central Air Conditioners Work?

Many people assume that air conditioners generate cool air, but this isn’t exactly true. In reality, ACs remove heat and humidity, leaving cool, dry air to circulate throughout the house.

Air conditioners work on the same principle as refrigerators and freezers. But instead of maintaining a very low temperature in a relatively small space, ACs keep your entire house comfortable on hot summer days.

Refrigerant is the key to this process. By traveling between the indoor and outdoor air conditioning units, refrigerant is able to absorb heat from inside and exhaust it to the exterior. Learn about the primary parts of an air conditioner and how the cooling cycle works.

The Anatomy of an Air Conditioner

Here are the major components that make air conditioning possible:

• The compressor is located in the outdoor condensing unit, the large box with metal fins and a big fan sitting on a concrete slab outside your house. The compressor pumps the refrigerant through the ac circuit just like your heart pumps blood through your body. As the heart of your air conditioner, this component is largely responsible for the noise you hear when the cooling system runs.
• The condenser coil is the first of two coils found in a split-system central air conditioner. This is where the hot refrigerant releases the heat it has collected from inside your house.
• The expansion valve is positioned between the condenser and the evaporator coil. It prepares the refrigerant to absorb heat before flowing into the indoor half of the system. This valve controls how much refrigerant will flow into the indoor unit based on how hot it is inside. This valve can open and close as needed to make sure the unit is absorbing the right amount of heat to meet the comfort needs of the home.
• The evaporator coil is the largest indoor air conditioning component, typically positioned adjacent to the blower. This is where heat is picked up from the indoor air via the refrigerant that flows through it before flowing back out to the outdoor unit.
• The blower and ductwork are responsible for circulating air around the house. As the blower runs, it draws in warm air, either from return ducts and registers scattered throughout the house or one central return register. Then, cooled air travels through supply ducts and blows out of supply registers located in each room.

Air Conditioning Cycle

When in cooling mode, the thermostat tells the air conditioner to turn on once the room temperature rises above the target temperature displayed on the thermostat. Then, the cooling system gets to work.

The refrigerant starts its journey by entering the compressor as a cool, low-pressure gas. The compressor squeezes the refrigerant, packing the molecules closer together and causing it to increase in temperature and pressure.

The refrigerant flows out of the compressor and into the condenser coil as a hot, high-pressure gas. The fan blows over the condenser coil, and the metal fins act as a giant radiator to disperse heat from the refrigerant as effectively as possible.

Once much of the heat is expelled, the refrigerant flows out of the condenser coil as a warm liquid. Then, it passes through the expansion valve, which expands the liquid refrigerant, causing a drop in pressure that turns it into a cold gas mixture.

The next stop is the evaporator coil. As the refrigerant weaves its way through this coil, the blower sends warm indoor air over it. The refrigerant within the evaporator coil absorbs heat from the air. Just like the condenser, the evaporator has metal fins to help promote as much heat transfer as possible. The blower then sends cool supply air into your home, lowering the indoor temperature in the process.

As the refrigerant absorbs heat in the evaporator coil, it goes from a cold gas to a cool, low-pressure gas. It is now ready to return to the compressor and begin the journey all over again.

A continuous flow of refrigerant passes between the condenser and the evaporator until the thermostat senses that the indoor temperature matches the programmed setting. Then, the thermostat tells the air conditioner to shut off until the interior heat gain triggers it to kick on again.

Air Conditioners Also Dehumidify

Your AC unit doesn’t just remove heat—it also lowers the humidity level. This is an important part of making your home comfortable in the summer, especially in Florida’s humid climate. Otherwise, you would feel cool but clammy, prompting you to turn down the temperature in an attempt to feel more comfortable.

Dehumidification occurs naturally as part of the air conditioning process. After all, warm air can hold more moisture than cold air, so the cooler temperature around the evaporator coil causes water to condense on the cold metal. This is the same principle that makes an ice-cold glass of water “sweat” on a hot summer day. As more moisture collects on the evaporator coil, it drips off into a condensate pan and is carried away through a condensate drain line.

Sometimes, air conditioners don’t remove enough humidity on their own. This is particularly true in places like Florida. Fortunately, you can install a whole-house dehumidifier to work alongside the cooling system. This eliminates that unpleasant cool-but-clammy feeling and can lower your energy bills.

Schedule Central Air Conditioner Services in Orlando or Orange City, FL

Now that you know more about how central air conditioners work, you may be ready to schedule a much-needed repair, replacement, or tune-up. Turn to Certified Climate Control for the job. We have over a decade of experience serving Central Florida residents with reliable, affordable AC services. Our friendly, knowledgeable technicians are happy to answer any questions you have about keeping your home comfortable all year round. To schedule a visit, please contact us at (407) 888-0678 if you live in Orange or Seminole County, or call (386) 675-6963 if you’re a Volusia County resident.