The Basics of Your AC Cooling System

August 14, 2023 0 By Jose White

The Basics of Your AC Cooling System

If you have ductwork in your home, this system distributes cooled air throughout the house via return and supply registers. It is the most efficient and quiet way to cool your home.

Tbyrd | HVAC remove heat from the indoor air by using a working fluid (refrigerant) that can change from liquid to gas and back again. The cycle begins in the evaporator coil, where cold liquid refrigerant absorbs heat.


The evaporator is responsible for cooling your home. It works in a similar way to the evaporator coils inside your freezer or refrigerator. It takes warm air from your home, blows it across the cool evaporator coil and absorbs heat in the process. This cools the air and it passes through a duct system to your living areas.

Cool air reduces humidity and prevents mold, mildew and fungus from growing in your home. The AC also helps remove toxins, pollutants and other allergens from your home environment. It also creates a less attractive environment for insects as it lowers body temperature and minimizes their breeding potential.

The evaporator draws air in from your home through a duct system and uses it to convert low-pressure liquid refrigerant into high-pressure gas. It then runs through the compressor to increase its temperature and pressure. Then, it changes state again into a cold liquid and flows into the evaporator.


The compressor is the heart of your AC cooling system. Its job is to draw in refrigerant vapor at low pressure and temperature from the evaporator and compress it to high pressure and temperature.

The rotor receives mechanical energy from the shaft, causing it to spin. As the rotor rotates, it moves air over fixed rows of stators and rotor blades, each of which displaces some of the air from the rotor case. Air enters the rotor’s eye from the center and exits the eye radially, increasing its pressure as it does so.

This process is called isothermal compression and expansion. The ideal compressor would be perfect, but this is impossible with practical devices. However, some types of compressors utilize inter-stage cooling between compression stages, which comes close to isothermal operation. This helps reduce internal stress and friction. It also prevents the compressor from overheating. This feature is especially important for home compressors, as they typically operate under heavy load for extended periods of time.


A condenser is a metal box with fan that cools the refrigerant gas that gets hot from the compressor. It then transfers that heat into the air, which is blown through your home and returned to the outdoor unit via tubing.

Some people shade the condenser to lower energy bills, but this is a waste of time because the AC system is already outside where the sun’s rays are most effective at heating it. Plus, shading the unit will actually decrease efficiency because it slows down the fan which increases operating costs.

Instead, make sure the area around your outdoor unit is clear of grass clippings, leaves, twigs, mulch and debris that could clog the coil or block air flow. Also, if you see excessive condensation or fluid pooling around the unit, or hear odd noises, call Prestige Air to check on your cooling system. This could be a sign that refrigerant is leaking. This is a serious issue because the leak will affect your entire HVAC system.


A thermostat is a temperature sensor that sends a signal to your AC system when the room reaches a certain temperature. These sensors can be digital or mechanical. The most common ones in homes are digital programmable thermostats, which are a good choice for people who want to save energy.

Traditional bimetallic thermostats have two pieces of different metal bolted together to form a strip that works as a bridge in an electric circuit connected to your heating system. When the strip gets hot it expands slightly, which forces one of the metals to bend over the other. When this happens the “bridge” opens and electricity is cut off, turning off your heating.

Digital thermostats are more reliable and have the added benefit of being able to be programmed. They can save you up to 30% on your energy bills, depending on your schedule. They operate on low voltage (typically 24 volts AC) and typically make an audible “click” when they switch on or off.

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