April 10, 2024
When those hot California summers hit, you need a reliable air conditioner to keep you cool. As a homeowner, it’s important to understand how air conditioning works, including the AC refrigeration cycle and how it relates to key components.
Learn about the principles of heat transfer and the steps involved in cooling your home with the certified AC technicians at Service Champions.
The thermodynamics of air conditioning operates on the fundamental principles of heat transfer, which include the relationship between pressure and temperature, known as the law of thermodynamics and combined gas law. Together, the three “gas laws” state that the pressure-volume product is constant, volume is proportional to the absolute temperature, and pressure is proportional to the absolute temperature.
A separate principle called the second law of thermodynamics is also involved in your air conditioner’s operation. This thermodynamic law states that heat flows from hotter to colder bodies naturally, and that heat can only transfer from a colder body to a warmer body through external work.
While certain air conditioner components differ by equipment type, the cooling process typically requires specific parts to operate the refrigeration cycle that cools your Bay Area home. This cycle requires several main components:
When you think about how an AC unit works, it’s important to remember that refrigerant plays a vital role. Refrigerant, also called coolant, is the fluid used in the air conditioner’s refrigeration cycle. Its state changes to cool your home by absorbing heat from the inside, then pumping it outside to lower the indoor temperature. Safe, reliable refrigerant should be non-flammable, non-explosive, non-toxic, and non-corrosive. It should also be able to reach a high critical temperature at a low boiling point and liquify easily.
To better understand how your air conditioner works, it’s important to know the four main stages of the refrigeration cycle and what they involve.
The evaporator coil functions by allowing air to flow over the cold coils, transferring heat from the air to the refrigerant inside. After the air flows over the coils, it cools down, dropping approximately 20 degrees. Once the refrigerant absorbs heat, it changes from a liquid to a vapor, which is then transferred to the compressor.
The compressor is called the heart of the air conditioner because it’s the central pump for the refrigerant. The working principle of an AC compressor is to directly enable the heat exchange process, similar to how the heart circulates blood. It does this by absorbing the vaporized gas, increasing its pressure and temperature, since it must be warmer than the outdoor air. Once the temperature of the refrigerant is high enough, the compressor moves it through the outdoor condenser coils.
Once the refrigerant is compressed or pressurized, the condenser fan blows the hot outdoor air over the even hotter outdoor condenser coils. As the outdoor air flows over the coils, heat is removed from the refrigerant and released into the outdoor air. When the refrigerant loses thermal energy (known as heat rejection), it condenses back into a liquid and gets pumped back inside.
In step four (the final step), a metering device called the thermostatic HVAC expansion valve depressurizes the hot refrigerant, causing its temperature to drop. This component helps with cooling regulation by expanding the refrigerant into a larger volume so it’s colder than the indoor air. Once it cools down, it flows back into the evaporator coils, and the cycle repeats.
The HVAC blower motor moves conditioned air by spinning a fan that draws return air across the evaporator coil. This component forces conditioned air into your ductwork and into your home. The blower motor is activated by the thermostat and helps to maintain comfortable, consistent airflow in every room.
Although your air conditioner uses liquid refrigerant, it still requires an outdoor condenser fan, which is the primary mechanism for expelling heat from your home. This fan works by drawing outside air over the condenser coils and then cooling the high-pressure refrigerant. This process transitions the refrigerant from a vapor to a liquid, which is necessary for effective cooling.
If your outdoor condenser fan is malfunctioning and needs professional repair, your equipment could overheat, leading to lower efficiency, higher energy consumption, and potential failure, which may require a full replacement.
The highly skilled HVAC techs at Service Champions can help you identify and address common refrigerant issues. Here’s how these issues can impact your HVAC equipment’s efficiency:
When you look at the condenser coil vs. the evaporator coil, the condenser coil is outside, and the evaporator coil is inside, but both are vital to the cooling process. Keeping these coils clean is an easy way to maintain a reliable refrigeration cycle.
Both the evaporator and condenser coils act as insulation, and when they’re dirty, it inhibits heat transfer, forcing your AC to run longer and reducing the equipment’s capacity to cool your home. If needed, the trusted team at Service Champions can inspect and clean your coils as part of a good routine maintenance plan.
Choose Service Champions for heating, cooling, plumbing, electrical, insulation, and ductwork across the Sacramento area, South Bay, Concord, and the East Bay.
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