An HVAC compressor is one of the air conditioner’s components that handles Freon or another refrigerant. Freon has become a household name, but several types of refrigerants exist. Refrigerant flows through the compressor and other parts of the air conditioner, namely the condenser and evaporator. Each component performs a different function in the heat exchange process to cool your home. Without refrigerant, the system would not possess any cooling power.
Illustration by Ian Worpole
How does refrigerant work?
Refrigerant is a chemical compound that plays a crucial role in any cooling system. An air conditioner consists of a compressor, condenser, and evaporator. The refrigerant absorbs environmental heat and provides cool air, continually cycling from gas to liquid once it runs through these areas.
1. In the Compressor
The compressor circulates the refrigerant through the air conditioning system and performs the initial step in the cooling process. The compressor receives refrigerant that has absorbed heat from the home’s air. At this point, the refrigerant is a warm, low-pressure vapor. The compressor applies energy until the refrigerant becomes a hot, high-pressure vapor. Heating and pressurizing the refrigerant serve two purposes. One, the refrigerant must be heated to a temperature higher than the outside air to release heat as it travels through the condenser’s coils. Two, pressurization allows the refrigerant to flow smoothly through the coils.
2. In the Condenser
The condenser coil releases heat the refrigerant has absorbed from the home’s air.
Hot, high-pressure refrigerant vapor enters the condenser from the compressor. The refrigerant moves through the condenser coils while the fan supplies cool air. The fan’s air cools the refrigerant in the coils, and the condenser’s metal fins conduct heat away and into the outside air. The refrigerant condenses as it cools, becoming a liquid.
3. In the Evaporator
Refrigerant absorbs heat and humidity from your home’s air in the evaporator. The cold refrigerant flows through the tubing while warm air from the house passes over the coil. The refrigerant absorbs heat and humidity from the home’s atmosphere, and a fan blows the cooled air into the home through the vents. The warm refrigerant then flows outside to the compressor.
Types of Air Conditioner Refrigerant
Air conditioners use several types of refrigerants, but refrigerants are not interchangeable. An air conditioner can only use the refrigerant it has been designed to operate. Some refrigerants that were standard in the last century have been phased out of use, and new types of refrigerants continue to emerge.
Chlorofluorocarbons (CFCs), including R12.
CFCs, such as Freon, are no longer produced. CFCs were widely used in air conditioners until it was discovered CFCs contribute to greenhouse gasses and depletion of the ozone layer due to the chlorine they contain. Production of CFCs was phased out by 1995.
Hydrochlorofluorocarbons (HCFCs), including R22 Freon.
A hydrofluorocarbon (HCFC) is a chlorofluorocarbon (CFC) with an additional hydrogen atom. HCFCs, such as Freon22/R22, were standard in air conditioners from 1960 until 2005. HCFCs were also found to be linked to ozone depletion due to the presence of chlorine. Production, import, and use of HCFCs was phased out.
Air conditioners manufactured after 2010 are prohibited from using HCFC refrigerants. Air conditioners manufactured before 2010 which use R22 can still be used. However, the only sources for R22 are a dwindling stockpile and reclaimed refrigerant. Supply scarcity means the cost to recharge an outdated AC unit with Freon22 will be high.
Hydrofluorocarbons (HFCs), including R410A and R134.
Hydrofluorocarbons (HFCs) such as R410A and R134 are chlorine-free replacements for R22. Air conditioners were redesigned to use HFCs when R22 was phased out. Therefore, R410A cannot be used in R22 systems. R410A, also known as Puron, allows AC units to have higher efficiency ratings than R-22 resulting in increased comfort, reliability, and air quality.
R32 is the latest refrigerant, but it’s not entirely new. R32 is one of the ingredients in R410A. Eastern and European countries have begun using R32 instead of R410A in air conditioners.
R32 boasts of lower energy consumption and environmental impact than R410A. Its Global Warming Potential (GWP) is nearly 70% less than R410A. R32 is not a refrigerant blend, making it easier to reclaim and recycle. On the downside, R32 is highly flammable.
R32 may replace R410A one day, or something better may replace both.
Will the HVAC compressor run without Freon?
The HVAC compressor cannot run without Freon or some other refrigerant. The compressor can run with a low refrigerant level and possess some cooling power. However, running the air conditioner with less than the proper amount of refrigerant is not recommended.
HVAC technicians use gauges to measure the correct refrigerant level when air conditioners are installed. This measurement is referred to as the unit’s “charge.” The air conditioner maintains this level of refrigerant. The unit will only be undercharged if it develops a Freon leak or if the technician who installed or serviced it did not add the proper amount of refrigerant.
Air conditioners must contain the correct amount of refrigerant to function correctly. Although an undercharged system can still run, cooling power is reduced, the system works harder, and the air conditioner will eventually break down. The compressor is designed to handle a certain amount of refrigerant and may overheat if the refrigerant is low. The compressor or the entire air conditioner may need to be replaced if the compressor overheats. Low refrigerant levels also limit how much heat the evaporator coil can absorb, causing your AC to freeze up and eventually stop working. Furthermore, the system uses more energy when the refrigerant is low, leading to higher utility bills.
Where does Freon go in central air conditioning?
The first thing that happens in a refrigerant system is the compression of the refrigerant within the A/C compressor. The refrigerant system is self-contained and designed never to leak refrigerant; therefore, you should never have to refill it. Of course, refrigerant leaks can occur as your unit ages over time or with improper maintenance.
When you have your annual A/C tune-up, your HVAC professional will ensure that your unit’s refrigerant levels and pressure are adequate and that the refrigerant system is leak-free. If your unit’s refrigerant system springs a leak, the technician will need to repair the leak and recharge your refrigerant.
Please note that recharging an air conditioner is dangerous and should never be attempted by a homeowner. Calling an HVAC professional with a refrigerant certification is essential.
Freon or another refrigerant is necessary for an air conditioner to cool your home. The refrigerant absorbs the home’s heat and humidity. The compressor, condenser, and evaporator are the air conditioner parts that chiefly participate in the heat exchange process by handling the refrigerant.
Air conditioners use several types of refrigerants, but refrigerants are not interchangeable. CFCs, like Freon, and HCFCs, like R22, have been phased out and replaced with HFCs, like R410A. R32 is a newer, popular refrigerant in Eastern and European countries. It has many positive aspects, but its flammability is a potential concern.
Air conditioners cannot run without refrigerants. They can function with a low refrigerant level, but air conditioners need the correct amount of refrigerant to work correctly. Running the air conditioner with an inadequate amount of refrigerant is inefficient and can lead to costly repairs or replacements. An air conditioner’s refrigerant only needs to be recharged if it develops a leak or if the technician who installed or serviced it did not add the proper amount of refrigerant.