Air Conditioning Refrigerant

Air Conditioning Refrigerant

Refrigerant is a key component of just about every air conditioning system found in a vehicle. Thanks to its extremely low boiling point (below 0°F) it is able to absorb surrounding heat at very low temperatures, cooling down the air inside the cabin of a vehicle.

The principle of operation of an air conditioning system is based on thermodynamics, which says that heat always moves to a cooler state. In a vehicle, the air conditioning cycle starts with pressurized liquid refrigerant that evaporates and turns into low-pressure vapors when it passes through a metering device. Then, these low-pressure vapors enter the evaporator core which performs the function of a heat exchanger absorbing heat from the surrounding air. The evaporator core features a set of fins which help for better heat distribution when the blower motor forces air from the cabin through the core.

Having done its job, the lower-pressure vapors enter the receiver-drier that acts as a filter, removing moisture and different particles from the refrigerant. Then, properly filtered vapors enter the compressor that pressurizes the refrigerant and pumps it into the condenser via a high-durable rubber hose. Mounted in the front of the vehicle just behind the grille, the condenser cools down the hot refrigerant gas and turns it into liquid refrigerant that is returned into the system via the condenser’s outlet, so the cycle can repeat.

Not all refrigerants are the same. Thus, the first air conditioning systems came with Freon, also known as R12 refrigerant. It is very harmful to the environment, which is why it is no longer used in modern air conditioning systems. Instead of it, automakers began to use the R134a refrigerant which is more eco-friendly, yet is still harmful to the ozone layer. The newest air conditioning systems come with the R1234yf or R152a refrigerant. Both of them are less harmful to the environment. The latter is also less dense than the R134a refrigerant, which is good for the fuel economy. Whichever the type is used, it comes with some amount of oil to lubricate moving parts inside the compressor. Sometimes, trace dye can also be added to the refrigerant to make it easier to detect a leak.

Lack of refrigerant in the system

To keep the air conditioning system running efficiently, the refrigerant must be maintained at the proper level. A lack of refrigerant will cause a number of A/C problems:

A/C doesn’t perform as it should

A lack of refrigerant will reduce the heat-absorbing qualities of the air conditioning system. As a result, you may notice hot air blowing from the dashboard’s vents.

Clicking noise from the compressor

This abnormal noise can be accompanied by high-speed radiator fan operation and engine surging at idle. 

Blinking A/C button

On some vehicles, the air conditioning control module can alert the driver of an issue with the system. If so, the A/C button will blink. 

Refrigerant leaks

While refrigerant leaks are usually difficult to detect because they are colorless and odorless, you can try to inspect the crimped end of A/C lines, the compressor and the condenser for leaks with an ultraviolet lamp and goggles or a special electronic leak detector.

Refrigerant related troubleshooting

Since refrigerant is harmful to the environment, any problems related to the air conditioning operation must be fixed by a professional. He or she will check the entire system for leaks before replacing any A/C component and refilling the system with refrigerant.

Being a sealed system, any air conditioning system with a low refrigerant level has a leak somewhere. To fix a leak, a professional will need to inspect the system with special equipment to determine its source. Once it is determined, he or she will remove the rest of the refrigerant from the system, following a special refrigerant evacuation procedure. When a leaking part is replaced or fixed, the specialist will recharge the system by adding the right amount of refrigerant recommended by the manufacturer.