Vehicle climate control is important, especially if you drive a service vehicle that provides transport to customers. Keeping chauffeured passengers comfortable in all weather conditions is a necessity. Many specialty vehicles, like limousines and buses, require additional A/C systems to keep the larger cabins at a comfortable cool temperature.
Have you ever wondered how a vehicle air conditioning system works? Here is an overview that will explain how.
The beginning of the cycle starts with the compressor. The compressor is the “heart” of the car’s air conditioning system. It is a pump driven by the engine’s drive belt that takes refrigerant and pressurizing it and passing it along, then returned back to the compressor. To start this cycle the compressor’s clutch is engaged when you switch on the AC.
The condenser releases heat from the A/C system’s refrigerant passing through it from the compressor. The refrigerant enters the condenser form the compressor as a high-pressure vapor, but as it flows through the condenser and cools and turns back into a cooler high-pressure liquid.
For vehicles that have an additional A/C unit installed, an extra condenser and electric fan is necessary. The more air flow across the condenser makes a colder temperature out of the AC vents.
The receiver drier is used for an A/C system that have an expansion valve. Accumulators are inline after the evaporator within an A/C system that utilizes an orifice tube. Most receiver drier contain a filter that traps debris that may be inside the A/C system. Receiver driers contain a material called desiccant that is used to absorb moisture that may have gotten inside the A/C system during manufacture, assembly or service. Moisture can also get into the A/C components from humidity in the air.
The AC high pressure switch is a safety switch installed into the high side line of the air conditioning system. When the pressure rises too high the switch will turn off the compressor to prevent damage from occurring. Also available are low pressure, binary, and trinary switches for automotive AC applications. A binary switch protects the system when there is too much pressure or too low pressure. A trinary switch does the same a binary plus a switch with an additional fan engagement signal.
The expansion valve removes the pressure and heat from the refrigerant, changing it from a hot liquid to a cold vapor into the evaporator. Expansion valves also control the flow determined by the temperature of the evaporator by a sensing bulb that is clipped onto the low side outlet line. This signal tells the valve to increase or decrease the amount of flow through the evaporator. Without this, sensing to much refrigerant could pass through the evaporator coils causing the coil to freeze and block the airflow.
As the refrigerant goes through the expansion valve it turns into a low-pressure gas and rapidly cools the evaporator coil inside the AC unit case. The fan mounted on the evaporator case the inlets of the fan pull the warm air out of the vehicle, blows through the evaporator’s coils and cools the air coming out of your AC vents.
Replacement air conditioning parts and more are available on our online store. If you have a question, give our team of experts a call at 1-800-362-6224.