How Your Car's Air Conditioning Works

There are few things in life as satisfying as pushing the air conditioning button and enjoying a rush of cool, refreshing air. Car air conditioning has been around longer than you might think – Packard invented the first automotive AC in 1939.

The system uses a special liquid called refrigerant gas to cool your vehicle?s cabin. Older systems used R-12 or Freon, but newer vehicles use the more environmentally friendly R-134A.

Compressor

The car’s air conditioning is responsible for circulating refrigerant throughout the air conditioning system, cooling and dehumidifying your car. Its engine, clutch and piston work together for optimal energy efficiency, engaging and disengaging only as needed to minimize strain and power usage.

The compressor draws in low-pressure gaseous refrigerant and pumps it through a high pressure/low pressure closed-loop system. This converts the refrigerant from its gaseous state to a liquid and transfers it to the condenser.

The condenser is a radiator-like part that pulls heat from the refrigerant. It cools the liquid to form a vapor that goes to the expansion valve or orifice tube, turning it back into a gaseous state.

Condenser

A car air conditioning condenser is a heat exchanger that looks like an engine radiator. It is surrounded by cooling fins and uses air flowing over it to cool the refrigerant. The refrigerant enters the condenser as a high-temperature, highpressure gas and exits as a cooler, higher-pressure liquid.

The condenser is crucial in preventing your car engine from overheating. If it fails, the engine may overheat and cause damage to the engine.

Signs that the AC condenser is failing include a reduction in cooling performance and strange noises or smells. It is important to keep the condenser clear of obstructions, and ensure that it has adequate airflow.

Evaporator

Like a mini radiator in your dashboard, the evaporator converts liquid refrigerant back into a gas through a series of coils. The resulting cold air is then blown into the cabin by the blower fan.

The evaporator is where the low-pressure liquid refrigerant really does its work. After leaving the condenser, it passes through a thermal expansion valve or an orifice tube where its pressure and temperature drop significantly.

When the low-pressure refrigerant passes through the evaporator, it cools the air and removes moisture. The air is then blown out through the vents by the blower fan, providing you with that nice cool, refreshing air.

Heater Core

A heater core is sort of like a mini radiator, but it takes the heat from your engine coolant instead of cooling it. When you turn your car on, the blower fan blows air over the heater core to transfer the coolant’s heat into the cabin’s airflow.

A functioning heater core allows you to moderate the temperature of the air entering your cabin for comfort, safety, and defrosting your windshield. Common symptoms of a heater core problem include a sweet smell, lukewarm or cold cabin air, and a need to continually add coolant.

The heater core is a large component located under the dashboard inside your vehicle’s cabin. Repairing or replacing a heater core requires disassembling your car’s dash.

Coils

A car air conditioner evaporator coil, or evaporator core, cools the air before it is circulated through vents. As warm air passes over the coil, it causes refrigerant in a

liquid state to evaporate and cool the air.

As the air cools, it releases its heat to the condenser coil, which dissipates the hot refrigerant into a cooler, high-pressure liquid for further circulation.

Dirty evaporator coils create an insulating layer that limits the effectiveness of your AC system. Regular cleaning of these coils promotes proper airflow, reduces unpleasant odours and excessive energy consumption, and extends the lifespan of your air conditioning system.

Blower Motor

The blower car log book servicing is an electric component that pushes heated or cooled air through the dashboard vents based on the climate system settings and fan speed chosen. It operates on a wiring system and source of electric current that includes fuses, a resistor module and, in some cases, a relay.

The blower motor is normally fitted with a fuse to prevent excessive current overloads that may damage other components of the air conditioning system. Other potential problems include a fan that is blowing only at one speed. A simple voltmeter check can help diagnose problems with the blower motor circuits.