How Does Car Air Conditioning Work?

How Does Car Air Conditioning Work?

Imagine being stuck in traffic at noon under the blazing sun during Ramadan, with sweat dripping from your forehead. What prevents this discomfort? It’s the car’s air conditioning system, commonly known as the “air conditioner.”

Historical Background Since 2010, 99% of new cars have been equipped with air conditioning. This technology has been around longer than you might think. Packard was the first to introduce car air conditioning in 1939, and by 1940, they equipped their cars with it. By 1969, half of the cars sold had air conditioning systems.

Basic Principles The car air conditioning system relies on four main principles: evaporation, condensation, compression, and expansion. These principles are part of thermodynamics, but let’s simplify:

• Evaporation: When you wipe your hand with cologne, it feels cold because the alcohol evaporates, taking heat from your hand.
• Condensation: On cold days, moisture condenses on windows when humid air contacts the cold glass.
• Heat from Pressure: When inflating a bicycle tire, the pump heats up due to the compressed air.
• Cold from Expansion: Using deodorant, the expanding gas feels cold because it cools rapidly.

How the System Works The car air conditioning system comprises five main components:

1. Compressor: Driven by the engine’s crankshaft, it compresses the refrigerant gas into a high-pressure state, starting the cooling cycle.
2. Condenser: Located in front of the radiator, it cools the high-pressure gas into a liquid by dissipating heat.
3. Receiver-Drier/Accumulator: Contains desiccant to remove moisture and filters out contaminants. The receiver-drier is used in systems with an expansion valve, while an accumulator is used in systems with an orifice tube.
4. Expansion Valve/Orifice Tube: Reduces the pressure of the liquid refrigerant, turning it into a low-pressure mist. The expansion valve is used in some systems, while the orifice tube is used in others.
5. Evaporator: Located inside the cabin, it absorbs heat from the air, cooling it before it’s blown into the car interior.

The refrigerant cycle involves these steps:

• The compressor pressurizes the refrigerant, turning it into a hot gas.
• The condenser cools the gas into a liquid.
• The liquid passes through the receiver-drier or accumulator, removing moisture and contaminants.
• The expansion valve or orifice tube lowers the pressure, turning the liquid into a mist.
• The evaporator absorbs heat from the cabin air, cooling it before it’s circulated inside.

Refrigerants Initially, cars used R-12 refrigerant, but due to its environmental impact, it was replaced by R-134a. Newer systems use R-1234yf, which has a lower global warming potential.

Maintaining Your System Regular maintenance, such as checking refrigerant levels and ensuring components are in good condition, is crucial. Low refrigerant levels or damaged parts can reduce the system’s efficiency.

We hope this article clarifies how your car’s air conditioning works. Stay tuned for more tips on maintaining your car’s AC system and understanding its impact on the engine and fuel consumption.