How does a car air conditioner work?
Throughout North America, the climate changes every year. Cooler spring temperatures give way to warmer weather. In some areas it lasts two months, while in others it takes six months or longer. It's called summer.
With summer comes heat. Heat can make your car unbearable to drive, which is why Packard introduced air conditioning in 1939. Starting with luxury cars and now spreading to almost every car in production, air conditioners have kept drivers and passengers cool for decades.
What does an air conditioner do?
An air conditioner has two main purposes. It cools the air entering the cabin. It also removes moisture from the air, making it more comfortable inside the car.
In many models, the air conditioner turns on automatically when you select the defrost mode. It wicks moisture away from the windshield, improving visibility. Often cold air is not needed when the defrost setting is selected, so it is important to know that the air conditioner is operating even when warm is selected on the heater control panel.
How does it work?
Air conditioning systems work about the same from manufacturer to manufacturer. All brands have some common components:
- compressor
- capacitor
- expansion valve or throttle tube
- receiver/dryer or battery
- evaporator
The air conditioning system is pressurized with a gas known as refrigerant. Each vehicle specifies how much refrigerant is used to fill the system, and it's usually no more than three or four pounds in passenger cars.
The compressor does what its name suggests, it compresses the refrigerant from a gaseous state to a liquid. liquid circulates through the refrigerant line. Because it is under high pressure, it is called the high pressure side.
The next procedure takes place in the condenser. The refrigerant passes through a grid similar to a radiator. Air passes through the condenser and removes heat from the refrigerant.
The refrigerant then travels close to the expansion valve or throttle tube. A valve or choke in the tube reduces the pressure in the line and the refrigerant returns to a gaseous state.
Next, the refrigerant enters the receiver-drier, or accumulator. Here, the desiccant in the receiver drier removes the moisture carried by the refrigerant as a gas.
After the receiver-drier, the cooler-drier of the refrigerant passes into the evaporator, still in gaseous form. The evaporator is the only part of the air conditioning system that is actually inside the car. Air is blown through the evaporator core and heat is removed from the air and transferred to the refrigerant, leaving cooler air leaving the evaporator.
The refrigerant enters the compressor again. The process is repeated many times.
