Understanding the basics of a car's air conditioning system is quite helpful. It allows you to understand the process as a whole. Once the basics are understood it is time to move on and discover the details of the components that encompass an automobile's air conditioning system.
Many might believe that the A/C system's job is to project cold air into the driver's compartment of a vehicle. In reality this air is not necessarily cold; it just has an absence of heat or at least has less heat than the interior of the car had previously. This process is not difficult but includes various parts, both big and small. We will focus on the main components: compressor, refrigerant, condenser, expansion valve and evaporator.
The compressor is the unit that applies pressure to the refrigerant by moving the liquid refrigerant from the evaporator into a condenser. The inlet side is also known as the low pressure side while the outlet is called the high pressure side. As it the refrigerant passes through the compressor the temperature is raised to a temperature higher than the outside air.
The refrigerant carries the heat through the process. The refrigerant cools the air by removing heat from the interior of the vehicle. A side benefit is this process also dries the interior air. There are different types of refrigerant but R-134a is the only one recommended by car manufacturers since its launch in the early 1990s.
Before the 1990s R-12, also known as Freon, was the refrigerant of choice used. R-12 was found to cause damage to the earth's ozone layer so it was phased out as R-134a came on the scene to replace it.This new refrigerant is thought to be better for the environment and thus recommended by car manufacturers.
The condenser is found at the front of the radiator so that it can be around the air provided by the fan and the air that is forced in by the motion of the vehicle. The condenser is heated as the compressed refrigerant flows through it. The condenser then becomes hotter than the air coming into the condenser. This causes the refrigerant to develop into a cool liquid while traveling through the expansion valve.
The expansion valve regulates the transfer of the refrigerant liquid into the evaporator. As the compressor starts up the expansion valves job is to open and allow in the liquid refrigerant. Once inside of the expansion valve the refrigerant is pressurized and then flows into the evaporator as it is needed.
The evaporator is a long coil that the liquid refrigerant enters after passing through the expansion valve. This component adds heat to the refrigerant by a fan blowing warm air over it. Once the R-14a refrigerant has absorbed the heat from the air the air becomes cooled. This cooler air is then blown into the interior of the vehicle.
The evaporator also has the job of removing moisture from the air by turning it into water. This water drains off unless your evaporator gets too cold. If this occurs it can allow the evaporator coil to freeze up, making the whole air conditioning system unable to work properly.
The components all must work properly or else the whole process can break down. If the evaporator gets too cold it can freeze up and stall the system until it heats back up. This and other issues can come up with the system. An understanding of a car's A/C system will help you better maintain it which in turn allows you to continue to enjoy the cool air blown into the vehicle's interior compartment.