#auto air conditioning
Automobile Air Conditioning Systems
Automobile air conditioning systems are a closed pressurized system. It consists of a compressor, condenser, accumulator that is sometimes called a receiver dryer, and an expansion valve or an orifice tube and finally an evaporator. These components work together in your automotive ac system to create an output air temperature in the low 40В° Fahrenheit range.
When you boil it down, the most important function of the automobile air conditioning system is to turn a high pressure Freon to a low-pressure refrigerant and this is done by the orifice tube or the expansion valve.
In the picture to the right the low pressure side is highlighted in blue and the high pressure side in red. Most systems today use the orifice tube type systems. You will find some vehicles that use an expansion valve instead of the orifice tube. An example would be heavy equipment, large trucks and a lot of Chrysler vehicles use the expansion valve. Note that you will have either one or the other but not both.
How Air Conditioning Works
In a basic air-conditioning system, the heat is stored and transferred in the following steps. The refrigerant leaves the belt driven clutch operated compressor as a high pressure, high temperature vapor.
It is moved towards the condenser, where the vapor becomes a high pressure, high temperature liquid. It is changed from a gas to a liquid by the heat that is removed by the condenser component and the condenser fan that blows across it.
Sidebar ; The r134a stop leak freon pictured to the right should only be used on a system with a very slow leak on the low side. It will not seal large refrigerant leaks. Be sure to follow the directions that come with the kit carefully so you don’t make things worse.
After the condenser the refrigerant is then circulated to the accumulator or receiver dryer where moisture and contaminants are removed. This is also where most of the Freon is stored until it is needed.
The expansion valve or orifice tube controls the flow of the refrigerant into the evaporator that is mounted inside the passenger compartment. It’s this step that converts the freon from a high pressure to a low one. This is where the auto AC system is the coldest.
In fact if this step is not controlled properly the evaporator can turn into a block of ice. Many manufacturers place a probe on or near this part so they can monitor exactly how cold the evaporator coils are.
You may have heard people talk about low out put of cold air due to ice and not really understand why. You would think ice is a good thing on a hot day! If the evaporator freezes airflow through it is actually reduced and along with it the air temperature from the ducts is not as cool as it could be.
Heat absorption from the air inside the passenger compartment by this low pressure Freon causes the liquid to vaporize and move out of the evaporator as a gas.
The refrigerant then returns to the compressor as a low-pressure gas, where it is compressed into a high-pressure vapor as the system starts another cycle. As a side note when you understand this flow and operation of the automobile air conditioning system you have also learned how your home ac works as well as your refrigerator.