Modern air conditioning system consists of refrigeration system, heating system, ventilation and air purification device and control system.

1. Ventilation system: its function is to ensure indoor ventilation when the car is driving, that is, continuously flush fresh air into the car room and expel dust, carbon dioxide and harmful gases from the engine. In cold winter, fresh air shall also be heated to ensure appropriate indoor temperature.

2. Heating system: its function is to heat the air inside the car or the fresh air entering the car from the outside, so as to achieve the purpose of heating and dehumidification.

3. Refrigeration system: its function is to reduce the temperature inside the vehicle when the ambient temperature outside the vehicle is high, so that passengers feel cool and comfortable.

4. Air purification system: its function is to filter the introduced air, continuously remove the dirty gas in the car and keep the air in the car clean.

5. Control system: the control system is mainly composed of electrical components, vacuum pipeline and operating mechanism. On the one hand, it is used to control the temperature and pressure of the refrigeration and heating system, on the other hand, it is used to control the temperature, air volume and flow direction of the indoor air, so as to improve the functions of the air conditioning system.

Automotive air conditioning is generally composed of compressor, electric clutch, condenser, evaporator, expansion valve, receiver dryer, pipes, condensing fan, vacuum solenoid valve, idler and control system. Automobile air conditioner is divided into high-pressure pipeline and low-pressure pipeline. The high-pressure side includes the output side of the compressor, the high-pressure pipeline, the condenser, the receiver dryer and the liquid pipeline; The low pressure side includes evaporator, accumulator, return pipeline, compressor input side and compressor oil pool.

Receiver dryer - in fact, it is a device for storing refrigerant and absorbing refrigerant moisture and impurities. On the one hand, it is equivalent to the fuel tank of the car, which replenishes the refrigerant for the extra space of the leaked refrigerant. On the other hand, like an air filter, it filters out impurities in the refrigerant. The receiver dryer is also equipped with certain silica gel material to absorb water.

Condenser and evaporator - although they are called differently, they are similar in structure. They are devices that are filled with metal sheets for heat dissipation on a row of curved pipes, so as to realize the heat exchange between the outside air and the materials in the pipes. The condensed refrigerant in the condenser is condensed into gas. Its principle is similar to that of the engine cooling water tank (the only difference is that the water in the water tank is always liquid), so it is often installed in the front of the vehicle to enjoy the cool wind from the front together with the water tank. In short, where the condenser is cool, so that it can dissipate heat and condense. The evaporator is opposite to the condenser. It is the place where the refrigerant changes from liquid to gaseous (i.e. evaporation) to absorb heat.