Operation of car A/C system

Air conditioning system components and functions：

The automobile air conditioning system is a device that cools, heats, ventilates and purifies the air in the cabin.
The traditional automobile air conditioning system is composed of a condenser, liquid storage tank, compressor, high and low pressure pipelines, evaporator, and expansion valve.

Composition：

1—liquid storage tank (with drying tank) 2—condenser

3—Refrigerant pressure and temperature sensor 4—Compressor;

5—Quick connector 6—Maintenance connector 7—Refrigerant pipe

8—Evaporator 9—Air conditioner 10—Air inlet box 11—Expansion valve

Function：

Modern car air conditioners have four functions, any one of which is designed to make passengers comfortable:

(1) The air conditioner can control the temperature inside the car. It can both heat and cool the air to control the temperature inside the car to a comfortable level.

(2) The air conditioner can remove moisture from the air, and the dry air absorbs human sweat to create a more comfortable environment.

(3) The air conditioner can inhale fresh air and has ventilation and ventilation functions.

(4) The air conditioner can filter the air and remove dust and pollen in the air.

Principles of automobile air conditioners：

According to natural phenomena, when any substance is cooled, it will definitely release heat. A compression refrigeration unit is used in the vehicle for this purpose. The refrigerant circulates in closed pipes and constantly switches back and forth between liquid and gaseous states. The principle is to compress gas; liquefy (condensate) the gas by releasing heat; and vaporize the liquid by reducing pressure while absorbing heat, as shown in the figure below.

1—Compressor; 2—Cooling air; 3—Condenser;

4—low pressure side; 5—high pressure side; 6—hot fresh air;

7—Evaporator; 8—Cooled fresh air; 9—Expansion valve

This is not cooling, but removing heat from the air inside the car.

The compressor extracts cool, low-pressure gaseous refrigerant. The refrigerant is compressed in the compressor and its temperature increases. Such refrigerant is forced into the circulation pipeline (high-pressure side, at this stage, the refrigerant is gaseous and under high temperature and high pressure).

The refrigerant enters the condenser (liquefier) ​​after a short journey. The compressed and heated gas in the condenser has heat removed by the air flowing through it (windward air and fan air). When it reaches the dew point determined by the pressure, the refrigerant gas begins to condense and becomes a liquid (at this stage, the refrigerant is liquid, the pressure is high, and the temperature is medium).

The liquid, compressed refrigerant continues to flow to a narrow point, which may be a throttle valve or an expansion valve. Here the refrigerant is injected into the evaporator and the pressure is reduced (low pressure side).

In the evaporator, the injected liquid refrigerant is depressurized and evaporates (vaporizes). The heat of vaporization required for this is obtained from the hot fresh air flowing through the evaporator lamellae, so that the air temperature drops and the vehicle interior becomes cooler (at this stage, the refrigerant is in the vapor state, the pressure is low and the temperature Low).

The refrigerant, which has become gaseous again, flows out of the evaporator. It is extracted again by the compressor and flows in the loop again (at this stage, the refrigerant becomes gaseous again, with low pressure and low temperature).