Working Principle of New Energy Vehicle Air Conditioning System
There are differences in system composition between electric vehicles and traditional vehicles, and different types of electric vehicles have different characteristics. Pure electric vehicles do not have an engine as a power source for the air-conditioning compressor, and there is no waste heat from the engine that can be used to achieve the effects of heating and defrosting. Fuel cell electric vehicles also do not have an engine as a power source for the air conditioner compressor, but the fuel cell engine can generate relatively stable waste heat. Next, introduce the working principle of the electric vehicle air conditioning system.
For hybrid electric vehicles, the engine cannot be used as the power source of refrigeration compression at any time due to its control strategy. The first thing that the automobile air conditioner adjusts to the air inside the compartment is to adjust the temperature of the air, and to reduce the air temperature through refrigeration. According to the characteristics of electric vehicles, the cooling air conditioning methods that can be selected for electric vehicles at present mainly include thermoelectric refrigeration, electric compressor refrigeration, and waste heat refrigeration. Among them, waste heat refrigeration can be considered in fuel cell electric vehicles.
Electric Vehicle Air Conditioning System: Refrigeration System
Semiconductor refrigeration, also known as thermoelectric refrigeration, is a solid-state refrigeration technology. It does not use refrigerants and has no operating parts. Its thermopile acts as a compression refrigeration compressor, the cold end and its heat exchanger are equivalent to a compression refrigeration evaporator, and the hot end and its heat exchanger are equivalent to a condenser. When energized, free electrons and holes move from the cold end of the thermopile to the hot end under the action of the external electric field, which is equivalent to the compression process of the refrigerant in the compressor. At the cold end of the electrothermal stack, electron-hole pairs are generated through the heat absorption of the heat exchanger, which is equivalent to the heat absorption and evaporation of the refrigerant in the evaporator. At the hot end of the electrothermal stack, the recombination of electron-hole pairs occurs, and at the same time, the heat is dissipated through the heat exchanger, which is equivalent to the heat generation and condensation of the refrigerant in the condenser.
Thermoelectric air conditioning has the following characteristics: thermoelectric elements need a DC power supply to work; changing the direction of the current can produce the reverse effect of cooling and heating; Under load conditions, the cooling plate can reach the maximum temperature difference in less than 1 minute after being powered on; the cooling speed and temperature can be adjusted by adjusting the working current of the component, and the temperature control accuracy can reach 0.001°C, and it is easy to realize continuous adjustment of energy; Under design and application conditions, its cooling efficiency can reach more than 90%, while its heating efficiency is much greater than 1; small size, light weight, and compact structure are conducive to reducing the curb weight of electric vehicles; high reliability, long life and easy maintenance ; There are no rotating parts, so there is no vibration, no friction, no noise and shock resistance.
