There are four main indexes to evaluate the quality of automobile air conditioning, namely temperature, humidity, flow rate and cleanliness.
1. temperature
The comfortable temperature for people is 22℃-28℃ in summer and 16℃- 18℃ in winter. When the temperature is lower than 14℃, people will feel "cold". The lower the temperature, the more stiff the hands and feet will be, and the driver can't operate flexibly. When the temperature exceeds 28℃, people will feel hot and dry, unable to concentrate, and slow thinking, which will easily lead to traffic accidents. If it exceeds 40℃, it is called harmful temperature, which will cause harm to human health. In addition, the required temperature of human face is slightly lower than that of feet, that is, "the head is cold and the feet are warm", and the temperature difference is about 2℃.
2. Humidity
The relative humidity that people feel comfortable is 50%-60% in summer and 40%-50% in winter. People will feel comfortable in this humid environment. When the humidity is too low, the skin will itch. This is because when the humidity is too low, the skin surface and clothes are dry, and the friction between them generates static electricity. If the humidity is too high, people will get bored. This is because the water in human skin cannot evaporate, which interferes with the normal metabolic process of human body.
3. Flow
People are more comfortable in flowing air than in still air, because flowing air can promote heat dissipation inside and outside the human body. Therefore, wind speed is one of the important contents of automobile air conditioning. The air velocity should be below 0.2 m/s, and it is better to change at a low speed.
Step 4 clean
The fourth evaluation index of automobile air conditioning performance is cleanliness. Due to the small interior space and high occupant density, the air in the fully enclosed space is prone to oxygen deficiency (O,) and high concentration of carbon dioxide (CO:). Carbon monoxide (CO) in automobile engine exhaust gas and road dust easily enter the car, causing air turbidity in the car and seriously affecting the health of passengers. Therefore, it is necessary to purify the air inside the car.