Abstract: The air conditioner filter has the function of filtering dust and preventing pollution inside the air conditioner. Dirty filters can easily breed bacteria and affect the health of users. At the same time, the reduced air volume of the air conditioner causes insufficient cooling. When the air conditioner filter is dirty and blocked, the air pressure on both sides will change. Combining the inherent fan characteristic curve and the system resistance curve of the wall-mounted air conditioner cross flow fan, a method for detecting the cleanliness of the air conditioner filter using a differential pressure measurement device is proposed. Analyze the influence of air-conditioning air volume, data sampling time, distance between air-conditioner and ceiling, angle of air-conditioning baffle, position of differential pressure measuring device on the evaporator and other factors on the pressure difference between the two sides of air-conditioning filter, and test and research. The results indicate that the higher the air-conditioning wind speed, the more obvious the pressure difference between the two sides of the filter, and the angle of the air-conditioning baffle and the air outlet position of the differential pressure measuring device will affect the data gradient of the pressure difference on both sides of the air-conditioning filter.

Key words: Differential pressure, Air conditioning filter, Cleanliness