When it is used in the north, it is inevitable that the equipment will be frosted due to the influence of low temperature weather. I will discuss the harm of equipment frosting and the method to solve the problem.

Frosting hazard of air source heat pump: when the air source heat pump unit operates in winter, when the surface temperature of the heat exchanger outside the room is lower than the dew point temperature of the surrounding air and lower than 0 ℃, the surface of the heat exchanger will frost. The formation of frost worsens the heat transfer effect of the heat exchanger and increases the resistance of air flow, reducing the heating capacity of the air source heat pump unit, even stopping the unit when it is serious.

Defrosting method of air energy heat pump:

1. Frost sensor method: It is used to control defrosting by detecting the thickness of the frost layer. The principle of this method is simple, but it involves high gain signal amplifiers and expensive sensors. As a test method, it is feasible and economical in practical application.

2. Timing control method: as the name implies, defrosting control is carried out according to the preset time. This method is easy to produce unnecessary defrosting action, resulting in unnecessary waste.

3. Maximum average heating capacity method: for a certain atmospheric temperature, there is a unit with corresponding evaporation temperature, at this time, the average heating capacity of the unit is the largest. The defrosting control is carried out with the maximum heating effect produced by the heat pump unit as the goal. This defrosting method has theoretical significance, but it is difficult to implement.

4. Time temperature method: it means that when the defrosting detection element feels that the surface temperature of the heat exchanger fin tube and the heating time of the heat pump unit reach the set value, the defrosting starts. Because the coil temperature is set as a fixed value, this method can not take into account the changes in ambient temperature and humidity, which is easy to cause wrong operation. Moreover, this method is sensitive to the installation position of the temperature sensor.