Defrosting judgment method

Abstract

A defrosting judgment method comprises the following steps that a temperature difference starting point is selected, specifically, a temperature difference average value is calculated, the temperature difference variation rate is calculated, and if the sum of k1 times of temperature difference variation rates is larger than a first set threshold value or smaller than a second set threshold value, the temperature difference starting point is calculated again, otherwise whether frosting occurs or not is judged; the temperature of an evaporator and an outdoor environment temperature are continuously collected for k2 times, and if the k2 times of temperature difference variation rates exceed the temperature difference variation rate of the set proportion and are larger than a frosting judgment threshold value, whether deforesting is needed or not is judged, otherwise the temperature difference starting point is calculated again; and the temperature of the evaporator and the outdoor environment temperature are continuously collected for k3 times, and if the continuous k3 times of temperature difference variation rates are smaller than the standard temperature difference variation rate, it is considered that frost layers are accumulated thickly, a defrosting step is executed, otherwise calculation is conducted again. According to the defrosting judgment method, wave disturbance caused by changing system working states can be removed, and the defrosting condition can be judged accurately.

Description

technical field [0001] The invention belongs to the technical field of air conditioners, in particular to an air conditioner defrosting judging method. Background technique [0002] In winter, the air conditioning system is used in the heat pump working condition. The heat exchanger on the outdoor side acts as an evaporator, and the temperature is relatively low. When the outdoor temperature is around 0°C, the evaporator is most prone to frost. If the defrosting is not done in time, the heat transfer effect of the evaporator will be poor, the energy efficiency ratio of the system will be reduced, and problems such as liquid return may occur. Therefore, timely defrosting is required. [0003] At present, the commonly used defrosting judgment methods include: timing defrosting, judging defrosting by evaporating coil temperature, judging defrosting by the difference between evaporating coil and outdoor temperature, etc. Judging whether there is frost by temperature or temperat...

AI Technical Summary

Problems solved by technology

However, when encountering severe weather such as thunderstorms or occasions where the ambient temperature fluctuates greatly, even if there is no frost, the coil temperature will fluctuate accordingly, resulting in misjudgment; moreover, the coil temperature will vary with the compressor Frequency conversion and fan speed regulation fluctuate greatly, making the temperature change rate of the coil reach the defrosting condition, resulting in misjudgment

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