Air source heat pump unit defrosting control method and air source heat pump

Abstract

A defrosting control method of an air source heat pump unit comprises the steps that when the air source heat pump unit conducts heating, the environment temperature T2 and the evaporation pressure P1 of the heat pump unit under the heating cycle are collected, the evaporation temperature T1 is obtained by calculating the collected evaporation pressure P1 through a programming formula, and a curvilinear equation f (delta T) with the difference value T = T2-T1 changing along with time is generated, and calculating the derivative of the curvilinear equation f (delta T), obtaining the variation trend of the difference value delta T between the evaporation temperature T1 and the environment temperature T2 according to the derivative calculation result, comparing according to the derivative calculation result, judging whether the air source heat pump needs to be defrosted or not, and defrosting by automatically adjusting the frequency of the variable-frequency compressor and the frequency of the variable-frequency fan. According to the defrosting control method provided by the invention, defrosting is carried out by adjusting the frequencies of the compressor and the fan in real time under the condition that the heating circulation direction is not changed, and the problems that energy is wasted, defrosting water is difficult to treat and comfort is affected are solved. The invention further provides an air source heat pump for realizing the method.

Description

technical field [0001] The invention relates to the technical field of air source heat pumps, in particular to a defrosting control method for an air source heat pump unit based on frequency conversion technology. Background technique [0002] After the air source heat pump unit runs for a period of time under heating conditions in winter, frost will form on the surface of the fin heat exchanger when the ambient temperature is lower than 0°C, and the frost on the fin heat exchanger will block the passage between the fins and increase the air flow resistance , so that the heat transfer capacity of the fin heat exchanger is reduced. As the frosting continues, the frost layer on the fin heat exchanger will gradually thicken, and the heat transfer efficiency of the unit's circulation loop will also drop sharply, which in turn leads to the attenuation of the unit's heating output. No matter how severe the frost is, it will freeze and leak the fin heat exchanger, so that the air ...

AI Technical Summary

Problems solved by technology

The defrosting process is a cooling operation process, not only cannot make hot water, but also needs to consume the heat of the hot water on the user side, and the hot water after the temperature is lowered must be discharged to the hot water side, which further reduces the water temperature and affects the comfort of the user

After the defrosting is over, the heat pump unit needs to bring up the lowered water temperature again. It has to be said that this is also a waste of energy.

Same as the hot air defrosting method, there is also the problem that the defrosting water is not easy to handle and will freeze soon

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