Defrosting method of air source heat pump hot water unit

Abstract

The invention relates to a defrosting method of an air source heat pump hot water unit. The air source heat pump hot water unit comprises a water tank, a water side condenser, a compressor, a four-wayvalve, a gas-liquid separator, an evaporator, an electrical control system, an electronic expansion valve and a filter. The air source heat pump hot water unit has the characteristics that a first temperature sensor is installed at a side air inlet of the evaporator, a second temperature sensor is installed at a coil pipe inlet of the evaporator, a third temperature sensor is installed at an airsuction port of the compressor and a fourth temperature sensor is installed at a water inlet of the water side condenser. The information collected by the electrical control system comprises a temperature T1 sensed by the first temperature sensor, a temperature T4 sensed by the second temperature sensor, a temperature T6 sensed by the third temperature sensor and a temperature T7 sensed by the fourth temperature sensor; and the air inlet temperature T2 of the evaporator for limiting start of defrosting is set in the electrical control system. According to the defrosting method of the air source heat pump hot water unit, the problems that defrosting is carried out under the conditions of no frost and thin frost when the unit runs at low temperature are solved, and the problem that the heating capacity and the service life of the unit are affected by frequent starting of an air source heat pump during low-temperature operation is solved.

Description

technical field [0001] The invention relates to a defrosting method for an air source heat pump hot water unit. Background technique [0002] When the air source heat pump unit is running at low temperature heating, frosting on the air side evaporator is a common phenomenon; slight frosting at low temperature is beneficial to increase the evaporation temperature of the system, thereby increasing the low-temperature heating capacity of the system, but serious frosting will This will lead to a severe attenuation of the heating capacity of the unit; therefore, how to accurately determine whether the air-side evaporator is frosted in a low-temperature environment, and whether the frost is serious, which will affect the heating of the unit. Contents of the invention [0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method to avoid the problems of no-frost defrosting and thin-frost defrosting when the unit is running at ...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method to avoid the problems of no-frost defrosting and thin-frost defrosting when the unit is running at low temperature, and solve the problem of frequent start-up of the air source heat pump system at low temperature that affects the heating capacity of the unit The defrosting method of the air source heat pump hot water unit with the service life problem

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