Air-cooled heat pump unit and control method of electronic expansion valve in air-cooled heat pump unit

Abstract

The invention discloses an air-cooled heat pump unit and a control method of an electronic expansion valve in the air-cooled heat pump unit. The air-cooled heat pump unit comprises a compressor, a four-way valve, an air-side heat exchanger, a gas-liquid separator, the electronic expansion valve, a water-side heat exchanger and a controller. The control method comprises the following steps that 1,when the unit is about to start heating operation, firstly, the environment temperature is detected; 2, when the unit starts heating operation, the fin temperature of the unit and the heat pump unit hot water outlet temperature are detected; 3, according to the detected environment temperature, the detected fin temperature and the detected heat pump unit water outlet temperature, a superheat degree target value is calculated and determined through a special calculation formula; and 4, the controller of the unit compares the superheat degree target value with an actual superheat value. Throughthe implementation of the air-cooled heat pump unit and the control method of the electronic expansion valve in the air-cooled heat pump unit, the energy efficiency value of the unit is improved, theheating state under low-temperature and high-humidity working conditions is improved, the heating operation range is expanded, the unit can operate under worse working conditions, and outstanding progress is achieved.

Description

technical field [0001] The invention relates to the technical field of air source heating, in particular to an air-cooled heat pump unit and a control method for an electronic expansion valve therein. Background technique [0002] A defect of the air source heat pump unit is that the fins of the evaporator will frost during heating, and the frosting of the fins will cause the evaporation temperature and pressure to drop. At this time, it is necessary to ensure a reasonable superheat of the unit to prevent the compressor from running with liquid , The exhaust superheat of the unit is controlled by the electronic expansion valve, and it is necessary to continuously adjust the opening of the expansion valve according to the change of the evaporation pressure of the evaporator, so as to maintain a reasonable superheat of the unit. [0003] The concept of traditional electronic expansion valve control is to set a fixed exhaust superheat target value, and the electronic expansion ...

AI Technical Summary

Problems solved by technology

[0002] A defect of the air source heat pump unit is that the fins of the evaporator will frost during heating, and the frosting of the fins will cause the evaporation temperature and pressure to drop. At this time, it is necessary to ensure a reasonable superheat of the unit to prevent the compressor from running with liquid , the exhaust superheat of the unit is controlled by the electronic expansion valve, and it is necessary to continuously adjust the opening of the expansion valve according to the change of the evaporating pressure of the evaporator, so as to maintain a reasonable superheat of the unit

[0003] The concept of traditional electronic expansion valve control is to set a fixed exhaust superheat target value, and the electronic expansion valve is controlled according to the fixed target value. When the fin frosting causes the evaporation temperature and pressure to decrease, the fixed target value The control cannot ensure that the unit runs at a reasonable superheat, and it is easy to cause the compressor to run with liquid

Images