Method and system for reducing frosting degree of air-source heat pump hot water unit in winter

Abstract

The invention relates to a waste heat utilizing method and a waste heat utilizing system for reducing the frosting degree of an evaporator of an air-source heat pump hot water unit in winter. In order to overcome the defects in energy dissipation and influence on the system stability, which are existed in the existing defrosting technology, the invention provides a technical proposal as follows: domestic hot water after use is pumped into a waste water heat exchanger and then undergoes heat exchange with medium water in the waste water heat exchanger; the medium water after the heat exchange is pumped into a phase-change heat storage device and then flows into an air heater arranged at the air inlet side of the evaporator of the air-source heat pump hot water unit; the medium water flowing out of the air heater then flows into an evaporator of a water source heat pump unit and then flows back into the waste water heat exchanger. By using the method of heating and warming up the air with the waste hot water, the method and the system improve the temperature of the air entering the evaporator, reduce the relative humidity of the air, greatly reduce the frosting possibility, not only save the energy consumed for defrosting, but also increase the heat supply of the unit and enhance the reliability and the stability of operation of the system.

Description

technical field [0001] The invention belongs to the field of energy technology, and in particular relates to a waste heat utilization method and system capable of reducing the frosting amount of an evaporator of an air source heat pump hot water unit in winter. Background technique [0002] The air source heat pump hot water unit absorbs low-grade heat energy in the surrounding air through the heat pump cycle to produce domestic hot water. It has the advantages of energy saving, safety, environmental protection, and less floor space. It is a hot water supply that has boomed in recent years. The method has been applied in quite a few hot water supply projects. However, the heating capacity of the air source heat pump water heater unit decreases rapidly with the decrease of the temperature. When the temperature in winter drops to a certain level and the surface temperature of the evaporator is lower than 0°C and lower than the dew point temperature of the air, the evaporator ...

AI Technical Summary

Problems solved by technology

Someone once proposed to heat the air by relying on the sensible heat discharged from the subcooling of the condensed refrigerant liquid. This method will reduce the heating capacity of the unit, and can only increase the inlet air temperature by about 0.5°C, which cannot meet the requirements at all; in addition, The evaporator will not be frosted during most of the year. When the temperature is high, heating the evaporator inlet air will increase the inlet and outlet temperature and pressure of the compressor, which is not good for the compressor.

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