A heat pump water heater system with adjustable evaporator flow

Abstract

The invention discloses an evaporator flow-adjustable heat-pump water heater system. An exhaust pipe of a compressor is respectively communicated with a condensing coil or a hot-gas by-pass pipe through a three-way reversing valve; an outlet pipe of the condensing coil is communicated with a first inlet pipe of a liquid accumulator through an expansion valve; an outlet pipe of an evaporator is connected with a second inlet pipe of the liquid accumulator; a first outlet pipe of the liquid accumulator is connected to the suction side of the compressor; a second outlet pipe of the liquid accumulator is connected with a refrigerant inlet; an outlet of a refrigerant pump is communicated with an inlet pipe of the evaporator through a connecting pipe; the hot-gas by-pass pipe is communicated with an inlet of the evaporator through a one-way valve; a liquid-state refrigerant in the liquid accumulator passes through the evaporator through the refrigerant pump. The full-liquid state liquid supply is realized by adopting the evaporator, so that the problems that the variable working condition operation circular flow is not matched with the heat exchange area, and the winter operation circular flow is insufficient are effectively solved, the evaporating temperature can be properly improved, the size of a heat exchanger can be further reduced on the basis of increasing flow, the variable working condition operation property of a heat-pump water heater is improved, and the total operating efficiency is improved.

Description

technical field [0001] The invention relates to a heat pump water heater, in particular to a heat pump water heater system with adjustable evaporator flow. Background technique [0002] The general definition of a heat pump in the engineering field is: a machine or device that can absorb heat in a low-temperature environment, increase its temperature, and output heat to a high-temperature environment. The air source heat pump water heater continuously absorbs heat from the air and sends it to cold water through the thermodynamic cycle process of refrigerant continuous evaporation, compression, condensation, throttling, and evaporation, so as to realize the function of heating water. [0003] The power consumption of heat pump water heaters is usually only a quarter of that of electric water heaters. At the same time, there are no potential safety hazards such as electric leakage and dry burning. It does not need to rely on sunlight for heating like solar water heaters. to 2...

AI Technical Summary

Problems solved by technology

[0004] In traditional heat pump water heaters, as the system runs, the temperature on the side of the condenser gradually increases, which increases the temperature difference between the evaporation temperature and the condensation temperature, increases the dryness of the refrigerant after the throttle valve, and the gaseous refrigerant entering the evaporator Can not play a cooling role and the specific volume is large, which reduces the utilization rate of the heat exchange area of ​​the evaporator

When the water vapor in the air is at a temperature of -5°C to 11.5°C and a relative humidity of 65% to 100%, once the temperature is lower than the dew point, it is easy to condense and then frost. Therefore, when the air source heat pump water heater is running in winter, the outdoor heat exchange Frost is easy to form on the surface of the device, which affects the hot water output rate

In winter, the evaporating temperature is low, and the refrigerant flow rate of the system is small. Most of the refrigerant accumulates on the side of the condenser and liquid receiver. The heat transfer area of ​​the evaporator is not fully utilized, and the heat transfer efficiency is low, which affects the heating effect.

[0005] To sum up, the traditional heat pump water heater system has low flow regulation capacity on the evaporator side and poor adaptability to variable working conditions.

During winter and summer operation, there is a problem of mismatching refrigerant charge and evaporator heat transfer area

In variable working conditions, there is a problem that the refrigerant at the inlet of the evaporator is too dry

The key to the above two problems is that the evaporator area is not fully utilized, and the evaporator refrigerant flow adjustment is unreasonable

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