Heat-pump water heater and control method thereof

Abstract

The invention discloses a heat-pump water heater and meanwhile further provides a control method of the heat-pump water heater. The heat-pump water heater comprises a compressor and an evaporator. A gas-liquid separator is arranged between the compressor and the evaporator, and a heating device is arranged in the gas-liquid separator. It can be guaranteed that the suction gas superheat degree of the compressor reaches a target value by means of the method that the heating device heats refrigerant media inside the gas-liquid separator, so that the situations that part of the liquid refrigerantmedium enters the compressor, thus the liquid impact phenomenon is caused, and the service life of the compressor is seriously affected are avoided. According to the control method of the heat-pump water heater, the target suction gas superheat degree of the compressor is set, the actual suction gas superheat degree of the compressor is controlled to reach the target suction gas superheat degree of the compressor by means of the method that the refrigerant media are heated by the heating device, through control over the suction gas superheat degree of the compressor by adopting the control method of the heat-pump water heater, the simple and flexible effects are achieved, the adjusting speed is high, and it can be guaranteed that a refrigerant sucked by the compressor is a gaseous refrigerant.

Description

technical field [0001] The invention relates to the field of heat pump water heaters, in particular to a heat pump water heater and a control method thereof. Background technique [0002] At this stage, air-energy heat pump water heaters and air-conditioning systems that are popular on the market generally use gas-liquid separators to prevent liquid cold medium from entering the compressor, causing problems such as compressor liquid shock and oil dilution damage to bearings. The control is controlled by electronic expansion valves or The opening of the throttling element is used to ensure the suction superheat of the compressor, but in the defrosting process, the electronic expansion valve or the throttling element is usually controlled by a fixed opening, which will cause a large amount of liquid refrigerant to enter the gas-liquid separation The device will cause part of the liquid cold medium to enter the compressor and cause liquid shock, which will seriously affect the ...

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Problems solved by technology

In this patent, by controlling the opening of the electronic expansion valve, the refrigerant flow rate of the system is adjusted, so as to realize the optimal operation state of the compressor under this working condition, but in the process of defrosting, the electronic expansion valve or the throttling element are usually fixed open In this way, a large amount of liquid cold medium will enter the gas-liquid separator, causing part of the liquid cold medium to enter the compressor and cause liquid shock, which will seriously affect the service life of the compressor.

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