Heat pump water heater and control method thereof

Abstract

The invention discloses a heat pump water heater, comprising: a CO2 transcritical circulation system and a controller, the controller is used to: determine the preset optimal exhaust pressure of the circulation system after the heat pump water heater is started, and real-time Adjust the discharge pressure of the compressor to achieve the preset optimal discharge pressure, and adjust the outlet water temperature of the gas cooler in real time to achieve the target outlet water temperature; the outlet water temperature of the gas cooler is equal to the target After the outlet water temperature, obtain the actual outlet temperature of the gas cooler in real time, calculate the real-time optimal discharge pressure of the circulation system, and adjust the discharge pressure of the compressor in real time to achieve the real-time optimal discharge pressure . The invention also discloses a corresponding control method. By adopting the embodiment of the present invention, it is possible to effectively avoid the negative impact of coupling factors on the circulation system of the heat pump water heater, and reduce the waiting time for the circulation system to enter a stable stage.

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] As an energy-saving product, the air source heat pump water heater has made great progress in recent years. The refrigerant CO2 is naturally environmentally friendly, non-toxic and non-polluting. It is the most promising refrigerant in the 21st century and is widely used in heat pump water heaters. In the CO2 transcritical circulation system of the heat pump water heater, the high-temperature and high-pressure CO2 refrigerant is cooled by water in the gas cooler to release heat, thereby increasing the temperature of the water, and the outlet water temperature can be adjusted by controlling the outlet water flow. In addition, for the CO2 transcritical cycle system, when the evaporation temperature and the outlet temperature of the gas cooler are constant, different COP values ​​can be obtai...

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Problems solved by technology

However, in the process of implementing the present invention, the inventors found that the prior art has at least the following problems: for the CO2 transcritical circulation system, the change of the water flow will affect the outlet temperature of the gas cooler, and the change of the optimal exhaust pressure is affected by the gas cooling The effect of the outlet temperature of the

As a result, during the system adjustment process, the outlet water temperature decreases, the exhaust pressure also decreases, the outlet water temperature rises, and the exhaust pressure also rises periodically, which makes the control system fall into the negative influence of coupling factors.

Therefore, using the control strategy of the prior art, the circulatory system cannot quickly enter a stable state, and may even enter an abnormal state with periodic fluctuations

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