Heat pump unit and its control method and device

Abstract

The invention discloses a heat pump unit and a control method and device thereof. The control method includes: acquiring outdoor environment temperature and the operation mode of the heat pump unit; acquiring the initial flow of a variable-frequency water pump according to the outdoor environment temperature and the operation mode of the heat pump unit, and controlling variable-frequency water pump to output according to the initial flow; acquiring the water temperature difference between the target water outlet temperature of the heat pump unit and the actual water outlet temperature of the heat pump unit, and regulating the operation frequency of a variable-frequency compressor according to the water temperature difference; during the regulating of the operation frequency of the variable-frequency compressor, judging whether the absolute value of water inlet and outlet temperature difference is larger than a preset value or not; if so, regulating the output of the variable-frequency water pump according to the absolute value of the water inlet and outlet temperature difference, and stopping the regulating of the operation frequency of the variable-frequency compressor. By the method, a system can provide water flow according to needs, the energy consumption of the variable-frequency water pump can be reduced, and system operation stability can be increased.

Description

technical field [0001] The invention relates to the technical field of air conditioners, in particular to a control method for a heat pump unit, a control device for the heat pump unit, and a heat pump unit with the control device. Background technique [0002] The traditional heat pump / air conditioning unit uses a fixed-speed water pump to provide power for the water circulation system. When the system load changes, the water flow of the system cannot be adjusted as required, resulting in energy waste. Under the pursuit of high energy efficiency of heat pump / air conditioner units in today's market, traditional heat pump / air conditioner units are gradually unable to meet the needs of users, and the frequency conversion water pump can automatically adjust the water flow of the system through appropriate control, saving system energy consumption to a certain extent , so it is favored. [0003] Among them, how to control the capacity output of the frequency conversion water pu...

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Problems solved by technology

[0004] This method has a better effect when used in combination with a fixed-frequency compressor, because the capacity output of the heat pump side is relatively stable. However, when this method is used in combination with a variable-frequency compressor, there will be large fluctuations in the outlet water temperature. Because in the heating mode, when the inlet water temperature rises, the frequency conversion compressor will reduce the frequency, and the capacity output will decrease. user comfort

Moreover, when the heat demand on the user side decreases, the return water temperature will increase, that is, the inlet water temperature will increase. If the frequency conversion water pump is controlled according to the above method, the water flow rate of the frequency conversion water pump should increase, which is obviously important for energy saving. is unfavorable

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