Refrigerant flow control method and system

Abstract

The invention relates to the field of air conditioner control, and provides a refrigerant flow control method for solving the problem that during low-temperature heating of a frequency conversion heatpump air conditioner, control over the refrigeration flow and the heat exchange capacity of an outdoor heat exchanger are not matched. The method comprises the steps that S1, after heating begins, whether the outdoor heat exchanger reaches the defrosting control condition or not is judged, if yes, the S2 is executed; S2, defrosting operation is carried out, after the defrosting is finished, an expansion valve is controlled to be recovered to the initial opening degree, the frosting time and the running duration after defrosting begin to be subjected to time keeping, and the S3 is executed; S3, when the frosting time reaches the preset frosting time, the S4 is executed; S4, valve adjusting time begins to time keeping, when the pressure adjusting time reaches the preset valve adjusting time, the opening degree of the expansion valve is controlled, the preset opening degree interval is reduced, the running duration after defrosting is subtracted from the preset valve adjusting time, andthe result is divided by the preset coefficient; S5, whether the outdoor heat exchanger reaches the defrosting control condition or not is judged, if yes, the S2 is executed, if not, the S4 is executed. The method is suitable for the control over the low-temperature heating mode of the frequency conversion heat pump air conditioner.

Description

technical field [0001] The invention relates to the field of air conditioner control, in particular to the control of refrigerant flow during low-temperature heating of a frequency conversion heat pump air conditioner. Background technique [0002] At present, the flow control of the expansion valve of the inverter heat pump air conditioner is too rough when heating at low temperature. One is that the expansion valve of the outdoor heat exchanger is set to a fixed opening during the entire frosting process. At the beginning of frosting, when the expansion valve is set to a fixed opening The passing refrigerant flow can meet the matching requirements of the outdoor heat exchanger, and the refrigerant can be completely evaporated. However, in the process of low-temperature heating and frosting, as the frost layer increases, the heat transfer capacity of the outdoor heat exchanger gradually decreases. The flow cannot be completely evaporated, resulting in an increasingly mismat...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is: to overcome the problem of insufficient heat exchange capacity caused by the mismatch between the refrigerant flow control method and the heat exchange capacity of the outdoor heat exchanger when the frequency conversion heat pump air conditioner is heating at low temperature, and propose a refrigerant flow control method and system

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