Two-stage compression air conditioner system and control method thereof

Abstract

The invention discloses a two-stage compression air conditioner system and a control method thereof. The air conditioner system comprises a two-stage compressor, a four-way reversing valve, an outdoor heat exchanger, a first throttling device, a flash evaporator, a second throttling device and an indoor heat exchanger, wherein the opening of the first throttling device and the second throttling device is adjustable. The air conditioner system further comprises a bypass pipeline, a heat accumulator and a control valve, wherein the bypass pipeline is connected between a first end interface of the outdoor heat exchanger and an air suction port of the two-stage compressor, a first heat exchange pipe of the heat accumulator is serially connected onto a pipeline between an air exhaust port of the two-stage compressor and a first end interface of the indoor heat exchanger, a second heat exchange pipe of the heat accumulator is serially connected onto the bypass pipeline, and the control valve is used for selectively opening or closing the pipeline between the first end interface of the outdoor heat exchanger and the air suction port of the two-stage compressor and the bypass pipeline. The two-stage compression air conditioner system disclosed by the invention has the advantages that the operating efficiency of the system can be improved; the defrosting speed is fast and refrigerant which is not fully evaporated can be prevented from entering the compressor during defrosting.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a two-stage compression air conditioning system and a control method thereof. Background technique [0002] At present, the intermediate air supply volume of the two-stage compression air conditioning system with a flash evaporator cannot be adjusted. When the compressor uses the same frequency, changes in other parameters in the system may cause fluctuations in the intermediate air supply volume, which will make the compressor run from the optimal state. efficiency point, causing the compressor not to operate at the best efficiency point. [0003] In addition, the conventional defrosting method of the two-stage compression air-conditioning system is that during the heating process, when the defrosting condition is reached, the compressor is first stopped, and then turned on to the cooling mode for defrosting. When the defrosting is over, stop the machine, and then turn...

AI Technical Summary

Problems solved by technology

Although this defrosting method can solve the above-mentioned problems existing in the traditional defrosting method, since the defrosting method uses the heat generated by the compressor to store heat, the phase change temperature point of the phase change heat storage material used will inevitably be If the temperature is lower, the heat absorption and heat release speed of the heat storage material will be slower, so that the defrosting speed will be slower, and the defrosting time will be prolonged, which will also affect the heating effect and comfort

Especially for the two-stage compression air conditioning system with defrosting function, when heating, due to the existence of the flash evaporator, the refrigerant must be subcooled again when it flows through the flash evaporator, that is, the refrigerant flowing into the outdoor heat exchanger must be at Lower temperatures than single-stage compression, so frosting will be more severe and frequent, so defrosting will be slower

Moreover, defrosting when the accumulator has insufficient heat storage will cause a large amount of refrigerant that cannot be evaporated to enter the compressor, thereby posing a fatal threat to the reliability of the compressor.

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