Injection oil return control method and device for air-conditioning system and air-conditioning system

Abstract

The invention discloses an injection oil return control method and device for an air-conditioning system and the air-conditioning system. The injection oil return control method comprises the steps that when it is detected that an injection oil return electromagnetic valve is closed, the oil return operating time of a compressor is kept from zero, and the exhaust superheat degree of an exhaust pipe is calculated continuously; if first preset conditions are met, the injection oil return electromagnetic valve is controlled to be opened, and the first preset conditions include that the compressor is at least started for a preset time, the accumulated oil return operating time of the compressor exceeds a second preset time, and the exhaust superheat degree of the exhaust pipe at least reaches a first preset numerical value after operation lasts for a third preset time; and when it is detected that the compressor is stopped or the injection oil return electromagnetic valve is kept open for a fourth preset time, the injection oil return electromagnetic valve is controlled to be closed. By the adoption of the technical scheme, refrigeration oil can be recovered into the compressor in time, the situation that too much refrigerant liquid is brought into the compressor, and consequentially liquid impact of the compressor is caused can also be avoided, and thus the reliability and safety of injection oil return can be improved.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a method and device for controlling oil return of an air-conditioning system and an air-conditioning system. Background technique [0002] In today's economic society, air conditioners are welcomed by people because of their good refrigeration and other effects, and are widely used. [0003] For an air conditioning system with a flooded shell and tube evaporator, since the refrigerant liquid is evaporated inside the flooded shell and tube evaporator, the refrigerant oil will be stored at the bottom of the shell and tube. If it is not led back to the compressor in time, it will As the cycle continues, more and more refrigerated oil will accumulate at the bottom of the shell and tube, causing the compressor to lack oil, affecting the reliability and performance of the compressor, and eventually making the compressor unable to operate normally. At present, the refrigerated...

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Problems solved by technology

[0004] However, due to the lack of effective control of the injection oil return technology, the current injection oil return technology cannot realize that the refrigeration oil can be recovered to the compressor in time, and it can also avoid bringing more refrigerant liquid to the compressor to cause compression. The machine liquid hits or even burns the compressor, with low reliability and safety

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