Multi-connected air-conditioning system and its control method

Abstract

The present invention relates to the technical field of air conditioning, and specifically provides a multi-connected air-conditioning system and its control method, aiming at solving the problem that the existing multi-connected air-conditioning system is easy to exhaust the compressor due to the single-compressor operation after a single compressor inhales a large amount of refrigerant after the oil return operation low temperature problem. The multi-connected air conditioning system includes multiple compressors and multiple gas-liquid separators corresponding to the multiple compressors. Gas balance pipes and liquid balance pipes with adjustable communication status are connected between the multiple gas-liquid separators. The control method includes The following steps are as follows: within the first set period of time after the oil return operation of the air conditioning system is completed, the states of multiple compressors are obtained; according to the states of the multiple compressors, the connection state of the liquid balance pipe is adjusted. Through such a setting, it is possible to avoid the problem that the compressor continuously sucks a large amount of liquid refrigerant during part of the operation of the compressor after the oil return is completed, which causes the exhaust gas temperature to be too low.

Description

technical field [0001] The invention relates to the technical field of air conditioning, and specifically provides a multi-connected air conditioning system and a control method thereof. Background technique [0002] Due to its flexible system layout, reliable and stable operation, and flexible allocation from small load operation to large load operation, the multi-connected air conditioning system has been widely used in buildings, shopping malls, factories and other environments. Compared with ordinary air conditioning systems, the amount of refrigerant circulating in multi-split air conditioning systems is larger. Especially for large-scale multi-connected systems, the refrigerant charge is especially large. In order to prevent excessive liquid refrigerant from entering the compressor to cause liquid hammer, a multi-connected air conditioning system usually includes multiple compressors and corresponding multiple gas-liquid separators. The multiple gas-liquid separators...

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Problems solved by technology

[0005] In order to solve the above-mentioned problems in the prior art, that is, in order to solve the problem that the exhaust gas temperature is low due to the continuous suction of a large amount of liquid refrigerant by the operation of some compressors in the existing multi-connected air-conditioning system after the oil return operation, on the one hand, the present invention provides a multi- A control method for an on-line air-conditioning system, the multi-on-line air-conditioning system includes a plurality of compressors and a plurality of gas-liquid separators corresponding to the plurality of compressors, and a gas balance pipe is connected between the plurality of gas-liquid separators and a liquid balance pipe whose communication state can be adjusted, the control method includes the following steps: within a first set time period after the oil return operation of the air conditioning system is completed, obtain the states of the multiple compressors; state of each compressor, adjust the communication state of the liquid balance pipe

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