Multi-split air-conditioning system and supercooling and enhanced vapor injection method thereof

Abstract

The invention relates to a multi-split air-conditioning system and a supercooling and enhanced vapor injection method thereof. The multi-split air-conditioning system comprises a compressor, an outdoor side heat exchanger, an indoor unit heat exchanger, a gas-liquid separator, an intermediate heat exchanger, a first four-way valve and a second four-way valve which are connected through pipelines. As the second four-way valve, a first branch circuit and the intermediate heat exchanger are arranged in the multi-split air-conditioning system, during cooling operation, the intermediate heat exchanger serves as a subcooler, a cooling medium flows in different directions through adjustment by the first branch circuit and the second four-way valve after passing through the intermediate heat exchanger, and accordingly, the cooling medium of the first branch circuit cools down a main-circuit cooling medium to achieve the supercooling purpose; and during heating operation, the intermediate heat exchanger serves as an economizer, the cooling medium passes through the first branch circuit and the second four-way valve after passing through the indoor unit heat exchanger, and then is sprayed into a medium-pressure cavity of the compressor through a jet orifice to supply a medium-pressure gaseous cooling medium for the compressor. The structure is simple and the supercooling and enhanced vapor injection purposes are better achieved.

Description

technical field [0001] The invention relates to a multi-connected air-conditioning system and a method for overcooling the system and increasing enthalpy by injecting air, belonging to the field of vapor compression refrigeration and air-conditioning. Background technique [0002] The multi-connected air-conditioning system has a high EER, and the cold (heat) is directly transported by the refrigerant, reducing the heat exchange link, and is suitable for various load-changing places. For multi-connected air conditioning systems, in order to prevent the refrigerant from flashing before entering the evaporator, a subcooling device is usually added to the outdoor unit to increase the subcooling degree, so that the refrigerant is in a supercooled state when it enters the throttle part of the indoor unit. [0003] For the vapor compression refrigeration system, the subcooling cycle can improve the cooling capacity and performance coefficient of the refrigeration cycle. At present...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a multi-connected air-conditioning system and a method for overcooling the multi-connected air-conditioning system and increasing enthalpy by jetting, so as to overcome the limited ability of the subcooler to supercool the refrigerant in the refrigeration process in the prior art and the heating effect. In the process, an economizer is used to increase the intermediate pressure of the gaseous refrigerant to realize the injection of gas to increase the enthalpy, the defect of complex structure and high cost

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