Multi-split air conditioning system and low-temperature refrigeration method

Abstract

The invention provides a multi-split air conditioning system, which comprises a compressor or a plurality of parallel compressors, two independent outdoor heat exchangers, two four-way valves, two electronic expansion valves and a one-way valve. According to the multi-split air conditioning system, the adoption of only one outdoor heat exchanger is replaced by the adoption of the two outdoor exchangers, so that the aim of reducing the area of a condenser is fulfilled by switching off one outdoor heat exchanger during the low-temperature refrigeration of the multi-split air conditioning system, and system pressure and exhaust and return air temperature can be controlled and maintained within reasonable ranges to reduce the liquid coolant returning risk of the system and ensure the reliability of the system; during the high-temperature heating of the multi-split air conditioning system, the area of an evaporator is reduced by switching off one outdoor heat exchanger, and the system pressure and the exhaust and return air temperature can be controlled and maintained within reasonable ranges to reduce the risks of high temperature and high pressure of the system and ensure the reliability of the system.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a multi-connected air conditioning system and a low-temperature refrigeration method. Background technique [0002] The outdoor heat exchanger of the existing multi-connected air-conditioning system is basically made into a whole flow path. This whole flow path is beneficial to the production process and the control of the outdoor unit when the outdoor unit is relatively small. The capacity of outdoor units is getting bigger and bigger. At present, there are 30 or even larger outdoor units. This kind of outdoor heat exchanger with integrated flow path is used for low-temperature refrigeration. Condenser, this may cause the condensation effect to be too good, the evaporator cannot be completely evaporated, and the cooling capacity of the internal unit is too sufficient to cause the compressor of the outdoor unit to start and stop frequently or cause the system to return t...

AI Technical Summary

Problems solved by technology

[0002] The outdoor heat exchanger of the existing multi-connected air-conditioning system is basically made into a whole flow path. This whole flow path is beneficial to the production process and the control of the outdoor unit when the outdoor unit is relatively small. The capacity of outdoor units is getting bigger and bigger. At present, there are 30 or even larger outdoor units. This kind of outdoor heat exchanger with integrated flow path is used for low-temperature refrigeration. Condenser, this may cause the condensation effect to be too good, the evaporator cannot be completely evaporated, and the cooling capacity of the internal unit is too sufficient to cause the compressor of the outdoor unit to start and stop frequently or cause the system to return to liquid refrigerant, which may cause the compressor to burn out in severe cases; When it is hot, the exhaust temperature of the compressor is high, and the system pressure will be high at this time, and the outdoor heat exchanger is all used as an evaporator. The return air temperature is very high, and if the return air temperature is high, the exhaust temperature will be higher. In such a vicious cycle, the compressor will always work under high pressure, and the compressor will eventually be burned. The air volume of the outdoor unit fan is used to adjust the heat exchange efficiency of the outdoor unit heat exchanger. However, even if the outdoor unit fan is turned off for relatively large outdoor units, only using the convective heat exchange between the heat exchanger and the air still cannot solve the problem of insufficient evaporation during low-temperature cooling. The system pressure is too high when the system is completely flooded and the high temperature is heated, resulting in the risk of burning the compressor

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