Multi-online system

Abstract

A multi-split system includes an outdoor unit, a distribution device, and a plurality of indoor units. The distribution device includes a gas-liquid separator, a first heat exchange assembly, a first electronic expansion valve, a second heat exchange assembly, a second electronic expansion valve, a third electronic expansion valve connected in parallel with the second electronic expansion valve. When the flow rate of the refrigerant passing through the first electronic expansion valve is greater than a first preset value, the distribution device is configured to calculate a value of superheat degree according to the outlet temperature of the indoor heat exchanger of each cooling indoor unit and the temperature of the refrigerant flowing into the second heat exchange assembly, and to perform a PI control over the second electronic expansion valve and the third electronic expansion valve according to the value of superheat degree.

1 . A multi-split system, comprising an outdoor unit, a distribution device, and a plurality of indoor units, wherein
 the distribution device comprises a gas-liquid separator, a first heat exchange assembly, a first electronic expansion valve, a second heat exchange assembly, a second electronic expansion valve, a third electronic expansion valve connected in parallel with the second electronic expansion valve, in which the distribution device is configured to acquire a flow rate of a refrigerant passing through the first electronic expansion valve, and when the flow rate of the refrigerant passing through the first electronic expansion valve is greater than a first preset value, the distribution device is configured to acquire an outlet temperature of an indoor heat exchanger of each cooling indoor unit of the plurality of indoor units and a temperature of the refrigerant flowing into the second heat exchange assembly respectively, and to calculate a value of superheat degree according to the outlet temperature of the indoor heat exchanger of each cooling indoor unit and the temperature of the refrigerant flowing into the second heat exchange assembly, and to perform a PI control over the second electronic expansion valve and the third electronic expansion valve according to the value of superheat degree.   
     
     
         2 . The multi-split system according to  claim 1 , wherein when the flow rate of the refrigerant passing through the first electronic expansion valve is less than a second preset value, the distribution device is further configured to acquire a temperature of the refrigerant discharged to the outdoor unit from the first heat exchange assembly, and to calculate the value of superheat degree according to the temperature of the refrigerant flowing into the second heat exchange assembly and the temperature of the refrigerant discharged to the outdoor unit from the first heat exchange assembly, in which the second preset value is less than the first preset value. 
     
     
         3 . The multi-split system according to  claim 1 , wherein the distribution device calculates the value of superheat degree according to following formula:
     ΔSH=T 2 b  Average−i Tm2,
   in which T2bAverage is an average value of the outlet temperature of the indoor heat exchanger of each cooling indoor unit, and Tm2 is the temperature of the refrigerant flowing into the second heat exchange assembly.   
     
     
         4 . The multi-split system according to  claim 2 , wherein the distribution device calculates the value of superheat degree according to following formula:
     ΔSH=Tm 3− Tm 2,
   in which Tm3 is the temperature of the refrigerant discharged to the outdoor unit from the first heat exchange assembly, and Tm2 is the temperature of the refrigerant flowing into the second heat exchange assembly.   
     
     
         5 . The multi-split system according to  claim 1 , wherein the multi-split system works under a main cooling mode. 
     
     
         6 . The multi-split system according to  claim 1 , wherein the outlet temperature of the indoor heat exchanger of each cooling indoor unit is detected by a temperature sensor provided at an outlet of the indoor heat exchanger of each cooling indoor unit, and the temperature of the refrigerant flowing into the second heat exchange assembly is detected by a temperature sensor provided at an outlet of the second electronic expansion valve. 
     
     
         7 . The multi-split system according to  claim 2 , wherein the multi-split system works under a main cooling mode. 
     
     
         8 . The multi-split system according to  claim 3 , wherein the multi-split system works under a main cooling mode. 
     
     
         9 . The multi-split system according to  claim 4 , wherein the multi-split system works under a main cooling mode.