Variable refrigerant flow system

Abstract

A multi-split system includes an outdoor unit, a distribution device, a plurality of indoor units. Each indoor unit includes an indoor heat exchanger and a throttling element, and the distribution device includes a plurality of first controlling valves and a plurality of second controlling valves corresponding to each indoor unit. When any one of the plurality of indoor units receives a mode switching instruction, the 20 indoor unit sends the mode switching instruction to the distribution device. The distribution device determines on or off statuses of a first on/off valve and a second on/off valve corresponding to the indoor unit according to the mode switching instruction.

1 . A multi-split system, comprising an outdoor unit, a distribution device, a plurality of indoor units, in which each indoor unit comprises an indoor heat exchanger and a throttling element, and the distribution device comprises a plurality of first controlling valves and a plurality of second controlling valves corresponding to each indoor unit,
 when any one of the plurality of indoor units receives a mode switching instruction, the indoor unit sends the mode switching instruction to the distribution device;   the distribution device determines on or off statuses of a first on/off valve and a second on/off valve corresponding to the indoor unit according to the mode switching instruction.   
     
     
         2 . The multi-split system according to  claim 1 , wherein when any one of the plurality of indoor units is under a heating operating mode, the distribution device controls the second on/off valve corresponding to the indoor unit to open, and controls the first on/off valve corresponding to the indoor unit to close, and controls an opening of the throttling element in the indoor unit by an indoor controller in the indoor unit, in which
 when the indoor unit receives an instruction indicating switching to a cooling operating mode, the distribution device controls the second on/off valve corresponding to the indoor unit to close, and controls the throttling element in the indoor unit to reach a standby opening by the indoor controller in the indoor unit;   the distribution device controls the throttling element in the indoor unit to reach a maximum opening by the indoor controller in the indoor unit after a first preset time so as to make the indoor unit be filled with a medium-pressure liquid refrigerant, the distribution device controls the first on/off valve corresponding to the indoor unit to open after a second preset time, in which the second preset time is longer than the first preset time.   
     
     
         3 . The multi-split system according to  claim 1 , wherein when any one of the plurality of indoor units is under a cooling operating mode, the distribution device controls the first on/off valve corresponding to the indoor unit to open, and controls the second on/off valve corresponding to the indoor unit to close, and controls an opening of the throttling element in the indoor unit by an indoor controller in the indoor unit, in which
 when the indoor unit receives an instruction indicating switching to a heating operating mode, the distribution device controls the first on/off valve corresponding to the indoor unit to close, and controls the throttling element in the indoor unit to reach a maximum opening by the indoor controller in the indoor unit;   the distribution device controls the second on/off valve corresponding to the indoor unit to open after a second preset time.   
     
     
         4 . The multi-split system according to  claim 1 , wherein the multi-split system comprises a two-pipe heat recovery multi-split system and a three-pipe heat recovery multi-split system. 
     
     
         5 . The multi-split system according to  claim 1 , wherein
 when any one of the plurality of indoor units is under a cooling operating mode, the indoor unit may be controlled to be switched to a cooling standby mode, a cooling stopping mode or a heating operating mode;   when any one of the plurality of indoor units is under a cooling standby mode, the indoor unit may be controlled to be switched to a cooling stopping mode or a heating operating mode;   when any one of the plurality of indoor units is under a cooling stopping mode, the indoor unit may be controlled to be switched to a cooling operating mode or a heating operating mode;   when any one of the plurality of indoor units is under a heating operating mode, the indoor unit may be controlled to be switched to a heating standby mode, a heating stopping mode or a cooling operating mode;   when any one of the plurality of indoor units is under a heating standby mode, the indoor unit may be controlled to be switched to a heating stopping mode or a cooling operating mode;   when any one of the plurality of indoor units is under a heating stopping mode, the indoor unit may be controlled to be switched to a cooling operating mode or a heating operating mode.   
     
     
         6 . The multi-split system according to  claim 2  or  3 , wherein the first preset time is in a range of 20 to 40 seconds, and the second preset time is in a range of 50 to 70 seconds. 
     
     
         7 . The multi-split system according to  claim 2 , wherein the standby opening is 72 P, and the maximum opening is 480 P. 
     
     
         8 . The multi-split system according to  claim 2 , wherein the multi-split system comprises a two-pipe heat recovery multi-split system and a three-pipe heat recovery multi-split system. 
     
     
         9 . The multi-split system according to  claim 3 , wherein the multi-split system comprises a two-pipe heat recovery multi-split system and a three-pipe heat recovery multi-split system. 
     
     
         10 . The multi-split system according to  claim 3 , wherein the first preset time is in a range of 20 to 40 seconds, and the second preset time is in a range of 50 to 70 seconds.