Air conditioner

Abstract

To obtain an air conditioner which ensures safe operation and protection of the device and can carry out an operation with favorable energy efficiency by efficiently compressing the refrigerant. The air conditioner 100 is capable of performing a cooling/heating mixed operation, constituting a refrigerant circuit by piping connection of a heat-source side unit 10 having a heat-source side heat exchanger 15 and a compressor 11, a plurality of load-side units 50 having a load-side throttle device 51 and a load-side heat exchanger 52, and a cooling/heating branch unit 30 having a gas/liquid separator 31. It is further provided with a bypass pipe 21 forming a bypass for splitting the refrigerant discharged by the compressor, an opening/closing valve 22 for bypass for controlling the split of the refrigerant to the bypass pipe through opening/closing, and control means 40 for executing processing to split the refrigerant by opening the opening/closing valve 22 for bypass if it is judged that there is an abnormal rise or a fear of the abnormal rise in a refrigerant pressure on a discharge side of the compressor 11 when operating the heat-source side heat exchanger 15 functioning as an evaporator.

1 . An air conditioner capable of a cooling/heating mixed operation in which a refrigerant circulates through a refrigerant circuit formed by connecting, with piping:
 a heat-source side unit having a heat-source side heat exchanger and a compressor;   a plurality of load-side units each having a load-side throttle device and a load-side heat exchanger; and   a cooling/heating branch unit having a gas/liquid separator for supplying a gas refrigerant to said load-side unit that carries out a heating operation and for supplying a liquid refrigerant to said load-side unit that carries out a cooling operation,   the air conditioner comprising:   a bypass pipe forming a bypass into which the refrigerant discharged by said compressor is split;   an opening/closing valve for bypass that controls a split flow of the refrigerant to said bypass pipe by opening/closing; and   control means for executing processing in which it is judged if there is an abnormal rise or a fear of the abnormal rise in a refrigerant pressure on the discharge side of said compressor when a state in which said load-side units involved in the operation carry out both the heating operation and the cooling operation and said heat-source side heat exchanger functions as a condenser is changed to another state in which all of said load-side units involved in the operation carry out the heating operation and said heat-source side heat exchanger came to function as an evaporator, and if it is judged that there is the abnormal rise or a fear thereof, said opening/closing valve for bypass is made to open so as to split the refrigerant to said bypass pipe.   
     
     
         2 . (canceled) 
     
     
         3 . The air conditioner of  claim 1 , wherein
 said plurality of load-side units are constituted by a high-ability unit and a low-ability unit; and   said control means controls said opening/closing valve for bypass to be an open state when said high-ability unit changes to other operation modes except said cooling operation in a cooling/heating simultaneous operation in which said low-ability unit performs heating operation and said high-ability unit performs cooling operation.   
     
     
         4 . The air conditioner of  claim 1 , wherein
 said control means judges on the basis of a signal from pressure detection means for detecting a pressure of the refrigerant on a discharge side of said compressor if the pressure of the refrigerant on said discharge side exceeds a predetermined pressure or not so as to judge said abnormal rise.   
     
     
         5 . The air conditioner of  claim 1 , wherein
 said control means judges on the basis of a signal from temperature detection means for detecting an ambient temperature of said heat-source side unit if said ambient temperature exceeds a predetermined temperature or not so as to judge the fear of said abnormal rise.   
     
     
         6 . The air conditioner of  claim 1 , wherein
 said heat-source side heat exchanger is constituted by piping connection of a plurality of heat exchangers in parallel with the refrigerant circuit and   one end of said bypass pipe and the piping to any of said heat exchangers are made to communicate with each other so that the refrigerant having passed through said bypass pipe returns to an intake side of said compressor through any of said plurality of heat exchangers.   
     
     
         7 . The air conditioner of  claim 1 , wherein
 said compressor is a variable-capacity compressor having an inverter circuit for changing a driving frequency and   said control means executes processing to open said opening/closing valve for bypass and to split the refrigerant to said bypass pipe in addition to the judgment on whether there is said abnormal rise or a fear of the abnormal rise when it is judged that said compressor is driving at a frequency not more than a predetermined driving frequency.   
     
     
         8 . The air conditioner of  claim 1 , wherein
 a throttle device for bypass for controlling an amount of said split refrigerant amount to be is further provided with said bypass and   said control means controls an opening degree of said throttle device for bypass on the basis of a pressure of the refrigerant on the discharge side of said compressor.   
     
     
         9 . The air conditioner of  claim 1 , wherein
 a capillary tube for controlling an amount of said split refrigerant to be constant is further provided with said bypass.   
     
     
         10 . The air conditioner of  claim 3 , wherein
 said control means judges on the basis of a signal from pressure detection means for detecting a pressure of the refrigerant on a discharge side of said compressor if the pressure of the refrigerant on said discharge side exceeds a predetermined pressure or not so as to judge said abnormal rise.   
     
     
         11 . The air conditioner of  claim 3 , wherein
   said control means judges on the basis of a signal from temperature detection means for detecting an ambient temperature of said heat-source side unit if said ambient temperature exceeds a predetermined temperature or not so as to judge the fear of said abnormal rise.     
     
     
         12 . The air conditioner of  claim 4 , wherein
 said control means judges on the basis of a signal from temperature detection means for detecting an ambient temperature of said heat-source side unit if said ambient temperature exceeds a predetermined temperature or not so as to judge the fear of said abnormal rise.