Heating medium compression apparatus, air conditioner, and heating medium compression method

Abstract

A heating medium compression apparatus includes: first and second compressors compressing a heating medium; suction side and discharge side pipings connecting the first and second compressors to a heat exchanger; a connection piping connecting a discharge side of the first compressor and a suction side of the second compressor in series; and a control unit controlling a flow rate of the heating medium flowing in the suction side piping, the discharge side piping, and the connection piping. The control unit alternatively connects the first or second compressor to the suction side and discharge side pipings, or connects the first and second compressors in series between the suction side and discharge side pipings and performs control such that the flow rate of the heating medium suctioned into the second compressor connected in series becomes higher than that of the heating medium discharged from the first compressor.

What is claimed is: 
     
         1 . A heating medium compression apparatus comprising:
 a first compressor and a second compressor that compress a heating medium;   a suction side piping and a discharge side piping that connect the first compressor and the second compressor to a heat exchanger;   a connection piping that connects a discharge side of the first compressor and a suction side of the second compressor in series; and   a control unit that controls a flow rate of the heating medium flowing in the suction side piping, the discharge side piping, and the connection piping,   wherein the control unit alternatively connects the first compressor or the second compressor to the suction side piping and the discharge side piping or connects the first compressor and the second compressor in series between the suction side piping and the discharge side piping and performs control such that the flow rate of the heating medium suctioned into the second compressor connected in series becomes higher than the flow rate of the heating medium discharged from the first compressor.   
     
     
         2 . The heating medium compression apparatus according to  claim 1 , wherein a maximum capacity of the second compressor is at least greater than or equal to a maximum capacity of the first compressor. 
     
     
         3 . The heating medium compression apparatus according to  claim 1 , further comprising a return piping that connects a discharge side and the suction side of the second compressor to each other,
 wherein the control unit further controls the flow rate of the heating medium flowing in the return piping.   
     
     
         4 . The heating medium compression apparatus according to  claim 1 , further comprising a bypass piping that connects the suction side piping and the connection piping to each other,
 wherein the control unit further performs control such that the bypass piping is opened or closed.   
     
     
         5 . The heating medium compression apparatus according to  claim 3 , wherein the suction side piping, the discharge side piping, and the return piping have valves for adjusting the flow rate, and
 the control unit controls opening degrees of the valves.   
     
     
         6 . The heating medium compression apparatus according to  claim 4 , wherein each of the suction side piping, the discharge side piping, and the bypass piping have valves for adjusting the flow rate, and
 the control unit controls opening degrees of the valves.   
     
     
         7 . The heating medium compression apparatus according to  claim 1 , wherein the first compressor and the second compressor are turbo compressors. 
     
     
         8 . An air conditioner comprising:
 the heating medium compression apparatus according to  claim 1 ; and   a heat exchanger that performs heat exchange between the heating medium supplied from the heating medium compression apparatus and atmospheric air.   
     
     
         9 . A heating medium compression method for controlling a flow rate of a heating medium to a heat exchanger by connecting a first compressor and a second compressor compressing the heating medium to the heat exchanger alternatively or in series, the heating medium compression method comprising:
 performing control such that the flow rate of the heating medium suctioned into the second compressor becomes higher than the flow rate of the heating medium discharged from the first compressor in a state in which the first compressor and the second compressor are connected in series between a suction side piping and a discharge side piping.