Fluid machine and refrigeration cycle apparatus

Abstract

A fluid machine 110 includes a power recovery mechanism 105 for recovering power from a working fluid, a sub-compressor 102 driven by the recovered power, a shaft 12 coupling the power recovery mechanism 105 and the sub-compressor 102 to each other so that the recovered power is transmitted from the power recovery mechanism 105 to the sub-compressor 102. The power recovery mechanism 105 is provided with a first suction port 26 and a second suction port 27 that open and close, as the first piston 21 rotates, so that the refrigerant flows into the high pressure-side working chamber 23 a. The second the suction port 27 is provided at a position facing the first suction port 26 in the axis direction of the shaft 12.

1 . A refrigeration cycle apparatus provided with a refrigerant circuit in which a refrigerant circulates, the refrigerant circuit comprising:
 a fluid machine including a power recovery mechanism for recovering power from a working fluid, a sub-compressor that is driven by the recovered power, and a shaft coupling the power recovery mechanism and the sub-compressor to each other so that the recovered power is transmitted from the power recovery mechanism to the sub-compressor;   a main compressor for compressing the refrigerant that has been pre-compressed by the sub-compressor in the fluid machine;   a heat radiator for cooling the refrigerant that has been compressed by the main compressor; and   an evaporator for evaporating the refrigerant discharged from the power recovery mechanism in the fluid machine wherein,   the power recovery mechanism includes:
 (a1) a first closing member; 
 (b1) a second closing member facing the first closing member; 
 (e1) a cylinder surrounding a part of the shaft in the circumferential direction, the cylinder having both ends closed by the first closing member and the second closing member; 
 (d1) a piston mounted on the shaft in the cylinder, the piston forming a working chamber between its outer circumferential surface and the inner circumferential surface of the cylinder; 
 (e1) a partition member partitioning the working chamber into a high pressure-side working chamber and a low pressure-side working chamber; 
 (f1) a first suction port provided in the first closing member so as to open and close, as the piston rotates, so that the working fluid flows into the high pressure-side working chamber; and 
 (g1) a second suction port provided in the second closing member at a position facing the first suction port in the axis direction of the shaft so as to open and close, as the piston rotates, so that the working fluid flows into the high pressure-side working chamber. 
   
     
     
         2 . The refrigeration cycle apparatus according to  claim 1 , wherein
 the power recovery mechanism further includes:
 (h1) a first discharge port provided in the first closing member so as to open and close, as the piston rotates, so that the working fluid flows out from the low pressure-side working chamber; and 
 (i1) a second discharge port provided in the second closing member at a position facing the first discharge port in the axis direction so as to open and close, as the piston rotates, so that the working fluid flows out from the low pressure-side working chamber. 
   
     
     
         3 . The refrigeration cycle apparatus according to  claim 2 , wherein
 the first discharge port has the same opening shape as the second discharge port.   
     
     
         4 . The refrigeration cycle apparatus according to  claim 2 , wherein
 the first discharge port has an opening area equal to an opening area of the second discharge port.   
     
     
         5 . The refrigeration cycle apparatus according to  claims 1 , wherein
 the first suction port has the same opening shape as the second suction port and has an opening area equal to an opening area of the second suction port, and   timings of the opening and closing of the first suction port match those of the second suction port.   
     
     
         6 . (canceled) 
     
     
         7 . The refrigeration cycle apparatus according to  claims 1 , wherein
 the power recovery mechanism further includes a suction path for supplying the working fluid from the outside of the power recovery mechanism to the high pressure-side working chamber through each of the first suction port and the second suction port, and   the suction path includes:
 (i) a common suction path extending from the outer circumferential surface of the second closing member toward the center of the shaft; 
 (ii) a first suction path branching from the common suction path and extending through the cylinder in the axis direction to reach the first suction port so as to allow the working fluid to be supplied from the common suction path to the high pressure-side working chamber through the first suction port; and 
 (iii) a second suction path branching from the common suction path at a more internal position than the first suction path in the radial direction of the shaft and extending in the axis direction to reach the second suction port so as to allow the working fluid to be supplied from the common suction path to the high pressure-side working chamber through the second suction port. 
   
     
     
         8 . The refrigeration cycle apparatus according to  claim 7 , wherein
 the first suction path has a larger cross-sectional area than the second suction path.   
     
     
         9 . The refrigeration cycle apparatus according to  claim 1  wherein
 the sub-compressor includes:
 (a2) a lower closing member; 
 (b2) an upper closing member facing the lower closing member; 
 (c2) a second cylinder surrounding a part of the shaft in the circumferential direction, the second cylinder having both ends closed by the lower closing member and the upper closing member; 
 (d2) a second piston mounted on the shaft in the second cylinder, the second piston forming a working chamber between its outer circumferential surface and the inner circumferential surface of the second cylinder; 
 (e2) a second partition member partitioning the working chamber into a low pressure-side working chamber and a high pressure-side working chamber; 
 (f2) a first suction port provided in the lower closing member so as to open and close, as the second piston rotates, so that the working fluid flows into the low pressure-side working chamber; and 
 (g2) a second suction port provided in the upper closing member at a position facing the first suction port in the axis direction of the shaft so as to open and close, as the second piston rotates, so that the working fluid flows into the low pressure-side working chamber. 
 
 
     
     
         10 . The refrigeration cycle apparatus according to  claim 9 , wherein
 the sub-compressor further includes:
 (h2) a first discharge port provided in the lower closing member so as to open and close, as the second piston rotates, so that the working fluid flows out from the high pressure-side working chamber; and 
 (i2) a second discharge port provided in the upper closing member at a position facing the first discharge port in the axis direction so as to open and close, as the second piston rotates, so that the working fluid flows out from the high pressure-side working chamber. 
   
     
     
         11 . The refrigeration cycle apparatus according to  claim 9 , wherein
 the fluid machine further includes a closed casing accommodating the power recovery mechanism, the sub-compressor and the shaft, and   the power recovery mechanism and the sub-compressor are arranged adjacent to each other in the axis direction in the closed casing so that the first closing member of the power recovery mechanism is used commonly as the lower closing member of the sub-compressor.   
     
     
         12 . (canceled) 
     
     
         13 . The refrigeration cycle apparatus according to  claim 5 , wherein
 the first suction port and the second suction port each are closed by the piston only when the piston is located at its top dead center, and   at least a part of the first suction port and at least a part of the second suction port each are exposed to the high pressure-side working chamber over the entire period except for the moment when the piston is located at its top dead center.   
     
     
         14 . The refrigeration cycle apparatus according to  claim 1 , further comprising:
 a bypass circuit bypassing the sub-compressor and connecting the outlet of the evaporator to the inlet of the main compressor;   a bypass valve provided in the bypass circuit so as to be opened when the refrigeration cycle apparatus is being started, wherein   the power recovery mechanism further includes:
 (h1) a first discharge port provided in the first closing member so as to open and close, as the piston rotates, so that the working fluid flows out from the low pressure-side working chamber; and 
 (i1) a second discharge port provided in the second closing member at a position facing the first discharge port in the axis direction so as to open and close, as the piston rotates, so that the working fluid flows out from the low pressure-side working chamber. 
   
     
     
         15 . The refrigeration cycle apparatus according to  claim 14 , wherein
 the first discharge port has the same opening shape as the second discharge port and has an opening area equal to an opening area of the second discharge port,   timings of the opening and closing of the first discharge port match those of the second discharge port,   the first discharge port and the second discharge port each are closed by the piston only when the piston is located at its top dead center, and   at least a part of the first discharge port and at least a part of the second discharge port each are exposed to the high pressure-side working chamber over the entire period except for the moment when the piston is located at its top dead center.