REFRIGERATION DEVICE

摘要

A refrigeration device using a refrigerant operating in a process in a supercritical condition can, even if a load varies, achieve improved performance coefficient with reliability of devices maintained.  A heat source heat exchanger (4) is connected to the discharge side of a high stage-side compression element (2d), and connection piping (72, 73, 74, 75) interconnects the heat source heat exchanger (4) and an expansion mechanism (5).  Connection piping (77, 2a) interconnects a utilization heat exchanger (6) and the suction side of a low stage-side compression element (2c).  A liquid-gas heat exchanger (8) exchanges heat between a refrigerant flowing in the connection piping (72, 73, 74, 75) and a refrigerant flowing in the connection piping (77, 2a).  A liquid-gas three-way valve (8C) switches between a state in which the refrigerant is caused to flow in that portion of the connection piping (72, 73, 74, 75) which passes through the liquid-gas heat exchanger (8) and a state in which the refrigerant is caused to flow in liquid gas bypass piping (8B) for interconnecting one end and the other end of that portion of the connection piping (72, 73, 74, 75) which passes through the liquid-gas heat exchanger (8).