抄録
A cryogenic Stirling engine has been reconstructed from a β-type Stirling cycle refrigerator. This engine is cooled by liquid nitrogen (-196℃) or dry-ice/methanol (-69℃) and heated by warm water (40℃). The working gas is helium of about 1 MPa. Its characteristics, such as net output power, indicated power and thermal efficiency, have been examined at different engine speeds and different cooling temperatures, and they are compared with theoretical ones expected from a simulation code SCM20. The maximum output power of 160W has been obtained at an engine speed of 1030rpm and a mean pressure of 1.24MPa. In this example, the figure of merit (FOM), defined as the ratio of output power to consumed cold, is 0.20 and 1.35 for the net and internal powers, respectively. The experimental results and also the theoretical considerations suggest that the cryogenic Stirling engine may be a promising prime mover for utilization of the cold heat of liquefied gases, such as LNG, liquid oxygen, liquid nitrogen and liquid hydrogen.
