Dynamic behavior of a directly combined binary turbine system consisting of steam and R123 turbines

The binary turbine system that employs steam as the primary working fluid has used Rll as the secondary working fluid because Rll has good characteristics as a working fluid in power plants. However, substitute LBMs (low boiling-temperature mediums compared with water) are being developed because of the destruction of the ozone layer by CFCs. In this paper, modeling and experimental investigations into the dynamics of a directly combined binary turbine system using R123 instead of Rll are described. The system consists mainly of a steam-and an R123-turbine, an R123 vapor generator, and an AC generator. The dynamic behavior of the system is similarly discussed from the viewpoint of the network theory with the previous report. The validity of the model was proven through comparison with our experimental results, which are the frequency responses examined with respect to generator load changes. In addition, the effects of the thermodynamic property of the secondary medium on the steady and dynamic characteristics of the system are also described.