An assessment of the performance of closed cycles with and without heat rejection at cryogenic temperatures

This paper presents optimized cycle performance that can be obtained with s ystems including a closed cycle gas turbine (CCGT). The influence of maximu m temperature, minimum temperature, and recuperator effectiveness on cycle performance is illustrated. Several power-plant arrangements are analyzed a nd compared based on thermodynamic performance (thermal efficiency and spec ific work); enabling technologies (available at present); and developing te chnologies (available in the near term or future). The work includes the ef fects of utilization of high temperature ceramic heat exchangers and of cou pling of CCGT systems with plants vaporizing liquid hydrogen (LH2) or lique fied natural gas (LNG). Given the versatility of energy addition and reject ion sources that can be utilized in closed gas-cycle systems, the thermodyn amic performance of power plants shown in this paper indicate the remarkabl e capabilities and possibilities for closed gas-cycle systems.