High Efficiency Solar Dynamic Space Power Generation System

Taking into account that space power technologies have undergone significant advances over the past few years, and great emphasis is being placed on the development of dynamic power systems at this time, a design study has been conducted to evaluate the applicability of a combined cycle concept - closed Brayton cycle (CBC) and organic Rankine cycle (ORC) coupling - for solar dynamic space power generation systems. In the solution here presented (solar dynamic combined cycle SDCC) the waste heat rejected by the CBC working fluid is utilized to heat the organic working fluid of an ORC system. This allows the SDCC efficiency to be increased compared to the efficiencies of two subsystems (CBC and ORC). Also in the field of small size space power systems (up to 50 kW) the efficiency of the SDCC can be comparable with the Stirling performance. However, the CBC and ORC designs are based on a great deal of maturity assessed in much previous work on terrestrial and SD power systems. This is not yet true for the Stirling cycles. The purpose of this paper is to analyze the performance requirements of the new space power generation system (SDCC). The significant benefits of the SDCC solution such as efficiency increase, mass reduction, specific area -collector and radiator- reduction, are presented and discussed in a Low Earth Orbit (LEO) space station application.