Solar-Powered/Fuel-Assisted Rankine Cycle Power and Cooling System: Sensitivity Analysis

The subject of this analysis is a solar power/cooling system based on a novel hybrid steam Rankine cycle. Steam is generated by the use of solar energy collected at about 100°C, and it is then superheated to about 600°C in a fossil-fuel-fired superheater. The addition of about 20–26 percent of energy as fuel doubles the power cycle’s efficiency as compared to organic fluid Rankine cycles operating at similar collector temperatures. A sensitivity analysis of the system’s performance to the size and type of its components was performed by a transient (hourly) computer simulation over the month of August in two representative climatic regions (Washington, D.C. and Phoenix, Ariz.), and led to the description of a system configuration which provides optimal energy performance. The newly designed turbine’s predicted efficiency is seen to be essentially invariant with system configuration, and has a monthly average value of about 73 percent.