The current work presents a thermodynamic and economic analysis for the use of ORC
systems to convert solar energy or low exergy energy to generate electrical power. The
organic working fluids investigated here were selected to investigate the effect of the
fluid saturation temperature on the performance of ORCs. The working fluids under
investigation are R113, R245fa, R123, with boiling points between 40 and 200 at
pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as
cooling resource, and allowing for a temperature difference 10 for effective heat
transfer. Consequently, the working fluids are condensed at 40 . A combined first- and
second-law analysis is performed by varying some system independent parameters at
various reference temperatures. The present work shows that ORC systems can be viable
and economical for the applications such as waste heat use and off-grid power generation
even though they are likely to be more expensive than grid power.