Performance analysis of an Organic Rankine Cycle with superheating under different heat source temperature conditions

► Analysis of ORC using R-12, R-123, R-134a and R-717 with isobaric superheating. ► Examined performances under fixed and variable heat source temperature conditions. ► For variable heat source, the temperature of heat source is kept 15 K above TIT. ► Compared efficiencies, irreversibility, work output etc. with increase in TIT. ► R-123 produces the maximum efficiencies with minimum irreversibility. This paper presents an analysis of non-regenerative Organic Rankine Cycle (ORC), based on the parametric optimization, using R-12, R-123, R-134a and R-717 as working fluids superheated at constant pressure. A computer programme has been developed to parametrically optimize and compare the system and second law efficiency, irreversibility of the system, availability ratio, work output, mass flow rate with increase in turbine inlet temperature (TIT) under different heat source temperature conditions. The calculated results reveal that R-123 produces the maximum efficiencies and turbine work output with minimum irreversibility for employed constant as well as variable heat source temperature conditions. Hence, selection of a non-regenerative ORC during superheating using R-123 as working fluid appears to be a choice system for converting low-grade heat to power.