Exergo-economic analysis of waste heat Organic Rankine Cycle

Abstract

Organic Rankine Cycle is one of the most promising solutions for utilisation of waste heat. Even though several devices have been operating successfully over the last decade, the technology is far from being widely implemented, with the cost being the primary hindrance. ORC typically yields low efficiency, and there is a number of safety concerns regarding working fluids and device operation. In the current study we have thermodynamically simulated the performance of several working fluids in an ORC system powered by waste heat. Energetic and exergetic analyses, according to the first and the second principles, show expected system outputs depending on the thermo-physical fluid parameters. Power output, thermal and exergetic cycle efficiencies and exergy destruction in individual cycle components were evaluated for a range of operational parameters. Sensitivity analysis included variation of high cycle pressure, expander inlet temperature, isentropic efficiency of the expander and the pump, and the pinch point temperature differences in the evaporator and the condenser. Economic analysis was conducted for the considered cycle designs, linking energetic and exergetic results with the component cost rates.