Energy and Exergy Analysis of an Organic Rankine Cycle with Internal Heat Exchanger

Abstract

In this study, energy and exergy analysis of an organic Rankine cycle with internal heat exchanger using R1234yf, R1234ze and R134a is carried out. The energy and exergy performances of an ORC system for different operating temperature have been analyzed. It is seen from the analysis that, boiler, condenser and subcooling temperature has significant effect on both energy and exergy efficiencies. It was observed that energy and exergy efficiency increased with the increase of boiler and supercooling temperature, and energy and exergy efficiency decreased with the increase of condenser temperature. In addition, exergy destructions of each component were determined. Since the turbine and pump are considered isentropic, exergy destructions in these elements have been neglected. It was determined that the highest exergy destruction was in the condenser with the rate of 72% and the least exergy destruction was in the heat exchanger with the rate of 1%. As a result, it has been observed that the R1234yf fluid chosen as an alternative to the R134a working fluid is the most suitable fluid for the ORC system.

Keywords

• working fluids
• exergy
• energy
• heat exchanger
• organic rankine cycle