A Thermodynamic Analysis of Cogeneration System in Parallel Circuit Based on Organic Rankine Cycle

Abstract

The combined heat and power generation system using Organic Rankine Cycle (ORC) has become a promising technology for efficient conversion of low-grade heat source to useful form of energy. In this study thermodynamic performance is investigated for a cogeneration system which consists of ORC power plant and an additional process heater as a parallel circuit. Nine different kinds of fluids of R143a, R22, R134a, R152a, R123, R113, isobutene, butane, and isopentane are considered as a working fluid of ORC. The effects of system parameters such as turbine inlet pressure, source temperature, and process heat load on the system performance including ratio of mass flow rates, net work production, and the first and second law efficiencies of thermodynamics for each fluid. Results show that there exists an optimal turbine inlet pressure to yield maximum net work. The selection of the working fluid for the combined system which assumes the maximum second-law efficiency is dependent on the source temperature level.