A comprehensive study on waste heat recovery from internal combustion engines using organic Rankine cycle

Abstract

There are a substantial amount of waste heat through exhaust gas and coolant of an Internal Combustion Engine. Organic Rankine cycle is one of the opportunities in Internal Combustion Engines waste heat recovery. In this study, two different configurations of Organic Rankine cycle with the capability of simultaneous waste heat recovery from exhaust gas and coolant of a 12L diesel engine were introduced: Preheat configuration and Two-stage. First, a parametric optimization process was performed for both configurations considering R-134a, R-123, and R-245fa as the cycle working fluids. The main objective in optimization process was maximization of the power generation and cycle thermal efficiency. Expander inlet pressure and preheating temperature were selected as design parameters. Finally, parameters like hybrid generated power and reduction of fuel consumption were studied for both configurations in different engine speeds and full engine load. It was observed that using R-123 as the working fluid, the best performance in both configurations was obtained and as a result the 11.73% and 13.56% reduction in fuel consumption for both preheat and Two-stage configurations were found respectively.