Performance evaluation of a diesel engine integrated with ORC system

Waste heat recovery from exhaust gas with organic Rankine cycle (ORC) systems is a promising method to improve the overall thermal efficiency of diesel engines. The performance of a diesel engine integrated with an ORC system is evaluated in this paper. Simulation models of the diesel engine and the ORC system are developed in GT-suite separately, and a combined system model is developed in Simulink environment. The engine simulation results are validated experimentally. The steady performance evaluation of the engine with ORC at different engine conditions is presented, and the acceleration performance of the diesel engine with and without ORC is evaluated. The performance of the engine during the ORC expander start-stop process is also discussed. The steady performance simulation results indicate that, the net power output increment, the brake specific fuel consumption (BSFC) reduction and the thermal efficiency improvement of the engine with ORC system can be up to 4.13 kW, 3.61 g/(kW h) and 0.66%, respectively. The transient performance simulation results show that the ORC system has minimal effects on the acceleration performance of the engine.