LOU Zongyong ¹, ZHANG Hongguang ², SONG Songsong ^{1, 2}

(1. Department of Automotive Engineering, Chengde Petroleum College, Chengde 067000, Hebei, China; 2. College of Environmental

and Energy Engineering, Beijing University of Technology, Beijing 100124, China)

Abstract:An organic Rankine cycle (ORC) system with an internal heat exchanger (IHE) is designed to recover exhaust energy from a stationary compressed natural gas (CNG) engine. According to the first and second laws of thermodynamics, the performances of the ORC system are analyzed. Thereafter, the stationary CNG engine-ORC with IHE combined system is presented. The electric efficiency and the brake specific fuel consumption (BSFC) are chosen to evaluate the operating performances of the combined system. The results show that,when the evaporation pressure is 3.5 MPa and the engine is operating at the rated condition, the net power output and the thermal efficiency of ORC system with IHE can reach up to 62.7kW and 12.5%, respectively. Compared with the stationary CNG engine, the electric efficiency of the combined system can be increased by 6.0%, while the BSFC can be reduced by a maximum 5.0%.

Key words:organic Rankine cycle; stationary CNG engine; performance analysis