Frontiers in Energy
Analysis of a 1 kW organic Rankine cycle using a scroll expander for engine coolant and exhaust heat recovery
. Sir Joseph Swan Centre for Energy Research, Newcastle University, Newcastle NE1 7RU, UK.. Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240, China.. School of Energy and Power Engineering, Beihang University, Beijing 100191, China.. Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China
Available online: 2017-12-14
The development of engine waste heat recovery technologies attracts ever increasing interests due to the rising strict policy requirements and environmental concerns. This paper presented the study of engine coolant and exhaust heat recovery using organic Rankine cycle (ORC). Eight working fluids were selected to evaluate and compare the performance of the integrated waste heat recovery system. Rather than the conventional engine ORC system mainly focusing on the utilization of exhaust energy, this work proposed to fully use the engine coolant energy by changing the designed parameters of the ORC system. The case study selected a small engine as the heat source to drive the ORC system using a scroll expander for power production. The evaluation results suggest that under the engine rated condition, the solution to fully recover the engine coolant energy can achieve a higher power generation performance than that of the conventional engine ORC system. The results suggest that adding a recuperator to the ORC system can potentially improve the system performance when the working fluids are dry and the overall dumped heat demand of the system can be reduced by 12% under optimal conditions. When the ORC evaporating and condensing temperature are respectively set at 85°C and 30°C, the integrated engine waste heat recovery system can improve the overall system efficiency by 9.3% with R600, R600a or -Pentane as the working fluid.