Experimental investigation of a revolving vane expander in a micro-scale organic Rankine cycle system for low-grade waste heat recovery

Organic Rankine cycles (ORCs) are a reliable solution for power generation from low-temperature waste heat. While the ORC is a mature technology in medium to large scale applications, several challenges remain to be solved for its widespread adoption in micro-scale, including the development of a low-cost, reliable, and efficient expander. In this study, a modified revolving vane expander (M-RVE) prototype is experimentally tested in a micro-scale ORC system for the first time. The M-RVE is tested in the range of suction pressures of up to 13.0 bar(a), suction temperatures of up to 63 degrees C, and shaft speeds of up to 1850 rpm. The M-RVE demonstrated filling factors of 1.2-2.7, an isentropic efficiency of up to 42.5%, and shaft power of up to 134 W. The significant impacts of lubrication on the performance of the M-RVE are discussed. A comparable performance with existing expanders in the literature is achieved, especially at pressure ratios close to the expander built-in volume ratio. The results of this study provide better guidance for further use of the M-RVE in micro-scale ORC systems and provide a benchmark for future improvements of the M-RVE prototype.(C) 2022 Elsevier Ltd. All rights reserved.