Experimental study of micro-scale organic Rankine cycle system based on scroll expander

Abstract

The organic Rankine cycle (ORC) is a promising technology to recover low grade waste heat. In this study, the experimental research is conducted to investigate the dynamic response performance of a micro-scale ORC system driven by low-grade heat sources at different loads. A scroll compressor is modified as the expansion machine in the ORC module and its isentropic efficiency under variable loads conditions is tested in the experiments. This work is investigated to assess the steady-state and dynamic performance of micro-scale ORC system at different loads conditions. The maximum electricity production and isentropic efficiency of the expander are 120 W and 43%, respectively, under the steady state experiments. On the other hand, in the dynamic experiment, the micro-scale ORC system has balance ability for disturbance caused by the load changes. If the disturbance is too large, the ORC system is unstable and could not be restored to a stable state by simple load reduction operation. The outcomes of experiment can establish foundation to the optimal system controls and give more information of optimal system design for the micro-scale ORC system.