Description
The aim of this work is to study the influence of component selection and sizing on the thermodynamic performance of an Organic Rankine Cycle (ORC) designed for ultra-low grade thermal energy recovery. The selected working fluid of the ORC is a refrigerant whose properties are adapted for energy recovery in a low temperature regime, below 100C. Following a mathematical model, validation of the results was conducted using experimental test using commercial water heater as a heat source, with temperature of the hot water ranging from 75 to 90 °C. The system was modeled, designed, assembled, and tested. The limits of the ORC system are evaluated and the results were tabulated. It was found that component efficiencies and sizing have significant impact on system efficiency of ORCs. Expanders are typically expensive, whereas the scroll expander, used in this study, has limited efficiency. Because of the Carnot limit, issues given less attention in traditional Rankine cycle performance analysis, such as pipe diameters on the liquid and vapor sides, become critical in ultra-low grade thermal energy recovery.
