Influence of Working Fluid Properties on System Performance and Screen Evaluation Indicators for Geothermal ORC System

摘要

The ORC(Organic Rankine Cycle)is one of the most effective approaches for recovering energy from low grade heat sources like geothermal water.This paper describes screening of fluids for geothermal ORC system.This study analyzed the influence of the working fluid properties of HC and HFC working fluids on the system performance and relates the properties to the molecular structures.HC and HFC working fluids were adopted.A theoretical ORC model was used to optimize the evaporating temperature to maximize the work output for each working fluid.The optimal working fluids are given for energy sources at 383.15 K,403.15 K and 423.15 K.The results show that for a specific source temperature,the optimized evaporating temperatures for all the working fluids are almost the same.Two indicators are given for screening working fluids.Fluids like R32,R134a and propylene(GWP<1500)provide better performance than others,by extracting more energy from the heat source.