Selection of Working Fluids for Low-temperature Solar Thermal Power Generation Organic Rankine Cycles

To select a suitable working fluid for low-temperature solar thermal power generation organic Rankine cycle,the PR equation of state was adopted to calcualte and analyze the thermal performances of organic Rankine cycles driven by low-temperature solar energy using 11 kinds of organic fluids with low boiling points.Results reveal that the maximum evaporation pressure at the inlet of the organic turbine tends to decrease with the increase of the critial temperature of the working fluid.On condition that the condensation temperature and the turbine inlet temperature remain constant,the thermal efficiency of the cycle will rise with the increase of the critical temperature of the working fluid.High thermal efficiency of the cycle can be obtained with appropriate condensation pressure in the condenser by use of n-hexane or normal pentane.So the above two fluids are likely to be the most promising fluids for low-temperature solar thermal power generation orgainc Rankine cycles.