The organic rankine cycle(ORC)generation technology uses organic fluids instead of water/steam to generate power through Rankine cycle and is mainly applied in waste heat recovery but not the solar thermal generation field.For solar heat source with different temperature levels(from 150 ℃ to400 ℃)

eight organic fluids such as R245 fa

n-pentane

cyclohexane

toluene

dodecane

decane

D4 and MDM were chosen as the candidate working fluids to carry out performance calculation for solar ORC power generation system with internal heat exchanger(IHE)under different conditions

according to the first law of thermodynamics.Moreover

the cycle performance was investigated from three aspects

like the evaporating pressure

evaporating temperature and pressure ratio of the turbine.The results show that

at a certain evaporation temperature

the cycle efficiencies of all the candidate working fluids but R245 fa and cyclohexane decreased with the increasing evaporating pressure.Increasing the evaporating pressure and pressure ratio helped to increase the cycle efficiencies of all the candidate fluids.Considering from all the factors

the R24 fa and n-pentane are suitable for ORC systems with IHE at temperature below 200 ℃

while the rest fluids were more proper to be used in ORC systems with IHE at temperature above 200 ℃.