Using R245 ca and R365 mfc as the working fluid

a secondary regenerative extraction organic Rankine cycle system driven by low temperature waste heat was designed.The MATLAB software and REFPROP 8.0software for refrigerants' physical property(offered by NIST)calculation and were applied to analyze the thermodynamic performance of this regenerative system.Moreover

three candidate schemes for the optimum extraction pressure were compared.The results show that

the system applying scheme III has the highest heat efficiency

in which the saturation pressure corresponding to the trisection temperature of the condenser outlet temperature and the generator inlet temperature is taken as the extraction steam pressure.The system applying scheme I has the best ability to work

in which the pressure corresponding to the trisection enthalpy at the steam turbine inlet and outlet is taken as the extraction steam pressure.As the degree of superheat of the steam increases

the heat efficiency and exergy efficiency of the system reduces with low rate.Therefore

the heat efficiency and exergy efficiency of the graded regenerative extraction organic Rankine cycle system can be increased without increasing the degree of superheat of the steam.