Patent ID: 7100380

Claim:
A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein said refrigerant is selected from the group consisting of CF 3 CF 2 C(O)CF(CF 3 ) 2 , (CF 3 ) 2 CFC(O)CF(CF 3 ) 2 , CF 3 (CF 2 ) 2 C(O)CF(CF 3 ) 2 , CF 3 (CF 2 ) 3 C(O)CF(CG 3 ) 2 , CF 3 (CF 2 ) 5 C(O)CF 3 , CF 3 CF 2 C(O)CF 2 CF 2 CF 3 , CF 3 C(O)CF(CF 3 ) 2 .