Organic rankine cycle fluid

1. 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 .

2. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat extracted from an internal combustion engine 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 .

3. A method as set forth in claim 2 wherein the step of extracting heat from said internal combustion engine is accomplished by extracting heat from exhaust gases leaving said internal combustion engine.

4. A method as set forth in claim 2 wherein the step of extracting heat from the internal combustion engine is accomplished by extracting heat from coolant flowing within the said combustion engine.

5. A method of operating an organic rankine cycle system wherein a pump is used to circulate liquid refrigerant to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing first through a plurality of nozzles and then through a turbine, with the resulting cooled vapor ten passing through a condenser for condensing the vapor to a liquid; wherein the step of introducing heat to the refrigerant is by way of extracting waste heat from an engine and further wherein said refrigerant is at least one 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 , perfluorocyclohexanone, and mixtures thereof.

6. A method as set forth in claim 5 wherein said engine is an internal combustion engine.

7. 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 CF 3 CF 2 C(O)CF(CF 3 ) 2 .

8. 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 CF 3 CF 2 C(O)CF(CF 3 ) 2 , and where said condenser further includes a water heater which utilizes waste heat from said turbine to generate hot water.

9. A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat extracted from an internal combustion engine 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 CF 3 CF 2 C(O)CF(CF 3 ) 2 .

10. A method of operating an organic rankine cycle system wherein a pump is used to circulate liquid refrigerant to an evaporator where heat is introduced to the refrigerant to convert it to vapor, with the vapor then passing first through a plurality of nozzles and then through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid; wherein the step of introducing heat to the refrigerant is by way of extracting waste heat from an engine and further wherein said refrigerant is CF 3 CF 2 C(O)CF(CF 3 ) 2 .