Non-azeotropic working fluid mixtures for rankine cycle systems

Abstract

A power generation system includes a non-azeotropic working fluid mixture and a Rankine cycle system. The Rankine cycle system includes a turbine generator that is driven by vapor of the first working fluid mixture, and a condenser that exchanges thermal energy between the vapor received from the turbine generator and a cooling medium. The working fluid mixture is characterized by a condenser temperature glide during phase change between approximately five degrees and thirty degrees Kelvin, a condensing pressure between approximately one tenth of one percent and eleven percent of a critical pressure of the working fluid mixture, and a condenser bubble point temperature between approximately one degree and nine degrees Kelvin greater than a temperature at which the cooling medium is received by the condenser.

What is claimed is: 
     
         1 . A power generation system, comprising:
 a non-azeotropic working fluid mixture; and   a Rankine cycle system comprising a turbine generator that is driven by vapor of the working fluid mixture, and a condenser that exchanges thermal energy between the vapor received from the turbine generator and a cooling medium;   wherein the working fluid mixture exhibits a condenser temperature glide during phase change between approximately five degrees and thirty degrees Kelvin, a condensing pressure between approximately one tenth of one percent and eleven percent of a critical pressure of the working fluid mixture, and a condenser bubble point temperature between approximately one degree and nine degrees Kelvin greater than a temperature at which the cooling medium is received by the condenser.   
     
     
         2 . The system of  claim 1 , wherein the working fluid mixture comprises a first chemical component and a second chemical component, and the first chemical component and the second chemical component each comprise at least one of a hydrocarbon, a fluorocarbon, an ether, a hydrochlorofluorocarbon, a hydrofluorocarbon, a fluorinated ketone, a hydrofluoro ether, a hydrochlorofluoro olefin, a bromofluoro olefin, a fluoro olefin, a hydrofluoro olefin, a cyclic siloxane and a linear siloxane. 
     
     
         3 . The system of  claim 2 , wherein the first chemical component comprises at least one of R134a, R245fa, R236ea, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, HFE-7000, R1234ze, R1234yf, R1233zd and R1243zf. 
     
     
         4 . The system of  claim 3 , wherein the second chemical component comprises at least one of pentane, hexane, isohexane, cyclopentane, cyclohexane, R245fa, R1234ze, isopentane, R161, R30, R134a, R1233zd, C7FK, isobutene, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, R236ea, HFE-7000, CF3I and R1243zf. 
     
     
         5 . The system of  claim 1 , wherein the condenser temperature glide is between approximately six degrees and twenty-five degrees Kelvin. 
     
     
         6 . The system of  claim 5 , wherein the condenser temperature glide is between approximately eight degrees and twenty degrees Kelvin. 
     
     
         7 . The system of  claim 1 , wherein the condensing pressure is between approximately one percent and eight percent of the critical pressure of the working fluid mixture. 
     
     
         8 . The system of  claim 7 , wherein the condensing pressure is between approximately two and one half percent and seven and one half percent of the critical pressure of the working fluid mixture. 
     
     
         9 . The system of  claim 1 , wherein the condenser bubble point temperature is between approximately one degree and five degrees Kelvin greater than the temperature at which the cooling medium is received by the condenser. 
     
     
         10 . The system of  claim 1 , wherein the working fluid mixture exhibits a global warming potential less than approximately 675. 
     
     
         11 . The system of  claim 10 , wherein the global warming potential is less than approximately 150. 
     
     
         12 . The system of  claim 1 , wherein the condenser comprises one of a plate-frame counter-flow heat exchanger, a one pass direct expansion shell and tube counter-flow heat exchanger, and a plate-shell counter-flow heat exchanger. 
     
     
         13 . A power generation system, comprising:
 an intermediate heat exchanger comprising a condenser passage that receives a first working fluid, and an evaporator passage that receives an organic, non-azeotropic second working fluid mixture, wherein the heat exchanger transfers thermal energy from the first working fluid to the second working fluid mixture;   a first Rankine cycle system comprising a first pump that directs the first working fluid through an evaporator and the condenser passage; and   a second Rankine cycle system comprising a second pump that directs the second working fluid mixture through the evaporator passage, a second turbine generator that is driven by vapor of the second working fluid mixture, and a condenser that exchanges thermal energy between the vapor received from the second turbine generator and a cooling medium;   wherein the second working fluid mixture is characterized by a condenser temperature glide between approximately five degrees and thirty degrees Kelvin, a condensing pressure between approximately one tenth of one percent and eleven percent of a critical pressure of the second working fluid mixture, and a condenser bubble point temperature between approximately one degree and nine degrees Kelvin greater than a temperature at which the cooling medium is received by the condenser.   
     
     
         14 . The system of  claim 13 , wherein the second working fluid mixture comprises a first chemical component and a second chemical component, and the first chemical component and the second chemical component each comprise at least one of a hydrocarbon, a fluorocarbon, an ether, a hydrochlorofluorocarbon, a hydrofluorocarbon, a fluorinated ketone, a hydrofluoro ether, a hydrochlorofluoro olefin, a bromofluoro olefin, a fluoro olefin, a hydrofluoro olefin, a cyclic siloxane and a linear siloxane. 
     
     
         15 . The system of  claim 14 , wherein the first chemical component comprises at least one of R134a, R245fa, R236ea, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, HFE-7000, R1234ze, R1234yf, R1233zd and R1243zf. 
     
     
         16 . The system of  claim 15 , wherein the second chemical component comprises at least one of pentane, hexane, isohexane, cyclopentane, cyclohexane, R245fa, R1234ze, isopentane, R161, R30, R134a, R1233zd, C7FK, isobutene, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, R236ea, HFE-7000, CF3I and R1243zf. 
     
     
         17 . The system of  claim 13 , wherein the evaporator transfers thermal energy into the first working fluid from a thermal source fluid received from one of a geothermal reservoir, a combustion engine, a solar-thermal system, an incinerator and an industrial system, and the cooling medium comprises at least one of a liquid and a gas. 
     
     
         18 . The system of  claim 13 , wherein the evaporator comprises a solar-thermal system. 
     
     
         19 . The system of  claim 13 , wherein the first working fluid comprises a first chemical component and a second chemical component, and the first chemical component and the second chemical component each comprise at least one of a hydrocarbon, a fluorocarbon, an ether, a hydrochlorofluorocarbon, a hydrofluorocarbon, a fluorinated ketone, a hydrofluoro ether, a hydrochlorofluoro olefin, a bromofluoro olefin, a fluoro olefin, a hydrofluoro olefin, a cyclic siloxane and a linear siloxane. 
     
     
         20 . The system of  claim 19 , wherein
 the first chemical component comprises at least one of R134a, R245fa, R236ea, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, HFE-7000, R1234ze, R1234yf, R1233zd and R1243zf; and   the second chemical component comprises at least one of pentane, hexane, isohexane, cyclopentane, cyclohexane, R245fa, R1234ze, isopentane, R161, R30, R134a, R1233zd, C7FK, isobutene, 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone, R236ea, HFE-7000, CF3I and R1243zf.