Tri-generation system using cascading organic rankine cycle

Abstract

A tri-generation system comprises a heat generation system, a first rankine cycle system, a second rankine cycle system, a cascaded heat exchange unit, at least one first heat exchanger coupled to the second rankine cycle system for heating a third fluid, at least one second heat exchanger disposed at one or more locations in the first rankine cycle system for heating a fourth fluid, and an absorption chiller coupled to the at least one first heat exchanger and the at least one second heat exchanger for receiving the heated third fluid and the heated fourth fluid. The first rankine cycle system is coupled to a first heat source and configured to circulate a first working fluid to remove heat from the first heat source. The second rankine cycle system is coupled to at least one second heat source and configured to circulate a second working fluid to remove heat from the at least one second heat source. The first and second working fluids are circulated in heat exchange relationship through the cascaded heat exchange unit for condensation of the first working fluid in the first rankine cycle system and evaporation of the second working fluid in the second rankine cycle system.

1 . A tri-generation system, comprising:
 a heat generation system comprising at least two separate heat sources having different temperatures;   a first rankine cycle system comprising a first expander, wherein the first rankine cycle system is coupled to a first heat source among the at least two separate heat sources and configured to circulate a first working fluid to remove heat from the first heat source;   a second rankine cycle system comprising a second expander, wherein the second rankine cycle system is coupled to at least one second heat source among the at least two separate heat sources and configured to circulate a second working fluid to remove heat from the at least one second heat source, the at least one second heat source comprising a lower temperature heat source than the first heat source;   a cascaded heat exchange unit through which the first and second working fluids are circulated in heat exchange relationship for condensation of the first working fluid in the first rankine cycle system and evaporation of the second working fluid in the second rankine cycle system;   at least one first heat exchanger coupled to the second rankine cycle system for heating a third fluid;   at least one second heat exchanger disposed at one or more locations in the first rankine cycle system for heating a fourth fluid;   an absorption chiller coupled to the at least one first heat exchanger and the at least one second heat exchanger for receiving the heated third fluid and the heated fourth fluid; and   at least one generator unit coupled to the first expander and the second expander.   
     
     
         2 . The system of  claim 1 , wherein the first working fluid comprises a first organic working fluid the second working fluid comprises a second organic working fluid. 
     
     
         3 . The system of  claim 1 , wherein the second rankine cycle system comprises a condenser coupled to the at least one second heat source selected from a group comprising an oil heat exchanger, an engine jacket, a water jacket heat exchanger, a lower temperature intercooler, a higher temperature intercooler, or combinations thereof. 
     
     
         4 . The system of  claim 3 , further comprising a partial evaporator, wherein the condenser is coupled to the oil heat exchanger, the engine jacket, the water jacket heat exchanger, the engine jacket, the lower temperature intercooler, the higher temperature intercooler, or combinations thereof through the partial evaporator that partially evaporates the second working fluid before entering the cascaded heat exchange unit. 
     
     
         5 . The system of  claim 1 , wherein the at least one second heat exchanger is disposed at a location between an evaporator and the first expander. 
     
     
         6 . The system of  claim 1 , wherein one or more locations in the first rankine cycle system comprises a location between an expander and the cascaded heat exchange unit. 
     
     
         7 . The system of  claim 1 , wherein the at least one first heat exchanger is selectively activated and deactivated depending on the amount of heat required for heating the third fluid and the at least one second heat exchanger is selectively activated and deactivated depending on the amount of heat required for heating the fourth fluid. 
     
     
         8 . The system of  claim 1 , wherein the first rankine cycle system and the second rankine cycle system are selectively activated and deactivated depending on the amount of power required. 
     
     
         9 . The combined heat and power cycle system of  claim 1 , wherein the first working fluid comprises steam. 
     
     
         10 . The recovery system of  claim 1 , wherein the first rankine cycle system further comprises an evaporator coupled to the first heat source, and wherein the first heat source comprises an engine exhaust unit. 
     
     
         11 . The system of  claim 1 , further comprising a first control valve to control flow of the second working fluid into the at least one first heat exchanger. 
     
     
         12 . The system of  claim 1 , further comprising a second control valve situated in the first rankine cycle system to control flow of the first working fluid into the at least one second heat exchanger and the cascaded heat exchange unit. 
     
     
         13 . The system of  claim 1 , wherein the at least one first heat exchanger is disposed at a location between the second heat source and the absorption chiller. 
     
     
         14 . The system of  claim 1 , wherein the first expander and the second expander are coupled a first generator unit and a second generator unit respectively. 
     
     
         15 . The system of  claim 1 , wherein the heat generation system comprises a combustion engine, a gas turbine, or combination thereof. 
     
     
         16 . The system of  claim 1 , wherein the heat generation system produces electricity, mechanical power, or combination thereof. 
     
     
         17 . The system of  claim 1 , wherein the at least one first heat exchanger is disposed between the second heat source and the absorption chiller. 
     
     
         18 . The system of  claim 17 , wherein the absorption chiller rejects a portion or all of the condensed third fluid back to the second rankine cycle system. 
     
     
         19 . A tri-generation system, comprising:
 a heat generation system comprising at least two separate heat sources having different temperatures;   a first organic rankine cycle system comprising a first expander, wherein the first rankine organic cycle system is coupled to a first heat source among the at least two separate heat sources and configured to circulate a first organic working fluid to remove heat from the first heat source;   a second organic rankine cycle system comprising a second expander and a condenser, wherein the condenser is coupled to at least one second heat source among the at least two separate heat sources and configured to circulate a second organic working fluid to remove heat from the at least one second heat source, the at least one second heat source comprising a lower temperature heat source than the first heat source;   a cascaded heat exchange unit through which the first and second working fluids are circulated in heat exchange relationship for condensation of the first organic working fluid in the first rankine cycle system and evaporation of the second organic working fluid in the second rankine cycle system;   at least one first heat exchanger disposed coupled to the second rankine cycle system for heating a third fluid;   at least one second heat exchanger disposed at one or more locations in the first rankine cycle system for heating a fourth fluid;   an absorption chiller coupled to the at least one heat exchanger for receiving the heated third fluid and the heated fourth fluid, wherein the absorption chiller rejects a portion or all of the condensed third fluid back to the second rankine cycle system;   at least one generator unit coupled to the first expander and the second expander; and   one or more control valves to control flow of the first working fluid into the at least one first heat exchanger and the cascaded heat exchange unit, to control flow of the second working fluid into the at least one second heat exchanger, or combination thereof.   
     
     
         20 . The system of  claim 19 , wherein the at least one second heat source comprises an oil heat exchanger, an engine jacket, a water jacket heat exchanger, a lower temperature intercooler, a higher temperature intercooler, or combinations thereof. 
     
     
         21 . The system of  claim 20 , further comprising a partial evaporator, wherein the condenser is coupled to the oil heat exchanger, the engine jacket, the water jacket heat exchanger, the engine jacket, the lower temperature intercooler, the higher temperature intercooler, or combinations thereof through the partial evaporator that partially evaporates the second working fluid before entering the cascaded heat exchange unit. 
     
     
         22 . The system of  claim 19 , wherein the at least one first heat exchanger is selectively activated and deactivated depending on the amount of heat required for heating the third fluid, the at least one second heat exchanger is selectively activated and deactivated depending on the amount of heat required for heating the fourth fluid, and the first rankine cycle system and the second rankine cycle system are selectively activated and deactivated depending on the amount of power required. 
     
     
         23 . The recovery system of  claim 19 , wherein the first rankine cycle system further comprises an evaporator coupled to the first heat source, and wherein the first heat source comprises an engine exhaust unit. 
     
     
         24 . The system of  claim 19 , wherein the heat generation system comprises a combustion engine or a gas turbine for producing electricity, mechanical power, or combination thereof. 
     
     
         25 . A tri-generation system, comprising:
 a heat generation system comprising at least two separate heat sources having different temperatures, wherein the heat generation system comprises a combustion engine or a gas turbine for producing electricity, mechanical power, or combination thereof;   a first organic rankine cycle system comprising a first expander and an evaporator, wherein the first rankine organic cycle system is coupled to a first heat source among the at least two separate heat sources and configured to circulate a first organic working fluid to remove heat from the first heat source;   a second organic rankine cycle system comprising a second expander and a condenser, wherein the condenser is coupled to at least one second heat source among the at least two separate heat sources and configured to circulate a second organic working fluid to remove heat from the at least one second heat source, the at least one second heat source comprising a lower temperature heat source than the first heat source, wherein the at least one second heat source comprises an oil heat exchanger, an engine jacket, a water jacket heat exchanger, a lower temperature intercooler, a higher temperature intercooler, or combinations thereof;   a cascaded heat exchange unit through which the first and second working fluids are circulated in heat exchange relationship for condensation of the first organic working fluid in the first rankine cycle system and evaporation of the second organic working fluid in the second rankine cycle system;   at least one first heat exchanger disposed coupled to the second rankine cycle system for heating a third fluid;   at least one second heat exchanger disposed at one or more locations in the first rankine cycle system for heating a fourth fluid;   an absorption chiller coupled to the at least one heat exchanger for receiving the heated third fluid and the heated fourth fluid, wherein the absorption chiller rejects a portion or all of the condensed third fluid back to the second rankine cycle system;   at least one generator unit coupled to the first expander and the second expander;   one or more control valves to control flow of the first working fluid into the at least one first heat exchanger and the cascaded heat exchange unit, to control flow of the second working fluid into the at least one second heat exchanger, or combination thereof; and   a partial evaporator that partially evaporates the second working fluid before entering the cascaded heat exchange unit, wherein the condenser is coupled to the oil heat exchanger, the engine jacket, the water jacket heat exchanger, the engine jacket, the lower temperature intercooler, the higher temperature intercooler, or combinations thereof through the partial evaporator.