Organic rankine cycle system and method

Abstract

An ORC system configured to limit temperature of a working fluid below a threshold temperature is provided. The ORC system includes a heat source configured to provide waste heat fluid. The ORC system also includes a heat exchanger coupled to the heat source, wherein the heat exchanger includes multiple external or internal enhancement features. The external enhancement features are configured to reduce a first heat transfer coefficient between the working fluid and the waste heat fluid from the heat source, external to the heat exchanger. The internal enhancement features are configured to increase a second heat transfer coefficient between the working fluid and the waste heat fluid from a heat source, internal to the heat exchanger.

1 . An organic rankine cycle system configured to limit temperature of a working fluid below a threshold temperature, the system comprising:
 a heat source configured to provide waste heat fluid;   a heat exchanger coupled to the heat source, the heat exchanger comprising:   a plurality of at least one of external or internal enhancement features, wherein the external enhancement features are configured to reduce a first heat transfer coefficient between the working fluid and the waste heat fluid from the heat source, external to the heat exchanger and the internal enhancement features are configured to increase a second heat transfer coefficient between the working fluid and the waste heat fluid from a heat source, internal to the heat exchanger.   
     
     
         2 . The system of  claim 1 , wherein the heat exchanger comprises a preheater, an evaporator, and a superheater. 
     
     
         3 . The system of  claim 1 , wherein the external enhancement features comprise fins. 
     
     
         4 . The system of  claim 1 , wherein the internal enhancement features comprise internal fins, or turbulators or boiling surfaces. 
     
     
         5 . The system of  claim 1 , wherein the heat source is configured to introduce the waste heat fluid into the preheater or the evaporator. 
     
     
         6 . The system of  claim 1 , wherein the threshold temperature comprises about 300 deg C. 
     
     
         7 . The system of  claim 1 , wherein the first heat transfer coefficient comprises a range between about 3000 to about 5000 W/m 2 -K on the working fluid side, 100 W/m̂2-K on the gaseous waste heat fluid side. 
     
     
         8 . The system of  claim 1 , wherein the second heat transfer coefficient comprises a range between about 20000 to about 40000 W/m 2 -K on the working fluid side, 100 W/m 2 -K on the gaseous waste heat fluid side. 
     
     
         9 . The system of  claim 1 , wherein the heat source comprises a gas turbine exhaust. 
     
     
         10 . A method for providing an organic rankine cycle system to limit temperature of a working fluid below a threshold temperature, the method comprising:
 providing a heat source configured to convey waste heat fluid;   providing a heat exchanger coupled to the heat source, the heat exchanger comprising:   a plurality of at least one of external or internal enhancement features, wherein the external enhancement features are configured to reduce a first heat transfer coefficient between the working fluid and the waste heat fluid from a heat source, external to the heat exchanger and the internal enhancement features are configured to increase a second heat transfer coefficient between the working fluid and the waste heat fluid from a heat source, internal to the heat exchanger.   
     
     
         11 . The method of  claim 10 , wherein said providing a heat exchanger comprises providing at least one of a preheater, an evaporator or a superheater. 
     
     
         12 . The method of  claim 10 , wherein said external enhancement features comprise fins. 
     
     
         13 . The method of  claim 10 , wherein said internal enhancement features comprise fins, turbulators, and boiling surfaces.