Cooling tower apparatus and method with waste heat utilization

Abstract

A cooling tower system is disclosed. The cooling tower system includes a first heat exchanger that receives a process fluid from a first fluid circuit, and receives a working fluid from a second fluid circuit, thereby effecting thermal communication between the first fluid circuit and the second fluid circuit. The first fluid circuit includes a heat source disposed upstream of the first heat exchanger, and a cooling tower unit configured to transfer heat from the process fluid to a flow of ambient air. The second fluid circuit includes a waste heat expansion engine disposed downstream of the first heat exchanger in a direction of working fluid flow. The waste heat expansion engine is configured to extract power from the working fluid and transfer at least a portion of the power extracted to a component of the cooling tower unit.

What is claimed is: 
     
         1 . A method for operating a cooling tower system, the cooling tower system including a first fluid circuit containing a process fluid flowing therein, the first fluid circuit being in fluid communication with a cooling tower unit having a component that requires power for operation thereof,
 a second fluid circuit containing a working fluid flowing therein, and   a first heat exchanger in fluid communication with the first fluid circuit and the second fluid circuit, the method comprising:   transferring heat from a heat source of the first fluid circuit into the process fluid;   transferring heat from the first fluid circuit into the second fluid circuit via the first heat exchanger;   extracting power from the working fluid by expanding the working fluid through a waste heat expansion engine disposed within the second fluid circuit;   transferring heat from the first fluid circuit to an ambient environment via a flow of ambient air through the cooling tower unit; and   transferring at least a portion of the power extracted from the working fluid by the waste heat expansion engine to the component of the cooling tower unit.   
     
     
         2 . The method of  claim 1 , wherein the heat source is a power plant, and the process fluid exiting the power plant is low pressure steam. 
     
     
         3 . The method of  claim 1 , further comprising transferring the power extracted from the working fluid by the waste heat expansion engine to the component of the cooling tower unit in a form of electricity. 
     
     
         4 . The method of  claim 1 , further comprising transferring the power extracted from the working fluid by the waste heat expansion engine to the component of the cooling tower unit in a form of rotational torque. 
     
     
         5 . The method of  claim 1 , further comprising delivering the working fluid to the waste heat expansion engine as a liquid, and vaporizing the working fluid in the waste heat expansion engine. 
     
     
         6 . The method of  claim 1 , wherein the process fluid exiting the heat source is steam. 
     
     
         7 . The method of  claim 1 , wherein the cooling tower system further includes
 a third fluid circuit containing a cooling fluid flowing therein, and   a second heat exchanger in fluid communication with the second fluid circuit and the third fluid circuit, the method further comprising:   transferring heat from the second fluid circuit into the third fluid circuit via the second heat exchanger,   wherein the second heat exchanger is disposed downstream of the waste heat expansion engine and upstream of the first heat exchanger in a direction of working fluid flow.   
     
     
         8 . The method of  claim 7 , further comprising transferring heat from the third fluid circuit into the flow of ambient air via the cooling tower unit. 
     
     
         9 . The method of  claim 6 , wherein the cooling tower system further includes a second heat exchanger in fluid communication with the first fluid circuit and the second fluid circuit, the method further comprising:
 transferring heat from the second fluid circuit into the first fluid circuit via the second heat exchanger,   wherein the first heat exchanger is disposed downstream of the heat source and upstream of the cooling tower unit in a direction of process fluid flow,   wherein the second heat exchanger is disposed downstream of the cooling tower unit and upstream of the heat source in the direction of process fluid flow, and   wherein the second heat exchanger is disposed downstream of the waste heat expansion engine in a direction of working fluid flow.   
     
     
         10 . A cooling tower system, comprising:
 a first heat exchanger;   a first fluid circuit containing a process fluid flowing therein, the first heat exchanger receiving the process fluid from the first fluid circuit, the first fluid circuit including
 a heat source in fluid communication with the process fluid, the heat source disposed upstream of the first heat exchanger in a direction of process fluid flow, and 
 a cooling tower unit in fluid communication with the process fluid and a flow of ambient air, the cooling tower unit being configured to transfer heat from the process fluid to the flow of ambient air, the cooling tower unit disposed downstream of the first heat exchanger in the direction of process fluid flow, the cooling tower unit including a component that requires power for operation thereof; and 
   a second fluid circuit containing a working fluid flowing therein, the first heat exchanger also receiving the working fluid from the second fluid circuit, thereby effecting thermal communication between the first fluid circuit and the second fluid circuit, the second fluid circuit including a waste heat expansion engine in fluid communication with the working fluid, the waste heat expansion engine disposed downstream of the first heat exchanger in a direction of working fluid flow,   wherein the waste heat expansion engine is configured to extract power from the working fluid flowing therethrough and transfer at least a portion of the power to the component of the cooling tower unit.   
     
     
         11 . The system of  claim 10 , wherein the heat source is a power plant, and the process fluid exiting the power plant is low pressure steam. 
     
     
         12 . The system of  claim 10 , wherein the waste heat expansion engine is an organic Rankine cycle engine. 
     
     
         13 . The system of  claim 10 , wherein the waste heat expansion engine is a piston engine. 
     
     
         14 . The system of  claim 10 , wherein the component of the cooling tower unit is a fan. 
     
     
         15 . The system of  claim 10 , wherein the waste heat expansion engine is a metal hydride engine. 
     
     
         16 . The cooling tower system of  claim 10 , further comprising a second heat exchanger that receives working fluid from the second fluid circuit downstream of the waste heat expansion engine and upstream of the first heat exchanger in the direction of working fluid flow. 
     
     
         17 . The cooling tower system of  claim 16 , further comprising a third fluid circuit containing a cooling fluid flowing therein, the second heat exchanger also receiving cooling fluid from the third fluid circuit, thereby effecting thermal communication between the second fluid circuit and the third fluid circuit. 
     
     
         18 . The cooling tower system of  claim 17 , wherein the third fluid circuit is in fluid communication with the cooling tower unit. 
     
     
         19 . The cooling tower system of  claim 16 , wherein the second heat exchanger also receives process fluid from the first fluid circuit downstream of the cooling tower unit and upstream of the heat source in the direction of process fluid flow, thereby effecting further thermal communication between the first fluid circuit and the second fluid circuit. 
     
     
         20 . A cooling tower system, comprising:
 first means for exchanging heat;   a first fluid circuit containing a process fluid flowing therein, the first means for exchanging heat receiving the process fluid from the first fluid circuit, the first fluid circuit including
 means for generating heat in fluid communication with the process fluid, the means for generating heat being disposed upstream of the first means for exchanging heat in a direction of process fluid flow, and 
 a cooling tower unit in fluid communication with the process fluid and a flow of ambient air, the cooling tower unit being configured to transfer heat from the process fluid to the flow of ambient air, the cooling tower unit disposed downstream of the first means for exchanging heat in the direction of process fluid flow, the cooling tower unit including a component that requires power for operation thereof; and 
   a second fluid circuit containing a working fluid flowing therein, the first means for exchanging heat also receiving the working fluid from the second fluid circuit, thereby effecting thermal communication between the first fluid circuit and the second fluid circuit, the second fluid circuit including means for converting heat into power in fluid communication with the working fluid, the means for converting heat into power disposed downstream of the first means for exchanging heat in a direction of working fluid flow,   wherein the means for converting heat into power is configured to extract power from the working fluid flowing therethrough and transfer at least a portion of the power to the component of the cooling tower unit.