Cogeneration of power and heat by an integrated fuel cell power system

Abstract

Interconnection layouts are described that are particularly effective in the construction of a steam reformer/fuel cell combination for providing domestic heat and/or hot water as well as electricity. A distinguishing feature of the interconnections is that they use strategically placed heat exchangers that permit the operator to optimize the efficiency of operation of the integrated system, and provide a higher efficiency at optimum operation compared to prior art designs. Combinations of reformer/fuel cell systems with conventional furnaces or boilers are also described.

1 . A heat exchange system for the provision of electricity and heat from a cogeneration system comprising: 
 a first fluid loop for providing steam to a fuel reforming reaction to produce a hydrogen-rich reformate and a reformer exhaust;    a fuel cell stack for generating electricity from the hydrogen-rich reformate;    a second fluid loop for controlling the temperature of the fuel cell stack;    a third fluid loop for removing heat from at least one of the fuel reforming reaction and the fuel cell stack for use in a cogenerative application;    a first heat exchanger between the hydrogen-rich reformate and at least one other system fluid;    a second heat exchanger between the reformer exhaust and at least one other fluid; and    a third heat exchanger between the second fluid loop and the third fluid loop;    wherein the system produces heat for at least one of hot potable water and space heating.    
   
   
       2 . The heat exchange system of  claim 1  further comprising: 
 a radiator for cooling the second fluid loop.    
   
   
       3 . The heat exchange system of  claim 1  further comprising: 
 a fourth fluid loop in a heat exchange relationship with at least one of the first fluid loop and the second fluid loop for the preheating of potable hot water.    
   
   
       4 . The heat exchange system of  claim 3  further comprising: 
 a fourth heat exchanger between the reformer exhaust, the second fluid loop and at least one other fluid.    
   
   
       5 . The heat exchange system of  claim 1  further comprising: 
 a heat exchange loop in at least one of the first, second and third heat exchangers.    
   
   
       6 . The heat exchange system of  claim 1  wherein the cogenerative application comprises a hot water tank.  
   
   
       7 . The heat exchange system of  claim 1  wherein at least one of the heat exchangers is a condensing heat exchanger for removal of water from a gas.  
   
   
       8 . The heat exchange system of  claim 7  wherein the gas is reformate.  
   
   
       9 . The heat exchange system of  claim 7  wherein the gas is the reformer exhaust.  
   
   
       10 . The heat exchange system of  claim 7  wherein the condensing heat exchanger transfers heat from at least one of the second fluid loop and the third fluid loop to heat potable water.  
   
   
       11 . The heat exchange system of  claim 1  further comprising: 
 a furnace for providing supplemental heat to the third fluid loop for use in at least one of space heating, potable water heating, and provision of startup heating to the cogeneration system.    
   
   
       12 . The heat exchange system of  claim 11  wherein the furnace is connected in parallel with the third fluid loop.  
   
   
       13 . The heat exchange system of  claim 11  wherein the furnace is connected in series with the third fluid loop.  
   
   
       14 . The heat exchange system of  claim 1  further comprising: 
 means for using unheated external water for replenishing water in at least one of the fluid loops.    
   
   
       15 . The heat exchange system of  claim 1  further comprising: 
 a furnace for providing heat for at least one of space heating and potable water heating.    
   
   
       16 . The heat exchange system of  claim 15  further comprising: 
 a fuel processor assembly comprising a burner for burning a fuel to supply energy for a reforming reaction to produce a hydrogen-rich reformate and a fuel processor exhaust which is used in a cogenerative application; and,    a controller for providing sufficient heat for at least one of space heating and potable water heating by selectively activating at least one of the furnace, the fuel cell stack and the fuel processor assembly.    
   
   
       17 . The heat exchange system of  claim 1  further comprising: 
 means for cooling the second fluid loop; and    a controller for selectively activating the means for cooling the second fluid loop when space heating is not being provided by the system.    
   
   
       18 . The heat exchange system of  claim 1  wherein one of the first heat exchanger, the second heat exchanger and the third heat exchanger is a catalyzed reactor.  
   
   
       19 . The heat exchange system of  claim 18  wherein the catalyzed reactor is a PrOx reactor.  
   
   
       20 . The heat exchange system of  claim 18  wherein the catalyzed reactor is a methanation reactor.  
   
   
       21 . The heat exchange system of  claim 1  wherein the fuel cell stack is cooled using direct fluid injection.  
   
   
       22 . A heat exchange system for the provision of electricity and heat from a cogeneration system comprising: 
 a first fluid loop for providing steam to a fuel reforming reaction to produce a hydrogen-rich reformate and a reformer exhaust;    a fuel cell stack for generating electricity from the hydrogen-rich reformate;    a second fluid loop for controlling the temperature of the fuel cell stack;    a third fluid loop for removing heat from both the fuel reforming reaction and the fuel cell stack for use in a cogenerative application; and,    a heat exchanger between the reformer exhaust, the second fluid loop and the third fluid loop, wherein the heat exchanger recovers at least a portion of the system fluids and supplies heat for at least one of hot potable water and space heating.    
   
   
       23 . The heat exchange system of  claim 22  wherein the fuel cell stack is cooled using direct fluid injection.  
   
   
       24 - 89 . (canceled)