Temperature zones in a solid oxide fuel cell auxiliary power unit

Abstract

A method for fuel cell system thermal management includes: maintaining a first zone at a first selected temperature range, maintaining a second zone at a second selected temperature range, and maintaining a third zone at a third selected temperature range. The second zone is in thermal communication with a first sensor and comprises a reformer, while the third zone is in thermal communication with a second sensor and comprises a fuel cell stack. The second selected temperature range is greater than the first selected temperature range, while the third selected temperature range is greater than the second selected temperature range. A thermal management system for use with an auxiliary power unit includes a first air control valve in fluid communication with a process air supply and a fuel reformer zone, the first air control valve in operable communication with a controller; a second air control valve in fluid communication with a process air supply and a hot zone, the second air control valve in electronic communication with the controller; a reformer zone temperature sensor in thermal communication with the fuel reformer and in operable communication with the controller; a hot zone temperature sensor in thermal communication with the hot zone and in operable communication with the controller; a first outlet at the reformer zone; and a second outlet at the hot zone.

1 .- 13 . (canceled)  
   
   
       14 . A method of controlling temperature at an auxiliary power unit located in a vehicle comprising: 
 sensing a reformer zone temperature at a reformer zone;    determining whether said reformer zone temperature is at a first selected temperature range;    adding a process air flow to said reformer zone if said reformer zone temperature rises above about said first selected temperature range;    sensing a hot zone temperature at a hot zone;    determining whether said hot zone temperature is in a second selected temperature range; and    adding a second process air flow to said hot zone if said hot zone temperature rises above said second selected temperature range.    
   
   
       15 . The method in  claim 14 , further comprising reducing said process air flow to said reformer zone if said reformer zone temperature falls below said first selected temperature range.  
   
   
       16 . The method in  claim 14 , further comprising increasing said process air flow to said reformer zone if said reformer zone temperature increases above said first selected temperature range.  
   
   
       17 . The method in  claim 14 , further comprising reducing said second process air flow to said hot zone if said hot zone temperature falls below said second selected temperature range.  
   
   
       18 . The method in  claim 14 , further comprising increasing said second process air flow to said hot zone if said hot zone temperature increases above said second selected temperature range.  
   
   
       19 . The method in  claim 14 , wherein said adding said process air flow comprises controlling said process air flow via a first air control valve.  
   
   
       20 . The method in  claim 14 , wherein adding said second process air flow comprises controlling said second process flow air via a second air control valve.  
   
   
       21 . The method in  claim 14 , further comprising moving a reformer air from said reformer zone to said hot zone.  
   
   
       22 . The method in  claim 14 , further comprising moving a hot air to a waste energy recovery unit.  
   
   
       23 . The method in  claim 14 , wherein said first selected temperature range is about 300° C. to about 500° C.  
   
   
       24 . The method in  claim 14 , wherein said second selected temperature range is about 600° C. to about 800° C.  
   
   
       25 . The method in  claim 14 , wherein said second selected temperature range is about 725° C. to about 775° C.  
   
   
       26 - 42 . (canceled)  
   
   
       43 . A method for fuel cell system thermal management, comprising: 
 maintaining a first zone at a first selected temperature range;    maintaining a second zone at a second selected temperature range, wherein said second zone is in thermal communication with a first sensor and comprises a reformer and wherein said second selected temperature range is greater than said first selected temperature range; and    maintaining a third zone at a third selected temperature range, wherein said third zone is in thermal communication with a second sensor and comprises a fuel cell stack and wherein said third selected temperature range is greater than said second selected temperature range.    
   
   
       44 . The thermal management system in  claim 43 , wherein said third zone further comprises a waste energy recovery unit.  
   
   
       45 . The thermal management system in  claim 43 , wherein said first zone is in fluid communication with said second zone and said second zone is in fluid communication with said third zone.  
   
   
       46 . The thermal management system in  claim 43 , further comprising a controller in operable communication with said first sensor and said second sensor.