NOTE: Yellow/Red  cells indicate user input data.  You must input your own data in these cells to obtain results for your air heater.    
                                                                       
       
  Air Heater Leakage Determination    
           
      AH O2 In       AH O2 Out    
        %   %    
    Air Heater Leakage =                    X = % Air Heater Leakage    
                         
          AH O2 Out       O2 In Air    
      %   %    
               
                                                                       
                                                                       
  Air Heater Gas Exit Temperature Correction    
    NOTES:    
    Properly stated, "Corrected Gas Exit Temp" is as-measured temperature, and includes the temperature-reducing effect of air heater leakage.  "Uncorrected Gas Exit Temp" is the same temperature, but corrected to a "No Leakage" condition.  This seemingly backwards nomenclature came about in the early days of boiler design, when the designers would calculate air heater heat transfer and then had to "correct" the resulting temperature calculation to account for leakage.  
       
    The following calculation directly references the air heater leakage from the calculation just above.  If you already know air heater leakage percent and do NOT know inlet and outlet O2, then just input "fake" O2 values that result in the known leakage.  
      AH Leakage   CpA - Specific Heat of Air    
    AH Gas Exit Temp,
No Leakage 		  %   Default = .246                 =   °F  
    =             X           X   Gas Out Temp       Air In Temp   +   Gas Out Temp      
                                °F            
      %   CpG - Specific Heat of Gas            
      Default = .252    
                                                                       
       
  Air Heater X-Ratio    
    NOTES:    
    X-Ratio (XR) is the ratio of the heat capacity of the air passing through the air heater to the heat capacity of the gas passing through the air heater.  The gas out temperature used in this calculation must be at "No Leakage".  The calculation below directly references the gas exit temperature corrected to no leakage, calculated above.  
       
      Gas In Temp   Gas Out Temp    
        °F   °F    
    AH X-Ratio =                       =   (No Units)    
                     
        Air Out Temp   Air In Temp    
      °F   °F    
                                                                       
       
  Air Heater Gas Side Efficiency    
    NOTES:    
    Gas side efficiency is the ratio of gas temperature drop (at no leakage), to the Temperature Head.  Temperature Head is the gas inlet temperature minus the air inlet temperature.  The calculation below directly references the gas exit temperature corrected to no leakage, calculated above.  
       
      Gas In Temp   Gas Out Temp    
        °F   °F    
    AH Gas Side Efficiency =                       X 100%   =    
                     
        Gas In Temp   Air In Temp    
      °F   °F    
                                                                       

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