Module 4: Heat transfer calculations, miscellaneous topics and carbon credit
  Lecture 32: Steady state heat flow in furnaces and heat exchangers
 

Surrounding temperature is . Let the shell temperature facing the surrounding is   is unknown. Heat balance of the furnace is

[Heat flow by conduction to the outer shell = Heat loss from the shell to                                   the surrounding by convection and radiation]                (1)    

(2)

(3)


   is heat transfer coefficient for natural convection.  is view factor,  is emissivity of the shell and  is the area of the furnace. Heat transfer coefficient  can be evaluated by

(4)