Overall heat transfer coefficient for hX Recall from earlier the overall thermal resistance concent UA, R A)2(+R+ n An(n hAh Types of resistances involved with heat exchangers(covered in previous sessions Cold side internal convection Cold side fouling factor Conduction through wall Hot side external convection(smooth wall or may involve fins) Hot side fouling factor Bout 个个个↑ Review how these were Ain calculated IIIIImIII ↑↑↑1 B in Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 9 TA,in TA,out TB,in TB,out Overall heat transfer coefficient for HX • Recall from earlier the overall thermal resistance concept: • Types of resistances involved with heat exchangers (covered in previous sessions) – Cold side internal convection – Cold side fouling factor – Conduction through wall – Hot side external convection (smooth wall or may involve fins) – Hot side fouling factor • Review how these were calculated o h o h f h w o c f c o c c c h h A hA R R A R hA U A U A U A ( ) 1 ( ) ( ) ( ) 1 1 1 1 , ,     +  + +  = + = =