Heat transfer of heat: H= Thermal Resistance to Conduction: R=L/k Conduction Through a Composite Slab A(TH -TL) cond ΣRHeat transfer of heat: L T T k A t Q H H  L   R  L/ k Thermal Resistance to Conduction: Conduction Through a Composite Slab    R A T T P H L cond ( )