A certain radiator wall is made of copper with a conductivity k = 47 lb/sec-F at 212oF.

Question:

A certain radiator wall is made of copper with a conductivity k = 47 lb/sec-°F at 212oF. The wall is 3/16 in. thick and has circulating water on one side with a convection coefficient h1 = 85 lb/sec-ft-°F. A fan blows air over the other side, which has a convection coefficient h2 = 15 lb/sec-ft-°F. Find the thermal resistance of the radiator on a square foot basis.