Hot water at an average temperature of 70°c is flowing through a 15-m section of a cast iron pipe having a thermal conductivity of 52 w/m k and inner and outer diameters are 40 mm and 46 mm, respectively. the outer surface of the pipe, whose emissivity is 0.7, is exposed to the cold air at 10°c in the basement, with a heat transfer coefficient of 15 w/m2 κ. the heat transfer coefficient at the inner surface of the pipe is 120 w/m2 κ. taking the walls of the basement to be at 10°c also, determine the rate of heat loss from the hot water pipe. use the thermal resistance approach.