Given: A 0.20 m diameter thin-wall steel pipe transports saturated steam at a pressure of 20 bars. The convection coefficient on the inside of the wall is so high that the inner wall can be assumed to be at the temperature of the steam. The pipe passes through a room where the air temperature and surroundings are 25oC. The convection heat transfer coefficient on the outer surface of the pipe wall is 20 W/m2K. The outer surface of the steel pipe has an emissivity of 0.8. Find: a) Calculate the rate of heat loss per unit length from the pipe. b) If a 50 mm thickness of insulation with k = 0.058 W/mK is added to the pipe, calculate the rate of heat loss per unit length? The insulation has an emissivity of 0.8 on its outer surface. c) Calculate the simple payback time for adding the insulation using these costs; the insulation cost is $100/m; the cost of the steam is $4/109 J and the steam line operates for 7500 hr/yr. Assume: 1. Steady-state operation. 2