An overhead 25-m-long uninsulated industrial steam pipe of 100 mm diameter is routed through a building whose walls and air are at 25°C. Pressurized steam maintains a pipe surface temperature

of 150°C, and the coefficient associated with natural convection is h =10 W/m²K. The surface emissivity is ɛ = 0.8. a) What is the heat loss from the steam pipe? (b) If the steam is generated in a gas-fired boiler operating at an efficiency of 7f= 0.90 and natural gas is priced at Cg = $0.01per MJ, what is the annual cost of heat loss from the line?