A long, uninsulated steam line with a diameter of 89 mm and a surface emissivity of 0.8 transports steam at 200°C and is exposed to atmospheric air and large surroundings at an equivalent temperature of 20°C.
(a) Calculate the heat loss per unit length for a calm day.
(b) Calculate the heat loss on a breezy day when the wind speed is 8 m/s.
(c) For the conditions of part (a), calculate the heat loss with a 20-mm-thick layer of insulation (k = 0.08 W/m· K). Would the heat loss change significantly with an appreciable wind speed?