Question Four

[2 marks]

A 5-em-diameter pipe extends horizontally 2 m in the ambient air above the ground, dips into the ground vertically for 3 m, and continues horizontally at this depth for 20 m more before it enters the next building. The ambient air is at 8C, with a heat transfer coefficient of 22 W/m-C. The surface of the ground is covered with snow at 0C and the soil has a thermal conductivity of 1.5 W/m-"C. If hot water at 80C flows through the pipe at 1.5 m/s, determine the temperature drop of hot water as it flows through