A 12-m·long and 8-cm-diameter hot-water pipe of a districi heating system is buried in the...

A 12-m·long and 8-cm-diameter hot-water pipe of a districi heating system is buried in the soil 80 cm below the ground surface. The outer surface temperature of the pipe is 60°C. Taking the surface temperature of the earth to be 2°C and the thermal conductivity of the soil at that location to be 0.9 W/m·K. determine the rate of heat loss from the pipe.

FIGURE P3-138