Hot water at an average temperature of 80°C and an average velocity of 1.5 m/s is flowing through a 25-m section of a pipe that has an outer diameter of 5 cm. The pipe extends 2 m in the ambient air above the ground, dips into the ground (k = 1.5 W/m · K) vertically for 3 m, and continues horizontally at this depth for 20 m more before it enters the next building. The first section of the pipe is exposed to the ambient air at 8°C, with a heat transfer coefficient of 22 W/m² · K. If the surface of the ground is covered with snow at 0°C, determine
(a) The total rate of heat loss from the hot water

(b) The temperature drop of the hot water as it flows through this 25-m-long section of the pipe.

Transcribed Image Text:

8°C Hot water pipe 3 m 20 m. 0°C 80°C