3-152 Consider a 25-m-long thick-walled concrete duct (k = 0.75 W/m-K) of square cross section. The outer dimensions of the duct are 20 cm x 20 cm, and the thickness of the duct wall is 2 cm. If the inner and outer surfaces of the duct are at 100°C and 30°C, respectively, determine the rate of heat trans- fer through the walls of the duct. Answer: 47.1 kW 30°C. 100°C +16 cm -20 cm- FIGURE P3-152 25 m

3-152 Consider a 25-m-long thick-walled concrete duct (k = 0.75 W/m-K) of square cross section. The outer dimensions of the duct are 20 cm x 20 cm, and the thickness of the duct wall is 2 cm. If the inner and outer surfaces of the duct are at 100°C and 30°C, respectively, determine the rate of heat trans- fer through the walls of the duct. Answer: 47.1 kW 30°C. 100°C +16 cm -20 cm- FIGURE P3-152 25 m

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.9P: Heat is transferred at a rate of 0.1 kW through glass wool insulation (density=100kg/m3) with a 5-cm...

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Heat is transferred at a rate of 0.1 kW through glass wool insulation (density=100kg/m3) with a 5-cm thickness and 2-m2 area. If the hot surface is at 70C, determine the temperature of the cooler surface.
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