21. The 1 ft thick walls of a building are made of concrete (k = 2 Btu/h-ft-F). The outside temperature and heat transfer coefficient are 50 F and 2 Btu/h•ft°-F, re- spectively. Find the rate of heat transfer through 1000 ft° of the wall if the inside temperature and heat transfer coefficient are 120 F and 1 Btu/h-ft F, respectively. Both the inside and the outside of the wall are coated with 20 mils of paint (k = 0.1 Btu/h-ft-F) where 1 mil = IE-3 in. Compare the results with a bare wall.

21. The 1 ft thick walls of a building are made of concrete (k = 2 Btu/h-ft-F). The outside temperature and heat transfer coefficient are 50 F and 2 Btu/h•ft°-F, re- spectively. Find the rate of heat transfer through 1000 ft° of the wall if the inside temperature and heat transfer coefficient are 120 F and 1 Btu/h-ft F, respectively. Both the inside and the outside of the wall are coated with 20 mils of paint (k = 0.1 Btu/h-ft-F) where 1 mil = IE-3 in. Compare the results with a bare wall.

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.

Chapter10: Heat Exchangers

Section: Chapter Questions

Problem 10.51P

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