Q1- An industrial freezer is design to operate with an internal air temperature of -20 °C when the external air temperature is 25 °C and the internal and external heat transfer coefficient are 12 W m?/K and 8 W m?/ K, respectively. The walls of the freezer are composite construction, comprising of an inner layer of plastic (k= 1 W/m K, and thickness of 3 mm), and an outer layer of stainless steel (k=16 W/m K, and thickness of 1 mm). Sandwiched between these two layers is a layer of insulation material with k=0.07 W/m K. Find the width of insulation that is required to reduce the convection heat loss to 15 W/m?. Support the solution by drawing. (25mark)

Q1- An industrial freezer is design to operate with an internal air temperature of -20 °C when the external air temperature is 25 °C and the internal and external heat transfer coefficient are 12 W m?/K and 8 W m?/ K, respectively. The walls of the freezer are composite construction, comprising of an inner layer of plastic (k= 1 W/m K, and thickness of 3 mm), and an outer layer of stainless steel (k=16 W/m K, and thickness of 1 mm). Sandwiched between these two layers is a layer of insulation material with k=0.07 W/m K. Find the width of insulation that is required to reduce the convection heat loss to 15 W/m?. Support the solution by drawing. (25mark)

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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