Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. Consider a room whose air temperature is maintained at 20°C throughout the year, while the walls of the room are nominally at 30°C and 14°C in the summer and winter, respectively. The exposed surface of a person in the room may be assumed to be at a temperature of 32°C throughout the year and to have an emissivity of 0.90. The coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 W/m2.K. Calculate the following. Heat flux due to convection: q'onv i W/m? Heat flux due to radiation in the summer: W/m2 Heat flux due to radiation in the winter: qnd = i W/m?

Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. Consider a room whose air temperature is maintained at 20°C throughout the year, while the walls of the room are nominally at 30°C and 14°C in the summer and winter, respectively. The exposed surface of a person in the room may be assumed to be at a temperature of 32°C throughout the year and to have an emissivity of 0.90. The coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 W/m2.K. Calculate the following. Heat flux due to convection: q'onv i W/m? Heat flux due to radiation in the summer: W/m2 Heat flux due to radiation in the winter: qnd = i W/m?

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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Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. Consider a room whose air temperature is maintained at 16°C throughout the year, while the walls of the room are nominally at 30°C and 14°C in the summer and winter, respectively. The exposed surface of a person in the room may be assumed to be at a temperature of 32°C throughout the year and to have an emissivity of 0.90. The coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 W/m2.K. Calculate the following. Heat flux due to convection: q'onv W/m? Heat flux due to radiation in the summer: i W/m? Heat flux due to radiation in the winter: qad W/m? i ||
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