The outside temperature on a particular winter's day is 0°C. Consider two identical houses, each of external surface area 200 m² and internal temperature 20°C. The walls of the first are constructed of a single layer of brick, of thermal conductivity 1 W m and thickness 20 cm. What is the heat flux Q out of this house? What is its rate of heat loss in Watts? The walls of the second house are constructed of two layers of brick, each 10 cm thick, and a layer of insulation, also 10 cm thick. The insulation is made mostly out of air, thermal conductivity 0.01 W m-1 °C-1. What are the heat flux and the rate of heat loss from this house? How different would your answer be if you neglected the layers of brick in this calculation? -1 °C-1

The outside temperature on a particular winter's day is 0°C. Consider two identical houses, each of external surface area 200 m² and internal temperature 20°C. The walls of the first are constructed of a single layer of brick, of thermal conductivity 1 W m and thickness 20 cm. What is the heat flux Q out of this house? What is its rate of heat loss in Watts? The walls of the second house are constructed of two layers of brick, each 10 cm thick, and a layer of insulation, also 10 cm thick. The insulation is made mostly out of air, thermal conductivity 0.01 W m-1 °C-1. What are the heat flux and the rate of heat loss from this house? How different would your answer be if you neglected the layers of brick in this calculation? -1 °C-1

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.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.38P: 2.38 The addition of aluminum fins has been suggested to increase the rate of heat dissipation from...

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1.19 A cryogenic fluid is stored in a 0.3-m-diameter spherical container is still air. If the convection heat transfer coefficient between the outer surface of the container and the air is 6.8 , the temperature of the air is 27°C, and the temperature of the surface of the sphere is –183°C, determine the rate of heat transfer by convection.
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