With increasing emphasis on energy conservation, the heat loss from buildings has become a major concern. For a small tract house the typical exterior surface areas and R-factors (area x thermal resistance) are listed below Element Area (m²) R-Factors = Area > Thermal Resistance [(m² K/W)] 2.0 2.8 Walls Ceiling Floor Windows Doors 150 120 120 20 5 2.0 0.1 0.5 (a) Calculate the rate of heat loss from the house when the interior temperature is 22°C and the exterior is -5°C. (b) Suggest ways and means to reduce the heat loss and show quantitatively the effect of doubling the wall insulation and the substitution of double glazed windows (thermal resistance = 0.2 m² K/W) for the single glazed type in the table above.

With increasing emphasis on energy conservation, the heat loss from buildings has become a major concern. For a small tract house the typical exterior surface areas and R-factors (area x thermal resistance) are listed below Element Area (m²) R-Factors = Area > Thermal Resistance [(m² K/W)] 2.0 2.8 Walls Ceiling Floor Windows Doors 150 120 120 20 5 2.0 0.1 0.5 (a) Calculate the rate of heat loss from the house when the interior temperature is 22°C and the exterior is -5°C. (b) Suggest ways and means to reduce the heat loss and show quantitatively the effect of doubling the wall insulation and the substitution of double glazed windows (thermal resistance = 0.2 m² K/W) for the single glazed type in the table above.

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 1.20P: A high-speed computer is located in a temperature-controlled room at 26C. When the machine is...

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A high-speed computer is located in a temperature-controlled room at 26C. When the machine is operating, its internal heat generation rate is estimated to be 800 W. The external surface temperature of the computer is to be maintained below 85C. The heat transfer coefficient for the surface of the computer is estimated to be 10W/m2K. What surface area would be necessary to assure safe operation of this machine? Comment on ways to reduce this area.
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