The horizontal roof of a building has an emittance of 0.9. Air temperature is 1oC on a clear night. Sky acts as a black radiation sink at -60o If the underside of the roof is well insulated, estimate the roof temperature. Assume a convective heat transfer coefficient of 5 W/m2 K.

The horizontal roof of a building has an emittance of 0.9. Air temperature is 1oC on a clear night. Sky acts as a black radiation sink at -60o If the underside of the roof is well insulated, estimate the roof temperature. Assume a convective heat transfer coefficient of 5 W/m2 K.

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 1.48P: A horizontal, 3-mm-thick flat-copper plate, 1-m long and 0.5-m wide, is exposed in air at 27C to...

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Concept explainers

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.

Question

The horizontal roof of a building has an emittance of 0.9. Air temperature is 1^oC on a clear night. Sky acts as a black radiation sink at -60^o If the underside of the roof is well insulated, estimate the roof temperature. Assume a convective heat transfer coefficient of 5 W/m2 K.

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