The reflectivity of aluminum coated with lead sulfate is 0.35 for radiation at wavelengths less than 3 mm and 0.95 for radiation greater than 3 mm. Determine the average reflectivity of this surface for solar radiation (T < 5800 K) and radiation coming from surfaces at room temperature (T < 300 K). Also, determine the emissivity and absorptivity of this surface at both temperatures. Do you think this material is suitable for use in solar collectors?

The reflectivity of aluminum coated with lead sulfate is 0.35 for radiation at wavelengths less than 3 mm and 0.95 for radiation greater than 3 mm. Determine the average reflectivity of this surface for solar radiation (T < 5800 K) and radiation coming from surfaces at room temperature (T < 300 K). Also, determine the emissivity and absorptivity of this surface at both temperatures. Do you think this material is suitable for use in solar collectors?

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 2.61P

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Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 816C and 260C, respectively. Determine the rate of heat transfer by radiation between the plates in W/m2 and the radiative heat transfer coefficient in W/m2K.
1.28 The sun has a radius of and approximates a blackbody with a surface temperature of about 5800 K. Calculate the total rate of radiation from the sun and the emitted radiation flux per square meter of surface area.
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