A solar furnace consists of an evacuated chamberwith

Chapter 12, Problem 12.121

(choose chapter or problem)

A solar furnace consists of an evacuated chamberwith transparent windows, through which concen- trated solar radiation is passed. Concentration may beachieved by mounting the furnace at the focal pointof a large curved reflector that tracks radiation inci-dent directly from the sun. The furnace may be usedto evaluate the behavior of materials at elevated tem-peratures, and we wish to design an experiment toassess the durability of a diffuse, spectrally selectivecoating for which ???0.95 in the range ?4.5?mand ???0.03 for ??4.5?m. The coating isapplied to a plate that is suspended in the furnace.(a) If the experiment is to be operated at a steady-state plate temperature of T?2000 K, how muchsolar irradiation GSmust be provided? The irradiation may be assumed to be uniformly distributedover the plate surface, and other sources of inci-dent radiation may be neglected.(b) The solar irradiation may be tunedto allow opera-tion over a range of plate temperatures. Computeand plot GSas a function of temperature for500T3000 K. Plot the corresponding values of ? and ?as a function of Tfor the designated range.