Accession Number : AD0284862

Title :   SOLAR ABSORPTANCE AND TOTAL HEMISPHERICAL EMITTANCE OF SURFACES FORSOLAR ENERGY COLLECTION

Corporate Author : AERONAUTICAL SYSTEMS DIV WRIGHT-PATTERSON AFB OH

Personal Author(s) : BUTLER, C.P. ; JENKINS, R.J. ; PARKER, W.J.

Report Date : JUL 1962

Pagination or Media Count : 1

Abstract : The solar absorptance and the total hemispherical emittance are reported between 200 and 800 C for 6 polished metals, 8 metals with porous surfaces, and 15 coated metals. The surfaces were selected because their optical properties suggested they might be applicable for solar power collection. The method of measurement is described wherein the specimen is suspended by thermocouple wires in a black walled evacuated chamber. The solar absorptance is determined from the rate of temperature rise when the specimen is exposed to the radiation from a cored carbon arc whose spectral distribution simulates sunlight. The total hemispherical emittance is determined from the rate of temperature decay when the arc radiation is removed. The effect of microscopic roughness of the surface on the optical properties is investigated. An expression for the efficiency of a solar energy collection surface in terms of its solar absorptance, total hemispherical emittance, solar power concentration (mirror or lens), the solar irradiance, and the operating temperature is developed. The efficiencies of all surfaces treated are reported as a function of temperature. (Author)

Descriptors :   *COATINGS, *METALS, *SOLAR RADIATION, *SURFACES, ABRASIVES, ABSORPTION, CARBON ARC LAMPS, CERAMIC MATERIALS, GOLD, IRON, IRON COMPOUNDS, MOLYBDENUM, NICKEL, OPTICS, POROUS METALS, REFRACTORY COATINGS, REFRACTORY MATERIALS, SILVER, SILVER COMPOUNDS, STAINLESS STEEL, SULFIDES, SURFACE PROPERTIES, TANTALUM, TEMPERATURE, THERMIONIC EMISSION, THERMOCOUPLES, VACUUM APPARATUS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE