Letter | Published:

A Method of Calibrating Two-Sphere Non-directional Radiometers

Naturevolume 192page960 (1961) | Download Citation



WHEN two heated spheres, one black and one bright, but otherwise identical, are kept at the same temperature, they lose an equal amount of heat by conduction and convection1. Any difference in heat input is due to the difference in radiational exchange. Neither air temperature nor air velocity enters the calculations for determining the mean radiant temperature of the surroundings. The quantities needed are: the heat input of the two spheres; the temperatures of the two spheres (which should be equal); the surface area; the emissivities of the bright and the black sphere. Nickel1 or gold2 is used for plating the bright sphere.

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  1. 1

    Roose, H., Schweiz. Bl. Heizung und Lueftung, 1 (1938).

  2. 2

    Sutton, D. J., and McNall, jun., P. E., Research Report GR 2462-R2 (Minneapolis–Honeywell Regulator Co., Sept. 1953).

  3. 3

    Bedford, T., and Warner, C. G., J. Hyg. (Camb.), 34, 460 (1934).

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  1. Department of Microbiology and Public Health, Chicago Medical School, Chicago, Illinois



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