Abstract
Thermal insulations made of fibers, powders, or porous gels are characterized best with respect to their infrared optical thickness, (i) In optically thick insulations, where diffusion of infrared radiation occurs, the contributions from solid conduction and radiative transport are superimposed additively. (ii) For optically thin insulations a complex coupling mechanism causes the total heat transfer to be larger than the sum of the components; this holds especially for low emissivity boundaries. In this paper recent progress in the investigation of evacuated thermal insulations is reviewed.
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Fricke, J., Caps, R. Heat transfer in thermal insulations—Recent progress in analysis. Int J Thermophys 9, 885–895 (1988). https://doi.org/10.1007/BF00503253
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DOI: https://doi.org/10.1007/BF00503253