Load-Bearing Evacuated Fibrous Superinsulations — Improvements with Peg-Support and Metal-Coated Fibers
Optimization of load-bearing evacuated thermal superinsulations requires a detailed investigation of two thermal loss channels: The solid conduction via contacting fibers, and the radiative heat transfer. In this paper we report two important findings which allow to further improve thermal superinsulations: (i) with metal-coated fibers we obtained extinction coefficients of several hundred m2/kg; this corresponds to a drastic reduction of radiative losses compared to the case of non-coated fibers; (ii) with peg-supported insulation systems the solid conductivity was reduced to about 0.5·10-3 W/(m·K) at 1.15 bar external pressure; this could lead to an improvement by more than a factor of three compared to not-segmented fibrous insulations. The measurements were performed with evacuable and load-controlled guarded hot plate devices and with a FTIR spectrometer.
KeywordsPorosity Carbide Total Heat Attenuation Refraction
Unable to display preview. Download preview PDF.
- D. Büttner, J. Fricke and H. Reiss, Analysis of radiative and solid conduction components of the total thermal conductivity of an evacuated glass fiber insulation, measurements with a 700 x 700 mm2 variable load guarded hot plate device, AIAA 20th Thermophysics Conf., June 1985, Williamsburg,Va., paper No. 85 - 1019Google Scholar
- Report Union Carbide Corporation - Linde Division Tonawanda, N.Y., Contract No. EM-78-C-01-5160 (1979).Google Scholar