Experimental study on the effective thermal conductivity of core material of a vacuum insulation panel

Abstract

A measurement apparatus is designed and fabricated to measure the effective thermal conductivity of a VIP (Vacuum Insulation Panel) core specimen under various vacuum states and external loads. Using the apparatus, the effective thermal conductivity $\It{k_{eff}}$ of open-cell rigid PU foam, glass paper, silica gel and artificial staggered beam are measured and compared with theoretical models. Theoretical model of open-cell rigid PU foam has relative error of 8%; on the other hand, those of glass paper and silica gel deviate over 20%. That of staggered beam shows over 60% of relative error. Among the four specimens, glass paper and staggered beam are better than others in view of $\It{k_{eff}}$, while glass paper is preferred for the longer service time as a core of the VIP.