Investigation of edge taping method applied to vacuum insulation panels

Abstract

Vacuum insulation panel (VIP), commonly composed of an evacuated filler material and a vacuum envelope, is drawing attention for the outstanding insulation performance compared with conventional insulators. As an associated problem, however, its effective thermal conductivity may be increased, since additional heat is transferred through the envelope edge; this is called edge conduction. It is significantly large if the envelope includes an Al-foil layer. In this paper, the edge conduction for VIPs with Al-foil envelope is investigated from experiments, numerical results, and theoretical analyses. 'Edge taping method' is investigated as a means to reduce the edge conduction, where insulation stripes are attached along the edges of the envelope. Numerical analyses and experiments are performed to verify this method and an analytical solution is proposed. The results show excellent agreements among themselves and prove that the edge conduction can be substantially reduced by the edge taping. Also, dimensional analysis is performed and the 'easy-to-use' analytical solution is expressed in a dimensionless form. Use of the proposed relation helps one determine a quantitative sizing of physical parameters in the edge taping method. (C) 2016 Elsevier B.V. All rights reserved.