Estimation Method of Thermal Conductivity of Core Part in Vacuum Insulation Panel

Abstract

The area of application for Vacuumed insulated panels (VIP), including household electric appliances like refrigerator, boxes for heat and cold insulators and window glasses, is expanding rapidly by its advances of practical applications. Furthermore, VIP has been possibly used in building industries recently. However, the measurement method of its thermal conductivity has been not fully established. Especially, it is difficult to know the thermal conductivity of the core material in VIP. It must be the reason that laminated films lapping the core material in VIP facilitate the growth of the heat loss. In this study, it was proposed a way which could estimate the thermal conductivity of the core material using thermal conductivities measured by Guarded Hot Plate method. We have confirmed the accuracy of the proposed estimation by numerical simulations and experiments. Then we have just a simple assumption that the heat flow conducting through the VIP is separated to two heat flows in the directions of thickness and plane of VIP respectively. Furthermore it was shown that the thermal conductivity of the laminated film could be estimated.