Optimization of glass fiber based core materials for vacuum insulation panels with laminated aluminum foils as envelopes

Abstract

Two glass fibers with different production process, marble melt process and flame attenuation process (named as chopped strand and flame attenuated glass wool), as core materials of vacuum insulation panels (VIPs) respectively are investigated in this paper. The dependence of thermal conductivity of two glass fibers on gas pressure is determined based on theoretical calculation and experiment. Two VIPs are manufactured with laminated aluminum foils as envelopes and two glass fibers respectively as core materials for performance comparison of thermal conductivity and service life. The increase in thermal conductivity of VIP with time is measured, which depends on temperature and relative humidity. It is found that service life above 15 years can be expected for VIP with chopped strand mat core material and the high gas barrier envelope with four-layer structure of PA(15 μm)/metalized PET(12 μm)/Al(6 μm)/PE(50 μm) only if desiccants or getters are integrated into core materials.