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Di X.,Xian Jiaotong University | Di X.,Fujian Super Technology Advanced Material Co. | Gao Y.,Xian Jiaotong University | Bao C.,Xian Jiaotong University | Ma S.,Xian Jiaotong University
Energy and Buildings | Year: 2014

Thermal insulation performance and service life of vacuum insulation panels (VIPs) dramatically depend on the internal pressure of VIPs. To analyze internal pressure increase of VIPs, VIPs in various geometric sizes are manufactured from threefold metalized polymer laminate barrier envelopes and glass fiber chopped strand core materials. The gas permeation contribution to the internal gas pressure of VIPs through envelope surface area and perimeter are investigated based on theoretical calculation and experiments. The trend of calculated pressure increasing rate is consistent with experimental results. The gas permeation through barrier laminate surface area is measured by a helium leak detector while the thermal conductivity of VIPs is measured by thermal conductivity meter. The accelerated aging experiments are carried out at different temperatures and service life model is proposed based on Arrhenius law. A low cost composite adsorbent is investigated, absorption property of which for water vapor is measured at various relative humidity. As a result, it is recommended to use large square VIPs with thickness of 1.0-2.5 cm. Service life of 10-15 years or above 20 years can be achieved by adding different adsorbents for different application fields. © 2014 Elsevier B.V. Source

Di X.,Xian Jiaotong University | Gao Y.,Xian Jiaotong University | Bao C.,Xian Jiaotong University | Hu Y.,Fujian Super Technology Advanced Material Co. | Xie Z.,Fujian Super Technology Advanced Material Co.
Vacuum | Year: 2013

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. © 2013 Elsevier Inc. All rights reserved. Source

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