Study on the temperature dependence of gas permeation and adsorption behavior of the vacuum insulation panel with getter materials

Abstract

Vacuum insulation panel (VIP) is a high-performance heat insulation material that has contributed to the energy efficiency of refrigerators, vending machines, and cooler boxes. Glass wool or fumed silica covered by a laminated film are the core materials of VIP; by evacuating air inside, it is possible to reduce the gas thermal conductivity to be close to 0 and exhibit high thermal performance. In recent years, the research on long-term performance prediction has been conducted for use in building insulation. Specifically, various getter materials have been developed to improve the long-term performance of glass wool VIP. However, there are no studies that clearly show the adsorption behavior or temperature dependence inside VIP with getter materials. We measured the adsorption temperature dependence of two types of getters using the constant volume method and then observed the adsorption behavior inside VIP using VIP equipped with a micro pressure sensor. Regarding the internal pressure of VIPs equipped with the micro pressure sensor, the pressure fluctuation derived from the adsorbent was confirmed by the temperature change, and it was confirmed that the thermal conductivity changed accordingly. If the internal temperature of VIP increases, gases may be released from the getter. Therefore, in the building environment, it is necessary to select a getter that is suitable for the usage environment and to use an appropriate amount of getter.