Dependence of gas permeation and adsorption on temperature in vacuum insulation panels (VIPs) containing getter materials

2021 ◽  
pp. 174425912110171
Author(s):  
Hideya Yamamoto ◽  
Daisuke Ogura
Keyword(s):  
Glass Fiber ◽  
Adsorption Mechanism ◽  
Gas Adsorption ◽  
Gas Permeation ◽  
Fiber Core ◽  
Vacuum Insulation ◽  
Calculation Results ◽  
Long Term Performance ◽  
Term Performance

Vacuum insulation panels (VIPs) with a glass-fiber core has been considered to be difficult to operate for a long period of time, such as for building applications, because the thermal conductivity rises rapidly as the pressure increases. However, glass-fiber-core VIPs contain a material called a getter that continuously adsorbs permeated gas, and a theoretical model that considers the properties of the getter has not yet been developed. In this paper, the gas-adsorption mechanism by getters was investigated and a long-term-performance prediction model that considers the temperature dependence was proposed. Some gases were not adsorbed by the getter in the VIPs; however, a model was proposed that takes into account the non-absorbed gases by applying partial pressure to the adsorption isotherm in advance. The long-term performance of VIPs with different areas and volumes was compared with the measured values, and the validity of the calculation results was confirmed. These results show that the long-term performance of VIPs of different sizes can be accurately predicted when the getter performance is well understood.

Experimental and theoretical study on hygrothermal long-term performance of outer assemblies in lightweight passive house

2017 ◽  
Vol 41 (4) ◽  
pp. 299-320 ◽  
Author(s):  
Jan Radon ◽  
Krzysztof Was ◽  
Agnieszka Flaga-Maryanczyk ◽  
Jacek Schnotale
Keyword(s):  
Theoretical Study ◽  
Theoretical Calculations ◽  
Building Structure ◽  
Weather Station ◽  
Passive House ◽  
Hygrothermal Performance ◽  
Calculation Results ◽  
Long Term Performance ◽  
Term Performance

The article presents results of long-term experimental study of hygrothermal performance of envelope assemblies in a passive house located in Boruszowice (Southern Poland). The building was constructed in 2010 using prefabricated, lightweight technology. The construction of the walls and roof had been carefully planned to test both traditional solutions with higher thermal insulation and modified ones to improve the hygrothermal performance. Altogether, eight different walls and two roof constructions were integrated into the building structure and tested from the beginning of 2011 to the end of 2015 under real climate and usage conditions. In all assemblies, temperature was measured in three and relative humidity in four points at the surface and inside. Inner climate was measured by thermohygrometers installed in the rooms and outer climate was recorded by a weather station located near the building. Theoretical calculations were made using WUFI® Plus software. Based on experimental and calculation results, the main hygrothermal phenomena depending on construction specifics and used materials are presented.

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

2020 ◽  
Vol 172 ◽  
pp. 21001 ◽  
Author(s):  
Hideya Yamamoto ◽  
Daisuke Ogura
Keyword(s):  
Thermal Conductivity ◽  
Temperature Dependence ◽  
Pressure Sensor ◽  
Glass Wool ◽  
Adsorption Behavior ◽  
Vacuum Insulation ◽  
Long Term Performance ◽  
Term Performance ◽  
Vacuum Insulation Panel

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.

Centre of Panel Thermal Conductivity Performance Analysis of Aerocor-Centrifugal Hybrid Ultrafine Glass Fiber VIP Core Materials

2015 ◽  
Vol 1120-1121 ◽  
pp. 1511-1515
Author(s):  
Ahmad Farooq ◽  
Ali Abd El-Aty
Keyword(s):  
Thermal Conductivity ◽  
Glass Fiber ◽  
Orientation Angle ◽  
Superior Performance ◽  
Core Material ◽  
Experimental Development ◽  
Fiber Core ◽  
Fiber Orientation Angle ◽  
Long Term Performance ◽  
Term Performance

This paper includes analysis on the recent advancement of glass fiber core based vacuum insulation panels (VIPs) in China, including the experimental development of mixed ultrafine fiberglass prototype core material consisting of Centrifugal and Aerocor glass wool mixture at different ratios. Pore sizes exhibited by these prototypes generally range between 15-25μm. Extensive centre of panel thermal conductivity (Kcop) were performed from which thermal performance graphs were extracted and analyzed prudently. Kcop analysis verified superior performance of the prototypes over traditional glass fiber core samples, hinting greater service life. The study concludes that in order to optimize the long term performance of current industrial glass fiber core material reduction of pore size at less than 10μm range as well as reduction of x-z axis fiber orientation angle to less than 450 would potentially decrease core structural sensitivity towards both gaseous and solid conductivity at increase of internal pressure.

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