The performance of vacuum insulation panels (VIPs) is strongly affected by several factors, such as panel thickness, design, quality of vacuum, and material type. In particular, the core materials ...inside VIPs significantly influence their overall performance. Despite their superior insulation performance, VIPs are limited in their widespread use as structural materials, because of their low material strength and the relatively expensive core materials. As an alternative core material that can compensate these limitations, foamed concrete, a type of lightweight concrete with very low density, can be used. In this study, two different types of foamed concrete were used as VIP core materials, with their effects on the thermal behavior of the VIPs having been evaluated using experimental and numerical methods. To confirm and generate numerical models for VIP analysis, micro-computed tomography (micro-CT) was utilized. The obtained results show that insulation effects increase effectively when panels with lightweight concrete are in a vacuum, and both foamed concrete types can be effectively used as VIP core materials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
•Installations of VIPs in Chinese building sector were investigated.•Fiberglass cloth outer layer protected the VIP from alkaline cement mortar.•Masonry cavities between VIP and wall could promote ...inner drying against moisture.•Peephole-VIP increased the VIP/wall interface bond strength to about 50%.•Beijing and Shanghai require VIP thickness of 16mm and 14mm, respectively.
Energy used for heating, ventilation and air conditioning in commercial and residential buildings contributes to a significant portion of the total energy consumed in many countries. Energy efficient vacuum insulation panels (VIPs) present thin but highly effective insulation solutions, to reduce thermal losses for both new and renovated buildings. This study presents a comprehensive review of VIP comprising glass fibre core and laminated aluminium foil envelope materials, which are used in building envelopes in China. Characterization of the material composition, procedures for installation method, as well as future outlook have been investigated and discussed. The outer barrier layer of fibreglass cloth (FGC) protects VIP from localized alkaline cement and mechanical stress. Insulation assembly debonding from building walls was curbed by a combination of reinforced fibreglass mesh and plastic spacer. Besides, masonry cavities are created in some narrow spacing between the VIP and existing wall against unforeseen moisture conditions. Furthermore, owing to an interlocking surface topology of novel Peephole-VIP/wall interface, bond strength is increased to about 50%. Nonetheless, energy lost due to thermal bridge effect was rather high.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Energy efficiency solutions are being pursued as a sustainable approach to reducing energy consumption and related gas emissions across various sectors of the economy. Vacuum Insulation Panel (VIP) ...is an energy efficient advanced insulation system that facilitates slim but high-performance insulation, based on a porous core material evacuated and encapsulated in a barrier envelope. Although VIP has been on the market for decades now, it wasn’t until recently that efforts have been initiated to propose and adopt a global standard on characterization and testing. One of the issues regarding VIP is its durability and aging due to pressure and moisture dependent increase of the initial low thermal conductivity with time; more so in building applications. In this paper, the aging performance of commercially available VIP was investigated experimentally; thermal conductivity was tested in accordance with ISO 8302 standard (guarded hot plate method) and their long-term performance was analyzed based on a non-linear pressure-humidity dependent equation based on IEA/EBC Annex 39, with the aim of evaluating durability of VIP. The center-of-panel thermal conductivity after 25 years based on initial 90% fractile with a confidence level of 90% for the thermal conductivity (λ90/90) ranged from 7.3–8.2mW/(mK) for silica core VIP. Significant differences between manufacturer-provided data and measurements of thermal conductivity and internal pressure were observed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Almost every major city’s skyline is known for high-rise iconic buildings with some level of curtain wall system (CWS) installed. Although complex, a CWS can be designed for energy efficiency by ...integrating insulated spandrel components in space-constrained areas, such as slabs/plenums. The main aim of this study was to experimentally examine the thermal performance of an optimized curtain wall spandrel system integrated with vacuum insulation panel (VIP) as spandrel insulation. The study is based on robust experimental evaluations, augmented with appropriate numerical computations. The main study is constituted of six parts: (1) evaluation of VIP specifications and thermal properties; (2) analysis of VIP spandrel configuration, fabrication, and installation in a test building facility; (3) thermal bridge characterization of VIP spandrels; (4) monitoring and assessment of VIP durability within the spandrel cavities; (5) thermal performance analysis; and (6) assessment of related limitations and challenges, along with some further reflections. In all, 22 VIPs (each of size 600 mm2) were used. The effective thermal conductivity of VIPs ranged from 5.1–5.4 (10−3 W/mK) and the average value for initial inner pressure was approximately 4.3–5.9 mbar. Three VIP spandrel cases were fabricated and tested. The results proved that the Case 3 VIP spandrel configuration (composed of a double-layer VIP) was the most improved alternative for integrating VIPs.
Glass fiber core vacuum insulation panels (VIPs) are becoming an increasingly attractive option for building envelope construction due to lower cost and availability around the world. Although fumed ...silica core VIPs have shown superior long-term performance under accelerated aging tests compared to glass fiber core VIPS, these laboratory test results have yet to be verified with long-term field performance data. In 2011, glass fiber core VIPs were installed in a commercial building retrofit project in Yukon, Canada (one of Canada's most northern territories), and have been continuously monitored since. This paper summarizes the thermal performance of the glass fiber core VIPs over the period of 2011–2018 in an extreme cold climate. Findings from this study provided data to validate glass fiber core VIP accelerated aging test results and the aging rate of VIPs in a cold and dry climate was determined. These results will help developing a better understanding of the long-term performance of glass fiber core VIPs in a real-world context.
► A review is conducted on mass transfer modeling in vacuum insulation panels. ► The focus is on multilayer membranes with metalized polymer films. ► Sorption–diffusion model is used for gas ...permeation through barrier envelopes. ► Very low permeation rates are due to the metal coating on polymer films. ► Permeation through the metal coating is a defect driven process.
A vacuum insulation panel (VIP) is a very efficient thermal insulation system for buildings. It is constituted of an evacuated porous core material, enveloped in a gas barrier membrane. The total conductivity measured is as low as 5mW/(mK). The high performance is due to the low pressure inside the panel and the gas barrier envelope plays a key role in maintaining the vacuum during the whole VIP service life. Indeed, due to the permeation of atmospheric gases through the envelope, a slow increase of pressure and humidity occurs over time, which involves a thermal conductivity increase in the mean time. This review paper details the mass transfer models used to predict the permeation rates of gases through the VIP envelope. The sorption–diffusion model for gas permeation through polymer membranes is presented as well as alternative permeation models. The parameters which play a key role for mass transfer are detailed. The adaptation of the permeation models from homogeneous polymer membranes to multilayer gas barrier membranes is then presented, including an important section about metal-coated polymer films. The conclusions of the works based on several approaches are reported.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Vacuum insulation panels (VIPs) have a thermal resistance that is about a factor of 10 higher than that of equally thick conventional polystyrene boards. VIPs nowadays mostly consist of a ...load-bearing kernel of fumed silica. The kernel is evacuated to below 1 mbar and sealed in a high- barrier laminate, which consists of several layers of Al-coated polyethylene (PE) or polyethylene terephthalate (PET). The laminate is optimized for extremely low leakage rates for air and moisture and thus for a long service life, which is required especially for building applications. The evacuated kernel has a thermal conductivity of about 4 X 10 W * m * K at room temperature, which results mainly from solid thermal conduction along the tenuous silica backbone. A U-value of 0.2 W * m * K results from a thickness of 2 cm. Thus slim, yet highly insulating facade constructions can be realized. As the kernel has nano-size pores, the gaseous thermal conductivity becomes noticeable only for pressures above 10 mbar. Only above 100 mbar the thermal conductivity doubles to about 8 X 10 W * m * K, such a pressure could occur after several decades of usage in a middle European climate. These investigations revealed that the pressure increase is due to water vapor permeating the laminate itself, and to N2 and O2, which tend to penetrate the VIP via the sealed edges. An extremely important innovation is the integration of a thermo-sensor into the VIP to nondestructively measure the thermal performance in situ. A successful 'self-trial' was the integration of about 100 hand-made VIPs into the new ZAE-building in Wurzburg. Afterwards, several other buildings were super-insulated using VIPs within a large joint R&D project initiated and coordinated by ZAE Bayern and funded by the Bavarian Ministry of Economics in Munich. These VIPs were manufactured commercially and integrated into floorings, the gable facade of an old building under protection, the roof and the facades of a terraced house as well as into an ultra-low-energy 'passive house' and the slim balustrade of a hospital. The thermal reliability of these constructions was monitored using an infrared camera.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Vacuum insulation panel (VIP), which is composed of an evacuated core material encapsulated in an envelope and supplemented with a desiccant, is a high performance thermal insulation material. In ...this paper, thermos-physical properties of chopped fiber, centrifugal-spinneret-blow (CSB) fiber, flame-spinneret-blow (FSB) fiber and hybrid (CSB: FSB=1:1) fiber as fillers of vacuum insulation panel are explored. The results show that the increase of pore size can improve thermal insulation property; fibers distribute in 2-D structure, which can reduce the heat conduction, leads to reduce the thermal conductivity. VIP with chopped fiber has the best thermal insulation, and thermal conductivity is 1.4 mW/m.K. Due to difference of core materials, thermal insulation characteristics of VIP can be divided into three distinct regions based on the internal pressure range, i.e., (I) ≥12000 Pa region, (II) 80-12000 Pa region, (III) ≤ 80 Pa region. It also finds that service life of VIP can be improved by the reducing the pore size of core materials. VIP with different core materials shows different degradation and the degradation rate of VIP with FSB core material is minimum.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In order to upgrade internal thermal system for RC wall with less spatial loss, a new site-fabricable thermal system using quite thin vacuum insulation panel(VIP:5 mm and 8 mm) is developed here and ...compared with traditional XPS thermal system(45 mm) by Calibrated Hot box Method. In this new system, small pieces of plastic blocks in place of furring strips are arranged on lattice points of a square lattice on RC wall with VIPs in between them and with VIP joints covered by site spray foam. VIP system shown close score to Japanese Flat35 standards whereas XPS shown adequate score to it. For further upgrading of new system, improvement of joint heat bridge will be necessary.
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