Vacuum Insulation Panels Research Articles

The economics of thermal superinsulation in buildings

In comparison to conventional thermal insulators, superinsulation materials (SIMs), such as silica aerogel or vacuum insulation panels, provide a similar insulation performance at half to a quarter of the material thickness but this superior thermal insulation performance typically comes at a significantly higher material cost. However, under certain conditions, the use of superinsulation materials in building walls allows for the creation of additional floor space.Here, we derive a simple equation to quantify the cost to create such additional space using superinsulation materials as opposed to conventional thermal insulators. The equation has six independent variables, namely the thermal conductivity and cost of the superinsulation and conventional insulation materials, as well as two building geometry parameters. Notably, the cost to create additional floor space is independent of the heat transfer coefficient (U-value) of the wall.The real estate price distributions within major cities around the world are presented in order to compare the cost to create additional space with the potential financial benefit.The analysis of typical construction types, combined with the real estate data, shows that, from a financial perspective, the use of superinsulation such as silica aerogel or vacuum insulation panels (VIPs) is already clearly profitable in several major cities globally. Improvements of the production processes of superinsulation materials and the associated reduction in costs will be key drivers to make superinsulation materials economically feasible for many other locations in the future.

Effects of insulation materials and their location on the fire resistance of LSF walls

Lightweight walls incorporate insulation materials to compensate for their low thermal mass and to improve thermal performance. This helps in increasing the energy performance of the buildings. Since insulation materials are sensible heat storage materials, there is an increment in the room temperature. Phase Change Materials (PCMs) are used in lightweight walls due to their high thermal storage capacity and the resulting enhanced thermal comfort levels. However, the performance of the PCM incorporated building products/insulations in fire has not been investigated yet. This research has investigated the fire resistance of Light gauge steel framed (LSF) walls with PCM incorporated cellulose insulation through small-scale fire tests. It has also investigated the effects of using different insulation materials and their location on the fire resistance of LSF walls. Important results of this research are presented in this paper in the form of time-temperature profiles for cavity and externally insulated LSF wall configurations with and without PCM incorporated cellulose insulation. Findings reveal that externally insulated LSF walls have higher fire resistance levels than cavity insulated LSF walls based on insulation failure criterion. Importantly, adding PCM to cellulose insulation improves the fire resistance of both cavity and externally insulated LSF walls. PCM incorporated cellulose insulation can be used externally in LSF walls to enhance their fire and energy performance. However, the fire behaviour of Vacuum Insulation Panel (VIP) incorporated LSF wall is completely different to other wall systems.

Onsite monitoring of a wall retrofitted with an external vacuum insulation composite system

As it becomes more and more relevant to renovate existing buildings with energy efficiency as top priority towards a nearly Zero Energy Building (nZEB) stock, the need for new super-insulation materials to penetrate the construction market increases. A promising option is to incorporate vacuum insulation panels (VIPs) into an External Thermal Insulation Composite System (ETICS) - one of the most popular coating solutions used for insulating building walls. However, the widespread commercialization of VIP solutions for buildings still faces some uncertainties, such as regarding the long-term performance of the panels or the significance of the edge thermal bridging effects. In this context, studying onsite wall applications is of major importance in order to evaluate the actual performance of this innovative multilayer coating system under real exposure conditions.In this paper, the thermal behaviour of an ETICS façade incorporating a VIP insulation is studied. The building being retrofitted is located in Warsaw, Poland. Measurements of temperature, absolute humidity and heat flux are presented and discussed. Data is simultaneously recorded for a VIP ETICS wall and an adjacent conventional polystyrene-based ETICS wall. The VIP edge thermal bridging effect is also analysed. The thermal transmittance of both walls is estimated based on the experimental measurements. Furthermore, a computational algorithm for determining the thermal transmittance coefficient of the existing and the retrofitted wall based on temperature measurements is proposed. Additionally, a periodic infrared thermographic inspection is carried out during the 24-month monitoring period to identify anomalies.It was found that the VIP thermal resistance contribution is significantly higher than conventional expanded polystyrene-based solutions, even at the joint area between panels. No panels with vacuum loss or other anomalies were found during the monitoring period. The computational algorithm results based on the measurements were found to be accurate when compared with the predicted theoretical U-values.

Predicting the conductive heat transfer through evacuated perlite based vacuum insulation panels

The core material contributes ≥40% of the total cost of a fumed silica based vacuum insulation panel (VIP). Expanded perlites, which come at approximately one-tenth of the current price of fumed silica, have been identified as potential core material candidates. Though, the characteristic vacuum insulation properties i.e. evacuated thermal conductivity and half pressure value of expanded perlites are not suitable for most applications, these can be improved by altering their structural properties like particle size, pore size, porosity etc. during manufacture. The knowledge of the relationship between structural properties and the thermal conductivity of perlite is key to develop improved thermal performance VIPs.In the present work, it has been found that the thermal conductivity of the perlite cores lies between the thermal conductivities of two regular packing orders – simple cubic packing and the hexagonal close packing. Owing to the complex geometries involved, the thermal conductivity of particle beds arranged in these two packing structures was numerically calculated using finite element method. The dependence of the thermal conductivity on five parameters (particle size, intra-particle pore size, porosity, internal gas pressure and contact ratio) was observed and correlated with existing studies in literature. The model was also validated by experiments performed on expanded perlite. The developed framework can be employed to produce bespoke perlites for most cost-effective thermal insulation systems.

Analysis of indoor environment and insulation performance of residential house with double envelope vacuum insulation panels

Double envelope vacuum insulation panels (VIPs) have a possibility to significantly increase the service lifetime. In this paper, double envelope VIPs were produced and installed in the residential house. The performance of installed VIPs was evaluated by using the measuring data of heat flux meter. In addition, the total energy, the heating load and the indoor thermal environment of this house were measured and analysed. The average heating load and the average temperature difference between room temperature and ambient air temperature on the representative day was 2.49 kW and 29.9 oC, respectively. The heat loss coefficient per floor area was estimated as 0.69 W/(m2K) and it was almost the same as the value calculated at the time of design. The result of indoor environment measurement showed that the room temperature was maintained at around 20 oC and PMV was -0.5 oC or higher although the outside air temperature fluctuated between -5 oC and -10 oC. The effective thermal conductivities of double envelop VIPs were all estimated as 0.01 W/(mK) or less. It is considered that the insulation performance of the vacuum insulation panels is maintained.

Preparation, characterisation and thermal property study of micro/nanocellulose crystals for vacuum insulation panel application

In this work, bleached and unbleached micro/nanocellulose crystals (MNCC) were successfully extracted from raw banana fibre through a mechanochemical cellulose extraction method and integrated with fumed silica-based Vacuum Insulation Panel (VIP) core as a filler material. Both types of extracted MNCC were characterised for structural changes, chemical composition and thermal properties associated with insulation purpose. Thermal stability, specific heat capacity, thermal diffusivity and thermal conductivity were measured for both MNCC and compared with the commercially available Microcrystalline Cellulose (MCC). The effect of both MNCC on thermal conductivity of VIP was compared. The characterisation results concluded that the effect of the bleaching process in MNCC extraction was observed in particle size, crystallinity index, thermal diffusivity and thermal conductivity. VIP made with bleached MNCC showed lower thermal conductivity than unbleached MNCC. It was concluded that bleached MNCC extract would be comparatively a better filler material for VIP.

Numerical study of the feasibility of coupling vacuum isolation panels with phase change material for enhanced energy-efficient buildings

Effective thermal performance of a building envelope is crucial to reduce total energy consumption in buildings. In the past decades, different insulating materials and techniques have been proposed to improve building energy efficiency. Among various insulating materials vacuum insulation panels (VIPs), due to their extremely low thermal conductivity, become one of the emerging materials, striving for replacing conventional insulation materials. From different perspectives, phase change material (PCM) is another promising material with a large amount of latent heat capacity to improve building thermal inertia. Much research has been conducted for PCMs or VIPs individually. However, there are rare studies found in the literature to integrate both materials in the building envelopes. Therefore, this study aimed to evaluate the feasibility of an energy-saving building wall by coupling VIP with PCM as a compact unit that could significantly reduce heat flux through the wall, thereby leading to a tremendous reduction in energy consumption. The aging effect of VIP is also considered to examine its long-term thermal performance and compared with that of a traditional thermal insulation material-expanded polystyrene (EPS). The results reveal that the combined utilization of VIP and PCM in the same building envelope can reduce the heat flux oscillation through the wall more effectively, as compared to using the individual one. The maximum heat flux oscillation through the wall is found in direct proportion to the amplitude of the input loading, and inverse proportion to the VIP and PCM thickness. In addition to decreasing the heat flux oscillation through the wall, the integration of the PCM layer also causes a time delay on the peak heat fluxes, showing great potential to shift the electricity load from peak to off-peak hours. Results also show that the VIP with extremely low thermal conductivity allows the building envelope to achieve the same thermal performance with up to 77.3% of wall thickness saved compared with EPS. Moreover, the optimal integrating location of PCM is found to be on the interior side of the VIP layer under various loading conditions. The optimal PCM melting temperature of the PCM-VIP-based wall is highly dependent on the input loading conditions in direct proportion.

Onsite monitoring of ETICS comparing different exposure conditions and insulation materials

This paper presents the onsite temperature monitoring of ETICS walls located in a Mediterranean climate, looking to compare different conditions and insulation materials. The walls incorporate several insulation products, including vacuum insulation panels. Different finishing coats and orientations were considered. Additionally, a 2D numerical model was used to simulate the transient thermal behaviour of the case study walls.The results show that walls with a greater insulation capacity finished with a white coloured surface were more likely to develop surface condensations, and consequently, microbiological growth. Black walls showed higher temperature amplitudes increasing the risk of the rendering cracking.

Ug-value and edge heat loss of triple glazed insulating glass units:A comparison between measured and declared values

Triple glazed low-e coated insulating glass units with argon filling of five different suppliers on the European market with a declared thermal transmittance in the undisturbed centre of glass (Ug-value) of 0.6 W/m2K have been purchased from resellers and tested in a guarded hot plate at vertical position. The measured results showed deviations towards higher values for all 5 types. These have been analysed by recurring to the determination of the two main factors namely the gas mixture in the two cavities and the emissivity of the coated glass panes. Non-destructive measuring methods for gas mixture analysis and standardized calculation methods for the Ug-value have been used to analyse the influence of these two factors. In a further step the edge heat loss due to the spacer of the insulating glass units has been measured by using two “halves” of each glazing type with a double edge running through the middle of the measured sample. This was done following a standardized test method for the determination of the edge heat loss of Vacuum Insulation Panels (VIP). Finally, pieces of the coated glass panes were cut out of the glazing units and their emissivity measured with both an infrared spectrometer and an emissiometer. Results showed an increased emissivity value for the coated surfaces leading to higher Ug values than measured. This is partly due to the exposure to air and the possible degradation of the coating. The investigation shows non-destructive emissivity determination is needed to get more accurate in-situ emissivity values of the coatings.

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

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.

Use of Insulation Based on Nanomaterials to Improve Energy Efficiency of Residential Buildings in a Hot Desert Climate

Building insulation based on nanomaterials is considered one of the most effective means of reducing energy consumption in the hot desert climate. The application of an energy-efficient insulation system can significantly decrease the energy consumed via a building’s air-conditioning system during the summer. Hence, building insulation has become an interesting research topic, especially with regards to the use of insulation based on nanomaterials due to their low U-values. In the present study, the use of nano vacuum insulation panels (VIPs) or polystyrene foam in the walls enabled a significant reduction in the annual energy consumption, a savings of 23% compared to the uninsulated wall in a study in New Aswan City. The application of nanogel glazing to the windows (two layers of clear glass filled with the nanogel) achieved approximately 11% savings in annual energy. This savings, twice that obtained by using double-glazed windows, could be due to the low U-value of nanogel compared to the U-values of argon or air. The embedded nanogel layer between two layers of argon and two layers of single clear glass showed a significant reduction in annual energy consumption, saving 26% compared to the use of a single layer of glass. Moreover, the integration between this window and embedded walls with 50 mm of polystyrene foam exhibited a significant improvement of energy efficiency by 47.6% while presenting the lowest value of simple payback period (SPP). This research provides a way for buildings to be insulated to make them more energy efficient as well as attractive from the economic standpoint.

The Green Logistics Idea using Vacuum Insulation Panels (VIPs)

This research aims to reduce fuel consumption in transportation systems using vacuum insulation panels (VIPs) for cold storage trucks. The material was vacuum Insulation Panels (VIPs) is a custom-made insulator using glass fibers pressed at 10 tons per square meter and the thermal conductivity conditions of the selected materials ranged between 0.0028 and 0.007 W/mK and has a size of 12 mm comparative experiment method of cold storage trucks equipped with VIPs and without VIPs of 4 model frozen cars. Which has Model 1 (4 Wheels Truck), Model 2 (4 Wheels large Truck), Model 3 (6 Wheels Truck), and Model 4 (10 Wheels Truck). The sensor installation in the cold room is distributed in every wall to achieve differentiation and distribution of cold temperatures. The results are calculated as the energy saving result, it was found Model 1 (4 Wheels Truck) have best fuel savings. This research can apply other types of cold storage trucks or research in the same way as the air wall by inserting VIPs insulation inside the external insulation to reduce heat transfer.

Experimental investigation on nanoalloy enhanced layered perovskite PCM tamped in a tapered triangular heat sink for satellite avionics thermal management

Miniaturization of circuitry has inherently led to higher heat dissipation which has to be controlled to avoid temperature fluctuation ensuring smooth functioning of the system where developments in the field of PCM provides flexible solutions for avionic Thermal Management (TM). This article focuses to analyse thermal performance of novel tapered triangular finned heat sink along with Vacuum Insulation Panels (VIPs) tamped with nanoalloy (n-LMA) enhanced organo-metallic Mn based layered perovskite Solid-Solid PCM (SS-PCM) to its compatibility for passive TM satellite auxiliary system. An inclusion of 5 wt% nanoalloy (Nano-encapsulated liquid Ga:In eutectic alloy) in SS-PCM increased the thermal conductivity by 21.05% (0.374 W/m-K) and charging and discharging enthalpy by 16.84% (74.56 J/g) and 17.61% (76.32 J/g) respectively. Thermo-physical property values were obtained through Field Emission Scanning Electron Microscope, Scanning Electron Microscope, Differential Scanning Calorimetry and Laser Flash Apparatus. Transient thermal performance analysis was carried out in tapered triangular finned heat sink with specific duty cycles (600s/5400s, 1200s/4800s and 1800s/4200s) for heat fluxes (2 W, 4 W, 6 W, 8 W and 10 W) and with/without VIP for different aspects of SS-PCM and SS-PCM/n-LMA. The effect of n-LMA influences the enhancement in thermal storage and heat transfer performance attributes with a maximum temperature drop of 6.98% over pure SS-PCM. Experimental study reveals better temperature reduction with a maximum of 53.81% decrement in overall heat sink temperature and VIP manifests unidirectional heat transfer through the heat sink reducing overall spatial temperature variation. Further, numerical validation was performed for obtained results with COMSOL application, demonstrating the suitability for real-time passive TM in satellite avionics space applications.

Superinsulation Materials for Energy-Efficient Train Envelopes

While traction energy is the main energy used in passenger trains, the energy required to condition the passenger area is significant and can account for up 40% of the total energy use. Due to space constraints, passenger train envelopes are usually only insulated with a few centimetres of conventional insulation materials, leading to relatively high U-values and high energy transmissions in climates where heating or cooling is necessary. Here, the use of superinsulation materials in trains for heating/cooling demand reduction was evaluated. Selected commercially available superinsulation materials were screened and benchmarked in terms of thermal conductivity, fire safety, behaviour under vibration and preferred use position within the train envelope. Both the specific vacuum insulation panels and silica aerogel boards that were tested were found suitable for the application in train envelopes in terms of their thermal, fire and mechanical properties. While vacuum panels have the best insulation performance, aerogel boards offer higher flexibility during installation and reduced risk of damage-related performance loss. Both materials can greatly enhance the energy efficiency and thermal comfort of trains and can be implemented cost-neutrally. However, new policy frameworks are likely to be necessary to promote energy efficiency and the broad implementation of thermal superinsulation in trains.

Microscopic experimental analysis on weatherability of roof insulation materials under multi field coupling environment

The weatherability of insulation materials directly affects its thermal insulation performance, so it is necessary to carry out the weatherability experiments for insulation materials. In this paper, three kinds of insulation materials, that is, polyurethane (PUR), foam concrete (FC) and vacuum insulation panel (VIP) are chosen to analyze their thermal conductivity under different kinds of weatherability experiments. For the different kinds of weatherability experiments, the experiments of damp-heat, freeze-thaw, high-low temperature and wet-dry are designed to analyze the thermal conductivity of the insulation materials and the microstructure of insulation materials. The experimental results show that thermal conductivity of FC has a downward trend under the damp-heat experiment, and the thermal conductivity of FC has increased in other experiments. The thermal conductivity of PUR increases in all weatherability experiments, but the thermal conductivity of VIP does not change in all weatherability experiments.

Melamine-formaldehyde rigid foams – Manufacturing and their thermal insulation properties

The manufacturing of novel melamine-formaldehyde rigid foam material, by blowing the melamine-formaldehyde (MF) resin emulsion with pentane and further catalytic and thermal curing, is presented in this work. The process of foaming is described in terms of particular process parameters, which are; the proportions of blowing, curing, emulsifying agents. The examination of the foam, by SEM images, shows that the foam pore sizes are in the range from 150 to 250 µm. The thermal characterization of the obtained foams, is described in terms of thermal conductivity contributions of solid, gas and radiation conduction to total thermal conductivity at atmospheric and vacuum condition. The foam with densities from 50 to 80 kg/m3achieve thermal conductivity at an atmospheric pressure of 33–34 mW/(m × K), while in a vacuum of 6–7 mW/(m × K). Compared to other organic polymer foams, MF foams have superior fire resistance and chemical stability. The innovation of MF rigid foams presented here, compared to other well-known MF flexible foam, is in their rigid structure, combined with low density and thermal conductivity, which makes this particular foam potentially useful in the manufacture of vacuum insulation panels (VIP).

Are nZEB design solutions environmental sustainable? Sensitive analysis for building envelope configurations and photovoltaic integration in different climates

It is believed that the overall environmental impacts of a nearly zero energy building (nZEB) are lower than conventional buildings. A question remains: is the most energy efficient solution also the best one in term of environmental sustainability?This paper tries to answer to this question by means of a holistic approach for the combined energy and environmental assessment also considering a new impact analysis method with different weights’ assignment. This approach is applied to a case study of a real nZEB. A sensitivity analysis on the materials selection, on the size and type of photovoltaic system with or without storage is proposed for different climates. The overall results of carried out analyses, indicate that a balance point between energy saving measures and renewable energy should be reached for minimizing the environmental impacts according to the life cycle approach. The combined analysis suggests that under both energetic and environmental point of views, in Mediterranean and Continental climates, it does not pay off to further increase the insulation level also by using innovative materials as vacuum insulation panels. Instead, the environmental analysis indicates that the maximization of installed photovoltaic power, without the integration of the storage system, is the best way to nullify the impacts considering a life-cycle of 50 years. On the contrary, the energy analysis does not recommend to exceed with the installed power but it suggests to associate a storage system for increasing the building self-consumption.

Comparison of thermal insulation performance of vacuum insulation panels with EPS protection layers measured with different methods

For reducing the energy use of buildings, the application of insulation materials can be a possible solution to improve energy efficiency. However, with the continuously tightening regulations, thicker and thicker insulations should be used (e.g., up to 20–25 cm in Hungary and about 40–50 cm in the Nordic countries) to fulfil the directives. In the past decades, developmental research started to focus on both decreasing the thickness and decreasing the thermal conductivity of materials parallels. With this research direction, the investigations of the new type of insulation materials took place. The use of materials having thermal conductivity with less than 0.020 W/mK spread over. These materials are the so-called super insulation materials. Besides Vacuum Insulation Panels (VIPs), aerogel-based materials belong to this group, too. This paper will present laboratory tests executed on two altered types of protected Vacuum Insulation Panels: a one side and a 2 side protected VIP, also called Vacuum Insulation Sandwich (VIS). The first one, type “A” contains 20 mm thick laminated fumed silica, covered with 10 mm thick expanded polystyrene on one side, while type “B” was the one where the 10 mm thick laminated fumed silica core was packed between two 10 mm thick EPS slabs. Firstly, thermal insulation performance was investigated by the so-called guarded hot-box method for U-value, where the samples were placed on a solid brick wall. Furthermore, the thermal insulation performance of protected VIPs was also tested with Hukseflux heat flux plates. To reveal the applicability limits caused by the thermal bridges infrared thermography images (IR) were taken, too. From the images and the measurement results, a theory was formed regarding the heat flow directions inside the encapsulated panels. The current article emphasizes the equivalent thermal conductivity for the assessment of the thermal protection performance of vacuum insulation panels. The paper states that by using VIPs at least, 70% reduction can be reached in the U-value compared to the value of the solid brick wall. Moreover, the paper points out that the use of EPS protection layer on both sides of the VIP has a promising effect by reducing the thermal bridges. Furthermore, the VIP protected with EPS slabs on both sides results in less equivalent thermal conductivity.

Elevated temperature thermal properties of advanced materials used in LSF systems

SUMMARYLightweight cold‐formed steel (CFS) construction solutions are increasingly adopted in low and mid‐rise buildings. Many different materials are used to construct CFS wall systems, without a full understanding of their thermal properties. For many of these materials, only ambient temperature thermal properties are available from their manufacturers. This creates difficulty in classifying the materials for use at elevated temperatures. In this study, a series of elevated temperature thermal property tests to measure specific heat, thermal conductivity, and mass loss was conducted for a range building materials from wallboards, insulation, and phase‐change materials (PCMs), used in Australia and several other countries. Simultaneous Thermal Analyser and Laser Flash Apparatus were used to determine the elevated temperature thermal properties of the selected materials, gypsum plasterboard, PCM incorporated gypsum plasterboard, magnesium sulphate board, fibre cement board, cellulose insulation, vacuum insulation panel, microencapsulated paraffin PCM, and bio‐based PCM. Their elevated temperature thermal properties are presented in this article, which also includes analyses of their chemical composition and associated chemical reactions at elevated temperatures. These results can be used in the selection of suitable energy‐efficient and fire‐resistive materials, and in heat transfer modeling to identify wall configurations with increased fire resistance and energy efficiency.

Solid wall insulation of the Victorian house stock in England: A whole life carbon perspective

Solid walls are a common feature of the pre-1919 Victorian housing stock in England, however their construction results in considerable heat loss, and thus large heating requirements. Solid wall insulation of these walls would improve energy efficiency, and in turn should reduce greenhouse gas emissions. However, the additional insulation needed comes with an embodied carbon cost. Current studies about whole life performance of solid wall insulation focus on a single building or building type only, without considering the diversity of building types in the pre-1919 Victorian house stock. This study fills this gap by investigating the whole life carbon performance of eight current market available insulation materials. The insulation materials studied include vacuuminsulated panels (VIPs), aerogel, phenolic foam, polyurethane (PUR), polyisocyanurate (PIR), expanded polystyrene (EPS), glass wool and wood fibre. The results show that solid wall insulation reduces whole life carbon emissions up to 1654 kgCO2e per m2, with the carbon payback time of all eight insulation materials being less than 23 years in the worst case scenario, and less than one year in the best case scenario. Both are considerably shorter than the service life of the insulation materials. More actions should be taken to promote the installation of solid wall insulation in the pre-1919 Victorian house stock as this work shows that the accumulated carbon reduction potential reached 268 MtCO2e from 2021 to 2050.