scholarly journals Experimental Verification of Theoretical Ageing and Service Life Prediction Model for Vacuum Insulation Panels

2021 ◽  
Author(s):  
Mahsa Nikafkar
Keyword(s):  
Thermal Conductivity ◽  
Service Life ◽  
Accelerated Ageing ◽  
Aging Effects ◽  
Building Sector ◽  
Microporous Silica ◽  
Vacuum Insulation ◽  
Ageing Model ◽  
Innovative Material ◽  
Multiple Variables

Vacuum Insulation Panels (VIPs) are a kind of the super-insulated materials (SIMs). VIPs are innovative material in various fields like the building sector as it encompasses a higher thermal resistance per unit of thickness compared to conventional insulation. To extensively use VIPs in the building sector, comprehensive performance analysis, and their properties such as thermal conductivity valuations are required to be done under simulated conditions to evaluate its longterm performance. However, different VIPs have varying durability, and as it stands, there is no comprehensive understanding of how all VIPs will behave in real conditions. This research investigates the effect of multiple variables (such as temperature, relative humidity) on VIP service life. The purpose of this research is to validate the theoretical ageing model of VIPs. First, the experimental thermal conductivity results from seven samples of three different VIP categories are collected using a heat flow meter. To measure the accelerated ageing results over 25 years, Arrhenius equation is applied. Next, NRC theoretical model is used to predict the ageing response of the samples. Finally, an analytical method is employed to verify and validate this model based on the collected data. Results shows that effect of ageing and environmental temperature have higher impacts on the performance of fibreglass panels than the fumed silicas. Additionally, the aging effects analysis reveals that microporous silica VIP products would maintain their superior thermal performance over time. Keywords: Vacuum insulation panel, Ageing, Thermal conductivity, accelerated ageing, modelling

scholarly journals Experimental Verification of Theoretical Ageing and Service Life Prediction Model for Vacuum Insulation Panels

2021 ◽  
Author(s):  
Mahsa Nikafkar
Keyword(s):  
Thermal Conductivity ◽  
Service Life ◽  
Accelerated Ageing ◽  
Aging Effects ◽  
Building Sector ◽  
Microporous Silica ◽  
Vacuum Insulation ◽  
Ageing Model ◽  
Innovative Material ◽  
Multiple Variables

Vacuum Insulation Panels (VIPs) are a kind of the super-insulated materials (SIMs). VIPs are innovative material in various fields like the building sector as it encompasses a higher thermal resistance per unit of thickness compared to conventional insulation. To extensively use VIPs in the building sector, comprehensive performance analysis, and their properties such as thermal conductivity valuations are required to be done under simulated conditions to evaluate its longterm performance. However, different VIPs have varying durability, and as it stands, there is no comprehensive understanding of how all VIPs will behave in real conditions. This research investigates the effect of multiple variables (such as temperature, relative humidity) on VIP service life. The purpose of this research is to validate the theoretical ageing model of VIPs. First, the experimental thermal conductivity results from seven samples of three different VIP categories are collected using a heat flow meter. To measure the accelerated ageing results over 25 years, Arrhenius equation is applied. Next, NRC theoretical model is used to predict the ageing response of the samples. Finally, an analytical method is employed to verify and validate this model based on the collected data. Results shows that effect of ageing and environmental temperature have higher impacts on the performance of fibreglass panels than the fumed silicas. Additionally, the aging effects analysis reveals that microporous silica VIP products would maintain their superior thermal performance over time. Keywords: Vacuum insulation panel, Ageing, Thermal conductivity, accelerated ageing, modelling

scholarly journals Aging effects on thermal properties and service life of vacuum insulation panels

2011 ◽  
Vol 35 (2) ◽  
pp. 128-167 ◽  
Author(s):  
Erlend Wegger ◽  
Bjørn Petter Jelle ◽  
Erland Sveipe ◽  
Steinar Grynning ◽  
Arild Gustavsen ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Service Life ◽  
Aging Effects ◽  
Vacuum Insulation

scholarly journals Durability Assessment of ETICS: Comparative Evaluation of Different Insulating Materials

2022 ◽  
Vol 14 (2) ◽  
pp. 980
Author(s):  
Roberto Landolfi ◽  
Maurizio Nicolella
Keyword(s):  
Thermal Conductivity ◽  
Service Life ◽  
Thermal Characteristics ◽  
Outdoor Exposure ◽  
Time Shift ◽  
Accelerated Ageing ◽  
Low Grade ◽  
Insulating Materials ◽  
System A ◽  
Durability Assessment

The External Thermal Insulation Composite System (ETICS) is a common cladding technology that is widely used thanks to its well-known advantages. Despite previous studies dealing with ETICS durability in real-building case studies or involving accelerated ageing tests in climatic chambers, little progress has been made in the knowledge of the long-term durability of the system. In order to realize optimized maintenance plans for this component, the durability of the whole system, and of the most-used insulating materials for the ETICS (i.e., cork, polyurethane, rock wool, glass wool, grey EPS, and fiberfill wood), has been investigated. Based on previous experiments on ageing cycles, different climatic chambers were used to accelerate performance decay by simulating natural outdoor exposure in order to assess different physical and thermal characteristics (thermal transmittance, decrement factor, time shift, water absorption, thermal resistance, and conductivity). Recorded trends show that materials with lower thermal conductivity exhibit lower performance decay, and vice versa. The durability of the ETICS with different insulating materials (as the only variable in the different samples) was evaluated in order to quantify service life and then correctly plan maintenance interventions. Life-cycle assessment must take into account service life and durability for each material of the system. A higher durability of insulating materials allows for the execution of less maintenance interventions, with the loss of less performance over time. This study shows the physical and thermal behavior of the ETICS during its service life, comparing the differences induced by the most-used insulating materials. As a result of accelerated ageing cycles, the analyzed ETICS reveals a low grade of decay and measured performances show little degradation; for thermal conductivity, differences between the measured and the declared conductivities by technical datasheet were observed.

Determining the thermal resistance of a highly insulated wall containing vacuum insulation panels through experimental, calculation and numerical simulation methods

2020 ◽  
pp. 174425912098003
Author(s):  
Travis V Moore ◽  
Cynthia A. Cruickshank ◽  
Ian Beausoleil-Morrison ◽  
Michael Lacasse
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Edge Effect ◽  
3D Simulation ◽  
Simulation Methods ◽  
Zone Method ◽  
Vacuum Insulation ◽  
Thermal Bridges ◽  
Wall Assembly

The purpose of this paper is to investigate the potential for calculation methods to determine the thermal resistance of a wall system containing vacuum insulation panels (VIPs) that has been experimentally characterised using a guarded hot box (GHB) apparatus. The VIPs used in the wall assembly have not been characterised separately to the wall assembly, and therefore exact knowledge of the thermal performance of the VIP including edge effect is not known. The calculations and simulations are completed using methods found in literature as well as manufacturer published values for the VIPs to determine the potential for calculation and simulation methods to predict the thermal resistance of the wall assembly without the exact characterisation of the VIP edge effect. The results demonstrate that disregarding the effect of VIP thermal bridges results in overestimating the thermal resistance of the wall assembly in all calculation and simulation methods, ranging from overestimates of 21% to 58%. Accounting for the VIP thermal bridges using the manufacturer advertised effective thermal conductivity of the VIPs resulted in three methods predicting the thermal resistance of the wall assembly within the uncertainty of the GHB results: the isothermal planes method, modified zone method and the 3D simulation. Of these methods only the 3D simulation can be considered a potential valid method for energy code compliance, as the isothermal planes method requires too drastic an assumption to be valid and the modified zone method requires extrapolating the zone factor beyond values which have been validated. The results of this work demonstrate that 3D simulations do show potential for use in lieu of guarded hot box testing for predicting the thermal resistance of wall assemblies containing both VIPs and steel studs. However, knowledge of the VIP effective thermal conductivity is imperative to achieve reasonable results.

scholarly journals Effect of Graphene and Carbon Nanotubes on the Thermal Conductivity of WC-Co Cemented Carbide

2019 ◽  
Author(s):  
Kui Chen ◽  
Wenkai Xiao ◽  
Zhengwu Li ◽  
Jiasheng Wu ◽  
Kairong Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Service Life ◽  
Bending Strength ◽  
Cemented Carbide ◽  
Engineering Practice ◽  
Shield Tunneling ◽  
Hardness Tester ◽  
Engineering Costs ◽  
Shield Machine

In recent years, it has been found in engineering practice that the service life of cemented carbide shield machine tools used in uneven soft and hard strata is substantially reduced. The study found that thermal stress is the main reason for the failure of cemented carbide shield tunneling tools when shield tunneling is carried out in uneven soft and hard soil. To maintain the hardness of cemented carbide, improving the thermal conductivity of the shield machine tool is of great importance for prolonging its service life and reducing engineering costs. In this paper, graphene and carbon nanotubes were mixed with WC-Co powder and sintered by SPS (Spark Plasma Sintering). The morphology was observed by using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A Rockwell hardness tester and bending strength tester were used to test hardness, bending strength and thermal conductivity. The results show that adding trace graphene or carbon nanotubes can increase the bending strength of the cemented carbide by approximately 50% while keeping the hardness of the cemented carbide unchanged. The thermal conductivity of the cemented carbide can be increased by 10% with the addition of 0.12% graphene alone.

scholarly journals Thermal insulation properties of green vacuum insulation panel using wood fiber as core material

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 3339-3351 ◽  
Author(s):  
Baowen Wang ◽  
Zhihui Li ◽  
Xinglai Qi ◽  
Nairong Chen ◽  
Qinzhi Zeng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Bulk Density ◽  
Thermal Insulation ◽  
Wood Fiber ◽  
Core Material ◽  
High Porosity ◽  
Total Thermal Conductivity ◽  
Wood Fibers ◽  
Vacuum Insulation ◽  
Vacuum Insulation Panel

Wood fibers were prepared as core materials for a vacuum insulation panel (VIP) via a dry molding process. The morphology of the wood fibers and the microstructure, pore structure, transmittance, and thermal conductivity of the wood fiber VIP were tested. The results showed that the wood fibers had excellent thermal insulation properties and formed a porous structure by interweaving with one another. The optimum bulk density that led to a low-cost and highly thermally efficient wood fiber VIP was 180 kg/m3 to 200 kg/m3. The bulk density of the wood fiber VIP was 200 kg/m3, with a high porosity of 78%, a fine pore size of 112.8 μm, and a total pore volume of 7.0 cm3·g-1. The initial total thermal conductivity of the wood fiber VIP was 9.4 mW/(m·K) at 25 °C. The thermal conductivity of the VIP increased with increasing ambient temperature. These results were relatively good compared to the thermal insulation performance of current biomass VIPs, so the use of wood fiber as a VIP core material has broad application prospects.

scholarly journals Aging effects on thermal conductivity of glass-forming liquids

2020 ◽  
Vol 101 (2) ◽  
Author(s):  
Pranab Jyoti Bhuyan ◽  
Rituparno Mandal ◽  
Pinaki Chaudhuri ◽  
Abhishek Dhar ◽  
Chandan Dasgupta
Keyword(s):  
Thermal Conductivity ◽  
Aging Effects ◽  
Glass Forming

scholarly journals Elaboration and Characterization of Composite Materials Based on Plaster-Gypsum and Mineral Additives for Energy Efficiency in Buildings

Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 22
Author(s):  
Bouzit ◽  
Taha
Keyword(s):  
Thermal Conductivity ◽  
Energy Efficiency ◽  
Composite Materials ◽  
Building Material ◽  
Building Materials ◽  
Building Envelope ◽  
Acoustic Properties ◽  
Building Sector ◽  
Acoustic Performance ◽  
Mineral Additives

The building sector is one of the largest energy consumers in the world, prompting scientific researchers to find solutions to the problem. The choice of appropriate building materials presents a considerable challenge for improving the thermal comfort of buildings. In this scenario, plaster-based insulating materials have more and more interests and new applications, such as insulating coatings developing the building envelope. Several works are being done to improve energy efficiency in the building sector through the study of building materials with insulation quality and energy savings. In this work, new composite materials, plaster-gypsum with mineral additives are produced and evaluated experimentally to obtain low-cost materials with improved thermo-physical and acoustic properties. The resulting composites are intended for use in building walls. Plaster-gypsum is presented as a high-performance thermal material, and mineral additives are of great importance because of their nature and are environmentally friendly. Measurements of thermal properties are carried and measurements of acoustic properties. The results show that it is possible to improve the thermal and acoustic performance of building material by using plaster as a base material and by incorporating thermal insulators. The thermal conductivity of plaster alone is greater than that of plaster with mineral additives, offer interesting thermal and acoustic performance. By varying the additives, the thermal conductivity changes. Finally, comparing the results, plaster with mineral additives is considered the best building material in this study

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