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.

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 Influence of Surface Emissivity and of Low Emissivity Shields on the Thermal Properties of Low Density Insulating Materials

2011 ◽  
Author(s):  
Mariacarla Arduini ◽  
Manuela Campanale ◽  
Lorenzo Moro
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Test Temperature ◽  
Transfer Factor ◽  
Thermal Characteristics ◽  
Expanded Polystyrene ◽  
Low Density ◽  
Insulating Materials ◽  
Insulating Material ◽  
Radiation Extinction

The theory of heat transfer through low density insulating materials explains the importance of thermal radiation in the overall heat transfer. As a matter of fact, in many semitransparent insulating materials, radiation has a considerable influence on measured thermal conductivity. In this work we continue the investigation (both experimentally and theoretically) on the heat transfer through low density insulating materials that we started some years ago and whose results have been presented in some International Conferences. Test have been done on low density insulating materials: expanded polystyrene with a density of 10 kg/m3 and polyester fibres with a density of 9 kg/m3 (these last tests are not yet completed and will not be discussed in this paper). The transfer factor T was measured in the heat flow meter apparatus of our laboratory [1]. The first measurements have been done with the two surfaces of the apparatus uncoated (emissivity ε = 0.91) at a mean test temperature of 283 K (10 °C) and then with the specimens enclosed in the aluminium foils (emissivity ε = 0.045) at the same mean test temperature. The results obtained from the measurements of the transfer factor T pointed out that a change of the emissivity ε of the surfaces from 0.91 to 0.045 caused a considerable decreasing of the transfer factor. Then the same panels have been cut into two slices and the aluminium foil has been interposed also between the slices, as shield, and the transfer factor was measured again in both cases: at first with the surfaces of the apparatus uncoated and then with the surfaces of the apparatus coated with the aluminium foils. In both cases the decreasing of the transfer factor τ was not negligible. The radiation extinction parameters have been then measured with a spectrometer and a model has been found to predict the transfer factor T in function of the testing conditions. We can conclude that in presence of a thin reflective metal cover placed on a low density insulating material, the thermal conductivity decrease immediately (about 7%) with a significant improvement of the thermal characteristics of the insulating material. If we put then some low emissivity foils between the slices of the material, another considerable decreasing of the thermal conductivity can be obtained (about 10%) and in presence of both aluminum foils (inside and outside). This fact confirms the importance of the contribution of radiation in thermal transmissivity of low density insulating materials and gives the possibility to reduce and to predict the thermal performances of such a material.

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

Evaluation of compression-recovery and thermal characteristics of multilayer bedding textiles

2020 ◽  
Vol 32 (5) ◽  
pp. 631-643
Author(s):  
Sedat Özer ◽  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Thermal Conductivity ◽  
Sleep Quality ◽  
Thermal Comfort ◽  
Sleep Duration ◽  
Human Body ◽  
Design Methodology ◽  
Thermal Characteristics ◽  
Air Permeability ◽  
Content Type ◽  
Thermal Comfort Properties

PurposeDesign of bedding textiles that contact the human body affects the sleep quality. Bedding textiles contribute to comfort sense during the sleep duration, in addition to ambient and bed microclimate. The purpose of this study is to evaluate the effects of different layer properties on the compression recovery and thermal characteristics of multilayer bedding textiles.Design/methodology/approachIn this study, woven and knitted multilayer bedding textiles were manufactured from fabric, fiber, sponge and interlining, respectively. Different sponge thickness, fiber and interlining weight were used in the layers of samples. Later, the pilling resistance, compression and recovery, air permeability and thermal conductivity of multilayer bedding textiles were investigated.FindingsThe results indicated that samples with the higher layer weight and thickness provide better compression recovery and lower air permeability properties. It was also found that knitted surfaces show the higher air permeability than the woven surfaces depending on the fabric porosity. Layer properties have insignificant effect on the thermal conductivity values.Originality/valueWhile researchers mostly focus on thermal comfort properties of garments, there are limited studies about comfort properties of bedding textiles in the literature. Furthermore, compression recovery properties of bedding textiles have also a great importance in terms of comfort. Originality of this study is that these properties were analyzed together.

scholarly journals Mineralogical and thermal characteristics of low-grade Jinlong bauxite sourced from Guangxi Province, China

2015 ◽  
Vol 122 (2) ◽  
pp. 917-927 ◽  
Author(s):  
Yan Wang ◽  
Shuwen Xing ◽  
Yong Zhang ◽  
Zhiwei Li ◽  
Yubo Ma ◽  
...  
Keyword(s):  
Thermal Characteristics ◽  
Low Grade ◽  
Guangxi Province

Thermal conductivity measurement of insulating materials up to 1000 °C with a needle probe

2021 ◽  
Vol 92 (6) ◽  
pp. 064903
Author(s):  
Yves Jannot ◽  
Dorsaf Khalifa ◽  
Léa Penazzi ◽  
Alain Degiovanni
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurement ◽  
Thermal Conductivity Measurement ◽  
Insulating Materials ◽  
Needle Probe

scholarly journals Simultaneously Enhanced Thermal Conductivity and Breakdown Performance of Micro/Nano-BN Co-Doped Epoxy Composites

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3521
Author(s):  
Chuang Zhang ◽  
Jiao Xiang ◽  
Shihang Wang ◽  
Zhimin Yan ◽  
Zhuolin Cheng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Frequency ◽  
Breakdown Strength ◽  
Epoxy Composites ◽  
Endurance Time ◽  
Insulating Materials ◽  
Power Frequency ◽  
High Frequency Devices ◽  
Co Doped ◽  
Enhanced Thermal Conductivity

Micro/nano- BN co-doped epoxy composites were prepared and their thermal conductivity, breakdown strength at power frequency and voltage endurance time under high frequency bipolar square wave voltage were investigated. The thermal conductivity and breakdown performance were enhanced simultaneously in the composite with a loading concentration of 20 wt% BN at a micro/nano proportion of 95/5. The breakdown strength of 132 kV/mm at power frequency, the thermal conductivity of 0.81 W∙m−1∙K−1 and voltage endurance time of 166 s were obtained in the composites, which were approximately 28%, 286% and 349% higher than that of pristine epoxy resin. It is proposed that thermal conductive pathways are mainly constructed by micro-BN, leading to improved thermal conductivity and voltage endurance time. A model was introduced to illustrate the enhancement of the breakdown strength. The epoxy composites with high thermal conductivity and excellent breakdown performance could be feasible for insulating materials in high-frequency devices.

Review of Technology Used to Improve Heat and Mass Transfer Characteristics of Adsorption Refrigeration System

2016 ◽  
Vol 24 (02) ◽  
pp. 1630003 ◽  
Author(s):  
Anirban Sur ◽  
Randip K. Das
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Waste Heat ◽  
Transfer Characteristic ◽  
Low Grade ◽  
Transfer Performance ◽  
Refrigeration System ◽  
Adsorption Refrigeration ◽  
System A ◽  
Absorption Refrigeration System

Researchers proved that, heat powered adsorption refrigeration technology is very effective methods for reutilization of low-grade thermal energy such as industrial waste heat, solar energy, and exhaust gases from engines. But to make it commercially competitive with the well-known vapor compression and absorption refrigeration system, the processes require high rates of heat and mass transfer characteristic between adsorbate and adsorbent as well as externally supplied heat exchanging fluid. This paper reviews various techniques that have been developed and applied to enhance the heat transfer and mass transfer in adsorber beds, and also discuss their effects of the performance on adsorption system. A comprehensive literature review has been conducted and it was concluded that this technology, although attractive, has limitations regarding its heat and mass transfer performance that seem difficult to overcome. Therefore, more researches are required to improve heat and mass transfer performance and sustainability of basic adsorption cycles.

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