Types Of Insulation Materials Research Articles

Effects and mechanism of thermal insulation materials on thermal runaway propagation in large-format pouch lithium-ion batteries

The large heat transfer area of large-format lithium-ion batteries primarily facilitates conduction heat, which is responsible for triggering the thermal runaway of adjacent cells. Therefore, the primary consideration is to utilize thermal insulation materials between cells in order to slow down or prevent the process of thermal runaway propagation. In this study, three varieties of thermal insulation materials were employed to insulate individual cells within a module comprising three large-format pouch cells. These materials include pre-oxygenated wire aerogel (AG-ST-POF), polymer-coated pre-oxygenated wire aerogel (PC-AG-ST-POF), and silicone (SI). The study experimentally examined the thermal runaway propagation (TRP) behavior of the battery module under conditions without insulation materials and with various types of insulation materials. The impact of thermal insulation materials on the TRP among cells was analyzed. The study revealed that none of the three materials completely suppressed the propagation of thermal runaway, although they did impede its progress. The overall impact of AG-ST-POF surpassed that of SI and PC-AG-ST-POF. Furthermore, the mechanism by which thermal insulation materials influence TRP was explored. The results of the thermophysical properties testing suggest that evaluating the impact of materials on TRP solely through thermal conductivity is not a reliable approach. Alternatively, the maximum service temperature and thermal diffusion coefficient are critical parameters for the selection of thermal insulation materials. This study can provide a valuable reference for process engineering design and application in the context of lithium-ion batteries, with the aim of mitigating the risk of TRP.

Thermal Performance Evaluation of TIM Combined with Residential Windows in Different Climatic Regions in Iran

Windows play a significant role in the increase and loss of heat from the building envelope and determine the quantity, quality, and distribution of daylight. A strategy that involves incorporating transparent insulating materials into a double-glazed window offers the potential to provide combined improvements in thermal and daylighting performance. The thermal properties of transparent insulation materials in windows depend on various factors, such as the type of insulation material, thickness, geometry and insulation structure, location, and orientation of the window, among others. The aim of this research is to optimize three criteria: "thickness," "location of transparent insulation relative to window layers," and "direction of the wall with transparent insulation of the building window." The goal is to minimize thermal loads and reduce energy consumption in residential buildings. To achieve this, a real model was selected, and Design Builder software was used to measure the "heating load," "cooling load," and the sum of these two loads as the "total thermal load" for all three criteria in three cities of Iran with different climates: Tehran (moderate climate), Ahvaz (warm climate), and Tabriz (cold climate). The results of the research showed that for the city of Tehran, 3-inch insulation in the middle of the double-glazed window and the south front is optimal. For the city of Tabriz, 5-inch insulation on the inner surface of the window and the western front is optimal. And for the city of Ahvaz, 3-inch insulation on the outer surface of the window and the eastern front is optimal. It is worth noting that the annual heating load and total annual heating load for all three criteria have the highest values in Tabriz city. Therefore, it is recommended to use HSNPS insulation in transparent windows to reduce energy consumption in Tabriz (cold climate).

Internal Insulation – four systems in one historic residential building

Reducing the heat loss from European buildings must include thermal retrofitting of the historic buildings. In these cases, where buildings have facades worthy of preservation, internal insulation is the only solution although external insulation is better hygrothermal solution. Inspections in buildings with internal insulation have in multiple cases shown mold growth problems at the intersection between the original wall and the insulation. Thus, there is a need for real-life testing; i.e., raising the level of reality by using professional craftsmen to apply internal insulation to existing buildings inhabited by ordinary users. Building owners are more likely to accept these solutions when they have been tested in reality, and not only in the lab or with simulations, on efficiency, robustness, and moisture safety. In Denmark, the older, worthy-of-preservation, historic buildings are commonly built with solid masonry facades. Consequently, internal insulation might involve hygrothermal risks for the external walls. The present study describes a case study of a typical historic building built in 1837. In specific, the paper focuses on the top (5th) floor of the building, which is a residential area (a commune). On the 5th floor, four different types of insulation materials were installed in eight different rooms. The performance of the four insulation materials was determined by monitoring the temperature and relative humidity at the intersections between the insulation and the existing wall, as well as the indoor and outdoor climate. Results of the measurements of the available period showed that relative humidity is increasing for most of the sensors, with an exception of a few sensors that appear to have decreased values compared to the first month. Furthermore, the risk of mold growth was calculated with the VTT mold growth model based on performed measurements and indicated minimum to non-existent mold growth risk so far.

Optical, Dielectric, and Electrical Properties of Tungsten-Based Materials with the Formula Li(2−x)NaxWO4 (x = 0, 0.5, and 1.5)

In the present study, three chemical compounds, Li2WO4, Li0.5Na1.5WO4, and Li1.5Na0.5WO4, are produced using the solid–solid method. Unlike the compound Li0.5Na1.5WO4, which crystallizes in the orthorhombic system with the space group Pmmm, both compounds Li2WO4 and Li1.5Na0.5WO4 crystallize in the monoclinic system with the space group P2/m. A morphological analysis reveals that all three compounds have a compact structure with some porosity present. An EDX analysis confirms the chemical composition of the three samples. The optical measurements provide information on the optical gaps and Urbach energies of the materials under consideration. Their dielectric characteristics are investigated in a frequency range of 100–106 Hz and at temperatures ranging from 300 to 600 K. Moreover, this research enables us to determine the ferroelectric transition as well as the type of dielectric material. In this study, an investigation of electrical conductivity was conducted for well-defined temperature and frequency values; which provided us with information about the mechanism of conduction and charge carrier transport models.

Integrating Passive Energy Efficient Measures to the Building Envelope of a Multi-Apartment Building in Sweden: Analysis of Final Energy Savings and Cost Effectiveness

A major challenge in building energy renovation is to cost effectively achieve notable energy savings. This paper investigates cost-effective passive energy-efficiency measures for thermal envelope retrofit of a typical Swedish multi-apartment building from the 1970s. Here, the use of different types of insulation materials for the retrofits of roof, exterior walls, and ground floor are analyzed along with changing windows and doors with varying thermal transmittance values. The cost-effectiveness analysis is based on the net present value of the investment costs of the energy-efficiently measures and the achieved energy cost saving. Different economic scenarios and renovation cases are considered in techno-economic analyses to determine the cost-effective energy-efficiency retrofit measures. The results indicate that improved windows reduce energy demand for space heating by up to 23% and yield the highest final energy savings. However, additional mineral wool roof insulation is the most cost-effective measure under all economic scenarios. This measure gave the lowest ratio of cost effectiveness of about 0.1, which was obtained under the stable scenario. The final energy savings that can be achieved in a cost-effective manner vary between 28% and 61%, depending on the economic scenario and renovation case. This analysis emphasizes the influence of different renovation cases and economic parameters on the cost effectiveness of passive energy-efficiency measures.

Evaluating carbon payback time by optimizing insulation materials for different orientations: A cradle-to-gate life cycle assessment

The European Union aims to reduce greenhouse gases emissions by 80–95% compared to 1990 levels by 2050. Therefore the life cycle concept has gained widespread acceptance as a model for evaluating the environmental impact of goods and services. In this study, the optimal thickness of various insulation materials for external walls, roofs, and floors using a Mediterranean climate zone's hot summers and mild winters for a hypothetical residential building for four cardinal orientations was determined. The criteria for determining the optimum thickness represent a turning point in terms of cooling energy consumption (electricity). The optimum thickness of nine different types of insulation materials was defined using the aforementioned approach. These materials included aerogel, polyisocyanurate, polyurethane, extruded polystyrene, expanded polystyrene, phenolic foam, cellulose fiber (cellulose), mineral wool, and glass wool (GW). The purpose of this paper is to calculate the carbon payback time (CPBT) using the cradle-to-gate life cycle assessment method by considering the global warming potential (GWP) of insulation materials at their optimum thickness. The CPBT is calculated as the ratio of the total building's GWP to the GWP of savings from cooling and heating (electricity and natural gas). The results indicated that when evaluating the average CPBT for four cardinal orientations (FCO), aerogel has the longest CPBT of 2.34 years, and GW has the shortest CPBT of just 0.09 years. Aside from cost payback time, the findings of this study provide a new perspective on selecting appropriate thermal insulation.

Evaluation of suitability for passive retrofit of wooden roof considering the specificity of historic buildings

Energy consumption and carbon emissions of buildings must be reduced according to the 2030 carbon neutrality policy. Many aspects of historic buildings should be considered in their improvement because of their historical value. Thus far, a new strategy to lower energy consumption and improve energy performance is required. This study intends to derive an optimal energy efficiency package to reduce the energy consumption of historic buildings. To accurately analyze energy efficiency, the condition of a historic building was evaluated through on-site inspections. The roof retrofit technology scenario was used to reduce energy loss in exposed rafters. The exterior of the building cannot be damaged as it has historical value. This retrofit technology was analyzed to determine the energy-saving effect and economic feasibility of the package to derive the optimal solution. Retrofit techniques were individually analyzed and packaged for the effective preservation of historic buildings. This study compared a total of six scenarios by combining three types of insulation materials, based on the location of internal insulation, to protect the exposed rafters. Considering energy-saving, economic feasibility, and damage weight, the scenario where polyurethane insulation was applied between battens was the best. However, the insulation of the roof must consider fire resistance as per the Building Act of the Republic of Korea. Considering flame-retardancy, the scenario in which glass wool was applied between batten was the best for the target building.

Cost analysis of insulation materials used to increase energy performance in buildings with Net Present Value method

Today, producing solutions for the effective and efficient use of energy resources is among the priority areas in almost every sector. In terms of energy consumption, each solution developed in the building sector significantly reduces total energy consumption. In this study, different types of insulation materials used in walls and roofs were investigated in terms of cost-effectiveness to improve the energy performance of a building located in the 1st-degree day zone in Türkiye. Four commonly preferred insulation materials for walls and roofs were tested at specific thicknesses. The Design-Builder simulation program simulated scenarios for the specified thicknesses, and energy consumption values were determined. The initial investment costs of each alternative were calculated, and energy savings were determined. The initial investment costs and energy savings were evaluated according to the Net Present Value method, and each alternative's priority ranking was revealed. According to the results obtained, when the materials used in the study are compared, it is determined that the material with the highest net present value for the roof is glass wool, and the material with the highest net present value for the wall is stone wool.

The Effect of a Magnetic Field on Solid–Liquid Contact Electrification for Streaming Flow Energy Harvesting

In recent years, the triboelectric nanogenerator (TENG) has been recognized as a promising method for energy harvesting and self-powered devices. However, in order to improve the output efficiency of the TENG, it is necessary to change the types of dielectric materials, which requires advanced technology and a high cost to implement. To address this issue, we developed a parallel electrode magnetic-TENG (Mag-TENG) based on contact electrification of a liquid–solid interface under the effect of the magnetic field, which enhances the output performance of the TENG without having to develop the dielectric material. Our experimental results achieved a higher output of the TENG under the influence of a magnetic field when an increase of the magnetic field strength went from 0 to 360 mT, and the flow rate of unsteady seawater was variable from 390 to 690 mL/min. Specifically, compared to the without-magnetic field case, the output current increased by approximately 6.5 times and the output voltage by 2.7 times. These findings suggested that using a magnetic field to enhance the TENG’s efficiency has significant potential for energy harvesting from seawater and self-powered flow sensors.

Breakdown characteristics in dielectric-confined microcavity discharge of plate electrodes

Breakdown characteristics in dielectric-confined microcavity discharge of plate-to-plate electrodes under DC voltage are investigated in this paper. Experimental and particle-in-cell/Monte Carlo code simulated results show that the breakdown characteristic curve (the relation between the breakdown voltage V br and the product pd of gas pressure p and electrode gap d or the V br–pd curve) with a microcavity effect will deviate from the traditional Paschen curve, and seed electron adsorption by the dielectric wall is considered as the deviation mechanism. A smaller microcavity height will enhance this deviation. Based on the extent of deviation, there exist two critical microcavity heights, h cr1 and h cr2, for the breakdown characteristic curve. When the cavity height h is larger than h cr1, the V br–pd curve conforms to Paschen’s law due to the minor adsorbed electrons. When h < h cr1, the V br values in the V br–pd curve begin to increase overall, compared to those in the Paschen curve. Specifically, when h cr2 < h < h cr1, the V br–1/h curve exhibits a positive linear relation; when h < h cr2, V br increases sharply with 1/h as a nonlinear relationship due to the massive adsorbed electrons. Additionally, the type of dielectric material used to construct the microcavity also has a significant impact on V br, which is related to the different electron adsorbility η of various dielectric walls. For deeper insight, a ‘microcavity effect’ analysis model was developed to discuss the modified V br–pd curve and provide the explanation for the critical values of microcavity heights and the influence of the dielectric material. Significant adsorption of charged particles (especially the seed electrons) by the dielectric wall will reduce the electron multiplication and further improve the breakdown voltage when the cavity height h is comparable to the product ηλ e (the dielectric electron adsorbility and electron mean free path). On this basis, the modified breakdown criterion considering the microcavity effect was derived. The analytical expressions of the two critical height values h cr1 and h cr2 (h cr1 = 100ηλ e, h cr2 = 10ηλ e) and the linear relation of V br–1/h curve in h cr2 < h< h cr1 are presented quantitatively.

Dielectric Material Technologies for 2-D Semiconductor Transistor Scaling

The 2-D semiconductors have been recognized as promising channel materials for the ultimately scaled transistor technologies beyond silicon. An essential technology enabler for 2-D semiconductor electronics is the development of dielectric materials interfaced with 2-D semiconductors. In this review article, we overview different types of dielectric materials that are suitable for different application scenarios, including high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> gate dielectrics, low- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> spacers, and thermal management materials under the paradigm of 2-D semiconductor electronics. A material selection guideline for dielectric materials and the key process technology modules are discussed in detail. A special emphasis is made on how each of the dielectric technologies may enable the further scaling and practical applications of 2-D semiconductor transistors. The state-of-the-art device technologies are summarized, and the remaining challenges toward practical applications are discussed from the industrial perspective.

2x1 slotted MIMO antenna with slotted ground for high frequency wireless application

The antenna is the radiating device for transmission and reception of signals. Multi transmitting and receiving antennas are superior to single antenna. The MIMO system fulfils the higher capacity requirements as well as it gives high reliability. In this research work antenna is designed using MIMO techniques. The strip patch type is elementary MIMO antenna that can be used for small devices and other low-profile wireless applications operating at 11.6 GHz. The two-element slot antenna utilising silted/slotted ground was the design's main focus. The developed 2x1 MIMO antenna with slotted ground produces −43 dB return loss and the frequency region 11.1 to 12 GHz for strong isolation at 11.6 GHz frequency. It is shown how to use various antenna parameters including gain, ECC, and radiation pattern. The antenna's geometry is based on a rectangular MPA and a silty or slotted ground combination. While the shape of the intended MIMO antenna gives sufficient isolation that is more than 13.5 dB in the requested band, no isolation strategy was used in the design. The selection of material while designing of patch antenna is also very important. The results of various antenna parameters may vary accordingly material chosen. In this paper designed antenna considered FR4 material while optimizing the design. For the design of antennas, various types of dielectric materials are utilised. High dielectric material FR-4 is suitable in low profile antenna design for frequency less than 10 GHz. The various MIMO antenna design parameters are discussed in the research shows the good value for wireless application.

Direct measurement of electrocaloric effect based on multi-harmonic lock-in thermography

We report on a direct measurement method for electrocaloric effects, the heating/cooling upon application/removal of an electric field in dielectric materials, based on a lock-in thermography technique. By use of sinusoidal excitation and multi-harmonic detection, the actual temperature change can be measured by a single measurement in the frequency domain even when the electrocaloric effect shows a nonlinear response to the excitation field. We demonstrated the method by measuring the temperature dependence of the electric-field-induced temperature change in two Sr-doped BaTiO3 systems with different ferroelectric-paraelectric phase transition temperatures, where we introduce the procedure for extracting the pure electrocaloric contribution free from heat losses and Joule heating due to leakage currents. This method can be used irrespective of the type of dielectric material and enables simultaneous estimation of the polarization change and power dissipation during the application of an electric field, making it a convenient imaging measurement method for the electrocaloric effect.

On the pyrolysis characteristic parameters of four flame-retardant classes of PVC sheathless cable insulation materials

Flame retardant cables are widely used today, while the comparison of thermal degradation behavior between PVC cable insulation materials with different flame-retardant levels has not been extensively studied so far. The thermal degradation behaviors of four flame-retardant and one non-flame-retardant PVC cable insulation materials were studied using thermogravimetric (TG) analysis and a combination of TG-Fourier transform infrared analysis. Generally, TG data differ at the first peaks but are similar at the second peaks for various types of insulation materials. This is because the reaction mechanisms of the first pyrolysis stage vary with the change of flame-retardant level, while the second pyrolysis stage is similar regardless of the flame-retardant level. Besides, the flame-retardant performance level cannot solely be evaluated based on the activation energy of these insulation materials. The coupled Fourier transform infrared spectroscopy (FTIR) shows that during the pyrolysis of flame-retardant PVC insulation materials (ZA-BV, ZB-BV, ZC-BV, and ZR-BV), the amount of the seven major released components, arranged in order from most to least, is C-H bending > H2O > C-H stretching > CO2 > C-H aliphatic bending > CH2 deformation > C-Cl stretching. While for the non-flame-retardant PVC insulation material (BV), the series is CO2 > C-H bending > C-H stretching> H2O > C-H aliphatic bending > CH2 deformation > C-Cl stretching. The reported results provide a basis to evaluate the thermal degradation behavior of typical PVC cable insulation materials at present and can also provide essential data for the numerical simulation of an electrical fire.

Recent Advances in Ferroelectric-Enhanced Low-Dimensional Optoelectronic Devices.

Ferroelectric (FE) materials, including BiFeO3 , P(VDF-TrFE), and CuInP2 S6 , are a type of dielectric material with a unique, spontaneous electric polarization that can be reversed by applying an external electric field. The combination of FE and low-dimensional materials produces synergies, sparking significant research interest in solar cells, photodetectors (PDs), nonvolatile memory, and so on. The fundamental aspects of FE materials, including the origin of FE polarization, extrinsic FE materials, and FE polarization quantification are first discussed. Next, the state-of-the-art of FE-based optoelectronic devices is focused. How FE materials affect the energy band of channel materials and how device structures influence PD performance are also summarized. Finally, the future directions of this rapidly growing field are discussed.

A simple and efficient method for the preparation of SiO2/PI/AF aerogel composite fabrics and their thermal insulation performance

As a new type of insulation material, aerogels are characterized by a high specific surface area, high porosity, low density and low thermal conductivity, which makes them a new alternative to the use of traditional insulation materials. In this paper, a simple method for preparing aerogel insulation materials is proposed. Specifically, SiO 2 /PI/AF (aramid fiber) aerogel composite fabrics were successfully obtained by combining coating technology and finishing processes to use tetraethoxysilane (TEOS) as the precursor, polyimide (PI) powder as the reinforcing agent, and nonwoven AF as the substrate. These composite fabrics were characterized using field-emission scanning electron microscopy (FESEM), tensile testing with an Instron 5967, Fourier transform infrared spectroscopy (FT-IR) and thermal infrared imaging. The results show that the composite fabrics exhibited excellent performance and could effectively block heat transfer. Moreover, the thermal conductivity of the front decreased from 4.08 to 3.91 (W/cm·°C) × 10 -4 . This work provides a novel method for the structural design of thermal insulation clothing.

Electromagnetic particle simulation of secondary electron multipactor characteristics in inner surface of 110 GHz microwave output window

The secondary electron multipactor on the inner surface of the output window is one of the main factors limiting the power capacity of high power microwave. Therefore, it is of great significance to carry out relevant research. In this work, the process of secondary electron multipactor and the resulting loss of power are numerically simulated by using the electromagnetic particle model with one-dimensional spatial distribution and three-dimensional velocity distribution at the microwave frequency of 110 GHz. The influences of microwave electric field at the surface and dielectric material type on the power loss are studied. The simulation results show that the electron number density is higher than the critical cut-off number density after the secondary electron multipactor has reached the steady state, but the microwave electric field does not show obvious change. This is because the electrons in a very high electrostatic field are mainly concentrated in the domain of several micrometers near the dielectric surface, which is far less than the corresponding skin depth. The electron number density in the multipactor steady state increases with the microwave electric field increasing, but the ratio of the power loss to the microwave power at the surface increases slowly. After the multipactor reaches the steady state, the number density of electrons near the sapphire surface is the highest, followed by the number density near the crystal quartz surface, and the number density near the fused quartz surface is the lowest, so the corresponding power loss decreases successively. In order to verify the accuracy of the model, the simulated value of the multipactor threshold is compared with the experimental data, and the difference between them is discussed.

벽체 점형 열교 발생 부위의 단열재 두께에 따른 전열량 평가

In this study, in order to derive the performance evaluation methodology for thermal breaker required in the field, the effect on the thermal performance of the wall sample was investigated by using an analytical method for an thermal breaking anchor to prevent point-type thermal bridges.BRAccording to the thickness of the insulation material, the type of insulation material, and whether the anchor is insulated, the amount of heat transfer and the point-type thermal transmittance were calculated through heat transfer simulation and the difference was confirmed. For both grades “A” and “B” insulators, the amount of heat transferred was linearly changed according to the change in the thickness of the insulation. When a stainless steel thermal breaking anchor was applied, the point-type thermal transmittance was reduced by half compared to the case where a conventional steel anchor was installed.

Sensitivity analysis of design variables in life-cycle environmental impacts of buildings

Buildings are responsible for a large portion of global energy consumption and carbon emissions. Improvements in building design contribute to reducing environmental impacts of buildings. In this context, a crucial issue is to understand which design variables should be considered while which variables could be negligible. The objective of this study is to develop a framework for assessing the influence of various design variables throughout the design process in the environmental impacts of a building over its life cycle. This methodological framework combined building information modelling and life cycle assessment tools and a global sensitivity analysis using the Morris elementary effects method. A residential building was applied to demonstrate the developed framework. The influence of six design variables in early design stages (including, floor area, aspect ratio, floor height, orientation, window-to-wall ratio and number of floors), nine variables in detailed design stages (including, structure type of external and internal walls, type of insulation material for external and internal walls, insulation material for floors, waterproofing and insulation material for roof, type of window frame, and glazing type), and four variables in construction design stages (including, type of finishing for external walls, internal walls and floors, and roof tiles) are examined. Three environmental impact criteria (including, embodied, operational, and life-cycle environmental impacts) of a building are considered. The results identified the most influential variables throughout the design process, highlighting aspect ratio in early design stage, the structure and insulation materials for walls in detailed design stages, and the roof title in construction design stages. The outcomes of this research can assist in understanding the importance of design variables in each design stage throughout the design process of a building.

Thermal and Structural Behaviour of Sandwiched Reinforced Cement Concrete Wall Panels

The energy efficiency of a building predominantly depends on the temperature gradient across the wall. The use of Sandwiched Concrete Panels (SCP) to achieve energy efficiency inside buildings is gaining importance all over the world. This study focuses on comparing the temperature gradient across sandwich concrete wall panels made of two different insulation materials viz. Extruded Polystyrene (XPS) and Expanded Polystyrene (EPS) with two different sizes of steel (8 mm and 10 mm dia.) used as reinforcement and shear connectors. Two different concrete grades viz. M25 and M40 were studied. The thickness of concrete wythes on both sides of the SCP and the inner insulation material (XPS and EPS) were varied to understand their effect on thermal insulation. The external surface of the samples was subjected to an elevated temperature of 75 °C for 24 hours continuously and the temperature measurements across the SCP were recorded. This was done by simulating the real-time temperature effect using an indigenously developed oven, designed and fabricated to fit the SCP sample size which comprises an electronic thermostat and temperature sensor unit arrangement. Additionally, a one-dimensional finite element analysis was carried out to predict the theoretical interface temperature and inner surface temperature of the SCP samples with necessary assumptions. Both the experimental and FEA temperature values corroborated well. Further, all the samples were subjected to compression and flexural testing to evaluate their structural properties. Influence of type of insulation material used viz. XPS and EPS, size of steel reinforcement used viz. 8 mm and 10 mm dia. were found to be not that significant in terms of both thermal and structural behavior.