Structure Designing and Property Investigation of Flexible Multilayer Thermal Insulation Materials

2011 ◽  
Vol 15 (3) ◽  
pp. 21-27 ◽  
Author(s):  
Jinjing Chen ◽  
Weidong Yu
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Thermal Performance ◽  
Thermal Contact ◽  
Radiation Heat Transfer ◽  
Insulation Material ◽  
Insulation Materials ◽  
Compressive Loads ◽  
Multilayer Insulation ◽  
Gas Conduction

In this paper, a method of designing flexible multilayer insulation is analyzed and discussed, with focus on reducing the three basic modes of heat transfer (thermal radiation, solid spacer and residual gas conduction). The foundation for designing the new flexible thermal insulation material is provided. The insulation performances of different types (by choosing different reflection shields and spacers) of flexible multilayer insulation materials are obtained through measurements using a KES-F7 Thermal Labo II apparatus. The thermal performance of flexible multilayer insulation materials at different layers are also presented, and the best is about 20∼25 layers. To improve the thermal performance of multilayer insulation materials, treble spacers between double aluminized shields are applied. Aluminized shields with air, meshes, wool fibres, etc. are compared with each other. The aluminized shields with meshes fixed with down can reduce thermal contact, which reduces the radiation heat transfer more fully and can be more steady than the other spacers in the project applications. With the same layers and spacers, the thermal conductivity of crinkled aluminized shields is lower than that of the smooth aluminized shields. The effects of compressive loads on layer density and thermal performance are also investigated.

Comparative Analysis of the Use of Thermal Insulation Materials Depending on Climatic Conditions and Comfort Microclimate Supply Systems

2022 ◽  
Vol 906 ◽  
pp. 99-106
Author(s):  
Siranush Egnatosyan ◽  
David Hakobyan ◽  
Spartak Sargsyan
Keyword(s):  
Energy Efficiency ◽  
Comparative Analysis ◽  
Thermal Insulation ◽  
Thermal Performance ◽  
Climatic Conditions ◽  
Insulation Material ◽  
Insulation Layer ◽  
Transfer Resistance ◽  
Insulation Materials ◽  
Wide Range

The use of thermal insulation materials to reduce the heating and cooling demand of the building in order to provide energy efficiency is the main solution. But there is a wide range of these products on the market and, therefore, the choice and application of these materials is a rather difficult task, since many factors must be taken into account, such as environmental safety, cost, durability, climatic conditions, application technology, etc. Basically, comfort microclimate systems are designed based on normative standards, where the thickness of the thermal insulation material is selected depending on the required heat transfer resistance. These values are calculated taking into account climate conditions, that is the duration of the heating period, as well as taking into account sanitary and hygienic requirements. This article discusses the thermal performance of building materials, and also provides a comparative analysis of the use of thermal insulation materials depending on climatic factors and on the system providing comfort microclimate. Based on the calculations by mathematical modeling and optimization, it is advisable to choose the thickness of the thermal insulation, taking into account the capital and operating costs of the comfort microclimate systems. Comparing the optimization data with the normative one, the energy efficiency of the building increases by 50-70% when applying the optimal thickness of the thermal insulation layer, and when the thermal insulation layer is increased, the thermal performance of the enclosing structures has improved by 30%, which contributes to energy saving.

Radiation Effects in Heat Transfer Mechanisms by Dispersive Materials: Numerical Analysis in Diffusive Enclosure Model of Thermal Insulation

2018 ◽  
Vol 26 (04) ◽  
pp. 1850036 ◽  
Author(s):  
Muhd Azi Bin Che Seliman ◽  
Yoshio Hirasawa
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Thermal Insulation ◽  
Radiation Effects ◽  
View Factor ◽  
Insulation Material ◽  
Insulation System ◽  
Multilayer Insulation ◽  
Insulation Performance ◽  
Transfer Mechanisms

The current development of global warming and CO2 emission problems cannot be overlooked. Thus, global scale measures of efforts are becoming crucial. Thermal properties of insulation materials need to be considered as high performance thermal insulation systems are crucial for efficient energy saving. The most important parameter as indicator of a thermal insulation material is the effective thermal conductivity, but elements that affect the thermal insulation performance are rather complicated. Generally, conduction and radiation heat transfer are needed to be separately considered in precisely evaluating the thermal insulation performance as they coexist in the heat transfer process inside a multilayer insulation system. In this paper, numerical analysis of a complete diffusive enclosure model as a thermal insulation is observed to investigate the radiation effects by its dispersive heat transfer mechanisms. View factor of each relatively large dispersed material is derived in the enclosure model, where it is applicable to various shapes and any particular arrangements of dispersed materials. As this paper is the first part of a three-part working research paper, numerical analysis in this paper is carried out by assuming that the medium within the space inside the insulation system is taken to be nonparticipating, therefore conduction and convection effects during the heat exchange are negligible. This paper will be continued with application of the numerical analysis in observing radiation heating effects by wall-ceiling integration towards indoor environment and radiation–conduction heat transfer mechanisms in one-dimensional multilayer insulation system.

Development of Load-Bearing Thermal Insulation Recycled Concrete Block and Research on its Thermal Performance

2014 ◽  
Vol 1004-1005 ◽  
pp. 1503-1507 ◽  
Author(s):  
Xi Xi He ◽  
Xing Ming Liang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Insulation ◽  
Thermal Performance ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Masonry Walls ◽  
Insulation Material ◽  
Load Bearing

A new kind of 310mm thick load-bearing thermal insulation block utilizing construction waste as coarse aggregate was developed and produced. Internal thermal bridge is reduced by special design of holes pattern and cut off by mal-posed thermal insulation layer arrangement. By testing heat transfer coefficient of four kinds of masonry walls, different aggregate type, masonry unit type and insulation material which affect thermal performance of masonry were studied. Results show that heat transfer coefficient of walls with recycled aggregates is lower than that with natural aggregates under the same condition. By filling thermal insulation material in block holes, heat transfer coefficient is dramatically lowered. Among four types of masonry walls, heat transfer coefficient of 310mm thick load-bearing block wall with recycled aggregate is the lowest, and its thermal insulation performance is the best.

Bio-composite Thermal Insulation Materials Based on Banana Leaves Fibers and Polystyrene: Physical and Thermal Performance

2021 ◽  
pp. 1-16
Author(s):  
Gehad R. Mohamed ◽  
Rehab K. Mahmoud ◽  
Irene S. Fahim ◽  
Mohamed Shaban ◽  
H. M. Abd El-Salam ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Thermal Performance ◽  
Insulation Materials ◽  
Banana Leaves

Preparation and Properties of Phase Change Thermal Insulation Materials

2018 ◽  
Vol 281 ◽  
pp. 131-136
Author(s):  
Shi Chao Zhang ◽  
Wei Wu ◽  
Yu Feng Chen ◽  
Liu Shi Tao ◽  
Kai Fang ◽  
...  
Keyword(s):  
Phase Change ◽  
Thermal Insulation ◽  
Calcium Silicate ◽  
Phase Change Materials ◽  
Performance Test ◽  
Thermal Protection ◽  
Insulation Material ◽  
Insulation Materials ◽  
Short Time ◽  
Change Material

With the increase of the speed of vehicle, the thermal protection system of its powerplant requires higher insulation materials. Phase change materials can absorb large amounts of heat in short time. So the introduction of phase change materials in thermal insulation materials can achieve efficient insulation in a limited space for a short time. In this paper, a new phase change thermal insulation material was prepared by pressure molding with microporous calcium silicate as matrix and Li2CO3 as phase change material. The morphology stability, exudation and heat insulation of the materials were tested. The results show that the porous structure of microporous calcium silicate has a good encapsulation when the phase transition of Li2CO3 is changed into liquid. And the material has no leakage during use. The thermal performance test also shows that the insulation performance of the material has obvious advantages in the short term application.

Thermal Contact Electronic Packaging in Solar Pointing Space Environment

1991 ◽  
Vol 113 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Kurt O. Lund ◽  
Anthony M. Colangelo ◽  
Gregory S. McKim
Keyword(s):  
Heat Transfer ◽  
Space Shuttle ◽  
Thermal Contact ◽  
Thermal Modeling ◽  
Radiation Heat Transfer ◽  
Thermal Design ◽  
Space Environment ◽  
Radiation Heat ◽  
Flow Paths ◽  
Flux Intensity

A thermal design for a solar pointing Space Shuttle mission is presented. The apparatus, which will measure solar flux intensity variations, contains sensors and data acquisition electronics which must be maintained within certain temperature constraints. The thermal design, which utilizes parallel heat flow paths and conduction fins to reject dissipated heat, is shown by finite difference thermal modeling to maintain component temperatures within these constraints. In the thermal modeling, arithmetic nodes are used to represent surface radiosity for radiation heat transfer. Also, the concept of mean fin conduction length and effective fin capacitance are introduced as means of simplifying the model representation of the conduction fins. An experiment was conducted to evaluate the chip/fin contact conductance.

scholarly journals Thermal Performance of Oil Palm Fibre and Paper Pulp as the Insulation Materials

2014 ◽  
Vol 5 (2) ◽  
pp. 22-28
Author(s):  
S.H. Ibrahim ◽  
Sia W.K. ◽  
A. Baharun ◽  
M.N.M. Nawi ◽  
R. Affandi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Oil Palm ◽  
Total Density ◽  
Insulation Material ◽  
Paper Pulp ◽  
Particle Board ◽  
Environment Impact ◽  
Palm Fiber ◽  
Insulation Materials

 Energy consumption for residential use in Malaysia is keep increasing yearly in order to maintain the internal thermal comfort of the building. Roof insulation material plays a vital role in improving the thermal comforts of the building while reduce the cooling load of the building. Oil palm industry in Malaysia had grown aggressively over the past few decades. Tons of oil palm waste had produced during the process such as empty fruit bunch fiber. Another waste material that available and easy to obtain is paper. Paper is a valuable material that can be recycled. Waste paper comes from different sources such as newspaper, office and printing papers. This study will take advantage of the available resources which could contribute to reduce the environment impact. The aim of this study is to investigate the thermal performance of roof insulation materials using mixture of oil palm fiber and paper pulp with different ratio and thickness. This study found that the thermal performance of the paper pulp is slightly better compare to the oil palm fiber. Thermal conductivity of the particle board reduces around 4.1% by adding the 10% of paper pulp into the total density of the particle board. By adding 75% of paper pulp, the thermal conductivity of the particle board could be reduced to 24.6% compare to the oil palm fiber board under the similar condition. Therefore, from this study, it could be concluded that paper pulp has high potential to be used as a building insulation material.

scholarly journals Continuous, Strong, Porous Silk Firoin-Based Aerogel Fibers toward Textile Thermal Insulation

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1899 ◽  
Author(s):  
Haiwei Yang ◽  
Zongqian Wang ◽  
Zhi Liu ◽  
Huan Cheng ◽  
Changlong Li
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Hollow Fiber ◽  
High Performance ◽  
Large Scale ◽  
Low Density ◽  
Potential Candidate ◽  
Scale Production ◽  
Insulation Material ◽  
High Porosity

Aerogel fiber, with the characteristics of ultra-low density, ultra-high porosity, and high specific surface area, is the most potential candidate for manufacturing wearable thermal insulation material. However, aerogel fibers generally show weak mechanical properties and complex preparation processes. Herein, through firstly preparing a cellulose acetate/polyacrylic acid (CA/PAA) hollow fiber using coaxial wet-spinning followed by injecting the silk fibroin (SF) solution into the hollow fiber, the CA/PAA-wrapped SF aerogel fibers toward textile thermal insulation were successfully constructed after freeze-drying. The sheath (CA/PAA hollow fiber) possesses a multiscale porous structure, including micropores (11.37 ± 4.01 μm), sub-micron pores (217.47 ± 46.16 nm), as well as nanopores on the inner (44.00 ± 21.65 nm) and outer (36.43 ± 17.55 nm) surfaces, which is crucial to the formation of a SF aerogel core. Furthermore, the porous CA/PAA-wrapped SF aerogel fibers have many advantages, such as low density (0.21 g/cm3), high porosity (86%), high strength at break (2.6 ± 0.4 MPa), as well as potential continuous and large-scale production. The delicate structure of multiscale porous sheath and ultra-low-density SF aerogel core synergistically inhibit air circulation and limit convective heat transfer. Meanwhile, the high porosity of aerogel fibers weakens heat transfer and the SF aerogel cellular walls prevent infrared radiation. The results show that the mat composed of these aerogel fibers exhibits excellent thermal insulating properties with a wide working temperature from −20 to 100 °C. Therefore, this SF-based aerogel fiber can be considered as a practical option for high performance thermal insulation.

scholarly journals Use of 1D mechanical and thermal models to predetermine the heat transferable by a thermal interface material layer in space applications

2020 ◽  
Vol 234 (17) ◽  
pp. 3459-3473
Author(s):  
Simon Vandevelde ◽  
Alain Daidié ◽  
Marc Sartor
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Thermal Contact ◽  
Interface Layer ◽  
Thermal Interface Material ◽  
Space Applications ◽  
Thermal Interface ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Assistance Tool

This paper proposes the use of 1D basic models to build a design assistance tool capable of evaluating the heat transfer between a third-level electronic packaging and its support, considering a conventional configuration where a thermal interface material is placed between these two parts. Using this kind of tool early in the design process may facilitate choices concerning geometry and material. The packaging is modelled by a stepped beam (the equipment) and the interface layer by a nonlinear elastic foundation (the thermal interface material). Considering that the electronic equipment bends under the effect of the forces exerted by the fasteners, the tool makes it possible to determine the contact zone remaining operative after deformation, and the pressure distribution at the interface. Mechanical results are then used to calculate the steady-state heat transfer between the equipment and its support, taking into account the diffusion within the equipment and the thermal interface material, and also the thermal contact resistances, the latter being dependent on the contact pressure. A detailed case study is used to illustrate the utility of the approach. The 1D models are exploited to illustrate the interest of the design assistance tool. The influence of different parameters on the thermal performance is studied and a new innovative proposal is analyzed, which could lead to a significant increase in thermal performance.

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