Effect of Operating Temperatures on Thermal Conductivity of Polystyrene Insulation Material: Impact on Envelope-Induced Cooling Load

2014 ◽  
Vol 564 ◽  
pp. 315-320 ◽  
Author(s):  
Maatouk Khoukhi ◽  
Mahmoud Tahat
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Energy Performance ◽  
Building Envelope ◽  
Insulation Material ◽  
Cooling Load ◽  
Thermal Insulation Material ◽  
Insulation Materials ◽  
Energy Performance Of Buildings ◽  
The Impact

The impact of the thermal conductivity (k-value) change of polystyrene insulation material in building envelope due to changes in temperature on the thermal and energy performance of a typical residential building under hot climate is investigated. Indeed, the thermal and energy performance of buildings depends on the thermal characteristics of the building envelope, and particularly on the thermal resistance of the insulation material used. The thermal insulation material which is determined by its thermal conductivity, which describes the ability of heat to flow cross the material in presence of a gradient of temperature, is the main key to assess the performance of the thermal insulation material. When performing the energy analysis or calculating the cooling load for buildings, we use published values of thermal conductivity of insulation materials, which are normally evaluated at 24°C according to the ASTM standards. In reality, thermal insulation in building is exposed to significant and continuous temperature variations, due essentially to the change of outdoor air temperature and solar radiation. Many types of insulation materials are produced and used in Oman, but not enough information is available to evaluate their performance under the prevailing climatic condition. The main objective of this study is to investigate the relationship between the temperature and thermal conductivity of various densities of polystyrene, which is widely used as building insulation material in Oman. Moreover, the impact of thermal conductivity variation with temperature on the envelope-induced cooling load for a simple building model is discussed. This work will serve as a platform to investigate the effect of the operating temperature on thermal conductivity of other building material insulations, and leads to more accurate assessment of the thermal and energy performance of buildings in Oman.

PROCESSED STRAW AS EFFECTIVE THERMAL INSULATION FOR BUILDING ENVELOPE CONSTRUCTIONS

2012 ◽  
Vol 4 (3) ◽  
pp. 96-103 ◽  
Author(s):  
Jolanta Vėjelienė
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Building Envelope ◽  
Gas Content ◽  
Barley Straw ◽  
Conductivity Measurements ◽  
Insulation Materials ◽  
Thermal Transfer ◽  
The Impact

The efficiency of thermal insulation materials obtained from renewable resources depends on the possibilities of reducing thermal transfer via solid and gaseous conduction, thermal radiation and, in some cases, convection. The heat transfer mechanism for thermal insulation materials mostly depends on the structure and density of the material used. Efficient thermal insulation materials consist of a gaseous phase and a solid skeleton. Gas content in such materials can take more than 99% of material by volume. In this case, thermal transfer via solid conductivity is negligible. The current work analyses the possibilities of reducing heat transfer in the straw of a varying structure. For conducting experiments, barley straw was used. To evaluate the impact of straw stalk orientation in a specimen on thermal conductivity, strongly horizontally and vertically oriented specimens of straw stalks were prepared. To reduce heat transfer via gaseous conduction and convection in large cavities in straw stalks and between stalks, barley straw were chopped and defibered. In order to decrease heat transfer via radiation after thermal conductivity measurements, mechanically processed straw were coated with infrared absorbers. Due to thermal conductivity measurements of chopped and defibered straw, an optimal amount of infrared absorbers were determined.

The Research on Seismic Performance of the Insulation Material on the External Wall of a Building

2013 ◽  
Vol 395-396 ◽  
pp. 469-472
Author(s):  
Zu Xu Zou ◽  
Song Ping Mao
Keyword(s):  
Energy Efficiency ◽  
Seismic Performance ◽  
Thermal Insulation ◽  
Building Energy ◽  
Building Envelope ◽  
Building Energy Efficiency ◽  
Insulation Material ◽  
Thermal Insulation Material ◽  
External Wall ◽  
Insulation Materials

It is a problem on building energy efficiency of how to improve the heat insulation performance of building envelope, to make the building outer wall has good heat preservation effect, and to keep the necessary seismic performance. Exterior wall thermal insulation engineering, which is a key part on building energy conservation engineering construction quality acceptance and on building energy efficiency design, is an important part in building energy efficiency projects. Therefore, it is necessary to study the seismic performance based on the fact that the building is building energy efficiency. By the research on exterior insulation materials, the analysis on the performance of external thermal insulation materials currently used, and the research on the factors affecting the seismic performance of external thermal insulation material, It provides a guidance on evaluating the external wall thermal insulation material performance and quality, ensuring the quality of external thermal insulation material, and it is expected to achieve the effect of building energy efficiency.

scholarly journals Study on Water Absorption and Thermal Conductivity of Tunnel Insulation Materials in a Cold Region under Freeze-Thaw Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Youyun Li ◽  
Huan Wang ◽  
Li Yang ◽  
Shiqiang Su
Keyword(s):  
Thermal Conductivity ◽  
Water Absorption ◽  
Thermal Insulation ◽  
Insulation Material ◽  
Cold Region ◽  
Thermal Insulation Material ◽  
Freeze Thaw ◽  
Insulation Materials ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

A thermal insulation layer is often deposited on the lining structure of tunnels in cold regions to solve the problem of frost damage. When the air humidity in the tunnel becomes excessively high, the thermal insulation material tends to absorb water, leading to significant changes in thermal conductivity. Moreover, the temperature differences between the day and night cycles have been observed to be significant in portal sections of cold region tunnels, which facilitate the freeze-thaw cycle and, consequently, deteriorate the performance of the thermal insulation material. Therefore, the purpose of this study is to determine the changes in the water absorption, thermal conductivity, and microstructure of polyurethane and polyphenolic insulation boards under freeze-thaw conditions. To this end, an indoor water absorption test was conducted for both the insulation boards till they were saturated, which then underwent a freeze-thaw cycle test. It was determined that the water absorption and thermal conductivities of these boards increased linearly with the number of freeze-thaw cycles. In order to explore the change of thermal conductivity of thermal insulation materials after moisture absorption, this study provides insights into the relationship between the thermal conductivities and water contents of tunnel insulation materials under normal and freezing temperatures.

scholarly journals Preparation and properties of silicate inorganic exterior wall insulation based on thermal energy storage

2020 ◽  
Vol 24 (5 Part B) ◽  
pp. 3109-3118
Author(s):  
Zifan Zhou ◽  
Guofu Tu ◽  
Feng Xu ◽  
Zhaofeng Song ◽  
Na Li
Keyword(s):  
Thermal Conductivity ◽  
Fly Ash ◽  
Thermal Insulation ◽  
Thermal Energy ◽  
Testing Machine ◽  
Insulation Material ◽  
Exterior Wall ◽  
Thermal Insulation Material ◽  
Insulation Materials ◽  
Insulation Performance

The key to building energy conservation is how to make the exterior wall have good thermal insulation performance, reduce the heat loss of the building?s peripheral structure, develop new exterior wall insulation materials, and effectively achieve energy saving. In this paper, a new type of composite silicate insulation material was prepared by using fly ash, sepiolite fiber, basalt fiber, and cement as raw materials. According to the analysis of the action of each component of the composite silicate thermal insulation material, the composite silicate thermal insulation material is prepared by selecting different raw material ratios, and the fly ash and sepiolite fibers are analyzed by a thermal conductivity measuring instrument and a hydraulic universal testing machine. The influence of water-cement ratio on the thermal conductivity, tensile strength, and compressive strength of composite silicate insulation materials. Through research, it is found that this composite silicate exterior wall insulation material utilizes some abandoned resources to help the building exterior wall to store thermal energy. The preparation process is simple, the insulation performance is good, the mechanical strength is high, and there is great promotion value and application prospect.

A Novel Building Thermal Insulation Material: Expanded Perlite Modified by Aerogel

2011 ◽  
Vol 250-253 ◽  
pp. 507-512
Author(s):  
Zi Sheng Wang ◽  
Hao Chi Tu ◽  
Jin Xiu Gao ◽  
Guo Dong Qian ◽  
Xian Ping Fan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Property ◽  
Thermal Insulation ◽  
Production Cost ◽  
Building Materials ◽  
Low Cost ◽  
Insulation Material ◽  
Expanded Perlite ◽  
Thermal Insulation Material ◽  
Supercritical Fluid Drying

Aerogel is regarded as one kind of super thermal insulation materials which could be large-scalely used as building materials. However, the aerogel’s production cost and poor mechanical property limit the its applications. In this paper, we put forward a new low cost way to produce a novel building thermal insulation material: synthesized the aerogel within the expanded perlite’s pores, and using sodium silicate as precursor without adopting supercritical fluid drying and surface modification. The thermal conductivity of expanded perlite was successfully decreased after modified by aerogel.

scholarly journals Retrofitting a Building’s Envelope: Sustainability Performance of ETICS with ICB or EPS

2019 ◽  
Vol 9 (7) ◽  
pp. 1285 ◽  
Author(s):  
José D. Silvestre ◽  
André M. P. Castelo ◽  
José J. B. C. Silva ◽  
Jorge M. C. L. de Brito ◽  
Manuel D. Pinheiro
Keyword(s):  
Life Cycle ◽  
Energy Consumption ◽  
Thermal Insulation ◽  
Carbon Footprint ◽  
Energy Performance ◽  
Building Envelope ◽  
Expanded Polystyrene ◽  
Insulation Material ◽  
Economic Dimension ◽  
Heating And Cooling

This paper analyses the environmental, energy, and economic performances of the External Thermal Insulation Composite System (ETICS) using agglomerated insulation cork board (ICB) or expanded polystyrene (EPS) as insulation material applied in the energetic renovation of the building envelope during a 50-year study period. A comparison between ETICS using ICB and EPS, for the same time horizon, is also presented. The environmental balance is based on “Cradle to Cradle” (C2C) Life Cycle Assessment (LCA), focusing on the carbon footprint and consumption of nonrenewable primary energy (PE-NRe). The characteristics of these products in terms of thermal insulation, the increased energy performance provided by their installation for retrofit of the buildings’ envelope, and the resulting energy savings are considered in the energy balance. The estimation of the C2C carbon and PE-NRe saved is considered in the final balance between the energy and environmental performances. ETICS with ICB is environmentally advantageous both in terms of carbon footprint and of PE-NRe. In fact, the production stage of ICB is less polluting, while EPS requires lower energy consumption to fulfil the heating and cooling needs of a flat, due to its lower U-Value, and its lower acquisition cost results in a lower C2C cost. Comparing both ETICS’ alternatives with reference solutions, it was found that the latter only perform better in the economic dimension, and only for an energy consumption to fulfil less than 25% of the heating and cooling needs. This paper represents an advance to the current state-of-the-art by including all the life-cycle stages and dimensions of the LCA in the analysis of solutions for energy renovation of building envelopes.

The Impact of Various Factors on the Energy Performance of Selected Types of Family Houses

2019 ◽  
Vol 887 ◽  
pp. 109-116
Author(s):  
Dušan Katunský ◽  
Marek Farárik
Keyword(s):  
Thermal Insulation ◽  
Energy Performance ◽  
Energy Performance Of Buildings ◽  
Theoretical Assumptions ◽  
Comparison And Analysis ◽  
The Impact

The tightening of requirements for energy performance of buildings (EPB) during the period of 2013 to 2021 gradually results in designing buildings with requirements four times lower than we were accustomed to design and construct for many years (U-values, demand of heat for heating). It is necessary to pay increased attention to this topic due to the aforementioned reasons and gradually preparing the laic public, but mainly the professional public for designing, assessment and construction in accordance with the development of EPB requirements. The objective of this paper is to point out the actual requirements for the construction of single storey family houses. Theoretical assumptions, legislative and normative environment are stated for assessment of their thermal insulation properties. The paper contains comparison and analysis of calculated EPB values of the selected representatives of single-storey family houses representing a large portion of their construction in the practice at the present time.

scholarly journals Thermal Insulation and Mechanical Properties of Polylactic Acid (PLA) at Different Processing Conditions

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2091
Author(s):  
Mohamed Saeed Barkhad ◽  
Basim Abu-Jdayil ◽  
Abdel Hamid I. Mourad ◽  
Muhammad Z. Iqbal
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polylactic Acid ◽  
Thermal Insulation ◽  
Annealing Time ◽  
Insulation Material ◽  
Thermal Insulation Material

This work aims to provide an extensive evaluation on the use of polylactic acid (PLA) as a green, biodegradable thermal insulation material. The PLA was processed by melt extrusion followed by compression molding and then subjected to different annealing conditions. Afterwards, the thermal insulation properties and structural capacity of the PLA were characterized. Increasing the annealing time of PLA in the range of 0–24 h led to a considerable increase in the degree of crystallization, which had a direct impact on the thermal conductivity, density, and glass transition temperature. The thermal conductivity of PLA increased from 0.0643 W/(m·K) for quickly-cooled samples to 0.0904 W/(m·K) for the samples annealed for 24 h, while the glass transition temperature increased by approximately 11.33% to reach 59.0 °C. Moreover, the annealing process substantially improved the compressive strength and rigidity of the PLA and reduced its ductility. The results revealed that annealing PLA for 1–3 h at 90 °C produces an optimum thermal insulation material. The low thermal conductivity (0.0798–0.0865 W/(m·K)), low density (~1233 kg/m3), very low water retention (<0.19%) and high compressive strength (97.2–98.7 MPa) in this annealing time range are very promising to introduce PLA as a green insulation material.

scholarly journals A Compressive Peak Strength Model for CFRP-Confined Thermal Insulation Materials under Elevated Temperature

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 26 ◽  
Author(s):  
Yeou-Fong Li ◽  
Wai-Keong Sio ◽  
Ying-Kuan Tsai
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Thermal Insulation ◽  
Thermal Softening ◽  
Peak Strength ◽  
Insulation Material ◽  
Strength Model ◽  
Test Results ◽  
Thermal Insulation Material ◽  
Insulation Materials

In this paper, a compressive peak strength model for CFRP-confined thermal insulation materials under elevated temperature was proposed. The thermal insulation material was made by Portland cement with different portions of perlite. The compressive strengths of four different perlite ratios in weight, such as 0%, 10%, 20%, and 30% of thermal insulation materials, confined by one-layer, two-layer, and three-layer carbon fiber-reinforced polymer (CFRP) composite materials, were obtained. The test results indicated that the specimen’s compressive strength decreased with an increase in the amount of perlite replacement and increased with an increase in the number of CFRP wrapping layers. Based on the test results, a theoretical compressive peak strength model with some parameters was proposed. In the meantime, the compressive strengths of the above four different perlite ratios of thermal insulation materials under elevated temperature, such as ambient temperature, 100 °C, 150 °C, 200 °C, 250 °C, and 300 °C, were obtained. For compression tests of specimens with a fixed amount of perlite, the test results indicated that the specimen’s compressive strength decreased with an increase in temperature, highlighting a thermal softening phenomenon. Based on the test results, a compressive peak strength model with a thermal softening parameter was proposed to predict the peak strength under elevated temperature. Finally, a compressive peak strength model for thermal insulation material with CFRP confinement under different elevated temperature was derived, and it achieved acceptable results in comparison to the experimental results.

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