Application of an Anisotropic Material of Thermal Conductivity in Building Envelope

2011 ◽  
Vol 194-196 ◽  
pp. 829-834 ◽  
Author(s):  
Shun Yu Su ◽  
Jian Chen ◽  
Chun Zhi Zhang
Keyword(s):  
Thermal Conductivity ◽  
Anisotropic Material ◽  
Natural Ventilation ◽  
Laminated Composite ◽  
Building Envelope ◽  
Conductive Heat ◽  
Skin Envelope ◽  
Anisotropic Thermal Conductivity ◽  
Principal Axes ◽  
Double Skin

In this paper, mechanism of anisotropic material of thermal conductivity was revealed by rotating the original rectangular axes so as to determine the principal axes and make the cross-derivative terms disappear. The results indicated that the heat flux vector is commonly not perpendicular to the isothermal surface in anisotropic material. The advantage of anisotropic material of thermal conductivity was analyzed. The application of laminated composite with anisotropic thermal conductivity in double skin envelope was proposed to avoid its disadvantage. The interior envelope in double skin system may be made of laminated glaze or other laminated materials. Basing on the combine of anisotropic material and double skin envelope, the indoor cooling and heating load decrease in summer and winter respectively while the anisotropic material was used as interior building envelope. Especially in summer, the effect of energy saving is obvious since the partial magnitude of conductive heat in the interior envelope could be brought out from the cavity by natural ventilation through it.

scholarly journals Study on Performance of Anisotropic Materials of Thermal Conductivity

2011 ◽  
Vol 5 (1) ◽  
pp. 168-172 ◽  
Author(s):  
Shunyu Su ◽  
Jian Chen ◽  
Chunzhi Zhang
Keyword(s):  
Thermal Conductivity ◽  
Anisotropic Material ◽  
Natural Ventilation ◽  
Laminated Composite ◽  
Building Envelope ◽  
Conductive Heat ◽  
Skin Envelope ◽  
Anisotropic Thermal Conductivity ◽  
Principal Axes ◽  
Double Skin

The advantage and shortcoming of anisotropic material of thermal conductivity using as building envelope were analyzed in this paper. The thermal performance of anisotropic material of thermal conductivity was presented by rotating the original rectangular axes so as to determine the principal axes and make the cross-derivative terms disappear. The results indicated that the heat flux vector is commonly not perpendicular to the isothermal surface in anisotropic material. Double skin facade has been successfully applied in many building designs. The application of laminated composite with anisotropic thermal conductivity in double skin envelope was proposed to avoid its disadvantage. The interior envelope in double skin system may be made of laminated glaze or other laminated materials. Basing on the combination of anisotropic material and double skin envelope, the indoor cooling and heating load decrease in summer and winter respectively while the anisotropic material was used as interior building envelope. Especially in summer, the effect of energy saving is obvious since the partial magnitude of conductive heat in the interior envelope could be brought out from the cavity by natural ventilation through it.

Analysis of Heat Conduction of Anisotropic Building Materials

2011 ◽  
Vol 287-290 ◽  
pp. 1227-1232 ◽  
Author(s):  
Shun Yu Su ◽  
Jian Chen
Keyword(s):  
Heat Conduction ◽  
Building Materials ◽  
Anisotropic Materials ◽  
Building Envelope ◽  
Conductive Heat ◽  
Forced Ventilation ◽  
Heat Flux Vector ◽  
Double Skin ◽  
Heating Load ◽  
Building Designs

Heat conduction in anisotropic materials is quite different from that in isotropic materials. Heat flux vector is commonly not perpendicular to the isothermal surface in anisotropic materials. The advantage and disadvantage of anisotropic materials were analyzed in this paper. The thermal conductivities at one point are not equal in all directions for anisotropic materials. The technique of double skin facade has been successfully applied in many building designs. The application of combining building envelope of anisotropic materials and double skin facade was proposed to avoid its disadvantage. Basing on the combination of anisotropic materials and double skin facade in building envelope, the indoor cooling and heating load decrease in summer and winter respectively. Especially in summer, the effect of energy saving is obvious since the partial magnitude of conductive heat in the envelope made of anisotropic materials could be brought out from the cavity of double skin facade by natural or forced ventilation through it.

scholarly journals Collinear Deflection Method for the Measurement of Thermal Conductivity of Transparent Single Layer Anisotropic Material

2019 ◽  
Vol 9 (8) ◽  
pp. 1522
Author(s):  
Moojoong Kim ◽  
Kuentae Park ◽  
Gwantaek Kim ◽  
Jaisuk Yoo ◽  
Dong-Kwon Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Anisotropic Material ◽  
Crystal Orientation ◽  
Three Dimensional ◽  
Single Layer ◽  
Anisotropic Materials ◽  
Analysis Model ◽  
Anisotropic Thermal Conductivity ◽  
Property Measurement

Transparent anisotropic materials have garnered attention along with the growth of the semiconductor and display industries. Transparent anisotropic materials have the characteristic of varying electrical, optical, and thermal properties based on their crystal orientation, and many studies are being conducted on this topic. In order to utilize transparent anisotropic materials properly, thermal properties such as thermal conductivity are essentially required. However, due to the limitations of the existing thermal property measurement methods for transparent anisotropic materials, it is difficult to provide the thermal properties of transparent anisotropic materials. To address this problem, a transparent anisotropic collinear method capable of measuring the effective thermal conductivity of a transparent anisotropic material according to its crystal orientation is proposed in this paper. To this end, the internal temperature distribution of a transparent anisotropic material and the phase delay of the probe beam were theoretically derived through a numerical analysis model that uses a three-dimensional heat conduction equation. This model was applied to anisotropic thermal conductivity with orthorhombic structure. To verify the proposed method of measuring the thermal conductivity of a transparent anisotropic material, the thermal properties of 3 mm-thick A-plane sapphire glass were measured and compared with those of the existing literature. It was confirmed that the absolute errors were less than about 4 W/mk.

Contribution of natural ventilation in a double skin envelope to heating load reduction in winter

2009 ◽  
Vol 44 (11) ◽  
pp. 2236-2244 ◽  
Author(s):  
Yu-Min Kim ◽  
Soo-Young Kim ◽  
Sung-Woo Shin ◽  
Jang-Yeul Sohn
Keyword(s):  
Natural Ventilation ◽  
Load Reduction ◽  
Skin Envelope ◽  
Double Skin ◽  
Heating Load

scholarly journals Solar Chimney Applications in Buildings

Encyclopedia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 409-422
Author(s):  
Haihua Zhang ◽  
Yao Tao ◽  
Long Shi
Keyword(s):  
Natural Ventilation ◽  
Energy System ◽  
Assisted Ventilation ◽  
Building Envelope ◽  
Building Structures ◽  
Solar Chimney ◽  
Climate Conditions ◽  
And Performance ◽  
Modern Building ◽  
Ventilation Systems

A solar chimney is a renewable energy system used to enhance the natural ventilation in a building based on solar and wind energy. It is one of the most representative solar-assisted passive ventilation systems attached to the building envelope. It performs exceptionally in enhancing natural ventilation and improving thermal comfort under certain climate conditions. The ventilation enhancement of solar chimneys has been widely studied numerically and experimentally. The assessment of solar chimney systems based on buoyancy ventilation relies heavily on the natural environment, experimental environment, and performance prediction methods, bringing great difficulties to quantitative analysis and parameterization research. With the increase in volume and complexity of modern building structures, current studies of solar chimneys have not yet obtained a unified design strategy and corresponding guidance. Meanwhile, combining a solar chimney with other passive ventilation systems has attracted much attention. The solar chimney-based integrated passive-assisted ventilation systems prolong the service life of an independent system and strengthen the ventilation ability for indoor cooling and heating. However, the progress is still slow regarding expanded applications and related research of solar chimneys in large volume and multi-layer buildings, and contradictory conclusions appear due to the inherent complexity of the system.

Determination of Thermal Conductivity of Amorphous Silicon Thin Films via Non-Contacting Optical Probing

2006 ◽  
Vol 326-328 ◽  
pp. 689-692
Author(s):  
Seung Jae Moon
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Amorphous Silicon ◽  
Optical Transmission ◽  
Film Deposition ◽  
Transmission Measurement ◽  
Conductive Heat ◽  
Optical Transmission Measurement

The thermal conductivity of amorphous silicon (a-Si) thin films is determined by using the non-intrusive, in-situ optical transmission measurement. The thermal conductivity of a-Si is a key parameter in understanding the mechanism of the recrystallization of polysilicon (p-Si) during the laser annealing process to fabricate the thin film transistors with uniform characteristics which are used as switches in the active matrix liquid crystal displays. Since it is well known that the physical properties are dependent on the process parameters of the thin film deposition process, the thermal conductivity should be measured. The temperature dependence of the film complex refractive index is determined by spectroscopic ellipsometry. A nanosecond KrF excimer laser at the wavelength of 248 nm is used to raise the temperature of the thin films without melting of the thin film. In-situ transmission signal is obtained during the heating process. The acquired transmission signal is fitted with predictions obtained by coupling conductive heat transfer with multi-layer thin film optics in the optical transmission measurement.

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