Integration of Shading Device and Semi-Circle Horizontal Light Pipe Transporter for High-Rise Office Building in Tropical Climate

The blooming of a deep open plan in office buildings is accelerated due to economic profit reasons. This hinders the utilisation of daylight despite having abundance of daylight in tropical climate. Although a light pipe (LP) provides a means to illuminate the deep interior of the space, non-uniform daylight distribution still occurs due to the high illumination contrast across the room. The integration of a shading device (SD) in a room with an LP offers a solution to create a uniform daylight distribution. In this study, daylighting performances of 5 different types of an SD with different angles were analysed through a computer simulation software, namely Integrated Environment Solution Virtual Environment. The simulation was done using overcast and intermediate sky with sun conditions. The results showed that all SD cases improved the daylight uniformity across the room. A horizontal Venetian blind with an angle of +45o and −45o showed the best qualitative performance among all the cases. However, further shading and illumination are needed respectively to increase the potential daylight utilisation in an open plan office room. This study also concluded that a vertical Venetian blind did not provide a good daylight uniformity due to the vertical nature of the SD. A design recommendation guide for building designers is proposed at the end of this study to promote the integration of an SD and an LP in deep open plan high-rise office building.

Feather iridescence of Coeligena hummingbird species varies due to differently organized barbs and barbules

Hummingbirds are perhaps the most exquisite bird species because of their prominent iridescence, created by stacks of melanosomes in the feather barbules. The feather colours crucially depend on the nanoscopic dimensions of the melanosome, and the displayed iridescence can distinctly vary, dependent on the spatial organization of the barbs and barbules. We have taken the genus Coeligena as a model group, with species having feathers that strongly vary in their spatial reflection properties. We studied the feather morphology and the optical characteristics. We found that the coloration of Coeligena hummingbirds depends on both the Venetian-blind-like arrangement of the barbules and the V-shaped, angular arrangement of the barbules at opposite sides of the barbs. Both the nanoscopic and microscopic organization of the hummingbird feather components determine the bird's macroscopic appearance.

A Simplified Technique for Thermal Analysis of a Fenestration system with a Venetian Blind

A simplified 1-D numerical model of a window and horizontal Venetian blind assembly has been developed. This model provides a realistic estimate of the advantage of using blinds to control the window heat gain or loss. The free convective heat transfer rate from an isothermal vertical surface adjacent to a set of horizontal louvres has been studied numerically. This configuration is an approximate model of an indoor window glazing with a Venetian-type blind. Knowledge of the effect of blinds on the free convection at the indoor window surface is important for understanding and predicting the impact of shading devices on the overall thermal performance of a window. The convective heat transfer results are used in the one-dimensional model of the complete fenestration system to study the effect on key performance parameters. The results show that louvred blinds can have a significant beneficial effect on window thermal performance.

A Simplified Technique for Thermal Analysis of a Fenestration system with a Venetian Blind

A simplified 1-D numerical model of a window and horizontal Venetian blind assembly has been developed. This model provides a realistic estimate of the advantage of using blinds to control the window heat gain or loss. The free convective heat transfer rate from an isothermal vertical surface adjacent to a set of horizontal louvres has been studied numerically. This configuration is an approximate model of an indoor window glazing with a Venetian-type blind. Knowledge of the effect of blinds on the free convection at the indoor window surface is important for understanding and predicting the impact of shading devices on the overall thermal performance of a window. The convective heat transfer results are used in the one-dimensional model of the complete fenestration system to study the effect on key performance parameters. The results show that louvred blinds can have a significant beneficial effect on window thermal performance.

A numerical study of free convective heat transfer in a double-glazed window with a between-pane Venetian blind

The free convective heat transfer in a double-glazed window with a between-pane Venetian blind has been studied numerically. The model geometry consists of a two-dimensional vertical cavity with a set of internal slats, centred between the glazings. Approximately 700 computational fluid dynamic solutions were conducted, including a grid sensitivity study. A wide set of geometrical and thermo-physical conditions was considered. Blind width to cavity width ratios of 0.5, 0.65, 0.8, and 0.9 were studied, along with three slat angles, 0º (fully open, +/- 45º (partially open), and 75º (closed). The blind to fluid thermal conductivity ratio was set to 15 and 4600. Cavity aspects of 20, 40, and 60, were examined over a Rayleigh number range of 10 to 10⁵, with the Prandtl number equal to 0.71. The resulting convective heat transfer data are presented in terms of average Nusselt numbers. Depending on the specific window/blind geometry, the solutions indicate that the blind can either reduce or enhance the convective heat transfer rate across the glazings. The present study does not consider radiation effects in the numerical solution. Therefore, a post-processing algorithm is presented that incorporates the convective and radiative influences, in order to determine the overall heat transfer rate across the window/blind system.

A numerical study of free convective heat transfer in a double-glazed window with a between-pane Venetian blind

The free convective heat transfer in a double-glazed window with a between-pane Venetian blind has been studied numerically. The model geometry consists of a two-dimensional vertical cavity with a set of internal slats, centred between the glazings. Approximately 700 computational fluid dynamic solutions were conducted, including a grid sensitivity study. A wide set of geometrical and thermo-physical conditions was considered. Blind width to cavity width ratios of 0.5, 0.65, 0.8, and 0.9 were studied, along with three slat angles, 0º (fully open, +/- 45º (partially open), and 75º (closed). The blind to fluid thermal conductivity ratio was set to 15 and 4600. Cavity aspects of 20, 40, and 60, were examined over a Rayleigh number range of 10 to 10⁵, with the Prandtl number equal to 0.71. The resulting convective heat transfer data are presented in terms of average Nusselt numbers. Depending on the specific window/blind geometry, the solutions indicate that the blind can either reduce or enhance the convective heat transfer rate across the glazings. The present study does not consider radiation effects in the numerical solution. Therefore, a post-processing algorithm is presented that incorporates the convective and radiative influences, in order to determine the overall heat transfer rate across the window/blind system.

ANALISIS PENGARUH TIPE INTERNAL SHADING SEBAGAI STRATEGI PENDINGINAN PASIF PADA BANGUNAN

Abstrak: Strategi pendinginan pasif pada bangunan menjadi salah satu alternatif dalam memperoleh kenyamanan termal dengan meminimalkan konsumsi energi pendinginan bangunan. Posisi Indonesia yang dilewati oleh garis khatulistiwa mengakibatkan terjadinya penyinaran matahari sepanjang tahun. Hal ini memerlukan sebuah perlakuan khusus terhadap bukaan pada fasad bangunan. Penelitian ini bertujuan untuk menganalisis dan melihat pengaruh tipe internal shading pada interior bangunan terhadap variabel solar gain bangunan. penggunaan tipe shading berupa venetian blind, roller shades dan drapes akan diaplikasikan pada bangunan. hasil dari penelitian ini didapatkan bahwa penggunaan roller shades mampu menurunkan level solar gain sebesar 55 persen. Sedangkan penggunaan venetian blinds dan drapes memberikan hasil penurunan sebesar 31 persen dan 25 persen. Dari penelitian ini dapat disimpulkan bahwa penggunaan roller shades memberikan hasil yang cukup efektif dalam menurunkan solar gain pada bangunan.Kata-kata kunci: pendinginan pasif, internal shading, solar gainAbstract: Passive cooling strategy in buildings is an alternative in obtaining thermal comfort by minimizing building cooling energy consumption. The position of Indonesia, which is crossed by the equator, results in solar radiation throughout the year. This requires a special treatment of openings in the facade of the building. This study aims to analyze and see the effect of the type of internal shading on the interior of the building on the variable solar gain of the building. the use of shading types in the form of venetian blinds, roller shades and drapes will be applied to the building. the results of this study found that the use of roller shades was able to reduce the level of solar gain by 55 percent. Meanwhile, the use of venetian blinds and drapes resulted in a decrease of 31 percent and 25 percent, respectively. From this research, it can be concluded that the use of roller shades gives quite effective results in reducing solar gain in buildings.Keywords: passive cooling, internal shading, solar gain