Horizontal Shading Devices Research Articles

Solar and Shading Potential of Different Configurations of Building Integrated Photovoltaics Used as Shading Devices Considering Hot Climatic Conditions

This study investigates the use of building-integrated photovoltaics (BIPVs) as shading devices in hot climates, with reference to the conditions of Saudi Arabia. It used parametric numerical modelling to critically appraise the potential of eight design configurations in this regard, including vertical and horizontal shading devices with different inclination angles. The study assumed that the examined shading devices could be entirely horizontal or vertical on the three exposed facades, which is common practice in architecture. The study found that the examined configurations offered different solar and shading potentials. However, the case of horizontal BIPV shading devices with a 45° tilt angle received the highest amount of annual total insolation (104 kWh/m2) and offered effective window shading of 96% of the total window area on average in summer. The study concluded that, unlike the common recommendation of avoiding horizontal shading devices on eastern and western facades, it is possible in countries characterised with high solar altitudes such as Saudi Arabia to use them effectively to generate electricity and provide the required window shading.

Assessment of building façade performance in-terms of daylighting and associated energy consumption in architectural spaces

This paper examines the effect of vertical and horizontal shading devices on the quality of daylight in buildings and the associated energy saving. Excessive daylight in architectural spaces contributes negatively to the energy consumption in buildings. Blinds and shading devices are good solutions to attenuate the surplus amount of daylight in spaces. Accordingly, this study evaluates the effect of shading devices on the amount of light flux and the associated solar energy in buildings. It estimates the energy consumption attributed to lighting spaces for three common positions of shading devices. Computer simulation strategy was undertaken to correlate the illuminance level in spaces with room geometry and architectural shading elements. The Holophane model for lighting calculations was used to estimate the average illuminance level on workplane and correlate it with the expected saving energy in buildings. The study concluded that there is an optimal orientation for shading devices that keeps the internal illuminance level within the acceptable range with minimum amount of solar heat gain.Keywords: Shading device, Daylight Illuminance, Heat gain, Computer simulation, Energy consumption

Numerical study of the horizontal shading devices effect on the thermal performance of promotional apartments: Case of El-Alia-Biskra

The aim of this research is to evaluate the impact of horizontal shading devices on thethermal performance of promotional apartments in the city of Biskra. In this regard, various sizesof horizontal shading devices which allow making an adequate choice were proposed to guaranteethe best thermal comfort level for this apartment type. The simulations were performed by usingthe TRNSYS© software to estimate objectively the indoor thermal comfort of studied apartments.The comparative analysis between the simulation results of the existing apartments and theshading scenarios shows that the promotional apartments appear to be unsuited to the desertclimate and the analysis shows the effectiveness of the horizontal shading devices on the thermalperformance of the space by reducing the indoor air temperature during the summer period.

공공청사 리트로핏 설계 시 외부 수평 차양 장치에 따른 에너지 소비량 절감 방안

Purpose: Recently, significant heat loss through the window takes place in buildings. Nevertheless, there exists little literature concerning the exterior horizontal shading devices and the design criteria are not clearly settled yet. Applying the exterior horizontal shading devices is more efficient as compared to the interior shading devices in that solar radiation can be directly blocked before passing through the window or the envelope. The purpose of this study is to reduce the internal load by designing the exterior horizontal shading devices and verify the degree of reduction in energy consumption. Method: This study aims to reduce energy consumption in cooling and heating through proposing proper length and shape of the exterior horizontal shading devices in public buildings. In the process, actual energy data and the Design Builder simulation program are utilized. In addition, economic aspect is considered to figure out the optimal length of the exterior horizontal shading devices that maximizes efficiency. Result: As a result, the proper length and shape of the exterior horizontal shading devices are provided as follows: 1) Energy consumption in cooling and heating is minimized when the exterior horizontal shading devices are designed as 0.5m*2. 2) Electricity bill is the lowest when the exterior horizontal shading devices are designed as 3.3m*2. The gap between maximum and minimum electricity bill is about 7.8~14%.

Analysing the Impact of Horizontal Shading Device – A Case of Octagonal Shape Building

Analysing the Impact of Horizontal Shading Device – A Case of Octagonal Shape Building

A Study on the Effectiveness of the Horizontal Shading Device Installation for Passive Control of Buildings in South Korea

In South Korea, the evaluation criteria for installing shading devices are defined by regulations, but the standards of design methods are not clearly established. The installation of shading devices has become mandatory for some public buildings due to revised regulations. Therefore, a design of horizontal shading device is required, and indoor environmental problems which may occur due to their installation should also be taken into consideration. This research aimed to propose a design which takes into account the energy consumption which may occur if the horizontal shading device is installed and suggests an improved design method of horizontal shading devices when they are installed. Consequently, it was confirmed that as the protrusion of the horizontal shading device becomes longer, the incoming daylight is reduced and the indoor intensity of illumination becomes lower, and thus more lighting energy may be consumed in a room where the shading device is installed than in the one where it is not. Therefore, annual energy consumption was calculated by applying the lighting control and it was found that the total energy consumption decreased by the reduction of air-conditioning and fans and lighting energy consumption.

The effects of horizontal shading device orientation and surface material and the use of a compact silencer in forming acoustical barriers for a ventilated glass double skin facade

Acoustical discomfort due to traffic noise transmission via operable windows is a significant environmental stress for building occupants in urban areas. A ventilated double skin facade, DSF, can potentially address the issue of noise transmission and operable windows. A hypothetically designed glass DSF mock-up was constructed in the opening between the reverberation rooms at the University of Kansas to determine the noise reduction of the DSF mock-up based on the orientation and surface materials of the horizontal shading devices and the use of a compact silencer in place of a typical ventilation grille in the outer skin opening. The compact silencer provides natural ventilation by allowing outside air to flow within the cavity of the DSF. For these laboratory tests, the horizontal shading devices with sound absorbing material were oriented at 0, 30, 60, and 90 degree angles. The laboratory noise reduction measurements are presented for the mock-up with the several shading device orientations and materials and for the use of a compact silencer.

DESIGNING OF CONSTRUCTIVE SHADING DEVICES

The paper shows how to determine dimensions of stationary horizontal (canopies) and vertical (ribs) shading devices in order to prevent penetration of normal beam solar radiation into the buildings during warm season of the year. While analyzing formulae for insolation rate equations for determination of dimensions of canopies and ribs which are perpendicular and inclined to the plane of intensively irradiated fenestrations orientated to the South, South-East, South-West, East and West have been obtained in the paper. Sloping canopies have the smallest dimensions. What is more, an angle of slope with regard to opening plane must correspond to elevation of sun station at an hour when there is a maximum specific heat flow rate of normal beam solar radiation. The paper considers an influence of canopies and ribs on transmission of diffuse solar radiation which along with normal beam solar radiation serves for creation of natural illumination. As follows from the analysis of formulae it is possible to make a conclusion about an inefficiency of vertical shading elements due to large rib dimensions and decrease in transmission of diffuse solar radiation. Minimum distances from fenestration reveal to the canopy have been determined for various orientations proceeding from the position that the opening must be maximally illuminated by normal beam solar radiation during the cold season of a year in order to reduce heat inputs for building heating. On the basis of dependence analysis we have come to a conclusion that it is appropriate to design stationary shading devices for fenestrations orientated only to the South and they must be sloping canopies. It is necessary to select glazing with a small index of solar factor for openings orientated to other corners of the Earth and reduction of solar radiation heat inputs.

A Design Chart to Determine the Dimensions of a Horizontal Shading Device over an Equator-facing Window as a Function of the Latitude and the Shading Height

The main objective of this paper is to introduce a simple quick tool for architects represented by a design chart that determines the dimensions of an external horizontal shading device over an equator-facing window as a function of the latitude and the shading height, resulting in an automatic seasonal adjustment. This chart is applicable for any city all over the world at lower or middle latitudes where shading is an essential passive strategy.

Daylighting Strategies in Iranian Vernacular Residential Buildings in Hot and Dry Climate

Daylighting strategies and control of it, plays a significant role in energy efficiency and provision of visual comforts in buildings. This study conducted a review of literature and observation in a hot and dry region of Iran in order to investigate daylighting strategies and control of it by shading devices in the vernacular residential buildings. The results show thatdaylight in vernacular rooms was provided through door, window, Rozan, Moshabak, and Goljam. These components were equipped with thevertical and horizontalshading devices such as Orsi, Sarsayeh, Tabeshband and Kharakpoushto control the sunlight. The vernacular lighting strategy was in response to the energy efficiency and provided visual comfort.The vernacular concepts and schemes still can be adopted and reused by architects and developers. The study recommends appropriate daylight schemes and shading devices in design phase to achieve energy efficiency in new residential buildings.

A Study of Shading Device Configuration on the Natural Ventilation Efficiency and Energy Performance of a Double Skin Façade

Studies have shown that double skin facades (DSFs) are capable of improving building energy performance using the stack effect to dissipate heat as well as shading devices to screen undesired solar heat transmission. In this simulation study, the scenarios were made based on shading device configuration to see relationships among airflow patterns, the air velocity, the air temperature and the annual energy consumption. The ultimate goals of this study are not only to investigate the optimal controls of shading devices in naturally ventilated buildings but also to maintain the balance of natural ventilation efficiency and building energy saving. Initial findings indicated that that the air temperature and airflow patterns were highly dependent on the shading device configuration. In cases of 30-, 60- and 90-degree angle of horizontal shading devices, the air temperature of an exterior facing side's air cavity was greater than that of vertical shading devices. It was also found that the mean air velocity and airflow patterns of both shading devices at 0-degree angle were improved than the case of 90-degree angle. With regard to an annual energy consumption, it was discovered that horizontal shading devices at 30-, 60-, and 90-degree angle were more effective to reduce the energy use by 0.4%, 2.6% and 6.4% respectively than the case of 0-degree angle.

Impact of passive cooling techniques on energy demand for residential buildings in a Mediterranean climate

This study presents the thermal analysis of a building prototype, which was designed and built in accordance with energy efficiency measures to improve indoor thermal comfort, particularly in summer. The building prototype is located in Souidania (20 km southwest of Algiers, latitude 36°7N, Longitude 03°2E). The location is characterized by a temperate Mediterranean climate. In order to perform this analysis, various activities are carried out: a series of monitoring campaigns; dynamic simulations with TRNSYS software, calibration of the model with experimental data and comparative study with buildings that use different wall constructions. Based on a validated building thermal model, dynamic analysis is carried out in order to evaluate the impact of thermal mass and of eaves and night ventilation. The results demonstrate that cooling energy demand is more affected by thermal transmittance values than by the envelope thermal mass. A recommended guideline for the optimum overhang length for south-facing windows is proposed. Ultimately, it is found that the combination of both natural ventilation and horizontal shading devices improves thermal comfort for occupants and significantly reduces cooling energy demand.

Using simulation for studying the influence of horizontal shading device protrusion on the thermal performance of spaces in residential buildings

The building shape and spaces greatly influence ambient temperatures in those spaces. The thermal performance of interior spaces is highly influenced by a number of factors. On top of these factors are as follows: space ratios (height, width, length), walls and facade finishing colors, window openings (height, width, length) and the different types of windows glass, and the vertical and horizontal sun breakers. To achieve this aim, the research is done by the analytical and applied methods, using the simulation software Thermal Analysis Software, from the climatic analysis of New Assiut City as well as identifying the prevailing residential patterns, and detailed study of the selected residential building, identifying the software used, and analyzing the simulation results for ambient room temperatures of the hot periods for shading device protrusion of the selected model. The research ends with a number of results and recommendations. Such results may be applied in hot desert areas.

A study of summarized correlation with shading performance for horizontal shading devices in Taiwan

Good shading device settings would adjust their form and dimensions to adapt to the facade facing and fenestration system. The main function of the shading device proposed in this study is to provide shelter from solar heat gain and energy saving in Taiwan. This study provides a methodical procedure to establish summarized correlation for evaluating shading performance of horizontal shading devices based on the shading ratio and shading coefficient via the simulation of shading variables of 22–25° latitude north in Taiwan. These values have both been used to indicate and analyze shading effectiveness. Three main independent variables, the ratio of device depth to window height, the width to height ratio of an opening, and the facing azimuth, are used to determine a correlation to generate shading ratio models for a whole year. Furthermore, the yearly correlation models between shading ratio and shading coefficient for Hengchuen (22°N), Tainan (23°N), Taichung (24°N), and Taipei (25°N), respectively, are established as well. Summarized correlation models of the shading performance of horizontal shading devices can be useful under general condition for buildings. Most importantly, an optimal design and strategy regulations could be chosen to enable more suitable utilization and peak effectiveness of shading device systems for sustainable and energy-savings buildings.

Using simulation for studying the influence of vertical shading devices on the thermal performance of residential buildings (Case study: New Assiut City)

The building and spaces shape have a great impact on indoor temperature. Well-designed sun control and shading devices can dramatically affect indoor temperature. The thermal performance of interior spaces in hot arid desert is highly influenced by various passive design techniques, e.g. space dimensions, facade colors, fenestration ratio, glazing type; and vertical and horizontal shading devices. Simulation tools play an important role in taking decision during early design phase that could help in improving the thermal performance of buildings. The aim of this paper is to present the effect of vertical louvers length on the thermal performance of residential buildings in Egypt. To achieve this aim of the research, first, the climatic analysis of New Assiut City is introduced followed by identification for the prevailing residential patterns within the city and the selected residential model. Second, the role of the used simulation tool in enhancing the designs is highlighted. Finally, a simulation has been run for the selected residential model in New Assiut City over the four cardinal orientations. The results of the study showed that the vertical louvers with a protrusion of 38cm or more result in a decrease of 2°C in indoor temperature in all four orientation. However, for the northern façade it is noticed that any protrusion more than 38cm had only a slight effect on the indoor temperature.

Assessment of building façade performance in terms of daylighting and the associated energy consumption in architectural spaces: Vertical and horizontal shading devices for southern exposure facades

This paper examines the effect of vertical and horizontal shading devices on the quality of daylight in buildings and the associated energy saving. Excessive daylight in architectural spaces contributes negatively to the energy consumption in buildings. Blinds and shading devices are good solutions to attenuate the surplus amount of daylight in spaces. Accordingly, this study evaluates the effect of shading devices on the amount of light flux and the associated solar energy in buildings. It estimates the energy consumption attributed to lighting spaces for three common positions of shading devices. Computer simulation strategy was undertaken to correlate the illuminance level in spaces with room geometry and architectural shading elements. The Holophane model for lighting calculations was used to estimate the average illuminance level on workplane and correlate it with the expected saving energy in buildings. The study concluded that there is an optimal orientation for shading devices that keeps the internal illuminance level within the acceptable range with minimum amount of solar heat gain.

The impacts of ventilation strategies and facade on indoor thermal environment for naturally ventilated residential buildings in Singapore

The impacts of various ventilation strategies and facade designs on indoor thermal environment for naturally ventilated residential buildings in Singapore are investigated in this study based on thermal comfort index. Four ventilation strategies, nighttime-only ventilation, daytime-only ventilation, full-day ventilation and no ventilation were evaluated for hot-humid climate according to the number of thermal discomfort hours in the whole typical year on the basis of a series of TAS simulations. Parametric studies of facade designs on orientations, window to wall ratios and shading devices were performed for two typical weeks by coupled simulations between building simulation ESP-r and CFD (FLUENT). The results indicate that full-day ventilation for indoor thermal comfort is better than the other three ventilation strategies. With various facade design studies, it was found that north- and south-facing facades can provide much comfortable indoor environment than east- and west-facing facades in Singapore. It is recommended that optimum window to wall ratio 0.24 can improve indoor thermal comfort for full-day ventilation and 600 mm horizontal shading devices are needed for each orientation in order to improve thermal comfort in further.

Optimum Overhang Geometry for Building Energy Saving in Tropical Climates

abstractIn hot and humid climates, one draw back of using shading devices is the risk of reducing daylight level which in turn increases the use of artificial lighting. It is important to understand the magnitude of energy consumption for cooling and lighting when shading devices are adapted in order to propose optimum external horizontal shading strategies as design solutions. This study investigates the effect of six different alternatives of external horizontal shading devices on incident solar radiation, transmitted solar heat gains, natural-light penetration and energy consumption. The study was carried out using a standard, single fenestration perimeter office room in a typical high-rise office building. The investigation is conducted using eQUEST-3, which is a dynamic energy simulation program supported by DOE2.2 calculation engine. The results showed several optimum geometry of the external horizontal shading device depending on incident direct solar radiation, transmitted solar heat gains, natural-light penetration and energy consumption. This study concludes, considering the trade off between total heat gain and natural-light penetration to optimize the total energy consumption as the best option in designing external solar shading in hot and humid climates.

Investigations for improving the daylighting potential of double-skinned office buildings

This study looks at the daylighting implications of several options for the refurbishment of an existing office building in Brussels, with a perimeter ceiling height of 2.5 m and a width of 16 m. Each side has a double-skinned facade, with a 1.4 m wide maintenance walkway in the space between the internal and external glazing. Scale models in an artificial sky, and computer simulations, were used to examine the effects of changes to the walkway. Two changes in the building's form were also examined, re-entrant slots in the facade, and lowering of the central area of floor. The results from these experiments are generally applicable to buildings designed with double-skinned facades, buildings using horizontal solar shading devices, light shelves or buildings with low floor to ceiling heights. If an area of the floor space is considered to be daylit when it receives at least 300 Lux for over 50% of the working year, it was found that using the walkway options alone, the daylit area can be increased by up to 23%. Re-entrant façade slots produced no increase in the daylit area. Lowering the central floor area produced an increase of up to 14%. None of the walkway options were able to produce a daylit area of greater than 53% of the total floor space. Thus, until redirecting glazing becomes commercially viable, it is clear that shallowplan designs are the best option for new buildings. The RADIANCE computer modelling package was used in addition to scale-model measurements. The use of both of these methods of daylighting analysis is compared. The results of both methods show good agreement.