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Overhangs and vertical fins help reduce solar heat gain through south-facing glazed areas at the MRB building/ University of Arizona (left). IR thermal image shows surfaces temperature. Photo credit: Nader Chalfoun.
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Highly glazed facades have been increasingly built for aesthetics, to achieve green
buildings ratings, and to maximize daylight admission. In general, when the window area
increases, building energy consumption increases. The objective of this thesis is to
provide architects and engineers with a method to increase window area, attain daylight
benef...
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Highly glazed building facades have been increasingly built for aesthetics, daylight, and to achieve green building ratings such as LEED. Typically, as window areas increase, building energy consumption rises because of the excessive heat transfer through fenestration areas. Fixed shading devices can effectively control solar heat gain; however, th...
Citations
... Both traditional and modern architectural designs frequently use external overhangs and fins for several reasons: Firstly, they can effectively control solar heat gain by blocking the solar radiation before it reaches the window. Secondly, they maintain a visual connection with the outdoor environment, and lastly, they enhance daylighting performance by maximizing daylight admission while minimizing visual discomfort [2]. Although the extra light near the window will disappear by using these shades, there will be very little light at the end of the room, and if the depth of the space is visual discomfort [2]. ...
... Secondly, they maintain a visual connection with the outdoor environment, and lastly, they enhance daylighting performance by maximizing daylight admission while minimizing visual discomfort [2]. Although the extra light near the window will disappear by using these shades, there will be very little light at the end of the room, and if the depth of the space is visual discomfort [2]. Although the extra light near the window will disappear by using these shades, there will be very little light at the end of the room, and if the depth of the space is large, this issue will be more important. ...
... In Abboushi's master's thesis, an optimal combination of horizontal and vertical dynamic shades with a light shelf was presented. In his model, the use of horizontal and vertical shades that change throughout the year while adding a low-e coating on light shelves in hot and dry weather can prevent the increase in the cooling load and improve the increase in useful light [2] (Figure 9). In another type of combined light shelf, in order to change the direction of sunlight, the light shelf is combined with a set of mirrors that can move in two axes based on the direction of sunlight using a solar tracker [47]. ...
In areas with a deep floor plan, the distribution of natural light is not uniform. Consequently, relying solely on daylight may not suffice to meet the space's lighting requirements, necessitating the use of artificial lighting in darker areas. Therefore, a lighting system is needed that not only controls the glare near the windows but also increases the light at the end of the room and provides uniform daylight. One of the widely used systems is the "light shelf", which has three main functions: shading, increasing the depth of light penetration, and reducing glare. Review articles about light shelves were published in 2015 and 2017, while more than 80% of the studies have been carried out since 2016, and light shelves with more diverse forms and dynamic elements and many consolidations have been proposed. Therefore, there is a need for a more comprehensive review. The main question of this research is how different parameters (including climate, material, ceiling, and integrated systems) can help to increase the efficiency of light shelves. By using a systematic review, studies in the past three decades were classified in order to determine the effect of these parameters on improving lighting performance and controlling solar heat gain.
... To validate the obtained results in Phase 4, a comparative analysis is conducted to compare the results of this study with previous research conducted by Abboushi (2013), Gadelhak et al. (2013), Al Waary (2012), Al-Ashwal and Budaiwi (2011), and Hammad and Abu-Hijleh (2010. The variance of the percentage of reduction in total energy consumption obtained in this research falls within the range of plus and minus 4% compared to results obtained from closely related cases. ...
The absence or improper use of shading on the glazing of building windows causes overheating which increases both cooling load and glare, especially in the hot desert climate. However, integrating Daylighting Systems appropriately into building windows can contribute to reducing energy consumption by effectively utilizing daylight as a renewable resource instead of depending only on artificial light. This can help in achieving green, sustainable, high performance, and energy-efficient buildings. This paper proposes a set of integrated Daylighting Systems into building windows to optimize the energy efficiency performance of office buildings in the hot desert climate.
The integration of individual and collective Daylighting Systems with different configurations are explored to generate an extensive set composed of 87 alternatives in three different orientations. The energy simulation is conducted for these alternatives to investigate their performance on reducing the electric energy consumption of cooling and artificial lighting. The optimal set of energy-efficient integrated Daylighting Systems is determined based on the highest performance of reducing energy consumption for cooling and lighting while maintaining visual and thermal comfort. This optimal set of integrations is formulated into a multi-level utilization guide for facilitating the appropriate selection of optimal energy-efficient Daylighting Systems into building windows. This utilization guide will assist building designers to optimize the energy efficiency performance of buildings by selecting the most appropriate Daylighting Systems to be integrated into building windows. Such performance-based utilization guide will aid designers in making decisions from the perspectives of energy efficiency, and visual and thermal comfort.
... Since the heating loads decreased compared to a baseline façade system; the future target is given as, verifying the simulated energy performance data by testing the adaptive façade system experimentally [14]. Abboushi (2013) presented a master thesis on developing high performance office buildings façades by using adaptive shading and the selective reflector light shelf technologies [15]. Bianco et al. (2017) focused on the solution of high energy demand and discomfort conditions in buildings with large transparent façades. ...
Façade is accepted as a determinant component on energy performance of a building, forming the boundaries between inner and outer conditions. With an intention to improve the building energy performance of an existing office building, façade integrated shading devices are examined through the cooling energy consumptions. OpenStudio simulation software is used for calculating heating and cooling electricity consumptions. The ilding simulation model is validated by comparing the simulation results with monthly electricity consumption bills. Shading device requirements are determined by using the building model without shading devices and simulation results are studied together with the sun path diagram analysis results. Hourly and seasonal solar movements are considered as the main parameters affecting the ‘transparency’ and ‘elevation angles’ of the shading devices. As a result of the shading device requirement analysis, climate adaptive shading device (CASD) scenarios are presented for the case building. Consequently, existing shading devices and proposed CASD scenarios are compared and discussed in terms of electricity consumptions and window solar radiation energy parameters. As a result of the comparisons, shading devices that are adaptable to both hourly and seasonal solar movements gave the highest improvement results in terms of decreasing cooling energy consumptions. Also, suggestions are given for developing the best performing façade for further studies.
... The external movable shading device can block solar radiation at the exterior, thus providing advantages not only in terms of improving the lighting environment but also in terms of reducing the cooling load. There have been various studies focusing on methods of controlling external shades [2][3][4][5][6][7][8][9][10]. These studies describe methods of controlling shading devices mainly using the indoor and outdoor temperature or amount of solar radiation as control variables. ...
External movable shading devices are mainly used to improve the thermal and lighting environment of an interior space by preventing overheating during the cooling season as well as by preventing glare. An external movable shading device can be controlled using various methods, where parameters related to the lighting environment, such as daylighting and glare, are commonly adopted as major variables associated with the control of the shading device. In this paper, an algorithm is provided with which an external movable shading device can be operated in any one of three control modes as selected according to the operation purpose preferred by the occupant. The algorithm can be applied to external movable shading devices of various shapes. The shaded fraction is adopted as a major control element, and the control purpose of the external shading device is configured to include energy conservation, illuminance satisfaction, and glare protection. The algorithm includes an hourly evaluation procedure for obtaining the range of allowable shading device movement that satisfies each of the three operation purposes. Real-scale mockup tests for the three control modes were conducted during different time periods in summer to verify the performance of the control strategies. The test results regarding the energy and environment performance for each control mode show that the control algorithm can be selected to provide satisfactory compromises between energy and visual comfort factors. The result of this study can provide users with options for controlling movable shading devices on a building according to their preferred operation purposes.
... To validate the obtained results in Phase 4, a comparative analysis is conducted to compare the results of this study with previous research conducted by Abboushi (2013), Gadelhak et al. (2013), Al Waary (2012), Al-Ashwal and Budaiwi (2011), and Hammad and Abu-Hijleh (2010. The variance of the percentage of reduction in total energy consumption obtained in this research falls within the range of plus and minus 4% compared to results obtained from closely related cases. ...
Introducing daylight into buildings not only saves energy but also enhances users' productivity and well-being. Utilizing daylighting systems (DLS) has the potentials to maximize the benefits of daylighting and to make it function as an effective environmental system in buildings. This research paper aims to evaluate the impact and effective utilization of integrating DLS in office buildings in Egypt for improving energy efficiency and achieving users' comfort.
This paper adopted an experimental methodology for conducting both energy and daylighting analysis using the IES-VE simulation software. The base-case of this study is a high-rise office building with a built floor area of 1000 m2, four perimeter zones, and 40% window to wall ratio, in a hot climate zone (Cairo, Egypt). There are four types of DLS selected to be included in the integration and namely: light shelves, blinds, louvers, and sun-breakers. The developed scenarios for integrating DLS in office buildings involve both individual and collective DLS using artificial lighting dimming control.
The results of this paper include identifying the most effective scenarios of integrating DLS using the selected four types in office buildings for improving energy efficiency and achieving users' comfort. The results showed that the integration of DLS can achieve savings in the total energy consumption for up to 32.4% for the whole building and around 39% in the east, south and west orientations while maintaining the daylight illuminance level in the useful range. DLS with shading achieved the highest savings when using Horizontal Sun-breaker Double-slats (HSD) that saves 39%, 38.4%, 39.9%, in the total energy consumption in east, west and south zones respectively. These effective and efficient scenarios can be used by architects and building designers to achieve energy efficient buildings in the hot climate zone.
... 72% of the total electricity generated by US power plants goes to supply the building sector. Cooling, of commercial buildings consumes 38% of the total electricity provided for this sector [1]. ...
Building envelopes play a major role in improving the overall energy efficiency
as well as in providing a healthy indoor air quality for occupants in office
buildings.
The notion of this research is to develop an integrated façade technology that
interacts and adapts with the changing climatic conditions, in hot arid regions, in
order to improve occupants’ thermal comfort in mixed mode office buildings
through the use of natural ventilation and evaporative cooling techniques,
thereby reducing mechanical cooling energy loads.
In this research, façade design decisions were based on two main computer
simulation results; thermal comfort levels and the reduction in energy
consumption. The authors propose a double skin façade system that consists of
an external skin which works on multiple operating modes. This skin integrates
passive cooling strategies with the building envelope depending on the data
collected by external and internal sensors. My previous investigations showed
that shading, natural ventilation and evaporative cooling are the most effective
passive cooling strategies for hot and arid regions
In conclusion, this research will contribute in reducing energy consumption
in commercial buildings, and help provide a productive work environment.
Keywords: passive cooling, arid regions, evaporative cooling, double skin
facades, dynamic facades, thermal comfort, illuminance, glare, CFD simulation.
Sunlight is one of the most accessible environmental agents which has been used as primary energy source. In current study, the effect of daylight distribution in interior spaces on human thermal comfort conditions and energy consumption in the residential buildings is investigated based on light shelf using simulation methods and tools. Firstly, a comprehensive parametric study is presented to examine the impact of light shelf design parameters (including angle, depth and number of the light shelves) on two objective functions of building's total energy consumption (including heating, cooling and electrical energy) and predicted percentage of dissatisfied people. Then, employing genetic algorithm, a multi-objective optimization is conducted in order to minimize the two objective functions simultaneously. Light shelves are evaluated for three orientations of West, South and East; horizontally and vertically. Results show that the optimum angle, depth and number of light shelves for West orientation are 24.37°, 0.571 m and 5, respectively; for South orientation are 89.62°, 0.295 m and 4, respectively; for East orientation are 36.51°, 0.659 m and 4, respectively. In addition, results indicate that optimum conditions of light shelves decreases the total heating, cooling and electrical energy consumption by 27.819 kWh/m², 49.176 kWh/m² and 34.853 kWh/m², respectively.
چکیده
نور روز تاثیر قابل توجهی در کارآیی و کیفیت بهره گیری از محیط دارد. در این میان رفهای نوری از جایگاه ویژهای برخوردارند.
رفهای نوری یکی از فناوریهای نور روز ترکیب شده با پنجره؛ با عملکرد سه گانه سایه اندازی، افزایش عمق نفوذ نور به
بخشهای مرکزی و عمیقتر اتاق و کاهش خیرگی، و داشتن این مزیت که مانع دید به بیرون نمی شود، یکی از پرطرفدارترین
فناوریها محسوب میشود. این رفها با توجه به اقلیم، فضا، کاربری و... انواع مختلفی دارند. ابعاد و تناسبات مختلف، جنس،
فرم، زاویه نسبت به افق، ثابت یا متحرک بودن، داخلی، خارجی و یا ترکیبی از هر دو بودن، منفرد یا تکرارشونده بودن، تأثیر
فضاهای داخلی، ترکیب با عناصر مکمل و مسائل دیگر، گزینههای متعددی را پیش روی ما قرار میدهد که انتخاب نوع مناسب
را پیچیده میکند. در این پژوهش که از جنس مطالعات مروری می باشد، با بررسی مطالعات پیشین بر روی رف های نوری، به
طبقه بندی الگوهای مختلف رفهای نوری و متغیرهای آن برای فضاهای مختلف پرداخته می شود و بر اساس آن، کاربردهایی
در حوزه بکارگیری در فرآیند طراحی معماری پیشنهاد میشود.
