Fixed Shading Devices Research Articles

TRANSFORMATION OF PASSIVE DESIGN ELEMENTS FOR ACHIEVING THERMAL COMFORT IN RESIDENTIAL BUILDINGS OF MANSEHRA CITY, PAKISTAN FROM 1990 TO 2019

Among the most evolving issues in recent years, there is growing concern over global warming throughout the world. The construction industry has been considered among the major contributors to global warming. The use of building envelope along with the heating, cooling, and lighting design, operations, and infrastructures are the prime factors of this contribution. Due to this reason, the thermal comfort of buildings has become a major concern in building design globally. The following research explored the building design elements used for thermal comfort in residential buildings of Mansehra City of Khyber Pakhtunkhwa province in Pakistan and analyzed its transformation during the last three decades. The study proceeded by documenting and comparing various design elements to understand their transformation within documented time periods i.e. thermal mass, fixed shading devices, and the ratio of open and closed spaces. These elements were evaluated for their effectiveness in providing thermal comfort. It was concluded that these design elements have been adapted and modified with time with little concern for sustainability. It was found that the focus has shifted from building orientation, sun path, and wind directions to aesthetically pleasing forms only which makes them saleable and lack human comfort. The use of passive means to achieve thermal comfort was neglected. The research concludes by suggesting incorporation of appropriate thermal comfort components and methods into effective solutions for improved building designs, lower energy demand, and a better indoor atmosphere. Keywords: Thermal Comfort, Passive Design, Residential Building, Mansehra City, Global Warming

Multi-objective optimization of shading devices using ensemble machine learning and orthogonal design of experiments

Buildings are significant sources of energy consumption due to the non-optimal configuration of shading devices that results in excessive solar heat gain. Amorphous optimization of shading devices has not been explored in-depth using sophisticated modelling tools despite research efforts to optimize shading devices for different objectives such as energy consumption and occupant comfort. This study introduces updates to the existing framework for optimizing shading devices for multiple objectives. The objectives include occupants’ thermal Discomfort Hours (DH), Heating and Cooling loads (H/C), and total shading devices’ surface area. The existing framework in literature follows three main phases including data generation, Machine Learning (ML) models development, and optimization. In this study, three updates to the mentioned framework are proposed: First, the optimization of fixed shading devices is performed amorphously for maximizing the occupants’ thermal comfort; Second, the use of orthogonally structured training dataset to develop ML models; Third, incorporating the modern technique of Multi-Objective Manta-Ray Foraging Optimizer (MOMRFO) in the optimization phase. For only perimeter zones, amorphous shading devices can incur a maximum 12.7 % of H/C compared to the present situation of the case study when optimized for the H/C objective, while a maximum 2.8 % of DH can be saved compared to the present situation of the case study when optimized for the DH objective. Also, it is found that the payback period becomes high (18.35 years) when the DH objective is prioritized over other objectives. The study introduces a framework that couples orthogonal design of experiment with ensemble ML models to optimize the geometrical configuration of amorphous shading devices.

Modeling, Simulation, and Performance Analysis of a Liquid-Infill Tunable Window

Solar shading is important in buildings for better indoor thermal/light environment and energy conservation, especially in the tropical region. Compared with conventional windows with additional fixed shading devices, windows with adaptive self-shading functions take up less space and require less management labor. The present investigation focuses on a compact liquid-infill tunable window, which can provide adaptive shading with colored liquid-infill according to the surrounding environment. The numerical model of the liquid-infill tunable window was established on the basis of the law of energy and mass conservation, which enabled prediction of the adaptive response of the window under different boundary conditions. Then the thermal performance of this innovative window was analyzed in comparison with triple-layered clear glass windows. Influences of solar radiation level, incident angle, and ambient temperature were taken into consideration. The window was proven to be efficient in reducing indoor heat gain in the cooling season under strong solar radiation. With an 60° incident angle, the total indoor heat gain through window can be reduced by 1.60–8.33%. In the future, the established numerical model may be inserted into existing building simulation software as an energy-efficient window module to evaluate its energy and economic performance. The present study may inspire architectures and engineers in the design of near-zero energy and/or carbon neutral buildings.

Optimization of energy transmittance through building envelope for hot dry climate

Fenestrations of the buildings are playing an important role in the building’s energy efficiency for the tropical climate. The energy that comes from the glass window into the building can be restricted by providing shading on the windows. So, to provide the shading on the window, the most common way is fixed shade like overhang and fin. Shading devices are very helpful to control the SHGC and light transmittance through the fenestrations of the building. Most of the studies analyze the impact of WWR, shadings, and SHGC on a building’s energy demand but did not consider the combined effect of these parameters. By considering all the parameters of the building envelope in the analysis like WWR, orientation, shading devices, projection factor, and type of glass, the energy demand in the building can be significantly reduced. The goal of this paper is to analyze the variation of residential envelope transmittance value with the window-wall ratio, projection factor, and fixed shading devices and also to optimize the energy from building envelope elements in residential buildings using a statistical method, namely the Taguchi method. The transmittance of energy through the building envelope is calculated in 8 cardinal directions by providing shading with the fin and overhang. Based on the result, the optimum energy saving achieved by selecting the optimum combination of the process parameters for minimizing the energy from the building envelope is A1B1C3D2 i.e. window to wall ratio 7%, triple glazing type of glass used, shading with the overhang fin, and orientation in the west direction. The result shows the most significant factor among the selected parameter is the window to wall ratio. Also, by focusing on the building envelope parameters, an architectural designer may reduce the building energy demand significantly and offer more alternatives to achieve energy-efficient buildings.

Effect of overhang shade on the solar heat gain through window in composite climatic in mid-western India

Solar heat gain (SHG) through fenestration (window) dominates towards cooling demands in buildings and eventually increases electricity consumption. Integration of fixed shading devices (i.e. overhang) can reduce the solar heat gain through and overall energy consumption. In this manuscript, solar heat gain factor (SHGF) has been assessed for different designs of overhang. ASHRAE method of fenestration design and heat balance has been used for the estimation of the SHGF and solar gain in the buildings of different designs of overhangs. Further, the SHGF and solar gain have been used to determine accurate heating and cooling loads.The values have been estimated for the peak winter and summer months of December and June for Indore city, India. Significant reduction in heating and cooling loads in the buildings having windows with overhangs has been estimated in winter and summer seasons. Integration of overhang lowers the energy demand by over 50% and 30% in rooms having windows in south and east/west walls respectively. The results of the this study would be extremely beneficial for designing the fixed type shading device in buildings in order to controlthe heating and cooling loads and in achieving the sustainable development goals (SDGs 11, 12 & 13)

Efficient Shading Device as an Important Part of Daylightophil Architecture; a Designerly Framework of High-Performance Architecture for an Office Building in Tehran

(1) Background: considering multiple, and somehow conflicting, design objectives can potentially make achieving a high-performance design a complex task to perform. For instance, shading devices can dramatically affect the building performance in various ways, such as energy consumption and daylight. This paper introduces a novel procedure for designing shading devices as an integral part of daylightophil architecture for office buildings by considering daylight and energy performance as objectives to be optimal. (2) Methods: to address the topic, a three-step research method was used. Firstly, three different window shades (fixed and dynamic) were modeled, one of which was inspired by traditional Iranian structures, as the main options for evaluation. Secondly, each option was evaluated for energy performance and daylight-related variables in critical days throughout the year in terms of climatic conditions and daylight situations (equinoxes and solstices including 20 March, 21 June, 22 September, and 21 December). Finally, to achieve a reliable result, apart from the results of the comparison of three options, all possible options for fixed and dynamic shades were analyzed through a multi-objective optimization to compare fixed and dynamic options and to find the optimal condition for dynamic options at different times of the day. (3) Results: through different stages of analysis, the findings suggest that, firstly, dynamic shading devices are more efficient than fixed shading devices in terms of energy efficiency, occupants’ visual comfort, and efficient use of daylight (roughly 10%). Moreover, through analyzing dynamic shading devices in different seasons and different times of the year, the optimal form of this shading device was determined. The results indicate that considering proper shading devices can have a significant improvement on achieving high-performance architecture in office buildings. This implies good potential for daylightophil architecture, but would require further studies to be confirmed as a principle for designing office buildings.

Evaluating the Effect of External Horizontal Fixed Shading Devices’ Geometry on Internal Air Temperature, Daylighting and Energy Demand in Hot Dry Climate. Case Study of Ghardaïa, Algeria

The present study investigates the effect of fixed external shading devices’ geometry on thermal comfort, daylighting and energy demand for cooling and heating in the hot and dry climate of the city of Ghardaïa (Algeria). A parametric analysis was performed by using three software: RADIANCE 2.0 and DAYSIM 3.1 for daylighting simulation and TRNSYS.17 for thermal dynamic simulation. Three shading device parameters were assessed: the spacing between slats, the tilted angle and the slats installation. The vertical shading angle “VSA” is fixed; it is equal to the optimum shading angle measured for Ghardaïa. The simulation results indicate that fixed external shading devices have a significant impact on decreasing the energy demand for cooling; however, they are unable to reduce the total energy demand since they significantly increase heating loads. It was found that fixed external shading devices remove all risks associated with glare in summer by decreasing illuminance close to the window; however, they do not improve daylighting performance in winter because of glare. We note that even if the vertical shading angle “VSA” was the same for all cases, these did not present the same thermal and luminous behavior. This is mainly due to the amount and the way that the solar radiation penetrates space.

The Effect of Fixed External Shading Devices on Daylighting and Thermal Comfort in Residential Building

Building shading devices can improve the thermal comfort in indoor environment, and also reduce cooling and heating energy consumption in dry and hot climate. This study proposes the different kind of window’s fixed shading devices for energy consumption under near-extreme summer and winter conditions by conducting residential building energy simulations in Shiraz climate. Which fixed shading devices optimal configurations that give maximum energy consumption can be used in Shiraz climate. The study was based on modeling-simulation experiments where Ecotect models resented the actual building energy with and without shading devices to reducing heating and cooling load and peak consumption. The results obtained confirmed the accuracy of the model and the suitability of (horizontal, eggcrate and geometrical) of shading devices in reducing the solar gains in summer with reduced blocking of solar radiation in winter. In all cases it has been proven that excessive obstruction may yield an excessive reduction in a range of illuminances between 500 and 2000 lux, increasing lighting energy consumption. At the end results showed that horizontal, geometrical and eggcrate have the best function according to reduce energy and have enough day lighting in the zones in shiraz climate.

The effects of shading devices on office building energy performance in Mediterranean climate regions

Fixed shading devices (SDs) are still used as an essential and useful element in architectural design. Even with minor changes to be made when designing these devices, the energy performance of a building, especially in hot climate regions, can be significantly increased. In contrast to studies using one or a few parameters, this study aimed to make a comprehensive evaluation by considering more parameters simultaneously to determine energy-efficient fixed external SD scenarios that can be used in office buildings. This approach increases the accuracy of the results in terms of providing trade-offs. This study also aims to fill the gap of the research on SD strategies in Turkey. A total of 1485 scenarios were created with fixed external SDs (overhangs, horizontal and vertical louvers, and egg-crate variations) using the parameters of direction, glazing type, window-to-wall ratio (WWR), SD depth, and slope. Primary energy consumption values of all scenarios were calculated with the DesignBuilder software. Results were discussed according to the impact of each parameter on energy consumption and evaluated through descriptive statistical analysis. As a result, energy-efficient scenarios were determined. The best scenarios obtained for each SD type reduced the cooling energy consumption by between 37% and 49% compared to the no shading scenario using high-performance glazing type and by between 73% and 78% compared to the no shading scenario using low-performance glazing type. The total annual energy consumption was reduced by approximately 33% and 70%, respectively.

Energy Reduction, Daylight and View Quality Assessment of a Passive Dynamic Facade in Hot Arid Climate

Purpose This research aims to create a passive dynamic system with immediate responses to environmental conditions without needing an energy source to operate and reduce operation and maintenance costs. Design/Methodology/Approach There has been growing awareness in recent years of the energy consumption and interior environmental comfort of buildings. Substantial evaluation of the building envelope and indoor human experience is required to develop sustainable solutions, create a responsive system that enhances building performance and human comfort in terms of energy consumption and daylight quality. In this paper, a new proposed advanced integrated façade called a passive dynamic shading device (PDSD) is revealed. The system is designed to contribute to energy reduction, daylight availability, and view quality through its ability to change position and placement to respond and adapt to new climate conditions. The thermal expansion phenomenon was used in the actuation process, with heat-activated actuators that correspond to specific dry-bulb temperatures. This paper concisely demonstrates the functional mechanism and performance of the PDSD. Sophisticated energy and daylight simulations have been executed to distinguish between three case studies. Each case represents one architectural option: 1- without shading devices. 2- with conventional fix shading devices. 3- PDSD. Findings The result shows the PDSD can efficiently reduce overall energy consumption by up to 50%, increase the amount and quality of daylight by up to 60% compared to fixed shading devices, and obstruct the view from the interior 22% of the year. Research Limitations/Implications The limitation was with the thermal expansion mechanism since it expands due to the rise of temperature, which led to system movement in the ineffective time of a day. Social/Practical Implications The study is Creating a new affordable dynamic system comparing with an active dynamic façade system. The system is applicable on any building scale with simple construction. Originality/Value Unlike other dynamic façade system studies, in this study, the goal is to create a new passive system using the thermal expansion phenomenon and evaluate its effectiveness on energy reduction, daylight availability, and view quality.

Effect on Thermal Performance by Different Types of Fixed Sun Shading Devices

An application of sun-shading device is one of the options to elevate the exterior façade appearance while keeping the thermal performance at the best for the indoor. This research aimed to evaluate the effectiveness of selected types of fixed passive sun-shading devices installed at three-story terrace shop houses in Malaysia. Most previous studies on this passive strategy have been conducted via software simulation, in which results were not validated by field measurement. Therefore, this research employed stationary experiment on actual building and meteorological condition using three types of fixed shading devices: egg crates (SDE), vertical (SDV), and horizontal (SDH). SDE showed significant improvement on indoor thermal environment by reducing indoor air temperature (Ta ) of about 0.98 K on the average of a month and 2.11 K on the highest temperature on the average of a month. SDE also showed significant performance during the hottest sunny day, in which it reduced 1.23 K for the average of a day. Meanwhile, on the hottest peak time, SDE reduced 5.40 K compared to the control room. Similarly, for indoor mean radiant temperature (Tmrt), SDE showed notable performance during the high peak temperature on the average of a month (2.38 K) and during the hottest day (7.70 K) compared to control room, SDV, and SDH. On top of that, SDH also showed similar performance as SDE on the average of a month by a difference of 0.03 K. The experimental results also indicate that SDH showed the best performance at night by releasing heat faster than other types of sun-shading devices. This passive solution is one of the best options to improve indoor thermal performance and potentially contribute to energy savings on the building operation.

Simulation-supported shading design optimisation for a multi-storey building with passive cooling

This contribution reports on an ongoing research effort to reduce the heating demand and overheating risk in the cold and warm seasons respectively. A simulation-supported optimisation strategy for life cycle oriented buildings was pursued, resulting also in improved ratings in terms of the concurrently calculated mandatory Austrian energy certificate. Thereby, a range of different building types was considered, including a multi-storey building that uses locally available ecological construction materials and renewable energy. Apart from the heating demand of the building, the indoor environment for selected living units was specifically examined to avoid overheating risk and to increase the thermal comfort for the occupants. To reduce the indoor temperatures for different thermal zones, the dimensions of external shading elements were investigated. Likewise, natural ventilation scenarios were explored to improve summer-time thermal comfort conditions. The results suggest that by using properly dimensioned external fixed shading devices, especially in combination with natural ventilation, the indoor temperatures and also the thermal comfort can be improved significantly, while maintaining the passive house standard according to the Austrian energy certificate.

Solar Aperture of a Building Enclosure: The Case Study of a Well-Insulated Family House in Semi-Continental Climate

As thermal insulation of building enclosure has substantially improved over the last decades, solar heat gains comprise more important part in thermal balance of a building in semi-continental climate, often leading to overheating. The quality of the whole building enclosure should be assessed by its ability to transmit solar heat gains. Such thermal characteristic need to aggregate properties like glazing area in each facade, total solar energy transmittance of glazing, the efficiency of fixed shading devices and the operation of movable shading devices. In this paper, the surrogate horizontal effective collector area is used for the characterization of solar heat gains through a building enclosure. The parameter is called the solar aperture of a building enclosure. First, the formula for solar aperture is derived. Then, building energy simulation of a model family house is performed. The correlation of the solar aperture with overheating and space heating demand is analysed. Based on the analysis, the recommended trade-off values of the specific solar aperture are proposed for family houses in semi-continental climate. The trade-off values of the solar aperture will lead to reasonable promotion of solar heat gains during cold season and significant reduction of solar heat gains during warm season.

Comparison of static and dynamic shading systems for office building energy consumption and cooling load assessment

PurposeExterior shading devices and dynamic shading systems constitute an efficient way to improve energy efficiency and occupants’ comfort in buildings through the reduction of direct solar heat gains and disturbing glare. The purpose of this paper is to analyse the performance of different types of shading systems, fixed and dynamic, and their influence on the energy consumption and cooling loads for an office building located in Tallinn, Estonia. The scope is to determine the most performative configuration for energy consumption and cooling load reduction for office buildings and to provide designers and developers with the necessary knowledge to increase the performance of their buildings.Design/methodology/approachThere are many types of fixed shading devices, most of which use rectangular planar elements, the orientation and layout of which depends on the building location and façade orientation. The dynamic shading systems vary on the base of the building occupancy schedules and occupants’ preferences. The paper presents a method to determine the most efficient type and size of fixed shading devices in relation to different windows’ size and orientation, and the quantity of windows panes. At the same time the dynamic shading system using a control algorithm developed by the authors is compared.FindingsThe results show that solar shading is an efficient way to control the energy consumption of office buildings, though with different efficacy by the static systems depending on orientation, window and shading type. Evidence shows that dynamic blind systems have more uniform performance and usually outperform static shading.Originality/valueThe paper compares the performances of different static and dynamic shading devices and systems for the location in Tallinn. The dynamic shading system tested uses a control algorithm developed by the authors. The indications for the energy reduction and cooling loads are a valuable resource for designers and developers to increase the energy efficiency of their buildings.

Performance evaluation of a photovoltaic thermal-compound thermoelectric ventilator system

External fixed shading devices are generally used to adjust solar influx radiation and save energy in summer. However, they could block the beneficial solar radiation in winter. In this paper, a photovoltaic thermal-compound thermoelectric ventilator (PVT–TEV) system is proposed and investigated. The PVT–TEV system not only could prevent direct solar radiation from going into buildings in summer, but also could heat fresh air by the air-type PVT coupled with a thermoelectric ventilator system in winter. A PVT–TEV system was built in a room for testing the system. Results demonstrate that the performance of the PVT–TEV system is mainly affected by solar radiation when the system works in the sunny days of winter. The stronger the solar radiation is, the more the heat of PVT–TEV system gains and the higher the fresh air temperature is. The average electrical efficiency of PVT is 10%, the average thermal efficiency of PVT–TEV is 26.7% and the average COPh of PVT–TEV is 6.4. In the rainy day, the outdoor fresh air is heated when it flows through heat pipe exchangers of the thermoelectric ventilator. The higher the working voltage is, the more the heat TEV system gains and the lower the COPh of the TEV system is. The average COPh of PVT–TEV system is 1.73 when the operating voltage is 24 V. The PVT–TEV system provides an active and green method for building exterior shading device and supplying fresh air.

ALGAE AND BUILDING FAÇADE REVISITED. A STUDY OF FAÇADE SYSTEM FOR INFILL DESIGN

Buildings account for around 30 percent of the world’s total energy consumption and a similar percentage of the world’s greenhouse gas emissions the main cause of climate change. The building sector is a major energy consumer, and empirical research reveals that carbon-dioxide emissions from the building sector exceed those of the industry and transport sectors. Contextual juxtaposition has commonly been applied in designing a new building in the historic district. In the realm of design, such philosophy-based design approach requires objective measurements. When new glass building considered, the question on greenhouse gas emissions becomes significant. To minimize energy consumption and reduce sun glare, brise-soleil and horizontal fixed shading devices have been used as elements of building’s facade. Nowadays, algae as part of building facade system have been used in creating a healthier indoor environment. This paper is written based on an on-going architectural design-based research on the use and role of algae as part of the building facade system. The new building of ITB Innovation Park is used as an infill project. With the help of modelling and extensive literature survey, this research will investigate how far the building (facade) design is affected by considerations on energy consumption pattern and environmental condition.

Climate-based daylight analysis of fixed shading devices in an open-plan office

Office buildings consume large amounts of energy and are responsible for large amounts of greenhouse gas emissions worldwide. Among building energy efficiency measures, solar shading plays a significant role in reducing building energy consumption for cooling. This study analysed the influence of solar protection on daylighting of an open-plan office. Climate-based daylight modelling was used to predict such metrics as daylight factor, daylight autonomy and useful daylight illuminances. The results obtained showed that overhangs, and horizontal and vertical louvres have similar behaviours and sidefins have no relevance to indoor daylight conditions. In all cases, it has been proven that excessive obstruction may yield an excessive reduction in a range of illuminances between 500 and 2000 lux, increasing lighting energy consumption.

Impact of external shading devices on thermal and daylighting performance of offices in hot climate regions

Large windows and highly glazed façades have been increasingly used in new buildings, allowing access to daylight, solar gain and external view. Sunrays passing through non-shaded windows and glazed facades significantly increases the air temperature in summer, especially in hot climates such as in Jordan. This negatively affects thermal comfort, increases the cooling load and becomes a source of glare, which harms the visual environment. The current research examined the effect of using shading devices on air temperature, visual environment and users’ interaction in offices facing south-west façade at Jordan University of Science and Technology (JUST). Generally, shading devices are used to protect inner spaces from direct solar gain through openings, windows and large glazed surfaces. In such orientation, windows require special considerations to control solar gain, improve the visual environment and reduce glare. The research used real-time experiments and computer simulations to study how the shading devices will work in controlling air temperature and improving illuminance level. Three fixed shading devices (vertical fins, diagonal fins and egg crate) were installed in three identical offices in two stages: the first stage used temporary material while second one used improved design and permanent materials. Thereafter, the air temperature, illuminance level, thermal and visual environment were monitored and compared to non-shaded office. Computer simulations: IES/SunCast and Radiance were used to study solar and daylight distribution over the offices’ surfaces around the year. The results showed that the temperature in offices with shading devices compared to the office without shading devices was reduced to acceptable level. Visual environment was improved by controlling the illuminance level, improving uniformity and eliminating glare. Offices with diagonal fins and egg crate shading devices performed better compared to the office with vertical fins and the base case.

Genetic optimization of external fixed shading devices

In the present paper a genetic optimization (GO) has been carried out on an office room with a south facing window in order to design an optimal fixed shading device. Two different glazing systems have been taken into account, one standard double glass and an high performance glazing system specifically designed to prevent high sun loads. The shading device is a flat panel positioned parallel to the window and inclined by its horizontal axis. The device shades the window from direct sun penetration reducing the cooling loads in summer, but also affecting daylight and heat loads in winter limiting the sun gains, therefore the impact on the overall building energy consumption is investigated. A genetic optimization has been performed for identifying a possible geometry with the lower energy impact. Lighting loads, computed by the DAYSIM code, have been considered as inputs for the code ESP-r which drives the energy computation. The results demonstrate that electrical energy absorbed by the lighting system has to be always taken into account in designing energy efficient shading devices.

Conventional fixed shading devices in comparison to an electrochromic glazing system in hot, dry climate

Electrochromic glazing or exterior shading devices offer shading of the intense direct sun, reduce glare, and improve the daylight luminance within buildings. Additionally, they are important factors affecting energy performance of buildings as they impact the heating and cooling consumption. This analysis investigated the performance and the effectiveness of electrochromic glazing to prevent unwanted solar heat gains from entering a conditioned space. Then, these performances are compared to those offered by conventional fixed exterior shading devices in identical conditions. The aim of this analysis is to provide architects and designers with general guidance and appropriate design strategies for different window treatments and shading techniques during early design stages in hot, dry climate. A typical office building is modeled using DesignBuilder software. Building envelope characteristics, internal loads, and operating schedules including schedules for equipment, occupancy, interior lighting, heating, ventilating, air conditioning, and weather data are all unchanged throughout the simulation process. The windows shading condition and the glazing type are the only varying parameters. The output data show that electrochromic glazing provides the best performance in reducing solar heat gains compared to other tested shading conditions.