Movable Shading Devices Research Articles

Optimizing the Shading Device Configuration of Kinetic Façades through Daylighting Performance Assessment

When designing a façade, it is essential to consider the impact of daylight and how it can be optimized through external movable shading devices. To accurately evaluate the lighting performance of a kinetic facade, it is crucial to consider the operation of these shading devices, as they can significantly impact performance. This study proposes a high-precision methodology that utilizes digital tools and hourly data to examine the effectiveness of dynamic shading device systems in enhancing daylight performance and optimizing shading configurations using the Genetic Optimization algorithm. The study’s results demonstrate that the proposed methodology is accurate and effective, showing that the optimal operation scenario can exceed LEED v4.1 requirements while meeting daylight availability standards. Designers can achieve optimal performance by adjusting each parameter for a lighting energy-conserving kinetic façade. The limitations and applicability of this method are also discussed.

Exploring Energy Retrofitting Strategies and Their Effect on Comfort in a Vernacular Building in a Dry Mediterranean Climate

This research explores the energy behaviour of a traditional house on the Mediterranean coast of south-eastern Spain. The objective of the work is to determine the optimal passive strategies for rehabilitating a traditional house, improving its energy savings and comfort, considering the characteristics of the warm semi-arid Mediterranean climate. The main novelty of this article is that it demonstrates that the limits imposed by current regulations, based on globalised climate strategy approaches, undermine the energy efficiency capacity that passive solutions in vernacular architecture already employed. The methodology used consists of a systematised multi-objective study of various energy rehabilitation strategies. Four strategies were studied: raising the thermal insulation of enclosures, improving thermal insulation and solar control glazing with movable shading devices, increasing the size of windows and introducing the use of natural ventilation enhanced by ceiling fans. The results show that simultaneous improvement of these parameters reduces cooling and heating requirements by up to 87%, reducing the energy consumption of air conditioning systems. Indoor temperatures are also maintained within the comfort limits set by regulations for 91% of hours per year without the need for air conditioning systems. This results in a passive energy-efficient and comfortable house almost all year round. This work offers an alternative solution to the comfort standards of current Spanish regulations and demonstrates the need to adapt Fanger’s analytical method for comfort estimation. The research concludes that the comfort criteria of current energy regulations should be modified to better adapt the design criteria to the dry Mediterranean climate.

A Design Proposal for Improving Daylight Availability of a Deep-Plan Classroom by Using Tubular Daylight Guidance Systems and Movable Shading Devices

The use of daylight in educational settings has a significant impact on the well-being, attention, and academic achievement of students. However, providing adequate daylighting without glare can be difficult, especially in deep-plan layout classrooms, because daylight is not constant and its strength varies with distance from the façade, necessitating the use of additional solutions frequently. In this study, tubular daylight guidance systems (TDGS) and movable shading devices are proposed to increase daylight availability in the Yaşar University Faculty of Architecture Temporary Studio, which has a deep plan layout and receives daylight only from the southeast facade. The objective was to meet the LEED daylight evaluation requirements for each zone, which require sDA to be at least 55% and ASE to be at most 10% in the selected analysis area. To propose TDGS and movable shadings with the most efficient angles and positions; Rhinoceros, Grasshopper, and Climate Studio were used, and simulation results were validated by real-time measurements. The design proposal simulation results achieved a significant increase in daylight availability in the rear part of the room (zone 2-3), while glare was diminished near the façade (zone1). The proposed design strategy improved daylight availability through the room, demonstrating that the systems perform well together.

Optimization of Architectural Thermal Envelope Parameters in Modern Single-Family House Typologies in Southeastern Spain to Improve Energy Efficiency in a Dry Mediterranean Climate

The increasing regulatory requirements for energy efficiency in Europe imply a significant increase in insulation and solar control of buildings, especially in hot and semi-arid climates with high annual insolation such as the Spanish Mediterranean southeast. The consequences in architectural design to optimize compliance with the new technical and regulatory requirements of nearly zero-energy buildings are high. This paper analyzes the energy performance of a modern single-family house on the Spanish Mediterranean coast. The objective is to determine which design parameters most influence the energy improvement of this case study in order to establish design strategies that can be generalized to other new construction or energy retrofit projects, taking into account the specific characteristics of the warm and semi-arid Mediterranean climate. The scientific novelty of the work is to demonstrate that the design criteria of most modern single-family houses built or rehabilitated in the Spanish Mediterranean in the last decade comply with the energy efficiency requirements of Directive 2010/31/EU but are not specifically adapted and optimized for the special characteristics of the dry Mediterranean climate. This is the case of the house studied in this paper. The methodology used consisted of a systematized study of the main construction and geometric parameters that most influence the thermal calculation of this project: the thermal insulation thickness, thermal transmittance of the glazing, solar control of the glazing, total solar energy transmittance of the glazing with the movable shading device activated, size of glazing and the size of façade overhangs. The results obtained show that the use of mobile solar protection devices in summer, such as awnings or blinds, reduces the cooling need in summer up to 44% and the overall annual energy need (Cooling + Heating) up to 20%. This implementation is more efficient than increasing the thermal insulation of facades and glazing, reducing the size of windows or increasing overhangs. The most optimal solution is the simultaneous modification of several parameters. This reduces both heating need in winter and cooling need in summer, achieving an overall reduction in an annual need of 48%. This multiple solution improves the annual energy performance of the house much more than any solution consisting of modifying a single individual parameter. The results determine trends, explanations and deductions that can be extrapolated to other projects.

Evaluation of Building Energy Performance with Optimal Control of Movable Shading Device Integrated with PV System

Among the envelope components (e.g., walls, roofs, floors, and windows, etc.) affecting the cooling and heating load of buildings, windows are the most thermally vulnerable. Shading devices can minimize the thermal load on windows due to solar radiation and decrease radiation effects. However, the load changes due to convection and conduction should be considered. Therefore, when a shading device is applied to a window, control logic for thermal blocking and heat retention is necessary to prevent the load changes. In addition, by combining the opposite features of photovoltaic (PV) that require solar radiation and the shading device to block solar radiation, energy-saving and production can be achieved simultaneously. Therefore, this study minimized the thermal effects of windows using a movable shading device integrated with PV and evaluated the PV power generation. This study evaluated the effects on window heat transfer by applying artificial intelligence techniques, which have recently attracted attention, to system operation. To achieve this, artificial neural network (ANN)-based control logic was developed, and the control performance of the system was assessed using simulations. In ANN control, the window heat transfer was 86.3% lower in a cooling period and 9.7% lower in a heating period compared with that of a shading device fixed at 45°. Furthermore, the PV system produced 3.0 to 3.1% more electric power under optimal control during the cooling period.

Assessment of control strategy of adaptive façades for heating, cooling, lighting energy conservation and glare prevention

A movable shading device installed on an adaptive façade is able to change the positions of the shades according to the various control objectives (i.e. daylighting, thermal comfort, glare, energy, etc.) of the occupant. Since the key variables and the control method may change according to the control objectives, it is important to determine the hourly states of the shades in consideration of all of these factors. This study proposes a multi-purposes control strategy of adaptive facades for heating, cooling, lighting energy and glare. To depict the movements of the movable shading devices, the operable range is represented by an n number of fixed shade states having constant intervals. The control strategy entails deriving allowable shade states for glare prevention and energy conservation independently and then deriving the intersection range between the two shade state ranges. A case study was performed to verify the changes in hourly shade states and the energy performance of the envelope obtained by applying the proposed control strategy to an adaptive façade having a movable folding type shading device. The results of the case study show that hourly shade states were determined to satisfy the objectives of glare prevention and energy conservation simultaneously based on weather conditions and indoor requirement settings. From the case study, it can be seen that the proposed method can block the entry of direct solar radiation by lowering the unshaded fraction according to whether or not there would be discomfort glare while increasing the view factor in certain sections to promote the entry of diffuse solar radiation into the indoor space during the cooling and heating periods. The results of the case study also show that there can be large differences in the heating, cooling, and lighting energy performance of the building envelope for each orientation depending on the order of priority given to the objectives of the shading control, i.e. the objective of energy conservation only and the objective of simultaneous glare prevention and energy conservation. However, it was possible to effectively reduce the differences in energy proportions by adopting translucent shades.

Evaluation of the effectiveness of a multi-sectional facade with Venetian blinds and roller shades with automated shading control strategies

Daylighting plays an important role in building design. To maintain visual comfort and provide outdoor views, designers can use multi-sectional facades to extend daylit areas by daylight-redirecting devices and minimize undesired sunlight by movable shading devices. Beyond using specially designed light-redirecting systems, a combination of common shading devices – roller shades and blinds – may be used to meet aesthetic and cost requirements. However, the evaluation and simulation of multi-sectional facades are challenging, especially when the modeling involves complex fenestration systems and automated control strategies. In this study, we evaluate the effectiveness of multi-sectional facades with a roller shade and blind combination. Two control strategies are designed for two different multi-sectional facades, with a workflow developed for the evaluation. This workflow applies Radiance’s three-phase method for each shading state to model movable shades. External scripts are adopted to describe control algorithms and to generate annual results and daylight metrics. The workflow facilitates simulations of daylighting conditions for spaces equipped with both movable shading devices and daylight-redirecting devices under any customized control algorithms. The results demonstrate that the combinations of roller shades, blinds, and proper control algorithms greatly increase daylight near a rear wall compared to cases with only controlled roller shades, and do not cause glare. The combination with fixed blinds and controlled roller shades at the top section and another controlled roller shade at the middle section works well for rear spaces with south-facing or west-facing facades in both Taipei and New York.

Optimum design of building integrated PV module as a movable shading device

Building-integrated PV (BIPV) can be used as an external shading device as well as an electricity generator. In this study, the energy efficiency of the movable BIPV shading system installed over the windows has been investigated. In the first stage, the PV panels monthly electricity generation at different tilt angles and the building's monthly thermal load for the various overhang depth of windows were calculated. Based on the data obtained from these analyses, optimal condition for PV panel and overhang were determined for each month. In the next step, the geometry of the BIPV Panel was designed such that in each month the BIPV panel can provide obtained conditions. The movable BIPV shading was compared with the fixed modes include BIPV installed over the window with distance, BIPV installed over the window without distance, overhang, and no shading mode with fixed PV on the roof. The building annual thermal load integrated with the movable system, in comparison with four mentioned fixed modes is 12, 16, 15 and 20 % lower, and electricity generation, excessive to building thermal demand is 70, 142, 113, and 290 % higher respectively. The annual electricity generated by the movable PV is only 2 % higher than the fixed mode.

A Study on Multi-Objective Parametric Design Tool for Surround-Type Movable Shading Device

This study presents a multi-objective parametric design tool for four-axis surround-type movable shading device using solar position tracking in Seoul, South Korea. In order to explore large numbers of possible forms of shades, generic algorithms are utilized with real-time simulation of the performative criteria such as solar radiation, daylight glare probability (DGP), and solar shielding rate on window surface. This study outlines a workflow using a multi-objective engine called Octopus that runs within Grasshopper 3D, a parametric design tool, in addition to environmental performance simulation plug-in Ladybug. The workflow utilizes a performance-based design tool, which allows the designer to explore, sort, and filter solutions, and visually compare alternative solutions in terms of energy saving and indoor daylight quality in order to determine the optimal form of shade changing its shape every one hour. The result of deriving and analyzing the optimal shade shape through the genetic algorithm proposed in this study is as follows: On the one hand, on the summer solstice, shade shapes with shielding areas of almost 100% should be derived to achieve the most effective reduction of the direct solar radiation. The proposed movable shading device reduced direct solar radiation by 52.40% and 57.20% in the south- and east-facing windows, respectively. On the other hand, in winter when solar heat gain is important, the absence of sunshade is optimal in terms of heating load. However, in order to improve the indoor light environment, it is confirmed that it is possible to derive a certain shape of sunshade according to the sun’s trajectory. On the winter solstice, the problem of glare arises from 10:00 to 15:00 in the south and 10:00 in the east. Therefore, the proposed four-axis movable shading device can be configured to have a minimum protrusion length satisfying DGP less than 0.35 in winter.

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.

Gevo announces breakthrough development of renewable isoprene, a key chemical building block for producing rubber and rubber products

A movable shading device installed on an adaptive façade is able to change the positions of the shades according to the various control objectives (i.e. daylighting, thermal comfort, glare, energy, etc.) of the occupant. Since the key variables and the control method may change according to the control objectives, it is important to determine the hourly states of the shades in consideration of all of these factors. This study proposes a multi-purposes control strategy of adaptive facades for heating, cooling, lighting energy and glare. To depict the movements of the movable shading devices, the operable range is represented by an n number of fixed shade states having constant intervals. The control strategy entails deriving allowable shade states for glare prevention and energy conservation independently and then deriving the intersection range between the two shade state ranges. A case study was performed to verify the changes in hourly shade states and the energy performance of the envelope obtained by applying the proposed control strategy to an adaptive façade having a movable folding type shading device. The results of the case study show that hourly shade states were determined to satisfy the objectives of glare prevention and energy conservation simultaneously based on weather conditions and indoor requirement settings. From the case study, it can be seen that the proposed method can block the entry of direct solar radiation by lowering the unshaded fraction according to whether or not there would be discomfort glare while increasing the view factor in certain sections to promote the entry of diffuse solar radiation into the indoor space during the cooling and heating periods. The results of the case study also show that there can be large differences in the heating, cooling, and lighting energy performance of the building envelope for each orientation depending on the order of priority given to the objectives of the shading control, i.e. the objective of energy conservation only and the objective of simultaneous glare prevention and energy conservation. However, it was possible to effectively reduce the differences in energy proportions by adopting translucent shades.

가변차양 막재의 물리적 성능에 대한 분석

This study investigates the physical performances of membrane materials that can be possible applied to movable shading devices. Various experiments and tests were conducted in lab settings based on the guidelines suggested for standard tests for the materials. Result indicates that folded tensile strength was similar to tensile strength. The tensile strength of materials which were exposed to ultraviolet was 30 % of that of material which was not exposed to ultraviolet. The resistance against contamination of all tested material do not satisfy domestic requirements but meet some of foreign standards.

Prevention of summer overheating of buildings with added convex windows

When renovating an existing building, keeping the original window and installing added convex window is beneficial for the reduction of heating energy demand. This solution is free of the disposal and/or recycling of demolition waste. In the summer season as far as the transparent structures of the building are concerned, in general, heat protection has to be used. In the case of the added convex window, it can be provided by the external air curtain mode; the movable shading device is in the buffer zone. This is a well-protected place for it, so that it can be as simple and cheap as an inner shading device. In this article examinations of the efficiency of the external air curtain mode for the heat protection is presented. The summer overheating has been analysed in two experimental huts. It has been proven that simple shading device in added convex window tempers the summer overheating as efficiently as the combination of usual window and external shading device (which is exposed to heavy weather effects and is difficult to maintain).

The role of shading devices to improve thermal and visual comfort in existing glazed buildings

Buildings with large glazed surfaces may show severe thermal and visual discomfort issues, as an effect of the large incoming direct solar radiation. In order to avoid excessive solar gains and glare issues to the occupants, it is necessary to adopt suitable solutions that limit the incoming solar radiation, such as highly reflective coatings or movable shading devices. However, such devices must be accurately selected, according to the building location and to the exposure of the glazed façades, while also taking into account possible regulatory measures. This paper evaluates the effectiveness of a series of shading devices applied to an existing office building in Southern Italy. The building shows large glazed surfaces and has no overhangs, thus significant thermal discomfort is perceived in summer by the occupants. The aim is to identify those solutions that allow to improve thermal comfort while also keeping a sufficient illuminance level indoors, without disregarding the compliance with Italian regulations about the installation of shading devices and, of course, the need to keep costs on a reasonable level. The analyses are repeated for different building orientations, in order to provide general information.

Method of Deriving Shaded Fraction According to Shading Movements of Kinetic Façade

Exterior dynamic shading devices, installed on “kinetic façades”, generate shaded areas of various shapes on windows according to the shape of the shading elements and the direction of their movement. The calculation of the shaded area is vitally important because it is directly related to the solar heat gain calculation process in building energy assessments. This paper dis-cusses a dynamic calculation method for deriving shaded fractions in consideration of the irregular shapes and unique movements of the shading elements in kinetic façades. The planar-polygon method was adopted for calculating accurate shaded areas on a window generated by irregularly shaped shade elements. To account for movements of the shading elements, the range of movement directions (i.e., rotating, sliding, etc.) was divided into steps of equivalent intervals. Applying these two methods, a shaded area calculation tool for the kinetic façade was developed. Three movement directions of shading devices were chosen for calculating shaded area, and the values of shaded fractions for six kinetic façade types were derived for different façade orientations during the summer and winter solstices. Lastly, to simplify the detailed calculation method, estimation equations for two types of kinetic façade were derived from a trend analysis of the shaded fraction values. This study deals with both detailed and simplified methods (estimation equation) for deriving the shaded fraction. The detailed method can be a more accurate solution in deriving the shaded fractions generated by complex exterior movable shading devices. However, the simplified method can be adopted in the early design stages to review various shading devices within a brief duration of time.

Lighting and cooling energy assessment of multi-purpose control strategies for external movable shading devices by using shaded fraction

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.

A Comparative Study of the Building Energy Performance of Thermotropic Windows

This paper conducted a study on the energy-saving potential of a developed thermotropic window. Office buildings in different climate regions of China were compared in terms of heating, cooling and lighting energy demands. Results show that annual heating and cooling energy demands for office buildings differ largely, while lighting energy demand at different climates keeps a significant percentage of the total energy demand, ranging from 36.1% to 66.3%. Meanwhile, thermotropic windows achieve a great advantage in improving daylighting performance and in reducing the overall energy demand, by reducing the overall energy demand by 2.27%-8.7% and 10.1%-21.72%, respectively, compared to movable shading devices and Low-E windows. This means that this kind of thermotropic windows have a great potential in applications in different climatic regions and can be considered as a good substitute of solar shading devices and Low-E windows.

차폐면적비를 고려한 외부 가변차양 제어 알고리즘 개발

An external movable shading device is installed on an envelope to control light and thermal environments. This device is typically used to improve a visual comfort by blocking direct solar radiation, rather than limitedly applied to control a thermal environment. This paper proposes a shaded fraction control algorithm, which can be applied to external movable shading devices, to satisfy visual comfort and reduce heating and cooling load at the same time. The shaded fraction and profile angle are set for controlling parameter. The optimized shaded fraction is derived by considering glare, illuminance, heating load and cooling load through decision process of a control algorithm. Finally, allowable range of movements is determined by applying the optimized shaded fraction. Energy simulation is performed by applying shading control method such as energy reduction, glare protection, visual comfort. The simulation result confirms that the three control methods are satisfied to prevent glare and effective in energy savings than control methods proposed in previous studies.

FAST energy and daylight optimization of an office with fixed and movable shading devices

This paper describes the Energy and Daylighting optimization of a fixed inclined panel which shades an office room with a south exposed window. The window features also user deployable internal Venetian blinds. Energy analysis takes into account the primary energy required for heating, cooling and artificial lights. Different numerical codes have been employed in order to perform the simulations required by the optimization process: Daysim estimates the artificial light consumption based on daylighting distribution, ESP-r computes heating and cooling loads and modeFRONTIER integrates the simulation codes in an automatic optimization loop. The performance of an algorithm specifically designed to deal with problems involving long simulation times (combining response surfaces and genetic algorithms) has been successfully evaluated; the algorithm has then been applied in the optimization loop. The optimized solutions are analysed in this paper, in particular three solutions have been selected: minimum primary energy consumption, minimum hours of blind deployed and an intermediate solution. The analysis compares the primary energy consumption and daylighting performance on the basis of the Useful Daylight Illuminance indicator and the time history of illuminance on predefined locations.

Evaluating Thermal and Lighting Energy Performance of Shading Devices on Kinetic Façades

In order to evaluate the thermal and lighting energy performance of a kinetic façade using external movable shading devices, it is important to consider the operation of the shading devices since it can influence the performance significantly. This study proposes a calculation methodology which assesses the performance of the movable shading devices with the consideration of the movements of the shading devices. Calculation methods were derived by which solar heat gain, lighting energy requirement, and the primary energy equivalent to heating and cooling energy requirement can be obtained. Using the calculation methods, the optimal operation scenario for the movable shading devices was presented which can minimize the solar heat gain and lighting energy requirement. A comparison case study was carried out to demonstrate the use of the control strategies for a building where a drop awning was installed. The results showed that the optimal operation scenario suggested in this study can potentially deliver effective energy performance. The limitation and applicability of the suggested method were also discussed.