Solar Shading Systems Research Articles

Characterisation of view relative to solar-control systems

Solar shading can be an effective way of avoiding overheating by reducing solar gains in buildings. However, solar shading systems can block or obscure the view-out with the consequence that occupants may refrain from using the shading system. As such, there is a need to quantify the effects of shading on occupants’ perception of the view.In this study, we developed a method to identify the photometric parameters and compositions that are effective in characterising the view-out in relation to different solar-control systems. We hypothesized that the photometric composition, e.g., contrast, in the visual environment as a result of using solar-control systems impacts the subjective assessment of the view. We conducted objective photometric measurements using calibrated luminance cameras and subjective responses from 64 participants in a semi-controlled work environment to test the hypotheses. The participants were randomly allocated to a combination of five view-outs and six solar shading systems in a work environment where they answered questions related to the indoor environment and view quality. The relation between view and solar-control systems and their impact on the subjective view assessment was tested using linear mixed-effects models. The models were developed using forward and backward selection based on AIC and likelihood ratio tests (LRT) to test the effects of adding or removing variables. The achromatic contrast calculated based on the measured luminance data both locally and globally was significantly associated with view assessment and satisfaction when using different shading types.

Evaluating the impact of high-resolution irradiation data on the daylight performance assessment of adaptive solar shading systems

Adaptive solar shading systems offer a dynamic solution to balance daylight availability and glare control in buildings. While building performance simulation methods are useful to understand the potential of these systems to improve daylight conditions in indoor spaces, it is unclear if established practices such as the use of hourly averaged climate data are sufficient to accurately estimate the benefits of adaptive solar shading in real-world conditions. This study investigates how the time resolution of irradiance data in simulation models affects the predicted performance of adaptive solar shading systems. To that end, a series of simulations for models with time resolutions from 1 to 60 min are run, and the results are compared to quantify the variation in daylight metrics between different resolutions. The outcome of this comparison study reveals that while hourly averaged irradiance data generally suffices for daylight performance estimations, it is also likely to overlook short-term periods of glare discomfort that would be present in high-resolution irradiance data. In the context of adaptive shading design, capturing these discomfort periods can be key to providing solutions that achieve specific visual comfort goals. This suggests that the need for high-resolution irradiance data is project-specific, which emphasizes the need for more tailored approaches in the representation of adaptive shading systems in early building design.

Modeling a solar shading system that controls heat gain by using solar energy to change louver slat angles

In this study, we propose a model for a passive louver system that adjusts slat angles using solar heat energy. The model is structured in two stages: predicting the surface temperature of a solar collector plate and using this temperature to determine the slat angles. The system was installed and monitored in a building in Okinawa, Japan, to validate the model’s accuracy with field measurements. The validation showed that while the model accurately predicted the daily opening and closing times of the louvers, it faced limitations in minute-by-minute variations, making it less suitable for scenarios requiring instantaneous state evaluations, such as lighting environment assessments. Additionally, predicting the temperature for the double-skin façade was challenging and could affect overall model accuracy. Despite these issues, the model effectively achieved its primary goal of predicting annual energy consumption by accurately forecasting the daily opening and closing times of the louvers. The model’s fast computation speed and simplicity make it particularly suitable for annual energy simulations and easy to integrate with existing energy simulation programs. Further research is needed to enhance minute-by-minute reproducibility and integrate temperature predictions for double-skin façades, ensuring a comprehensive evaluation of both thermal and lighting environments.

An environmental quality assessment of office buildings: The impact of glass façade on internal and external users

People are spending an increasing amount of time inside buildings. Working spaces have a very strong influence on peoples’ activities and well-being. Therefore, the quality of indoor environment is important for all occupants, as it can contribute to illness and lack of productivity. An increasing number of office buildings with glass facades impact not only internal occupants, but also external users who spend time around those buildings. This paper aims to assess the interaction of internal and external users and the glass façades of office buildings in Zagreb, Croatia. The focus of this research is not only physical parameters of glass facade: materials, proportions, colours, thermal and acoustic characteristics, airtightness, and its impact on occupants. Also, the relationship between inside and outside is essential for spatial awareness. Having access to views of the outside and providing natural light are important for occupants’ well-being. Solar shading system, anti-glare protection, the tint of the glass, transparency and translucency of glass façade also significantly affect external users and their perception of the building. The graduate course ‘Architecture and Technology 1’ at the Faculty of Architecture, University of Zagreb, aims to educate master students on assessing the environmental performance of existing buildings. Analysing examples of built office buildings with glass facades and the results of student survey of internal and external users of those buildings, this paper discusses working conditions, indoor and outdoor atmosphere, technical solutions, as well as architectural approaches in accordance with implementation of principles of sustainable development. The results of this research should provide useful information on users’ satisfaction, well-being, and requirements for future application in glass facade design for office buildings.

Effect of green infrastructures supported by adaptative solar shading systems on livability in open spaces

Lack of thermal comfort in the existing building stock in many warm summer climates and the COVID-19 pandemic have increased residents' temporary occupation of urban open spaces. However, climate change and other effects such as urban heat islands are also negatively affecting the livability of these spaces. Therefore, strategies are needed to improve the thermal conditions in these areas. In this context, the research designs, simulates and assesses an urban green infrastructure supported by an adaptative solar shading system. For this purpose, a public square to be renovated in Seville (Spain) is chosen. After an analysis of the current situation, more vegetation is added. However, trees are not planted fully grown, so their cover is not enough in the short term and an artificial system that protects from the sun by casting shade and that adapts to both their growth and the seasons is included. The urban space is characterized by on-site measurements, proposing four (initial, intermediates and final) scenarios using computational fluid dynamics simulations in an holistic microclimate modelling system. In turn, changes in thermal comfort are analyzed using the COMFA model. Results show that the air and surface temperature are decreased, reducing the number of hours in discomfort by 21% thanks to incorporating the green structure and by 30% due to the vegetation. It can be concluded that the use of these temporary urban prostheses enables urban spaces regenerated with vegetation to be enjoyed without waiting 20 or 30 years for the trees to mature, encouraging people to spend more time outdoors from the start of the intervention.

Green Building Concepts and Technologies in Ethiopia: The Case of Wegagen Bank Headquarters Building

The building sector is a key contributor to climate change, accounting for 40% of global energy consumption and 39% of CO2 emissions. Presently, green buildings have been viewed as crucial strategies to reduce the negative effects of the construction sector. Yet green building research is often carried out in developed countries, while relatively little is known in sub-Saharan African countries. Therefore, this study attempts to investigate the extent of adoption of green building concepts and technologies in Ethiopian buildings, with particular reference to the Wegagen Bank Headquarters building. The study employed an interview, which was underpinned by observation. The quantitative data were analyzed through descriptive statistics while the qualitative data were analyzed through content and context analysis. Results revealed that while the building provides convenient access to transportation; it lacks designated open spaces. Based on the findings, the widely used technologies were energy-saving lighting, highly efficient plumbing fixtures, and external solar shading system. Lack of awareness, lack of policy, insufficient professional skills, the perception that green buildings are expensive, and lack of green building materials hindered the adoption of the concepts. Therefore, the study suggests developing green building policy and rating systems, professional capacity building, and awareness creation as important measures.

Design of adaptive solar shading system based on the Cuboctahedron

Design of adaptive solar shading system based on the Cuboctahedron

Effect of Roller Shades on Chromaticity and Colour Rendering Performance of Transmitted Daylight

Several studies have focused on the performance of roller shades in terms of glare, outdoor vision, daylight availability and energy performance. Currently, other parameters linked to visual amenity, such as chromaticity and colour rendition, are becoming relevant. When solar radiation passes through a window, it changes its spectral composition due to the presence of the solar shading system and the glazing. Against this background, the present study focuses on the spectral transmittance of eleven woven screen fabrics and its influence on the chromaticity and colour rendition. Results show that dark-coloured woven screen shades provide higher correlated colour temperature (CCT) values (range 6470 K - 6479 K) and therefore would produce “cooler” visual environments, while light-coloured woven screen shades provide lower CCT values (range 5210 K - 5644 K) creating “warmer” visual environments. Regarding colour rendering metrics, the light transmitted through all the studied woven shades shows excellent colour rendition. Finally, it is concluded that the combined analysis of optical properties, spectral data and its impact on parameters that determine the quality of lighting in an interior space enables an understanding of woven screens performance, which results in the possibility of taking appropriate decisions when selecting woven shades.

Characterization of view in relation to solar-control systems

In this study, we developed a method to identify the affecting parameters that can characterize the view-out in relation to different solar-control systems. We hypothesize that the photometric composition, e.g., contrast, in the visual environment as a result of using solarcontrol systems impacts the subjective assessment of the view out. To test our hypothesis, we conducted user assessment studies where we measured objective photometric measurements and subjective human responses in a real semi-controlled environment. The user-assessment study was done with 51 participants. The participants were randomly allocated to a combination of five views out and six solar shading systems in a work environment where they answered questions related to the indoor environment and view quality. The relation between view and solar-control systems and their impact on the subjective assessment of view out was tested through the development of linear mixed-effects models. The models were developed using forward and backward selection and likelihood ratio test (LRT) to test the effects of adding or removing variables.Photometric quantities were measured as achromatic contrast and calculated both locally and globally, which are two different algorithms for the calculation of contrast as perceived by humans. Both were found to be significantly associated with respectively view rating and satisfaction and could be used to characterize the view-out quality through commonly used shading devices.

Improving Liveability in Open Spaces Through the Integration of Adaptive Solar Shading Systems: A Case Study in Seville, Spain

Improving Liveability in Open Spaces Through the Integration of Adaptive Solar Shading Systems: A Case Study in Seville, Spain

Multi-state vertical-blinds solar shading – Performance assessment and recommended development directions

The aim of this paper is to evaluate the potential of a novel multi-state sun-tracking vertical-blind (ST-VB) concept using building performance simulation (BPS). A multi-domain simulation toolchain was developed and verified to evaluate the interior vertical-blind concept. The toolchain is used to quantify whole-building performance effects of design choices in the development of the initial concept within a larger framework of functional and aesthetic requirements. Multiple control concepts are tested, including different sun-tracking approaches, utilising the double-sided blind to switch between absorbing and reflecting solar radiation, and the ability to fully retract the blinds versus rotating them into an open position. Different possible materialisations of the blind are tested by evaluating the performance sensitivity of each of the potential control strategies to varying the blinds' solar and visible reflectance. The most promising ST-VB strategies perform substantially better than a conventional automated roller-blind strategy in terms of preventing visual discomfort (8% less DGPs0.4exc0deg), the admission of daylight (75–99% higher sDA300lx/50%), allowing for views to the outdoors (8–33% more hours with a view), and energy performance (11–35% reduction in primary energy consumption for heating, cooling and lighting). This research concludes with a set of recommendations for the development of the ST-VB system and by extrapolating the ‘lessons-learned’ for future research and development into multi-state solar shading systems. The novelty of this research can be found in that automated control concepts for interior vertical blinds have thus far been largely unexplored. Additionally, this research contributes to the body of knowledge on performance modelling of complex fenestration systems and the use of BPS in the, relatively new, context of product development.

Solar-shading systems designed to increase user satisfaction in public buildings, a case study of Britam Towers in Nairobi, Kenya

Solar-shading systems play various roles to the users of public buildings and may vary from user to user but some of the common user’s needs for these systems include; thermal comfort, energy-saving, daylight, and glare reduction. Understanding these needs can help Designers and Architects select from a wide array of Solar-Shading types and see which of them serves the needs of the users better. The Types of Solar-Shading Systems include either internal systems which are placed inside the building or can include external systems which are placed to the outside of buildings. To clearly understand the role Solar Shading Systems, play to satisfy Users’ needs, a case study of a Public Building in Nairobi, Kenya; Britam Towers, was selected. The case study found out that architects, designers, and developers play a preeminent role in coming up with projects that can better serve the User’s needs by creating designs that better suit the needs of the users have for using such Solar-Shading Systems. These designs may vary from building to building, region to region but the main withstanding factor to be noted is the functionality issue, as the Solar-Shading Systems should be able to meet the needs of users effectively and in turn, increase the user’s satisfaction.

Building Energy Management for Passive Cooling Based on Stochastic Occupants Behavior Evaluation

The common approach to model occupants behaviors in buildings is deterministic and consists of assumptions based on predefined fixed schedules or rules. In contrast with the deterministic models, stochastic and agent based (AB) models are the most powerful and suitable methods for modeling complex systems as the human behavior. In this paper, a co-simulation architecture is proposed with the aim of modeling the occupant behavior in buildings by a stochastic-AB approach and implementing an intelligent Building Energy Management System (BEMS). In particular, optimized control logics are designed for smart passive cooling by controlling natural ventilation and solar shading systems to guarantee the thermal comfort conditions and maintain energy performance. Moreover, the effects of occupant actions on indoor thermal comfort are also taken into account. This study shows how the integration of automation systems and passive techniques increases the potentialities of passive cooling in buildings, integrating or replacing the conventional efficiency strategies.

Assessment of angular visual transmittance of Perforated Masonry Walls patterns employed as solar shading systems

Perforated Masonry Walls are traditional construction systems typical of the Mediterranean area, especially in existing rural buildings. Practical reasons are linked to their original employment as a separation element meant to be air permeable to promote cross-ventilation. Successively, they started to be designed for achieving architectural goals, integrating them with additional internal glazing. Moreover, due to their geometry, they can behave like real solar radiation shades, permitting daylight influx while controlling solar penetration. The implication of the use of these systems on daylighting and energy fields have not been widely analysed. This research intends to establish a starting point for their detailed daylighting analyses, considering them as Complex Fenestration Systems. To do so, brick materials were characterized through direct measurements of visual reflectance on a heterogeneous group of brick samples. Results show that reflectance values fall within the range of 0.081–0.262. Angle-dependent transmittances of seven masonry patterns were produced using Bidirectional Scattering Distribution Functions (BSDF) calculated with Radiance. For which, the highest reduction in visual transmittance values was found for solar incidence angles greater than 45°, reaching peaks approximately at 55–65°. These were tested and compared as shading systems on a test room with a South oriented glazed façade, located in Milan. Their implementation resulted in a mean indoor illuminance decay of ~15%. Lastly, the perforation ratio was confirmed not adequate to provide an insight into the visual performance of shading devices.

Study on solar shading systems for designing nZEB kindergartens in Italy

The use of solar shading in buildings necessarily affects energy balance and energy demand. The aim of this study is to evaluate the efficiency of the most common solar shading for kindergartens to improve their energy and environmental performance. The research considers different types of solar shading for a southern orientation, their possible implementation with automated control systems, the relation with the window-to-wall ratio and finally the addition of vertical solar shading for eastern and western orientations.

Multi-Objective Analysis of a Fixed Solar Shading System in Different Climatic Areas

This study tackles the analysis of fixed external solar shading systems. The geometry of a building and of the shading system has been parametrically defined and a genetic optimization analysis has been carried out to identify an architectural solution that would allow the increase of energy savings, through a suitable window-to-wall ratio and an accurate design of the shading device. A multi-objective analysis has been performed with the aim of minimizing the energy consumption for space heating, cooling and artificial lighting, while ensuring the visual comfort of the occupants. The main goal of the study is to explore the influence of climatic context on the optimal design of shading devices. The analysis has been performed for three different latitudes across Europe. In all analyzed cases, a reduction of the annual energy consumption could be achieved, up to 42% if the optimal shading configuration is used. Moreover, the possibility of integrating the shading system with photovoltaic (PV) panels has been considered and the electricity production has been estimated.

Evaluation of School Building Energy Performance and Classroom Indoor Environment

Existing building stock represents potential for energy saving renovations. Energy savings and indoor climate comfort are key demands for sustainable building refurbishment. Especially in schools, indoor comfort is an extremely important issue. A case study of energy consumption in selected school buildings in temperate climatic conditions of Central Europe region was performed. The studied buildings are representatives of various school premises constructed throughout the last century. The evaluation was based on data analysis of energy audits. The goal was aimed at assessment of the school building envelopes and their influence on energy consumption. One of the studied schools was selected for detailed evaluation. The school classroom was monitored for indoor thermal and visual environments. The monitoring was performed to compare the current state and renovation scenarios. Results of the evaluation show that the school buildings are highly inefficient even if renovated. Indoor climate in classrooms is largely influenced by windows. Solar gains affect interior thermal stability and daylighting. Thermal insulation quality of building envelopes and efficient solar shading systems appear to be fundamental tasks of school renovation strategies.

Application of double glazed façades with horizontal and vertical louvers to increase natural air flow in office buildings

The results of previous researches clearly indicate that the main concern in applying double skin façades (DSF) is overheating of the cavity and increasing the cooling energy consumption in warm seasons. The present study intends to consider the excessive heat trapped between two skins of double glazed façades in hot arid climates as a driving force to reinforce the natural airflow across the floors of an office building. To meet this purpose, numerical simulation of airflow and heat transfer inside the cavity of the double glazed façades and the adjacent floors, as well as the effect of different types of solar shading systems in horizontal and vertical modes on the airflow has been investigated using the CFD technique. The results show that the stack effect formed inside the cavity has enough power for air suction from the floors of the building and reinforcement of the natural airflow. The type of shading device has a significant effect on the airflow behavior and the heat transfer rate in the facade. In double skin facades with horizontal louvers, the buoyancy forces inside the cavity are stronger and the ventilation rate in the building floors is higher than the model with vertical louvers. On the other hand, due to the stronger convective flow in the cavity with horizontal louvers, the heat flux on the interior glass is higher than the cavity with vertical louvers and part of the heat inside the cavity is transmitted through the interior skin to the occupied spaces.

Glare from Windows Assessment at Offices with Three Types of Internal Solar Shadings

Successful daylighting requires trade off and optimization between competing elements of façade, space, and lighting system. It also requires reliable tool for assessing the indoor visual comfort, especially discomfort glare from windows. The objective of the study was to investigate the users’ glare perception due to the use of internal solar shading systems by using laboratory experimentation with subjects and measurements. The purpose was to compare these results with a glare rating equation and Luminance Distribution Ratio (LDR) and to assess the reliability of this glare assessment tool to be used for assessing glare from window and in the context of humid tropics climate. The laboratory experimentations were conducted at three identical office rooms at the Department of Architecture of ITS in which each of the room’s windows was covered with different internal solar shading types e.i. Venetian, Horizontal, and Roller Blinds. Results showed good correlation between Luminance Distributions Ratio (LDR) with the users’ responses. Among the three internal shading, the Roller blind type had the highest correlation on both working activities and sitting positions to the glare perception as well as the fittest value complying the standard of luminance distribution. The research concluded that the Luminance Distribution Ratio method can be a reliable tool for assessing glare from window for many office situations in humid tropical climate.

Dynamic shading systems: A review of design parameters, platforms and evaluation strategies

The advancements in software and hardware technologies provide opportunities for solar shading systems to function dynamically within their context. This development has helped dynamic shading systems respond to variable environmental parameters such as sun angles and solar insolation. However, the technical understanding of system design, mechanism and controlling methods presents a challenge for architects and designers. Therefore, this study aims to review the current applications and trends of dynamic shading systems to clarify the potentials and limitations in enhancing system performance based on integrated design objectives. This study assessed several systems on the basis of a critical review to identify different models, applications and methodologies. This study is divided into two main sections: (i) design elements and platforms that engage with specific methods in creating a dynamic shading system and (ii) evaluation strategies to examine system performance. The systems were investigated based on the multiplicity and integration of the parameters involved through various components, such as architectural, mechanical, operational and automation components. The review analysed various studies on the following two bases: (1) geometric-based analysis, which distinguishes between simple and complex shading models, and (2) performance-based analysis, which assesses the shading systems based on two groups of methodologies, namely, theoretical and experimental. The outcome of the review reflects a clear classification of shading models and a comprehensive analysis of their performance. This study generally provides a systematic framework for architects based on thorough research and investigation. Finally, the study introduced several findings and recommendations to improve the performance of dynamic shading systems.