Shading Performance Research Articles

High-Performance Triboelectric Nanogenerator Based on Silk Fibroin-MXene Composite Film for Diagnosing Insomnia Symptoms.

In this study, we developed a flexible, biocompatible, and high-output electrical performance triboelectric nanogenerator (TENG) employing a silk fibroin (SF)-MXene composite film (SF-MXene-F) and a PDMS film as the friction layer. The inclusion of MXene in the SF film increased its surface charge density, presenting a practical approach to designing high-performance SF composite film-based TENGs. At a MXene content of 40%, our SF-MXene composite film-based TENG (SF-MXene-FTENG) achieved optimal output electrical performance, featuring a maximum open-circuit voltage (Voc) of 418 V, a maximum short-circuit current (Isc) of 11.6 μA, and a maximum output power density of 9.92 W/m2. The Voc and power densities of the SF-MXene-FTENG surpassed previously reported optimal values for SF-based TENGs by 1.6 and 3.8 times, respectively. Furthermore, leveraging the exceptional biocompatibility and light shading performance of TENGs, we designed a wearable smart TENG eye mask capable of diagnosing insomnia symptoms and monitoring sleep quality in real time. The SF-MXene-FTENG holds promising application potential as a wearable electronic device for diagnosing sleep-related diseases.

Adaptive shading: How microclimates and surface types amplify tree cooling effects?

Shading is the most critical process in tree cooling. Although the influence of tree features on shade supply has been extensively studied, the efficiency of shade performance in diverse environments remains poorly understood. The latter is crucial, as urban areas are highly heterogeneous, and local microclimates and land cover heterogeneity are among the most perceptible and observable aspects. We randomly selected several typical tree patches in Beijing to explore whether and how tree-shade efficiency varies with these factors. We used temporal variations as a proxy to study the impact of microclimatic heterogeneity on tree shade efficiency by comparing sunny and cloudy conditions, as well as different times of the day. In addition, we investigated the differences in shading efficiency over various surfaces by comparing pairs of regular urban surfaces (asphalt, concrete, permeable brick, and grass). We found that tree shade significantly improved the local thermal environment, but its effectiveness varied with the environmental conditions. Tree shading resulted in a higher cooling efficiency under greater external thermal stress. In addition, the cooling efficiency was greater on surfaces with higher temperatures. We also identified a notable characteristic of tree shading for cooling: the thermal environment beneath the tree shade tends to stabilize at a relatively constant value across various external conditions. These results provide practical guidelines for optimizing tree layouts in highly heterogeneous urban environments and enhancing limited tree resources for more effective and economical improvement of urban thermal conditions.

Research on Adaptive Control Systems for Building Shading Based on Decision Tree and Random Forest Classification Algorithms

Dynamic shading systems for buildings, due to their variable mechanisms and high adaptability, have the potential to reduce energy consumption in buildings significantly. However, the performance of dynamic shading is largely influenced by the control system employed. This study aims to explore an adaptive control method for building shading based on decision tree and random forest classification algorithms (machine learning), with the objective of minimizing energy demands related to lighting and cooling as much as possible. The adaptive control system model may independently modify the location of building shading in response to input environmental conditions, thereby achieving energy savings for both lighting and cooling. According to the findings, the automated control system model may reduce building energy consumption by 38% overall, which is close to the ideal level of energy conservation.

Color Stability of Single-Shade Resin Composites in Direct Restorations: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The objective was to compare the color match and color stability behavior of single- and multi-shade resin-based composites (RBCs) used for direct restorations. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized clinical trials evaluating the shade performance of single-shade RBCs in direct restorations were included. A search of the scientific literature was performed in five databases (April 2024). The meta-analysis was performed using RevMan 5.4, calculating the risk difference (RD) and 95% confidence interval (CI) of the dichotomous outcome using a random effects model. Bias was assessed using the RoB 2.0 tool, and certainty of evidence was assessed using the GRADEpro tool. Four studies were selected, with 263 restorations analyzed. The results showed comparable performance between single-shade RBCs and multi-shade RBCs in terms of color match and color stability over 12 months. Three studies had a low risk of bias with all expected results, and one study had some concerns. The certainty of evidence for color stability was considered low for all follow-up periods due to the small number of events and sample size. According to the United States Public Health Service Evaluation (USPHS) and the World Dental Federation (FDI), there is comparable clinical color performance between single-shade and multi-shade RBCs over 12 months.

A demethylated lignin improved PVA-based supramolecular plastic with tough, degradable, and water-resistant performances

Poly (vinyl alcohol) (PVA), as an excellent degradable plastic feedstock, is limited by its diminishing stability in wet environment, low strength, thermal instability and nonopaque properties. In response to these concerns, a PVA/demethylated lignin-based supramolecular plastic (DPVA-HA-Fe-5) was designed and produced from PVA, demethylated lignin (DL), humic acid (HA) and Fe3+ ions via a simple casting method. As compared with pure PVA plastic, the tensile strength of DPVA-HA-Fe-5 were increased by 411 % to 410.61 MPa, and the breaking strain was increased by 149 % to 239.47 %. Notably, the hydrophobicity of DPVA-HA-Fe-5 was also significantly improved. Although in highly humid environment (stored in RH = 100 % for 10 days) or in alkaline organic solvent (stored in pyridine for 3 h), DPVA-HA-Fe-5 also showed excellent mechanical strengths of 302.9 and 222.99 MPa, respectively, which are equivalent or even superior to the most of commercial petroleum-based plastics. Moreover, the prepared plastics showed an outstanding UV resistance and shading performance, and about 98.3 % protection against ultraviolet radiation B rays and 90.7 % protection against visible light were obtained. In short, the introduction of lignin to improve the performance of PVA-based plastic is a feasible method, and it could facilitate the development of high-value utilization of lignin.

Performance of Shading Against West Glass Facades to Optimise Daylight, Thermal Comfort and Energy Efficiency of Office Buildings

In tropical urban areas, the vertical facades of buildings often play a crucial role in capturing solar radiation and heat, especially for office buildings facing west during the afternoon. In Dhaka, a tropical city, the construction of major arterial roads connecting the northern and southern regions of the city has led to the emergence of numerous commercial buildings along these roads, predominantly facing in east or west directions. This research investigated the efficiency of different existing fenestration types (glass curtain walls, glass windows with horizontal and vertical louvres, overhangs, vertical fins, and egg crate shading) of west-facing office buildings in Dhaka in terms of daylight, thermal comfort and energy efficiency, and explore strategies to enhance existing performance. From the field survey, a 'case office building' was selected, and simulations were carried out with the six different fenestrations, as mentioned above, while keeping other aspects constant as found during the survey, e.g., floor plan, equipment and number of occupants. In this research, the simulation process encompasses daylighting simulation, energy simulation, and multi-objective optimisation. The study utilised a case model created with Rhinoceros and ClimateStudio, while performance metric optimisation was achieved using Grasshopper and Octopus. Multi-objective optimisation techniques were employed to improve the shading configurations. The TT toolbox facilitated data exportation and Design Explorer assisted in data visualisation. The window with egg crate shading was found to be the most effective fenestration type among the studied shading configurations. Further parametric simulation was conducted to develop an optimised egg crate shading design configuration. It was found that egg crate shading with a 1.0 m depth provided optimum daylight and solar heat gain inside the office building among the studied configurations in the context of Dhaka. A comparison was also made between the optimised egg crate option and a customised egg crate with some detailing (popularly known as brise soleil). Brise soleil showed better performance with 12.2% higher sDA and 98 lux additional average illuminance compared to the previous optimum one. The findings underscore the significance of employing optimisation methodology to devise shading configurations while also revealing substantial opportunities to enhance performance further by tailoring details on the optimised design recommended from simulation analysis.

Comparative assessment of essential oil composition and yield in Cinnamomum tamala leaves upon application of different drying practices

ABSTRACT Cinnamomum tamala or Indian bay leaf is a widely used spice in the Asian subcontinent. The aim of this study was to assess the contents and composition of essential oils and volatiles internal pool in C. tamala leaves obtained from different drying practices such as, sun drying, freeze drying, shade drying and simultaneous oven drying at 60°C and 40°C, when compared with market-available dry leaves. Out of five different practices tested, leaves when oven dried at 60°C performed best in terms of free-radical scavenging capacities, internal pool of volatile contents (257.25 ± 37.57 μg/g of dried leaf tissue) and yields of essential oils (0.25%). This was followed by freeze-dried leaves, which showed 0.2% essential oils yield. Among the natural drying, sun dried leaves exhibited high yield of essential oils (0.16%). Performance of shade dried leaves was shown to be lowest i.e. 0.11% essential oils yield but was comparable with the yield of market-available leaves.

Natural shading vs. artificial shading: A comparative analysis of their cooling efficacy in extreme hot weather

Shading, comprising both natural and artificial coverings, is an efficient and effective strategy to reduce heat stress in outdoor environments. Despite its recognized efficiency, there is limited comparative insight into the cooling performance of natural and artificial shading. This study examined the cooling efficacy of two covered walkways and two tree canopies, concerning microclimate conditions by various variables and thermal stress quantified by four thermal indices. Our findings highlight three key points: Firstly, the average cooling effects provided by natural and artificial shading were comparable, including reductions in air temperature (1.42 °C vs. 1.31 °C), mean radiant temperature (15.93 °C vs. 13.71 °C), and Physiological Equivalent Temperature (PET) (9.06 °C vs. 9.70 °C), Universal Thermal Climate Index (UTCI) (4.71 °C vs. 5.08 °C), and Hong Kong Heat Index (HKHI) (2.36 °C vs. 2.50 °C). Secondly, it is inconsistent which shading solution is better for microclimate improvement and heat stress alleviation, which is affected by canopy materials, configurations, and tree species. Thirdly, the four indices presented an inconsistent pattern in heat stress assessment. Notably, PET and UTCI showed similar patterns, while HKHI and modified PET presented lower sensitivity to high heat stress. This study offers valuable insights for urban designers to create sustainable shaded communities and also initiates a discourse for revising local heat warning systems, considering various thermal stress indices.

Assessing light performance of vertical greenery shading in tropical climate

Natural light is abundant in tropical climates and advantageous for incorporating daylighting into building designs. However, this daylight intensity often leads to excessive brightness indoors, specifically in high-rise buildings with glass façades. In addressing sustainability concerns, incorporating greenery outside glass façades can effectively shade and alleviate eyestrain for building occupants. Therefore, this study aimed to investigate the effectiveness of plant leaves in reducing the high light intensity on glass facades. An experiment was conducted using the Vernonia elliptica plant, which thrives in medium to high sunlight in tropical climates. Three different leaf area indexes (LAI) were examined in this study as the independent variables, while light illuminance and luminance served as the dependent variables. Two identical box models measuring 1 m × 1 m × 1 m were utilized for the experiment. The two models were oriented towards the west and north, representing intense and longer light exposure. The first, the base case, featured a glass façade without any other additional element, whereas the other incorporated greenery on its glass façade. The obtained results indicated that the impact of leaf density on illuminance and luminance is significant, specifically when the LAI is doubled. It was also found that denser foliage with longer leaf strands produced better results, specifically at low altitudes. These results can be used to implement vertical greenery shading in high-rise office buildings.

Parametric design of photovoltaic louver integrated shading devices for west facade windows of office buildings in central China

ABSTRACT In order to improve the shading performance and power generation effect of Photovoltaic shading integrated devices (PVSDs) on the west facade of buildings in China, a multi-objective optimization design method is proposed in this paper. Taking a west-facing office building in Zhengzhou, Henan Province, as an example, a parametric model of photovoltaic (PV) louvers for windows on the west facade is established, and parametric design research is carried out on the energy-saving potential of PV louver shading systems. Based on the optimization objectives of power generation of PV louvers, indoor thermal discomfort hours, building cooling load and lighting energy consumption, the performance of the west facade office with PVSD under different design strategies was simulated, and the optimal design strategy was determined according to the preference of decision makers. Compared with the basic type without a non-shading model, the indoor lighting energy consumption of the optimized west facade PVSD is slightly increased. However, overall performance is improved, with a 35% reduction in cooling load, a decrease of 804.59 kWh in total energy consumption, and a shortened summer thermal discomfort time of 404 hours. The power generation of PV louvers can replace 46% of the total energy consumption of the room. The results show that the installation of PVSD on the west facade window is important for alleviating the overheating inside the room and improving the energy-saving and power generation potential of the room.

A CASE STUDY: INTELLIGENT SHADING RETROFIT TO EXISTING HOME-OFFICE USING MULTI-OBJECTIVE OPTIMIZATION

ABSTRACT Improved energy performance and occupant comfort are driving building design decisions due to the increasing demand for sustainable and green buildings. However, despite the variety of technological developments in other fields, the range of solutions to improve building performance is limited. One of the main limitations for an early designer is a performance evaluation method to facilitate the design process. This paper offers a new shading performance optimization process that can help designers evaluate both daylighting and energy performance and generate optimized and flexible designs that can be further improved by implementing user-specific automation. The proposed performance optimization method utilizes parametric design, building simulation models, and Genetic Algorithms. Common shading design systems are explored through parametric design, and daylighting and energy modeling simulations are performed to evaluate shading device performance. Genetic Algorithms are used to identify design options with optimal energy and daylighting performance. A case study is conducted to verify the effectiveness of the overall process. Results are used to analyze the influence of design decisions among different shading designs. Finally, future directions in both shading design and energy optimization are presented.

A simple evaluation method of external Venetian blind shading performance for nearly zero energy buildings

A simple evaluation method of external Venetian blind shading performance for nearly zero energy buildings

Effects of orientation and dimensions of shading structures on thermal comfort

Shading structures can block strong solar radiation and improve pedestrians' thermal comfort in subtropical regions. However, the type, size, and orientation of such structures affect their shading performance. This study explored the effects of the dimensions and orientations of shading structures on pedestrians’ thermal comfort in subtropical Taiwan.In this study, the high accuracy of the Ladybug simulation tool was confirmed through comparison of its results with field measurements. After accuracy confirmation, this tool was used to calculate the physiological equivalent temperature (PET) under shading structures with various dimensions and orientations during the day in summer. The effective aspect ratio (eAR) was developed in this study as a dimensional parameter for shading structures.The simulation results indicated that within the eAR range of 0.22–4.0, lower eAR values were associated with higher average PET values and a greater proportion of time spent by pedestrians under the shading structures in discomfort in summer. The shading orientation also affected thermal comfort. Formulas for predicting PET from eAR were developed in this study, and a simple reference table that indicates the relationships of the dimensions and orientation of shading structures with thermal comfort was created. This table provides a reference for shading-related policy making and shading structure design. The results of this study have been applied to local building codes in Tainan City, Taiwan.

Applying expanded metal mesh for outdoor shades in outdoor thermal environments.

This study investigated the applicability of expanded metal meshes (EMMs) in horizontal shading devices. We performed simulations and experiments with EMMs with different opening ratios and directions. We established various experimental and control groups to measure air temperature, surface temperature, and black globe temperature. After the comparison of simulation and experimental data, we used Grasshopper to simulate long-term climate situations. The research results can serve as reference for users in Tainan and provide customized suggestions. The findings can serve as a paradigm for parametric design to analyze EMMs. In design projects involving outdoor horizontal shading devices, these results can be used in the design phase for evaluation. Full-day measurements revealed that EMMs with small openings exhibited favorable shading effects. In the Tainan area, we suggest using north-facing EMMs; in our simulations result, 70% of sunshine did not pass through the mesh in a day. For shading equipment in the morning, west-facing EMMs should be used because they blocked 50-90% of sunshine. For recreational areas in the afternoon and evening, east-facing EMMs can block 50-90% of sunshine after noon. In Taiwan, south-facing EMMs are not advised because their shading performance is suboptimal in the morning and afternoon.

Intelligent Bio-FeS-loaded chitosan films with H2O2 rapid response for advanced waterproof and antibacterial food packaging

A novel nanocomposite film (Cs/FeS film) for potential food packaging applications was fabricated using chitosan (Cs) and Bio-FeS biosynthesized by Deinococcus wulumuqiensis R12. The impregnation of chitosan with Bio-FeS nanoparticles was evidenced by the EDS mapping, FTIR and XRD. Compared with pure chitosan films, the Cs/FeS film exhibited improved shading performance, better water resistance, as well as high antioxidant capacity, making it an attractive option for food packaging. With the increase of Bio-FeS content, the physical properties were further enhanced to a certain degree. Furthermore, Bio-FeS nanoparticles were found to simultaneously endow Cs/FeS films with increased elasticity and ductility at a low filler content of 0.4%. In addition, Cs/FeS films exhibited excellent antimicrobial activity against Salmonella typhimurium (97.7% inactivation efficiency) and Staphylococcus aureus (99% inactivation efficiency). At the same time, the peroxidase-like properties of Bio-FeS enable the chitosan film to respond to H2O2 in food. Notably, chitosan film impregnated with Bio-FeS greatly outperformed commercial plastic wrap in terms of its ability to preserve meat, indicating its potential use in the development of novel preservation methods.

Energy performance of passive shading and thermal insulation in multistory hotel building under different outdoor climates and geographic locations

Though energy-efficient envelope is extensively studied, there is lack of attention on incorporating appropriate passive design strategies at the design-phase of a building in a specific climate and geographic location. This study has focused on the effect of outdoor climate and geographic location on the energy-saving potential of passive shading and thermal insulation for multistory hotel building in the northern hemisphere. The building was modelled and simulated by using DesignBuilder (Version 4.5.0.148). The cities were selected in such a manner that they represent warm, moderately hot, hot, and very hot outdoor climates but different geographic locations (according to Koppen category). The proposed shading strategy was featured by the combination of solar shading devices and self-shading. As an alternative option, the envelope was provided with high-performance insulation and glazing without solar shading. The results indicated that the outdoor climate and geographic location had significant influence on the energy-saving potential of both the options; the factors identified through sensitivity analysis were cooling degree days above the cooling setpoint (CDD-base STC), share of cooling and heating energy demands, global horizontal irradiance, and solar shading effectiveness. For instance, Khamis Mushait and Athens cities have warm outdoor climate, but they represent different geographic locations; therefore, the building's cooling energy demands in these cities were significantly different (98% and 52% respectively of the total energy demand). Accordingly, the energy saving potential of passive solar shading was maximum (65.2%) for Khamis Mushait, while it was minimum (13.1%) for Athens. Conversely, the saving by high-performance insulation ranged from −11.6% in Khamis Mushait to a maximum of only 8.5% in Athens, which is consistent with their heating demands (2% and 48% respectively).

A Study of Shading Devices in Modern Architecture for the Hot Humid Climate of Phnom Penh, Cambodia

Due to global warming caused by carbon dioxide emissions, for the last decade or longer, there has been a strong focus on reducing energy consumption. Among the many technologies, old and new, available for this purpose, one is a shading device, which is required in a hot and humid climates to protect building interiors from solar radiation that can penetrate the building, increasing the energy demand for the cooling load. Such shades are well-known and have been used widely since the dawn of the modern architectural era. In Phnom Penh, there are different kinds of shading devices in modernist architecture that demonstrate creativity in the shading of façades. To maximize their effectiveness in contributing to the fight against global warming, it is necessary to study their fundamental shadowing behaviors so that new technology can be developed and applied to today’s buildings. 
 This study aims to explore the shading types in modern architecture in Phnom Penh, and evaluate different aspects of these shading devices in terms of shadow performance by using an extension tool in Sketch-UP, Shadow Projector V.7 by TIG. 
 The results show that shading devices on modern buildings in Phnom Penh are defined by a deep overhang, and horizontal louvers hung from the overhang. Vertical fins, slanted fins, and egg-crate patterns are also used on the façades. According to the evaluation results, egg-crate provided the best shading performance among all shading cases and orientations studied. It was also found that a horizontal louver hung from the overhang can increase shading performance by 20% in all directions, and that it is more efficient than vertical fins for East, West, SE, and SW orientations. Moreover, the overhang is the most efficient in north-facing façades. Vertical fin types, on the other hand, are unreliable for East, West, SE, and SW orientations. The vertical slanted fin type is also unreliable in any orientation or season due to the slanted position and the sun's travel path. 
 The results of this study will help designers optimize the shadowing behavior of shading devices, particularly with respect to building orientation. The research findings highlight the fundamentals, which can be enhanced future studies that focus on compatibility assessment of shading devices used in new-era buildings.

Solar shelter: Exploring architectural design input for industrially-crafted shading devices

European Cities are strongly affected by the Urban Heat Island effect and Climate change impacts in recent and future summer periods. As such, the integration of passive cooling strategies is of increasing importance for the overall AEC (Architecture-Engineering-Construction) domain. Amongst other strategies, one of the most prominent strategies is the timely deployment of shading devices. While the shading device constructions connected to the inside, interstitial position or exterior of transparent building envelope components is thus an important part of the building, little change can be observed in the principal design and technology of such shading elements. Moreover, target conflicts between shading device deployment and architectural appearance can be observed in European Cities. For instance, the ensemble protection of the Vienna City morphology was - for a long time - considered to be more important than potent shading devices.The present contribution presents the approach of an effort toward highly-esthetical, functional shading devices that provide - despite their architectural-design approach - a high degree of shading performance. Together with the window-building industry, four different shading device designs have been designed, developed and virtually tested. The design process was guided by critical reviews by domain experts and performance simulation efforts. We present the genesis of the four designs and their performance implications as a proof of concept that effective shading systems can be understood as part of the esthetics of a building and practical passive cooling device at the same time.

Low-carbon assessment of building facades using dynamic CO2 intensity of electricity generation in Japan

To promote low-carbon power supply in a region, the demand due to building use should be synchronized with the optimal supply patterns. To this end, the usefulness of using the time-varying CO2 intensity of electricity in building design is discussed. Hourly intensities were first estimated and visualized for Tokyo, Japan, and the low-carbon impacts of improved façade performance were compared using case studies with a generic office model. Two cases were compared: one with increased solar shading performance of window glass and the other with combined measures of insulation, natural ventilation, and eaves. CO2 emission savings rate were more significant in the first case (19.4 %) than the second case (18.9 %) when a fixed annual emission intensity was used. In contrast, when hourly intensities were used, the savings rate was 18.1 % and 18.6 %, respectively, reversing the superiority. Consideration of the time-varying CO2 intensity could help evaluate building designs that limit electricity use during high CO2 intensity and shift it to periods of low CO2 intensity. The integration of time-varying factors not only in the mechanical system evaluation but also in building design itself should be integrated to promote the regional transition to a decarbonized society.

Optimal design of complex dynamic shadings: Towards sustainable built environment

Complex dynamic shading is one of many innovative technologies widely used to improve comfort and energy saving for the construction of a sustainable built environment for modern cities. However, the dynamic mechanism of the complex shading design has not always been well understood, which plays significant importance in the building performance of cities especially considering the complex environmental conditions. In this study, we aim to optimize the annual daylighting and energy performance of a complex, dynamic, origami-based shading system based case studies of a typical city building, which is located in the hot summer and cold winter (HSCW) zone in China. A modified parametric behavior maps (PBM) method was utilized for performance evaluation. A multivariate function was used to describe the interaction between the annual operation schedule and three environmental stimuli, i.e., hourly solar radiation reaching the south-facing window, hourly mean illuminance of the room, and hourly outdoor dry-bulb temperature. Radiance and EnergyPlus were integrated into the annual performance simulation of the dynamic shading. Experimental data has been used for validation of the dynamic strategy. The results indicated that the performance of the complex dynamic shading compared to the conventional static overhang shading depends largely on the annual operation schedule on an hourly basis. Indeed, the dynamic behaviors of complex shadings can improve the daylighting performance by 91.5% and energy performance by 19.9%, respectively, for office buildings with a large window-to-wall ratio in China's HSCW zone. This study will contribute to the performance-based design of complex dynamic shading, and further help to improve sustainability in urban design for modern cities.