Shading Strategies Research Articles

Impact of meteorological conditions, canopy shading and leaf removal on yield, must quality, and norisoprenoid compounds content in Franciacorta sparkling wine.

Climate change is a major concern in agriculture; in grapevine production, climate change can affect yield and wine quality as they depend on the complex interactions between weather, plant material, and viticultural techniques. Wine characteristics are strongly influenced by microclimate of the canopy affecting primary and secondary metabolites of the grapevine. Air temperature and water availability can influence sugar and acid concentration in grapes and relative wines, and their content of volatile compounds such as norisoprenoids. This becomes relevant in sparkling wine production where grapes are generally harvested at a relatively low pH, high acidity, and low sugar content and where the norisoprenoids significantly contributes to the final aroma of the wine. The effect of climate change on grapevine and wine, therefore, calls for the implementation of on-field adaptation strategies. Among them canopy management through leaf removal and shading have been largely investigated in the wine growing sector. The present study, conducted over 4 years (2010-2013) aims at investigating how leaf removal and artificial shading strategies affect grape maturation, must quality and the production of norisoprenoids, analyzed using an untargeted approach, in sparkling wine. Specifically, this paper investigates the effect of meteorological conditions (i.e., water availability and temperatures) and the effect of leaf removal and shading on Vitis vinifera L. cv. Chardonnay and Pinot noir, which are suitable to produce sparkling wine in the DOCG Franciacorta wine growing area (Lombardy, Italy). The effect of leaf removal and shading practices on norisoprenoids has been the focus of the study. No defoliation and artificial shading treatments play an important role in the preservation of the acidity in warm seasons and this suggests calibrating defoliation activities in relation to the meteorological trend without standardized procedures. This is particularly relevant in the case of sparkling wine, where the acidity is essential to determine wine quality. The enhanced norisoprenoid aromas obtained with a total defoliation represent a further element to direct defoliation and shading strategies. The obtained results increase knowledge about the effect of different defoliation and artificial shading applications in relation to meteorological condition supporting the management decision-making in the Franciacorta wine growing area.

Windows of Opportunities: Orientation, Sizing and PV-Shading of the Glazed Area to Reduce Cooling Energy Demand in Sub-Sahara Africa

In hot climates, such as sub-Sahara Africa, window sizing and orientation pose challenges as they add, through solar insolation, to the building cooling energy demand and thus the cause of indoor overheating risk. This risk can be reduced through passive building-design-integrated measures, e.g., optimizing the window size, orientation and solar shading strategies. Through an IDA-ICE building performance simulation tool, the current study explores the impact of window size, optimization and building-integrated PV panels as shading strategies on cooling energy demands in three cities (Niamey, Nairobi and Harare) in sub-Sahara Africa. Results show that thermal comfort and cooling energy demand are sensitive to a window-to-wall ratio (WWR) > 70%, while the need for artificial lighting is negligible for a WWR > 50%, particularly in the north for cities in the Southern hemisphere and the south in the Northern hemisphere. A WWR > 70% in the east and west should be avoided unless shading devices are incorporated. Internal blinds perform better in improving occupant thermal comfort but increase artificial lighting while integrating PV panels, as external shading overhangs reduce cooling energy but also produce energy that can be utilized for building services, such as air conditioning. In this study, the results and implications of the optimization of window size, orientation and building-integrated shading and operation are discussed.

Testing field adaptation strategies for delaying grape ripening and improving wine composition in a cv. Macabeo Mediterranean vineyard.

Under semiarid and warm climates, field practices for climate change adaptation have to be defined in order to modulate grape composition according to the desired wine styles. Under this context, the present study investigated several viticulture practices in cv. Macabeo for Cava production. The experiment was carried out over 3 years in a commercial vineyard located in the province of Valencia (eastern Spain). The techniques tested were (i) vine shading, (ii) double pruning (bud forcing), and (iii) the combined application of soil organic mulching and shading, all of them tested against a control. Double pruning significantly modified phenology and grape composition, improving the wine alcohol-to-acidity ratio and reducing the pH. Similar results were also achieved by shading. However, the shading strategy did not significantly affect yield, unlike double pruning, which reduced vine yield even in the year following its application. Shading alone or in combination with mulching significantly improved the vine water status, suggesting that these techniques can also be used to alleviate water stress. Particularly, we found that the effect of soil organic mulching and canopy shading on stem water potential was additive. Indeed, all the techniques tested were useful for improving wine composition for cava production, but double pruning is only recommended for premium Cava production.

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).

Effects of shade and deficit irrigation on maize growth and development in fixed and dynamic AgriVoltaic systems

Maize production is essential for global food security and represents a major supply in several value chains. However, the projected effects of climate change are likely to decrease drastically water availability for crops in many regions, affecting yield. AgriVoltaics (AV) systems are an innovative solution that may improve maize resilience in water-scarce regions mainly by protecting plants from excessive radiation and by reducing irrigation needs. However, shade from panels may also affect crop development and production. This study addresses the interplay between radiation transmission, crop development and irrigation needs of maize cropping in field conditions, by the description of crop development dynamics, distinguishing between fixed and dynamic panels. We showed that maize crop responded to both independent and combined stresses (shade and water deficit), with a significant decrease in leaf area index, total dry matter and grain yield. Concerning water use, we showed the potential of AV to reduce irrigation inputs (by up to 19–47% compared to unshaded plots) via reduced soil water depletion and reference evapotranspiration. The crop development was impacted by shade by increasing phyllochron and causing a generalized delay in phenology. At a finer temporal scale, we concluded that maize leaves react to shade by reducing stomatal conductance, net assimilation of CO2 and leaf temperature in a correlated way to radiation, opening the possibility to use this behavior to optimize water use and shading strategies. The spatial heterogeneities of radiation in fixed AV systems, compared to dynamic AV systems, were identified as a second-order effect at the plot level on leaf area index and phyllochron, compared to the effect of radiation reduction. Moreover, dynamic AV showed their ability to reduce the spatial heterogeneities in soil water depletion, showing the importance of controlled shade strategies in AV systems concerning water use.

An Analytical and Comparative Study: Design of Outdoor Shading Device Based on Fractal Geometry Strategies to Increase Thermal Comfort

Despite growing design demand, there has been little research on the design of shading devices for the outdoor environment. Heat-related illnesses are becoming a more pressing issue as temperatures rise due to climate change. Seeking shade is one effective way for humans to protect themselves. Blocking sun radiation is the main goal of shading. One of the most effective cooling strategies, found in nature, is the tree fractal strategy used to optimize shading. Similarly, Girih patterns are fractal in geometry. The purpose of this paper is to design a shading device based on the Girih fractal geometry inspired by tree concepts. Then employ the Islamic Girih fractal geometric patterns through their repeated units in a contemporary design with advanced tools. Thus, achieving significant contrast of solids and shapes against light and shade in contemporary designs. Two models of the same structure and different density were designed, then their shading data were evaluated and compared. This was done by using field measurements to estimate the impact of each shading strategy on thermal comfort during sunny days. The study is conducted in Cairo Egypt and the major goal is to improve users' thermal comfort as well as reflect on local social identity and distinctiveness.

Influence of Roller Blinds Shading Strategy on West and South Facing Buildings

This study investigates the impact of roller blinds as an energy-saving strategy in a subtropical climate. Lighting control experiments were performed on west-facing and south-facing windows in the Subtropical Performance-Testbed for Innovative eNergy Research in Buildings Laboratory (SPINLab). This study accepts sunlight below 8000 lux and requires the indoor lighting of at least a reading of 500 lux. For the west-facing window experiment, the curtain energy-saving strategy implemented in this study resulted in 10% less energy consumption for air-conditioning and saved 90% of the lighting power consumption of the west facing window building. For the south-facing window experiment, we found that sunlight can fully supplement the lighting without adjusting the roller blinds because the window opening is different from the sunlight direction. In addition, the significant heat flux difference between the west-facing and south-facing windows experiments is also reflected in the energy consumption of the air conditioners.

Analysis of Thermal Environment of Waterfront Space in Summer in Mountain City: A case study in Chongqing, China

A crucial component of the urban ecology, waterfront space plays a key role in mitigating the urban heat island effect. However, waterfront spaces in mountain cities differ greatly from those in plain cities in terms of spatial form and environmental factors. Accordingly, it is urgent to study and improve the thermal environment of waterfront spaces in mountain cities. According to the spatial morphological characteristics and shading means of the waterfront space in Chongqing, a typical mountain city in China, the summer thermal environment of the waterfront space has been studied through field measurements. The outdoor thermal environment factors assessed include air temperature, relative humidity, wind speed, and mean radiation temperature. The results showed that the cooling effect was more significant at 1 m from the water's edge and decreased as the elevation increased. Air temperature and humidity showed a clear stratification characteristic with increasing elevation. At the same time, viaduct-shading was the most effective way of reducing heat stress, followed by the combined shading of sun sails with building-shading, while tree-shading was the least. This study offers basic data for further study and optimization of shading strategies for waterfront spaces in mountain communities.

Sun-Safe Zones: Investigating Integrated Shading Strategies for Children's Play Areas in Urban Parks.

Although Open Space Ratio is a critical control in the Development Approval process, there are no ultraviolet radiation (UVR) protection guidelines for urban parks. This study explores key strategies for shade provision in children's play areas in urban parks, aiming to promote sun-safe play environments against alarming skin cancer trends. The literature review identified primary issues affecting UVR exposure in public venues, and the research comprises a shade audit of Beaton Park in Dalkeith. The methods involved using virtual park modeling and Shadow Analysis simulations to generate the daily average number of hours in shade for each month. Our recommendations based on this analysis are (a) a minimum canopy cover representing 50% of the entire ground cover; (b) a minimum diameter for a shade (umbrella) of about 2.5 times the diameter of the table; and (c) an ideal umbrella height of 90 cm from the table surface. This research proposes a potential nexus between landscape design and a UVR protection framework for child-friendly Sun-safe Zones (SsZ).

The Playground Shade Index: A New Design Metric for Measuring Shade and Seasonal Ultraviolet Protection Characteristics of Parks and Playgrounds.

Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground.

Shading apple trees with an agrivoltaic system: Impact on water relations, leaf morphophysiological characteristics and yield determinants

• Study of the effects of fluctuating shading on an apple orchard using agrivoltaism. • Shading in orchard allowed a less stressful environment and reduced water needs. • Shading increased specific leaf area and reduced leaf photosynthetic rates. • Strong shading over 3 years reduced floribundity and alternate bearing behaviour. • Shading has low impact on fruit size due to higher water content in shaded fruits. The installation of dynamic photovoltaic panels over apple orchards could meet the challenges of protecting orchards from climate change and drive the energetic transition. However, the impact of solar panel's shading on apple performance needs to be investigated before being commercially adopted. A dynamic agrivoltaic system was installed in the south of France over a 10-year-old 'Golden Delicious' apple orchard and studied during three experimental seasons (2019–2021). This study aimed to evaluate the impact of fluctuating shading (photovoltaic panel orientation to maximise panel light interception) on water relations, leaf morphophysiological characteristics and yield determinants. With the selected photovoltaic design and strategy, trees were grown under a fluctuating shading (variable shading between 4% and 88% during the day) with a mean shading rate of 50–55%. On average, the air temperature was reduced by 3.8 °C, while relative humidity was increased by 14% under shading conditions. Depending on the season, the lower radiation and stressful microclimate decreased the irrigation between 6% and 31%. Fluctuating shading reduced the photosynthetic capacity of leaves and increased their specific leaf area (thinner leaves). The reduction in carbohydrate assimilation under shading was associated with lower starch reserve accumulation in the shoots (-7%), lower flower intensity at the shoot scale (-31%) and a lower proportion of trees with a high floribundity in 2020 (-45%). However, less alternate bearing was observed under shading, and better frost protection resulted in a higher proportion of trees bearing fruit under photovoltaic panels (+31%) and number of fruits per fruit-bearing tree (+44%) in 2021. Fruit size was less sensitive than fruit number to shading. Fruit size was reduced by 17% in 2019 but maintained in 2020 and 2021, probably due to a better water status of shaded trees that accumulated more water. Fruit dry matter content under shading was reduced by an average of 24%. In conclusion, agrivoltaic systems may reduce alternate bearing behaviour in apple trees, showing the importance of carrying out a multi-year study. However, the fluctuating shading strategy tested in this study did not maintain sufficient yields, with yields below 40 t/ha in all three years of study. Identifying the positive and negative effects of shading in this study may be useful for the development of sustainable apple orchard shading strategies.

Comparing the performance of four shading strategies based on a multi-objective genetic algorithm: A case study in a university library

Through the control of excessive daylight in buildings, shading devices can reduce glare and improve occupants' visual comfort. However, shading devices may overly reduce illuminance levels. Many shading strategies are available, but they do not perform equally well, and traditionally, it has been difficult to select the most suitable shading strategy. This study proposed a parameterization method for the selection and design of a shading strategy that would reduce glare while maintaining a satisfactory daylighting level, through the construction of Pareto sets based on a multi-objective genetic algorithm. The objective function was created by combining a dynamic glare evaluation indicator, the spatial glare autonomy (sGA), and a self-constructed daylight index, the spatial daylight vote autonomy (sDVA), developed from a field survey. As a case study, the proposed method was used to compare the performance of four shading strategies, including vertical slats (Vs), a perforated aluminum sheet (PAS), serrated windows with southern orientation (Sw_S), and serrated windows with northern orientation (Sw_N) in a university library in Shanghai, China. It was found that the Sw_S and PAS had a relatively bad performance; the Vs performed better than the Sw_N in providing a more satisfactory illuminance level; and the Sw_N was more effective in reducing the glare. The multi-objective optimization process can be used to obtain near-optimal design parameters that create a visual environment with reduced glare while maintaining an acceptable illuminance level, for all four shading strategies. The developed method can be a helpful tool in the design of an appropriate daylighting environment.

Assessment of outdoor shading strategies to improve outdoor thermal comfort in school courtyards in hot and arid climates

• To encourage students to perform different activities and interact in open spaces of school • to improve OTC for students in school courtyards located in a hot, arid climate. • Significant reduction in the PET for courtyard temperatures based on the ENVI-met model reached 18.5°C • To integrate hybrid scenarios of staggered shading and trees whether in the current schools or in the early design stages Schools in hot arid climate depend on courtyard to encourage students’ for social activity. In order to improve Outdoor Thermal Comfort (OTC), applying passive mitigation strategies in the courtyard is critical issue. This paper aims to improve students’ thermal comfort in school courtyards throughout the study of a public school with an E-shaped style in New Assiut City. Hence, different shading strategies (shading with different heights, vegetation, and hybrid) are simulated by using ENVI-met model v 5.0.0 to improve OTC for students in school courtyards. Firstly, monitoring was conducted inside outer courtyards. Then nine scenarios of passive strategies were implemented inside two courtyards with a ratio H/W = 0.4 and 0.7. After that, Physiological Equivalent Temperature (PET) was used to compare different scenarios. The results found, by applying hybrid orthogonal and diagonal staggered shading with trees in wide canyons, significant reductions of PET values reached 18.5°C and 18.6°C respectively. In addition, the shading at height= 4 m hybrid with trees achieves the best OTC improvement in the school courtyards. Thus, PET values were located in comfortable and slightly warm ranges for wide courtyard with H/W ratio = 0.4, and this result is more sufficient than in deep canyon with H/W = 0.7. Hence, the study provides information for architects and planners to integrate hybrid scenarios of staggered shading and trees whether in the current schools or in the early design stages for them to reduce heat stress and improve students’ thermal comfort.

Le Corbusier’s Solar Shading Strategy for Tropical Environment: A Sustainable Approach

In warm and tropical climates, excess solar gain may result in high cooling energy consumption. Shadingis a simple method to block the sun before it can get into the building. The ‘brise-soleil’, or ‘sun-breaker’solution refers to a permanent sun shading technique, like the simple patterned concrete walls popularized byLe Corbusier. Le Corbusier in his design of buildings in tropical climate wanted to make a ‘pact with nature’unlike his earlier works of the cold climates where he was to ‘combat the nature’. Le Corbusier’s solar shadingstrategy in Unit De Habitation and Capitol complex in Chandigarh are pioneering example for his approachtowards dealing with the harsh tropical climate. This paper tries to rediscover the climate consciousness ofthe master architect in terms of Brise Soleil as his solar shading strategy for the tropical environment. Themethodology adopted in the research is through qualitative analysis. In this paper an attempt has been madeto analyse Brise soleil as a solar shading strategy with reference to the tropical architecture of Le Corbusier.The application of Brise Soleil in Le Corbusier’s tropical works such as Ministry of education in Rio de Janeiro,Unité d’ Habitation in Marseilles and Capitol Complex in Chandigarh has been studied. The relevance ofshading in today’s context with reference to climatic control and energy conservation and sustainability hasalso been discussed. Incorporation of Brise Soleil as a solar shading technique in buildings will certainlyreduce our dependency on artificial means for thermal comfort and minimize the environmental problems dueto excessive consumption of energy and will evolve a built form, which will be more climate responsive andmore sustainable.

Impact of key bioclimatic design strategies on buildings' performance in dominant climates worldwide

Bioclimatic design strategies are among the most promising sustainable approaches for improving energy efficiency of buildings. However, their contributions to reducing the energy consumption and carbon footprint of buildings are largely dependent on the alignment of building design with climatic conditions. The objective of this paper is to investigate the effect of key bioclimatic design strategies, namely green roof and walls, tree shading, natural ventilation, glazing system, blinds, building orientation and Trombe wall on the energy performance of a typical residential building in the three most dominant climates worldwide. These strategies are analyzed in Riyadh, Tetouan and Montreal cities, selected to represent those climates, viz. arid, temperate and cold climates, respectively. To this end, numerous dynamic thermal simulations were performed using EnergyPlus software. The findings of this research revealed that, individually, green roof and walls, and Trombe wall strategies have the highest performance in terms of energy savings and greenhouse gas (GHG) emissions mitigation for all selected locations. Moreover, blinds and tree shading strategies are too recommended for arid and temperate climates, while natural ventilation is advisable only for the last one. Additionally, significant energy saving could be achieved by optimizing the building orientation, especially in arid and cold climates. However, the greatest energy savings and GHG emissions mitigation were achieved (i) by combining green roof and walls, Trombe wall, blinds and tree shading techniques for arid climates, (ii) by adding natural ventilation to the last combination for temperate climates, and (iii) when green roof and walls design is combined with an optimal building orientation for cold climates, with a share of 33%, 58% and 19%, respectively. This work is intended to be a reference to help building designers and engineers to select the appropriate bioclimatic design strategies according to the building's climate.

Pre-sintering pigmentation techniques do not affect the fatigue behavior of adhesively luted 4YSZ restorations

This study aims to characterize the effect of shading techniques on the fatigue behavior of a 4YSZ ceramic (4 mol% yttrium stabilized zirconia) adhesively bonded to a dentin analogue (fiber-reinforced epoxy resin). 4YSZ ceramic discs (IPS e.max ZirCAD, Ø = 10 mm and 1 mm of thickness) were allocated according to the factor ‘shading technique’ into 4 groups: Brush– unshaded ceramic disc (IPS e.max ZirCAD BL) pigmented at the pre-sintered stage with pigment solution applied manually using a round liner brush; Immersion– unshaded ceramic disc pigmented through immersion in the solution for 1 s on only one side of the ceramic disc; Manufacturer– specimens already shaded by the manufacturer (IPS e.max ZirCAD MT A2 – Manufacturer group); Control– a control condition with absence of pigment (i.e. non-pigmented specimens). The specimens were sintered and a spectrophotometer (SP60, EX- Rite) was used to ensure that the same perceived color (i.e. pigment saturation) was achieved in the different shading strategies (Manufacturer, Brush or Immersion groups). To do so, the color differences (ΔE00) were calculated using the CIEDE 2000 equation; and an ΔE00 of up to 1.77 was considered as an acceptability threshold. Dentin analogue discs were obtained (Ø = 10 mm and 2.5 mm of thickness) and randomly allocated into pairs with the 4YSZ ceramic discs. Next, the pairs were adhesively bonded using a resin cement (Multilink N). The bonded assemblies (n = 15) were tested for fatigue using the step-stress test method (frequency of 20 Hz; 10,000 cycles per step, initial load 200 N; step-size of 100 N, up to 700 N; and after, step-size of 50 N, until specimen failure/fracture or radial cracks). Fatigue failure load (FFL) and number of cycles for failure (CFF) were recorded for statistical analysis. Fractographic features were accessed, and complementary roughness, topography, grain size and phase content analyses were performed. No statistical differences were observed in the fatigue behavior among the non-shaded condition (Control group – 880 N) and the shaded specimens (Manufacturer – 887 N, Brush – 820 N, and Immersion – 850 N groups; p > 0.05). However, the use of a brush shading technique induced slightly inferior fatigue mechanical behavior of the restorative set compared to the specimens already shaded by the manufacturer (p = 0.027). No differences in Weibull modulus were observed among the tested groups. The specimens pigmented by the brush technique demonstrated a rougher surface, with statistically higher Rz values, in addition to a larger grain size in comparison to all other conditions (p< 0.05). No m-phase content was identified (only t and c phases were detected). Thus, the shading techniques used to provide a Vita classic A2 shade does not negatively affect the mechanical fatigue properties of a bonded 4YSZ ceramic. However, the brush technique has detrimental effect on the fatigue behavior compared to when the ceramic was already provided in a shaded format by its manufacturer.

Comparing cooling efficiency of shading strategies for pedestrian thermal comfort in street canyons of traditional shophouse neighbourhoods in Guangzhou, China

In the context of climate change, the outdoor thermal environment is essential for urban health, particularly in hot and humid climate zones. In most cities in southern China, traditional shophouse neighbourhoods are regarded as a reference for climate-responsive urban morphology because multiple shading strategies are integrated, including deep canyons, semi-open arcades, and vegetation. In total, four shading strategies, namely, the height-to-width ratio of canyons and arcades, tree coverage area, and orientation, are employed in this study to compare their cooling efficiency in street canyons during summer daytime. The ENVI-met is employed for the microclimatic simulations and validated by site measurement data. The impact of varying sky view factor on the physiologically equivalent temperature was quantified to assess the cooling efficiency of each shading strategy. Our results demonstrate that the cooling efficiency of orientations varies significantly with sky view factor and is negatively associated with pedestrian thermal comfort in alleys, but positive in street canyons with arcades and trees. Varying the height-to-width ratio of canyons in arcade streets presents the best cooling efficiency, except in the east-west orientation. Shading by arcades shows a slightly higher cooling efficiency than tree coverage.

Performance of combined daylighting strategies in varied sky conditions: post occupancy evaluation of lecture rooms in a tropical climate

Due to the inadequate attention given to daylighting in lecture rooms in tropical wet and dry climate, this study, using field measurement, evaluates combined daylighting strategies in three lecture rooms labelled LLH, BMS and ANB with distinct bilateral glass louvre windows, window floor ratio, orientation and shading strategies. It determines the difference in illuminance in varied sky conditions, and the relationship between the strategies. Results revealed that under the clear sky condition, combined strategies in LLH and BMS rooms were effective in illuminance performance except during evening hours while the one in ANB was ineffective. Both rooms recorded poor daylight uniformity. Similar performance was obtained under overcast sky but they produced effective daylight uniformity. An effective daylighting was obtained throughout the process in the intermediate sky condition, however, the strategy in ANB room was ineffective in the evening hours. Only ANB room had an effective daylight uniformity in the intermediate sky. The strategy in LLH room had a strong positive relationship with BMS’s. The strategy in LLH had a weak positive correlation with ANB’s, but ANB’s strategy had strong positive correlation with BMS’s. Overall, the study contributes to the performance of combined daylighting strategies in tropical wet and dry climate.

Direct heat flux sensing for window shading control in passive cooling systems

Greenhouse gas emissions from space cooling are expected to double globally by 2050, giving urgency to the development of low-carbon cooling methods. Solar heat gain through windows is a leading contributor to cooling loads, and accordingly, operable shading strategies have been established that respond to numerous environmental parameters, including solar radiation, illumination, time of day, and indoor and outdoor air temperature. While these have shown excellent performance, optimal setpoints are typically specific to climates, seasons, and spaces, preventing development of controls with consistent effectiveness across varying conditions. Here we investigate an alternative parameter, window surface heat flux, in which a universal setpoint of 0W/m2 identifies transitions between window heat gain and loss. Examination of heat flux signals acquired with low-cost sensors first revealed the associated noise to be consistent but too great for control application. Representative noise characteristics were then used to construct noisy signals for simulations, allowing evaluation of noise mitigation by digital filtering methods and signal persistence requirements. Strikingly, shading controlled by the resulting output reduced window heat gain by 54–78% in six contrasting climates, comparable to or exceeding the performance of established approaches, indicating that heat flux sensing is now an outstanding candidate for shading control in passive cooling systems.

Subdivided venetian blind control strategies considering visual satisfaction of occupants, daylight metrics, and energy analyses

Thermal and lighting performance in buildings depend on their facade characteristics, and are important factors to achieve environmental sustainability. Application of an integrated model that balances these two performance indices would help optimise window and shading configurations by considering the comfort of occupants. As occupants infrequently operate shadings in shared spaces, the energy efficiency and visual comfort could be improved by planning appropriate shading strategies in initial design process. Thus, this paper presents a multi-stage study on the control strategies of venetian blinds by considering visual comfort and daylight metrics, and through energy analyses. First, the case study was performed in a south-oriented daylit office room. 30 people were interviewed via a survey about working on a laptop considering three different times of a day, five blind types, and three positions. The impact of daylight on their visual comfort was surveyed at different illuminance levels which were measured by daylight loggers. The useful daylight illuminance (UDI), Daylight Availability (DAv), spatial daylight autonomy (sDA), annual sunlight exposure (ASE), and simplified daylight glare probability (DGPs) were used to evaluate the results. Finally, the window and blinds were modelled for different window to wall ratios (WWRs) for long-term energy and daylight analysis, by considering bi-directional scattering distribution function (BSDF) materials and using the five-phase matrix method.Therefore, the positions of the occupants and their activities were determined to be important parameters in deciding the most suitable blind strategy. According to occupants’ working place and daytime, subdivided shadings are recommended, particularly in 90% WWR considering both energy efficiency (40% savings) and satisfaction of occupants.