Shading Depth Research Articles

Formulation of climate-based daylighting design prediction model for high performance tropical school classrooms

Daylighting is beneficial in buildings, including school classrooms, in which daylight can significantly affect the occupants’ performance. Also, daylight varies across different climates, including within the tropical region. Climate-based daylight modelling is recommended to accurately predict annual daylight performance in building spaces; however, it is often too complicated in practice. It is intended to have certain climate variables that can act as predictors for annual daylight performance in tropical school classrooms, where openings are typically installed on opposing façades. This study thus aims to propose a climate-based daylighting design prediction model for tropical school classrooms with symmetrical and asymmetrical opening typologies. The model considers horizontal shading depth and its height, and window-to-wall ratio, in relation with the climate variables. To achieve the objective, two classrooms with asymmetrical and symmetrical bilateral openings are modelled and optimized for 117 site locations in Indonesia. The spatial average UDI250-750lx is proposed as the reference metric that can ensure satisfaction of all daylight criteria. The annual global horizontal radiation (aGHR) is proposed as the predictor in the model, with prediction errors below 5 %. Simple equations have been derived to predict spatial average UDI250-750lx in tropical classrooms as a function of aGHR.

Daylighting design validation and optimisation of tropical school classrooms with asymmetrical bilateral opening typology

Daylighting is an essential factor in the design and operation of buildings, including schools. School buildings shall therefore be designed and constructed by considering climate variability that may affect daylighting performance. In some cases, such as in Indonesia, school classrooms are typically designed with symmetrical bilateral openings. However, recent literature suggests that such an opening typology may not necessarily lead to optimal daylight performance. This study investigated the potential of applying asymmetrical bilateral opening in tropical school classrooms by conducting validation with scale models and optimisation with climate-based daylight simulation. The window-to-wall ratio and external horizontal shading depth and elevation on opposing façades of the building model were considered input variables. Computational daylight simulation with Radiance (RAD) through the interface of Honeybee Plus (HB [+]) and optimisation using genetic algorithms (GA) were utilised to calculate annual daylight metrics (aUDI250-750lx, aUDI100-3000lx, sDA300/50% and ASE1000,250) and glare indices (DGP) under the climate of two Indonesian cities. Based on the optimisation, the recommended solutions are indeed in favour of asymmetrical opening configurations. These findings are crucial to improving the practice of designing tropical school classrooms with asymmetrical bilateral openings.

Impact of architectural design strategies on the indoor natural ventilation of public residential buildings in Singapore

The architectural design pattern of the public residential buildings developed by Housing and Development Board (HDB) of Singapore has evolved gradually throughout the past decades. However, the fact is that although the new generations of HDB blocks built in recent years are designed to be modernized, the usage of air-conditioning has been increasing in comparison with the old generations. This study aims to investigate the ventilation performance of HDB blocks built in different generations from a historical view. By conducting computational fluid dynamics (CFD) simulations on five typical blocks built in different generations, the area-weighted wind velocities in various rooms of the target units were obtained. The effects of design factors on wind velocity ratio (VR) in corresponding spaces were analyzed and compared. The results show that the old generations with parallel plan layouts generally facilitate cross-ventilation while the new generations with centralized plan layouts usually generate single-sided ventilation which is more sensitive to incoming wind direction. Meanwhile, the window-to-wall ratio and shading depth of the studied facades were validated to have positive and negative relations to the VRs respectively. Though the correlations are insignificant, they show significant disparities between the scenarios under different incoming winds.

Designing energy-efficient and visually-thermally comfortable shading systems for office buildings in a cooling-dominant climate

Windows and their control elements, including shading systems, are among the most critical building components affecting both energy consumption and occupant comfort. With the increasing demand for full-glazed facades, designers and researchers are actively devising advanced control strategies to address the challenges posed by excessive sunlight penetration and heat transfer. These strategies aim to harmonize the benefits of natural light with the need for comfortable indoor environments and energy consumption reduction. This study investigates the impact of external shading configurations for an office room in Tehran, categorized as group B in the Köppen climate classification, to reduce total building energy consumption and improve occupant thermal and visual comforts. The shading parameters include shading angle, shading depth, and the number of shading slats. More specifically, this study analyzes and compares two design configurations for the considered office room. The first configuration consists of a single southern window with horizontal shading, whereas the second configuration consists of two windows on the south and west, one being horizontal shading on the southern side and the other being vertical shading on the western side. There are a total of 1330 models investigated from which 20 models are selected as the most suitable solutions. Finally, this paper examines the effect of each design parameter on the overall performance of each configuration in terms of energy efficiency and visual-thermal comfort.

Influence of Transparent Envelope Parameters on Office Building Energy Use Intensity in the Different Thermal Climate Regions of China

The role of the transparent envelope in energy savings is crucial as it accounts for a significant proportion of the total energy loss (between 30 and 40%). This paper focuses on the identification of reasonable parameters for the transparent envelope in different climatic regions. To achieve this goal, typical urban office buildings from four different climatic regions are used as research objects. A total of 1600 scenarios were simulated to investigate the variation of energy use intensity, including transparent envelope parameters, meteorological parameters and different types of glazing. The results show that for south-facing transparent envelope facades, type D glazing is the most energy efficient in severe cold regions, type C in colder regions and type B in the other two climatic regions. No solar shading is required in the very cold region. Horizontal shading can be an effective method for saving energy in colder climates, while comprehensive shading can be beneficial in other regions. Deep shading is particularly energy efficient if it meets lighting requirements. For example, in Guangzhou, energy savings of 13.46%, 15.47%, 7.01% and 7.02% can be achieved in the east, west, south and north directions, respectively, using B-type glazing and a comprehensive shading depth of 900 mm.

Study of the tools used for early-stage carbon footprint in building design

The purpose of this study is to construct a digital tool and design process for building a carbon footprint calculation to change the current status of Taiwan's carbon footprint calculation in post-use assessment, and to incorporate both carbon emissions and energy consumption in the environmental impact assessment into the initial considerations of the architectural design. Through the connection of carbon emission calculation tools and optimization tools, the advantages and disadvantages of multiple schemes in relation to carbon emissions and energy consumption can be compared simultaneously, thereby assisting designers to achieve faster results when making design decisions. In addition to the building's area, orientation, and height, various schemes could also further facilitate architectural design plans with lower carbon emissions by adjusting factors such as the external shading depth and the window-to-wall ratio by calculating the building dimensions to pursue the maximum percentage of the visual field (maximum window area), thereby reducing carbon emissions. This study is expected to meet the needs of users by simplifying the calculation tools and operation interface required for carbon emission calculations, visualizing the calculation results, and enabling a comparison of multiple design schemes. In addition, it provides recommended projects that can be reviewed in the early decision-making stage of the architectural design process, and provides designers and planners with approximate building carbon emission calculations for projects. Furthermore, to facilitate a calculation process with the best view, the scheme simulation is optimized under the existing design conditions, and the optimal solution (Pareto optimal solution) is obtained following calculation classification and analysis. The simulated data can be listed for design reference, whereby users can make design decisions based on the design conditions.

On the Interaction between the Depth and Elevation of External Shading Devices in Tropical Daylit Classrooms with Symmetrical Bilateral Openings

External shading devices are an important design feature in tropical buildings, particularly for climate mitigation. However, the interaction between the depth and elevation of the shading devices and their impact on indoor daylight performance is not fully understood, especially for the case of tropical buildings with bilateral openings. This study therefore aims to evaluate the design possibilities of external shading devices with various depth and elevation in terms of daylight performance for the case of tropical school classrooms with bilateral openings in an Indonesian city. A computational simulation method using Radiance is utilized to perform annual daylight metrics calculations. Geometry, material, and simulation settings are prepared using the Ladybug tool under Grasshopper for four building orientations, namely 0°, 45°, 90°, and 135°. Sensitivity and uncertainty analyses are conducted for all design combinations. The results show that the interaction between a shading device’s depth and elevation is unique, depending on the building orientation and the availability of direct sunlight. In general, shading elevation is more influential, compared to shading depth, on the observed daylight metrics and the combined objective functions at all orientations.

Thermal comfort analysis of earth-sheltered buildings: The case of meymand village, Iran

Vernacular buildings are known for their localized passive settings to provide comfortable indoor environment without air conditioning systems. One alternative is the consistent ground temperature over the year that earth-sheltered envelopes take the benefit; however, ensuring annual indoor comfort might be challenging. Thus, this research monitors the indoor thermal indicators of 22 earth-sheltered buildings in Meymand, Iran with a warm-dry climate. Furthermore, the observations are used to validate the simulation results through two outdoor and indoor environmental parameters, air temperature and relative humidity during the hottest period of the year. Findings indicated that the main thermal comfort differences among case studies were mainly due to their architectural layouts where the associated variables including length, width, height, orientation, window-to-wall ratio, and shading depth were optimized through a linkage between Ladybug-tools and Genetic Algorithm (GA) concerning adaptive thermal comfort model definition and could enhance the annual thermal comfort by 31%.

Developing climate-responsive passive strategies for residential envelopes in the warm humid climate of South India

PurposeEnergy codes for residential buildings in India prescribe design guidelines for each climate zone. However, these guidelines are broad and similar for different cities under the same zone overlooking climatic variations due to altitude, location and other geographical factors.Design/methodology/approachTo develop strategies addressing the city-specific requirements, a stepwise simulation approach was used. Integrated Environmental Solutions–Virtual Environment (IES-VE) was used to create a prototype of a singly detached residence. The applicability of strategies is studied during the day and night times. Optimum orientation, the thickness of insulation, Window–Wall Ratio, the impact of cross-ventilation and shading depth are determined for two cities – Tiruchirappalli and Coimbatore under the warm-humid climate zone of India.FindingsResults indicate that optimum insulation thickness and WWR vary between both cities during daytime and night time. In Tiruchirappalli, roof and wall insulation using polyurethane board (100 mm) and foam concrete (25 mm) offers a maximum reduction of 2.2°C indoors. Foam concrete (25 mm) insulation for roof and expanded polystyrene (25 mm) for walls reduce a maximum of 2.6°C during daytime in Coimbatore. Further, night ventilation with 20% WWR allows an average decrease of 0.5–0.6°C in triply exposed spaces facing the South. The use of a 2'0" depth shading device shows a maximum reduction of 0.1–0.3°C.Originality/valueThe contribution of this work lies in developing city-specific inputs presenting the advantage of easy replicability for other cities in the Indian context.

Daylight Annual Illuminance Investigation in Elementary School Classrooms for the Tropic of Lhokseumawe, Indonesia

ABSTRACT This study investigated twenty-two (22) state elementary schools, regarding daylight annual illuminance in the classrooms, using climate-based daylight modelling (CBDM) metrics. This is due to the missing information on the annual daylight performance inside the classroom in Indonesia. Over 250 classrooms were assessed using Rhinoceros and Grasshopper computational platforms. Furthermore, Daysim simulation engine was employed through the advantage of Ladybug tools to connect and automate the simulation workflow parametrically. Since there were no prior studies using CBDM metrics for daylight assessment of classrooms in the Indonesian context, the illuminance range from 250 to 750 lux was taken as the target for the annual useful daylight illuminance (UDI), as suggested in the Indonesian daylighting standard. Result shows 35 classrooms under the good daylight performance, 171 classrooms in sufficient category and 50 others under unsatisfactory of annual illuminance. The most sensitive contributors are both corridor and back shading depth with Spearman correlation of -0.70 and -0.76 respectively. The strong sensitive variables both has p-values lower than 0.05 which indicates statistically significant for the model.

Sensitivity analysis of envelope design on the summer thermal comfort of naturally ventilated classrooms in Taiwan

This paper uses Monte Carlo Analysis (MCA) for sensitivity analysis of the influence of sunlight shading and ventilation performance of classrooms in Taiwan on students’ cumulative overheating risk and average learning efficiency. The parameters influencing the sunlight shading and ventilation performance of classrooms include window orientation, window opening rate, ventilation rate, and external shading depth. EnergyPlus and local TMY3 weather data are used to simulate the hourly thermal environment conditions of 400 sample classrooms in two climatic regions (Taipei and Kaohsiung). The sensitivity of design parameters to the thermal risk of naturally ventilated classrooms and students’ learning efficiency is judged by using standardized regression coefficient, and the order of importance is window opening rate, ventilation rate, orientation, and external shading depth.

Bryophyte communities’ responses to environmental factors in highly seasonal rivers

Historically, in river ecosystems close attention has been paid to aquatic vascular macrophytes, but recent literature shows the important role of bryophytes, especially in undisturbed conditions. For this reason, we explore whether aquatic bryophyte patterns change in altered physical habitats and in eutrophication along highly seasonal streams in Bulgaria. Specifically, we hypothesize that: (i) bryophyte assemblage patterns change in conditions of hydromorphological degradation and eutrophication; and (ii) bryophyte assemblage patterns can serve as a signal in assessing effects of nutrient enrichment and hydromorphological degradation. Biological data were collected for 30 river sites together with catchment land use, hydromorphological alterations (e.g. channelization, alteration of habitat and riparian vegetation, dykes), main abiotic characteristics of each site (flow velocity, substrate type, shading and mean depth) and water chemistry parameters.The data set mentioned above was used to describe the responses of bryophyte communities to two major pressures in rivers resulting in habitat destruction: hydromorphological alterations and eutrophication. The results clearly reflected that habitat degradation led to particular changes in the species-abundance patterns of bryophyte communities. Both studied pressure types resulted in loss of species and decreased bryophyte abundance. Hydromorphological degradation could be distinguished by morphological growth forms: presence of mosses of a more plastic shape (creeping pleurocarps), whereas eutrophication favours only the mesotrophic preferential Leptodictyum riparium. This moss should be applied as a conceptual signal species, the abundance of which indicates ranges of hydromorphological and nutrient pressure in seasonal rivers.

Optimization for Heating, Cooling and Lighting Load in Building Façade Design

The objective of this article is to provide a methodology for optimizing building facade with respect to the triple objectives of heating, cooling and lighting load, therefore to achieve the minimum annual energy cost. The variables to optimize are the dimension of window grid and the depth of shading system. Energy load is computed using building performance simulation program (TRNSYS). A criterion of daylight was calculated using the Radiance lighting simulation engine. The criterion is defined as the integrated time when the illuminance is above a threshold of 500 lux. When the threshold is below 500 lux, then artificial light is required. The variables have antagonistic effects on the objectives: window grid dimension and shading depth may have opposite effects on annual energy cost, by increasing indoor solar heat gain and daylight during winter time and leading to overheating problems during summer time. Therefore, a methodology is proposed to find the optimal solutions for the total energy demand. An optimization method - genetic algorithm, was performed in order to find the optimal façade design variables leading to the lowest annual energy cost. This method was applied to a single office room. The result shows that genetic algorithm could save time when looking for the optimal solutions with antagonistic objectives and would help architects to make early-design-stage decisions.

Recommendations for Horizontal Shading Depths for Vertical Building Facades in the Tropic Region with particular reference to Penang, Malaysia

In the tropics, direct penetrating sunlight brings in heat and glare as well. Architects have various openings in various orientations and need a simple and fast method to calculate the extent of exterior shading depth required for each opening. A computer program was used to analyze incoming sunlight through openings of various orientations in Penang, in all the twelve months of the year. Simulations done also took into consideration the various nett openings that can occur in any particular floor section. Results were then tabulated in a simple form that can easily be understood and used by consultant architects. It is hoped that guidelines like this can be incorporated in the building by laws as they can help reduce heat gain and glare problems of interiors in the tropical climate.

Three-dimensional volume rendering of spiral CT data: theory and method.

Three-dimensional (3D) medical images of computed tomographic (CT) data sets can be generated with a variety of computer algorithms. The three most commonly used techniques are shaded surface display, maximum intensity projection, and, more recently, 3D volume rendering. Implementation of 3D volume rendering involves volume data management, which relates to operations including acquisition, resampling, and editing of the data set; rendering parameters including window width and level, opacity, brightness, and percentage classification; and image display, which comprises techniques such as "fly-through" and "fly-around," multiple-view display, obscured structure and shading depth cues, and kinetic and stereo depth cues. An understanding of both the theory and method of 3D volume rendering is essential for accurate evaluation of the resulting images. Three-dimensional volume rendering is useful in a wide variety of applications but is just now being incorporated into commercially available software packages for medical imaging. Although further research is needed to determine the efficacy of 3D volume rendering in clinical applications, with wider availability and improved cost-to-performance ratios in computing, 3D volume rendering is likely to enjoy widespread acceptance in the medical community.