External Shading Research Articles

Comparative analysis of hydrogel-based thermotropic glazing and fixed horizontal overhangs in building performance

Thermotropic (TT) glazing is able to achieve energy-saving capabilities similar to external shading devices by dynamically regulating solar heat gain transmitted through windows in response to ambient climatic conditions. However, the building performance of TT glazing compared to traditional shading devices remains underexplored. This study aims to bridge this knowledge gap by comparing the building performance of hydrogel-based TT glazing and fixed horizontal external shading devices in terms of building energy consumption, daylighting performance, and thermal comfort. Experimental tests were conducted over a continuous ten-day period, focusing on the indoor temperature and illumination distribution within experimental rooms equipped with either TT glazing or fixed horizontal external shading device. Building performance models were developed using EnergyPlus and validated with experimental data. Subsequently, a comparative analysis was then conducted to evaluate the impact of TT glazings and fixed horizontal external shading devices on building energy consumption, daylighting performance, and thermal comfort across five typical climate conditions in China. The findings indicated that: (1) In five climate zones, TT provided the greatest energy savings in West-facing orientations, followed by East-facing orientations. (2) TT can replace fixed horizontal external shading device with a certain length to achieve similar building energy efficiency and indoor thermal comfort performance. (3) In regard to daylighting performance, TT achieved the desired values of sUDI<100lx,50 % and sUDI300–3000lx,50 % across all four orientations in the five climates. (4) In terms of thermal comfort, TT improved thermal comfort by reducing the annual daytime average PPDoverheating across all orientations in the five climate zones.

ANN-Based Optimal Control of External Shading Device during Heating Season in Small Office Building

ANN-Based Optimal Control of External Shading Device during Heating Season in Small Office Building

Integration of Photovoltaic Cells in Building Shading Devices:

This study focuses on the thermal performance simulation of the CSERS administrative building. It proposed the integration of shading elements on the south façade of the building to enhance thermal comfort for office occupants. These shading elements incorporate photovoltaic cells, displaying the potential of utilizing photovoltaic in external shading devices. The main objective of this approach is effectively address issues related to high internal temperatures and excessive solar radiation exposure. Furthermore, it ensures the preservation of key functions of the building envelope, such as thermal insulation, provision of natural lighting, and prevention of internal thermal glare. Comparative analysis is conducted between the building equipped with shading devices and the one without, with a focus on measuring the total electrical energy generated by the photovoltaic panels. Simulation programs such as SketchUp and EnergyPlus are utilized for this purpose. The results of the simulations reveal that strategically designed shading on south-facing windows leads to 17.15% reduction in annual heat gains transmitted to the building. In addition, the integration of photovoltaic shading devices demonstrates outstanding performance characteristics, contributing a productive capacity of around 5916.388 MW/h to the building. This integration effectively harnesses solar energy to improve the indoor environment of the building.

Effect of external shading on the temperature distribution performance of glass greenhouse in Wuhan region

The spatial temperature distribution within greenhouses plays a crucial role in agricultural management, particularly in large glass greenhouses that provide optimal growing conditions for crops. The current study investigated the effects of solar radiation and external shading on the spatial distribution of air temperature inside a large glass greenhouse. Experiments were conducted during summer in Wuhan, China, with cherry tomatoes grown under removable black plastic external shading (50 % transmittance). The use of external shading reduced greenhouse temperatures by 6.80 % on sunny days with air conditioning and 4.62 % on cloudy/rainy days without air conditioning. It also decreased the correlation between solar radiation and indoor temperatures by 60.71 % on sunny days and 7.20 % on rainy days. The greenhouse exhibited uneven temperature distribution in all directions, with much greater vertical temperature gradients (0.67 °C/m on sunny days, 0.33 °C/m on rainy days) compared to east-west and north-south directions. While external shading reduced overall temperature unevenness, on rainy days the north-south temperature difference was only 0.28 %, but the middle position was 2.24 % warmer than boundaries. The findings provide insights into regulating external shading techniques for large greenhouses in humid subtropical climates to optimize temperature management and crop production efficiency.

Daylighting Evaluation of Perforated Screen Façade with Light Shelf in the Tropics

The use of large glass facades in buildings without external shading devices leads to a high daylight level, uneven daylight distribution, and glare. A perforated screen facade (PSF) is one of the shading systems that can provide daylight and view and prevent direct solar radiation into a building. More research is needed about the daylight performance of PSF in integration with daylighting systems in the tropics. A combination of PSF and light shelf (LS), a daylighting system that can redirect daylight to the ceiling and enhance daylight distribution, is proposed to improve daylight levels and reduce glare. The research aims to evaluate the daylight performance of PSF and LS in the tropics. The research method is experimental with simulation utilizing IES-VE Radiance IES. Average Daylight Factor (DFavg), Useful Daylight Illuminance (UDI), and Daylight Glare Probability (DGP) of a room with a side window were compared with a room with PSF and LS. The results showed that implementing PSF and LS improved daylight performance by lowering the DFavg by 55%, increasing the UDI, and reducing the DGP.

Determination of Performance of Different Pad Materials and Energy Consumption Values of Direct Evaporative Cooler

The purpose of this study is to determine the performances of luffa and greenhouse shading netting (which can be used as alternatives to commercial cellulose pads, that are popular for cooling greenhouses), the contribution of external shading to the evaporative cooling performance, and the energy consumption of the direct evaporative cooler. In this experiment, eight different applications were evaluated: natural ventilation (NV), natural ventilation combined with external shading net (NV + ESN), cellulose pad (CP), cellulose pad combined with external shading net (CP + ESN), luffa pad (LP), luffa pad combined with external shading net (LP + ESN), shading net pad (SNP), and shading net pad combined with external shading net (SNP + ESN). The cooling efficiencies of CP, CP + ESN, LP, LP + ESN, SNP, and SNP + ESN were found to be 37.6%, 45.0%, 38.9%, 41.2%, 24.4%, 29.1%, respectively. Moreover, their cooling capacities were 2.6 kW, 3.0 kW, 2.8 kW, 3.0 kW, 1.7 kW, 2.0 kW, respectively. The system water consumption values were 2.9, 3.1, 2.8, 3.2, 2.4, 2.4 l h−1, respectively. The performance coefficients of the system were determined to be 10.2, 12.1, 11.3, 11.9, 6.6, 7.8. The system’s electricity consumption per unit area was 0.15 kWh m−2. As a result of the study, it was determined that commercially used cellulose pads have advantages over luffa and shading net materials. However, luffa pads can be a good alternative to cellulose pads, considering their local availability, initial cost, cooling efficiency, and capacity.

Impact of occupant behavior on optimal multi-objective solutions for the design of low-energy buildings

The occupant behavior plays a fundamental role in the actual performance of the buildings, especially for very low energy buildings. Since inconsistencies are discovered post-occupancy, known as Energy Performance Gap, it is necessary to better represent the occupants when optimizing the design of buildings. In this context, a multi-objective optimization of a low energy building was carried out for three different French climates with two models of occupant behaviors. The first is a standard fixed scenario (SF) while the second is an agent-based tool (NoMASS) that predicts occupancy scenarios according to sociodemographic characteristics and estimates occupants’ interactions with windows, external shadings and lighting based on probabilistic models. The results obtained show that the occupant model significantly influences the expected performance of the building as NoMASS model estimates greater heating needs and improved summer comfort. However, for our case study, there is no influence of the accuracy of representation of occupant behavior on the optimal solutions of building design. The optimization could be carried out with a less detailed model, thus reducing calculation times while maintaining comparable optimal results. The performance of the optimal solutions obtained can then be refined by simulating with the most detailed model.

Sensitivity of a Lumped-Capacitance Building Thermal Modelling Approach for Energy-Market-Scale Flexibility Studies

Despite all the literature on building energy management, building-stock-scale models depicting its impact for energy-market-scale optimisation models are lacking. To address this shortcoming, an open-source tool called ArchetypeBuildingModel.jl has been developed for aggregating building-stock-level data into simplified lumped-capacitance thermal models compatible with existing open-source energy-system modelling frameworks. This paper aims to demonstrate the feasibility of these simplified thermal models by comparing their performance against dedicated building simulation software, as well as examining their sensitivity to key modelling and parameter assumptions. Modelling and parameter assumptions comparable to the existing literature achieved an acceptable performance according to ASHRAE Guideline 14 across all tested buildings and nodal configurations. The most robust performance was achieved with a period of variations above 13 days and interior node depth between 0.1 and 0.2 for structural thermal mass calibrations, and with external shading coefficients between 0.6 and 1.0 and solar heat gain convective fractions between 0.4 and 0.6 for solar heat gain calibrations. Furthermore, three-plus-node lumped-capacitance thermal models are recommended when modelling buildings with structures varying in terms of thermal mass. Nevertheless, the ArchetypeBuildingModel.jl performance was found to be robust against uncertain key parameter assumptions, making it plausible for energy-market-scale applications.

Assessing the Impact of Climate Changes, Building Characteristics, and HVAC Control on Energy Requirements under a Mediterranean Climate

Assessing the Impact of Climate Changes, Building Characteristics, and HVAC Control on Energy Requirements under a Mediterranean Climate

Experimental Study on Design of External Shading Devices in Dental Unit Room

Experimental Study on Design of External Shading Devices in Dental Unit Room

Experimental study of ambient temperature and humidity distribution in large multi-span greenhouse based on different crop heights and ventilation conditions

Analyzing the distribution of temperature and humidity within a greenhouse is essential for optimizing ventilation strategies and improving crop quality and yield. The temperature and humidity distribution of eight-span greenhouse under natural ventilation and mechanical ventilation is studied experimentally. The influence of different crop height on temperature and humidity distribution in greenhouse and the influence of different mechanical ventilation strategies on temperature regulation were discussed. The results showed that the temperature difference between inside and outside the greenhouse decreased with the increase of crop height. Under natural ventilation conditions, the soil surface temperature is the highest, and the temperature at 0.5 m above the surface is the lowest, with the maximum temperature difference of 0.9 ℃. The temperature in the greenhouse was higher in the west and lower in the east, and the temperature difference decreased with the increase of crop height. In the east–west direction, the maximum temperature difference between tall crops, short crops and non-planted crops was 0.7 ℃, 0.9 ℃ and 1.0 ℃, respectively. High crops increase the relative humidity in the greenhouse and increase the uneven distribution of relative humidity. When growing tall crops, the difference between indoor and outdoor relative humidity is only 2.3 %. When the external shade and fan are turned on at the same time, the cooling effect is the best, the energy consumption is lower, and the temperature distribution is the most uniform. The results provide a valuable reference for optimizing greenhouse structure, formulating ventilation strategy and reducing agricultural energy consumption.

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

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

Passive strategies for energy-efficient educational facilities: Insights from a mediterranean primary school

This study investigates the thermal and energetic dynamics of primary school classrooms in a Mediterranean climate in Khoualed Abdel Hakeem, Ain Temouchent County, Algeria. The research highlights significant optimizations by focusing on passive strategies such as external shading devices, Window-to-Wall Ratio (WWR), glazing types, and building envelope adjustments. Our simulations, validated rigorously, showcase a remarkable congruence with actual electricity consumption, affirming the reliability and efficacy of our simulation model as a valuable predictive tool. A Vertical Shading Angle (VSA) of 60° proves optimal, resulting in an impressive 11% reduction in Annual Energy Consumption (AEC). A recommended WWR of 30% demonstrates an 11% decrease in AEC and improves thermal and energy efficiency. Double Low Emissivity (Double-Low E) glazing is found to be superior, resulting in a significant 14% decrease in AEC. Achieving a WWR of 50% in shaded areas helps maintain a well-balanced thermal environment, resulting in a 12% reduction in heating and cooling requirements. The integration of passive strategies in the optimized model showcases a remarkable 44% overall reduction in energy consumption. The results highlight the efficacy of passive strategies, promoting energy-conscious and ecologically responsible practices, advocating for their incorporation in educational facilities, and offering valuable insights for sustainable school building design.

Combining use of natural ventilation, external shading, cool roof and thermal mass to improve indoor thermal environment: Field measurements and simulation study

Thermal mass, natural ventilation, external shading and cool roof are commonly regarded as passive cooling measures. Combined use of these passive cooling measures could achieve a more comfortable indoor environment, and further reduce the building energy demand. The aim of this paper was to assess the short and long-term performances of individual and combination passive measures in a cooling-dominated region of China experimentally and numerically. The field measurement revealed that natural ventilation, external shading and cool roof can reduce the internal wall and indoor air temperatures. The mean air temperatures in the test chamber were 1.3, 2.0, and 1.1 °C lower than that in reference chamber. The combined use of natural ventilation, external shading and cool roof can maintain the daily indoor air temperature within the range of 26.2 and 28.1 °C. The mean air temperature in the test chamber was reduced by 2.8 °C. Long-term simulation results confirmed that applying combination mode of natural ventilation, cool roof and external shading, the indoor temperature, varying from 21.9 to 28.1 °C, is greatly improved compared with the case operated natural ventilation only, particularly during peak temperature hours. The effect of specific heat capacity on indoor air temperature is complex. Increasing the specific heat is not always beneficial to indoor thermal environment. Further, the greater the heat transfer coefficient leads to the higher indoor air temperature through entire summer. The maximum indoor air temperature is reduced by 2.6 °C when the heat transfer coefficient changes from 1.0 to 0.1 W/m2·K.

Influence of Sun Shading Devices on Energy Efficiency, Thermal Comfort and Lighting Comfort in a Warm Semi-Arid Dry Mediterranean Climate

The dry Mediterranean climate (BShs) is the European region with the highest number of hours of sunshine per year. The high annual solar radiation makes sun shading devices necessary to comply with current energy efficiency standards. However, these standards do not sufficiently consider their effect on the indoor lighting comfort of buildings. The objective is to qualitatively and quantitatively determine how movable sun shading devices jointly influence the energy efficiency, thermal comfort and lighting comfort of buildings in BShs climate. The scientific novelty of the work consists of demonstrating the limitations of the sun shading systems commonly used in southeastern Spain and determining the optimal technical solution in this climate to simultaneously improve thermal and lighting comfort. This research comparatively studies the influence of various movable sun shading systems on the daylighting and thermal performance of an educational building. This study conducted on-site measurements, user surveys and computer simulations to study how to improve the thermal and lighting performances of the building. This work demonstrates that interior solar shading provides little improvement in thermal comfort and reduces the cooling demand by only 25%. External movable sun shading improves thermal comfort and reduces the cooling demand by more than 60%, but only adjustable blinds or awnings achieve adequate and homogeneous illuminance values as they diffuse daylight. The paper concludes that energy efficiency standards should be modified to ensure adequate lighting comfort in buildings.

Multi-objective optimization for visual, thermal, and cooling energy performance of building envelope design in the composite climate of Jaipur (India)

Climate-responsive passive envelope features such as windows, louvers, and shading have significant impact on a building's energy and economic performance. This paper presents a multi-objective optimization (MOO) approach to enhance energy, visual and thermal performances of a building by considering a wide range of numerous design possibilities. A residential apartment building located in a semi-arid composite climate (Köppen climate classification: Bsh) of Jaipur, India is considered for the analysis. The multi-objective optimization approach involves three steps: firstly, developing a base simulation model using Rhinoceros software, and then performing multi-objective optimization by Octopus plugin, and finally applying multi-criteria decision-making to select the optimal values of thermal conductivity, window-to-wall ratio of south and west façades, solar heat gain coefficient, visual light transmittance, window sill height, louvers depth, distance between slits, slits angle, external shade depth, and shade (slits) count. The optimized results reported a six-fold Useful Daylight Illuminance (UDI) improvement, 72% cooling energy demand reduction, and 34% thermal comfort enhancement from the worst-case scenario. The presented approach can aid designers in selecting optimal envelope features during building design, refurbishment, and renovation or for green field development.

A growing soft robot with climbing plant-inspired adaptive behaviors for navigation in unstructured environments.

Self-growing robots are an emerging solution in soft robotics for navigating, exploring, and colonizing unstructured environments. However, their ability to grow and move in heterogeneous three-dimensional (3D) spaces, comparable with real-world conditions, is still developing. We present an autonomous growing robot that draws inspiration from the behavioral adaptive strategies of climbing plants to navigate unstructured environments. The robot mimics climbing plants' apical shoot to sense and coordinate additive adaptive growth via an embedded additive manufacturing mechanism and a sensorized tip. Growth orientation, comparable with tropisms in real plants, is dictated by external stimuli, including gravity, light, and shade. These are incorporated within a vector field method to implement the preferred adaptive behavior for a given environment and task, such as growth toward light and/or against gravity. We demonstrate the robot's ability to navigate through growth in relation to voids, potential supports, and thoroughfares in otherwise complex habitats. Adaptive twining around vertical supports can provide an escape from mechanical stress due to self-support, reduce energy expenditure for construction costs, and develop an anchorage point to support further growth and crossing gaps. The robot adapts its material printing parameters to develop a light body and fast growth to twine on supports or a tougher body to enable self-support and cross gaps. These features, typical of climbing plants, highlight a potential for adaptive robots and their on-demand manufacturing. They are especially promising for applications in exploring, monitoring, and interacting with unstructured environments or in the autonomous construction of complex infrastructures.

Examining the role of passive design indicators in energy burden reduction: Insights from a machine learning and deep learning approach

Passive design characteristics (PDC) play a pivotal role in reducing the energy burden on households without imposing additional financial constraints on project stakeholders. However, the scarcity of PDC data has posed a challenge in previous studies when assessing their energy-saving impact. To tackle this issue, this research introduces an innovative approach that combines deep learning-powered computer vision with machine learning techniques to examine the relationship between PDC and energy burden in residential buildings. In this study, we employ a convolutional neural network computer vision model to identify and measure key indicators, including window-to-wall ratio (WWR), external shading, and operable window types, using Google Street View images within the Chicago metropolitan area as our case study. Subsequently, we utilize the derived passive design features in conjunction with demographic characteristics to train and compare various machine learning methods. These methods encompass Decision Tree Regression, Random Forest Regression, and Support Vector Regression, culminating in the development of a comprehensive model for energy burden prediction. Our framework achieves a 74.2 % accuracy in forecasting the average energy burden. These results yield invaluable insights for policymakers and urban planners, paving the way toward the realization of smart and sustainable cities.

DESIGNING DAYLIGHTING FRAMEWORK FOR NORTHERN HEMISPHERE CLIMATE: STUDY OF ANALYSIS &amp; RECOMMENDATIONS FOR ADAPTIVE EXPANSION APPROACH FOR LONDON CENTRAL MOSQUE, UNITED KINGDOM

Any religious building's holistic and ceremonial performance is profoundly and dramatically impacted by lighting research. In this study, the current situation is examined via the lens of analysis, and a performance - based preamble design proposal analysis for the study of adaptive expansion approach for London Central Mosque. Numerous studies have been done on the significance of the ornamentation of mosques and its acoustics impacts on the congregational activities. However, few exceptions are given on the importance of daylighting effect in the mosques. Looking at the massive and widely compacted end-users in London Central Mosques especially during peak season given that the numbers of devotees is increasing each year, the objective is to understand the analysis and recommendations needed for the adaptive expansion approach in designing a daylighting framework for the northern hemisphere climate. The performance of the lighting design for London Central Mosque was the subject to few case studies referred that focused on the evolution and morphology of daylighting in religious and historical areas. Thus, this research will then conduct an observation and analysis studies as the method to materialize the findings. This study was also anticipating recommendations that suggest both passive and active design implications towards the idea of adaptive expansion. As a result, the outcome discussions demonstrate numerous implementation criteria ranging from design stages of site analysis, climate aspects to the electrical fittings and external shading devices well recommended for the best proposal assisting and improving the mosque's current circumstances. The study's findings also indicate that minimal glare and efficient lighting distribution help to reduce energy consumption, enhance reading quality, and properly illuminate public and private religion events and other activities carried out in the situation of optimum brightness of London Central Mosque.

Building Optimisation Vis-À-Vis Solar Shading for Improved Comfort and Energy Efficiency in Classrooms

Excessive solar radiation negatively affects classroom occupants' perfor­mance and thermal comfort, especially in buildings with West and East-facing glazed openings. This study utilises fixed external shading devices and triple-glazed low-emissivity windows to optimise a classroom building in Nigeria. Employing hybrid ventilation mode in EnergyPlus simulations, the optimised model shows a 44% reduction in discomfort hours, a 23% decrease in cooling load, and a 16% drop in energy demand compared to the original design. Comparative analysis of the optimised model with the as-built and West-East oriented classroom reveals a 16% and 10% reduction in energy consumption per conditioned area, along with 56 KWh/m² and 32 KWh/m² savings in cooling demand, respectively. Despite the effectiveness of fixed shading in curbing solar gains, occasional glare persists. This research underscores that shading alone may not fully meet thermal comfort requirements, emphasising the importance of building fabrics, building orientation and climate-sensitive design.