Search Results (24)

The Daylight Glare Probability (DGP) includes the luminance of a glare source quadratically, but the solid angle only linearly. While this is in line with formulae of other glare metrics, it must be questioned for small glare sources, if the glare stimulus can no longer be distinguished from larger stimuli causing equal vertical illuminance at the eye, especially in the peripheral visual field. To account for this, the modified version Daylight Glare Metric (DGM) was previously developed. We conducted two studies to evaluate the effect of the modified DGM. First, in a laboratory study under an artificial sky with an LED sun, 35 test subjects evaluated different glare situations. Second, we performed a comprehensive simulation study for an office space, including three locations, three view directions, and 17 window systems (electrochromic glazing, fabric shades). The results from the perception study under the artificial sky provide evidence that the adapted DGM is better suited to predict glare from small, bright sources. The results from the simulation study for a realistic office setting show that, compared to the DGP, the DGM reduces glare ratings for many hours of the year, thus underscoring the practical relevance of improving the DGP formula. Full article

Buildings consume energy and are responsible for a significant portion of greenhouse gas emissions in Australia. Increased standards are being set for building thermal performance. Given the rising demand for energy-efficient housing solutions, this work explores the potential application of innovative technologies to enhance the thermal performance. Since modular construction is attracting popularity owing to numerous advantages, including its efficiency and cost-effectiveness, optimising the thermal performance is a way to further improve its popularity, particularly in diverse Australian climates. Smart materials are unique and have desirable properties when subjected to a change in the external environment. Integration of smart insulation materials in prefabricated buildings forecasts a potential to expand the horizon of thermal performance of prefabricated buildings and subsequently lead towards an enhanced energy performance. This work investigates the effects of aerogel, phase change materials (PCMs), and electrochromic glazing. To assess their potential to improve the thermal performance of a modular house, building energy performance simulations were conducted for three different climatic conditions in Australia. Individual implementation of innovative technologies and their combined effects were also quantified. The combination of the three innovative technologies has yielded total annual energy savings of 15.6%, 11.2%, and 6.1% for Melbourne, Perth, and Brisbane, respectively. Full article

Saudi Arabia has a large part of the country’s power consumption in the building area, mainly operated by cooling demands under extreme climatic conditions, where the summer temperature is more than 45 °C and solar radiation peaks are more than 1200 W/MIC. Facing this challenge, this research examines the translation of biometric principles in the design of adaptive building construction for dry areas. We present a comprehensive, four-phase method structure: removing thermoregulatory and shading strategies from desert vegetation; computer display simulation using EnergyPlus 9.7.0 and CFD (ANSYS Fluent 2022 R2); and the development of an implementation guideline. Our findings achieve three central insights. First, the dynamic factor system, such as the electrochromic glazing tested in our student project, reduced the use of HVAC energy by 30%, while advanced materials, such as the polycarbonate panel, demonstrated notable thermal stability. Secondly, the synergy between cultural knowledge and technical performance proved to be decisive; vernacular-inspired Mushrabias improved generic louver not only in thermal efficiency but also in user acceptance, which increased the 97% approval rate in post-acquisition surveys. Finally, we demonstrate that scalability is economically viable, indicating a seven-year payback period for simulation, phase-transit material (PCM), which aligns with the budgetary realities of public and educational projects. By fusing the plant-induced strategies with rigorous computational modeling and real-world applications, the work provides actionable guidelines for permanent failure design in the warm-dry climate. It underlines that maximizing energy efficiency requires the cohesion of thermodynamic principles with the craft traditions of local architecture, an approach directly aligned with the Saudi Green Initiative and the ambitions of global carbon neutrality goals. Full article

Deep reinforcement learning (DRL)-based HVAC control has shown clear advantages over rule-based and model predictive methods. However, most prior studies remain limited to HVAC-only optimization or simple coordination with operable windows. Such approaches do not adequately address buildings with fixed glazing systems—a common feature in high-rise offices—where the lack of operable windows restricts adaptive envelope interaction. To address this gap, this study proposes a multi-zone control framework that integrates HVAC systems with electrochromic windows (ECWs). The framework leverages the Q-value Mixing (QMIX) algorithm to dynamically coordinate ECW transmittance with HVAC setpoints, aiming to enhance energy efficiency and thermal comfort, particularly in high-consumption buildings such as offices. Its performance is evaluated using EnergyPlus simulations. The results show that the proposed approach reduces HVAC energy use by 19.8% compared to the DQN-based HVAC-only control and by 40.28% relative to conventional rule-based control (RBC). In comparison with leading multi-agent deep reinforcement learning (MADRL) algorithms, including MADQN, VDN, and MAPPO, the framework reduces HVAC energy consumption by 1–5% and maintains a thermal comfort violation rate (TCVR) of less than 1% with an average temperature variation of 0.35 °C. Moreover, the model demonstrates strong generalizability, achieving 16.58–58.12% energy savings across six distinct climatic regions—ranging from tropical (Singapore) to temperate (Beijing)—with up to 48.2% savings observed in Chengdu. Our framework indicates the potential of coordinating HVAC systems with ECWs in simulation, while also identifying limitations that need to be addressed for real-world deployment. Full article

Adaptive façades, also known as climate-adaptive building shells (CABSs), could make a significant contribution towards reducing the energy consumption of buildings and their environmental impacts. There is extensive research on glazed adaptive façades, mainly due to the available technology for glass materials. The technological development of opaque adaptive façades has focused on variable-thermal-resistance envelopes, and the simulation of this type of façade is a challenging task that has not been thoroughly studied. The aim of this study was to configure and validate a simplified office model that could be used for simulating an adaptive façade with variable thermal resistance via adaptive insulation thickness in its opaque part. Software-to-software model comparison based on the results of an EnergyPlus Building Energy Simulation Test 900 (BesTest 900)-validated model was used. Cooling and heating annual energy demand (kWh), peak cooling and heating (kW), and maximum, minimum, and average annual hourly zone temperature variables were compared for both the Adaptive and non-adaptive validated model. An Adaptive EnergyPlus model based on the BesTest 900 model, which uses the EnergyPlus SurfaceControl:MovableInsulation class list, was successfully validated and could be used for studying office buildings with a variable-thermal-resistance adaptive façade wall configuration, equivalent to a heavyweight mass wall construction with an External Insulation Finishing System (EIFS). An example of the Adaptive model in the Denver location is included in this paper. Annual savings of up to 26% in total energy demand (heating + cooling) was achieved and could reach up to 54% when electro-chromic (EC) glass commanded by a rule-based algorithm was added to the glazed part of the variable-thermal-resistance adaptive façade. Full article

This study examined the optical–thermal performance and energy efficiency of electrochromic (EC) glazing in residential buildings situated in regions characterized by hot summers and warm winters. Traditional glazing systems, such as double-layer (DL) and low-emissivity (LE) glazing, often face challenges in achieving an optimal balance between indoor lighting, glare control, and heat regulation. Using EnergyPlus simulations for a typical residential building, this research evaluated the performance of EC glazing under four control strategies, considering seasonal variations (summer and winter), building orientations, and energy demands for cooling, heating, and lighting. The results indicate that EC glazing dynamically adjusts the solar transmittance from 0.320 under low solar radiation to 0.012 at high levels, significantly reducing the glare and convection heat gains. The transmitted radiation heat gain for EC glazing is remarkably only 23.7 J·m⁻², compared to 736.8 J·m⁻² for DL glazing. Furthermore, EC glazing achieves a total energy consumption of 189.52 MJ·m², representing a significant 33.0% reduction compared to DL glazing. These findings underscore the potential of EC glazing to improve both the energy efficiency and visual comfort in residential settings. This study highlights the importance of optimizing control strategies, particularly in response to seasonal and directional variations, offering valuable insights for sustainable building design in climates with diverse thermal requirements. Full article

Mosques, revered as sacred spaces, are distinguished by their sustainable architectural designs. A critical aspect of these designs is the implementation of daylighting strategies, essential for ensuring adequate light levels, particularly for reading the Holy Quran. Traditional daylighting typologies in mosques, such as multi-lateral lighting, clerestories, skylights, and shading devices, are widely recognized. However, the potential application of electrochromic (EC) switchable glazing within mosque architecture remains underexplored. This study delves into the effectiveness of various daylighting typologies, assessing their performance before and after the integration of EC switchable glazing in the Al-Shagroud Mosque located in Saudi Arabia. Employing comprehensive radiance simulations in accordance with the LEEDv4.1 standards, the study evaluates additional metrics including useful daylight illuminance (UDI_{300–3000lux}), workplane illuminance (WPI), uniformity index (Ui), and daylight glare probability (DGP) under multiple scenarios. The results demonstrate that clerestory lighting effectively meets LEEDv4.1 benchmarks but exhibits limitations in achieving uniform light distribution, particularly in the men’s prayer hall. In contrast, the women’s prayer hall benefits from a combination of clerestory lighting and shading devices, which improves light quality and mitigates glare issues. However, the use of skylights without adequate shading leads to excessive WPI and high DGP levels, compromising visual comfort. Moreover, managing daylight quantity and quality through the integration of different typologies, including hybrid models, presents substantial challenges. The integration of EC switchable glazing, while maintaining optimal WPI and reducing DGP, offers enhanced visual comfort in prayer areas. Nevertheless, this technology faces difficulties in ensuring even light distribution, as evidenced by lower uniformity index values. This research highlights the critical need for optimizing daylighting in mosques to balance sustainability and comfort, without detracting from their sacred ambiance. Full article

Electrochromic glazing alters its optical properties in the absence/presence of an electrical charge, varying from clear to dark to control daylighting and solar heat gains. This study aims to evaluate the impact of an electrochromic glazing, with indoor glare or temperature control, on the energy performance and thermal and visual comfort of an office room under three European climates, using a calibrated simulation model. The novelty of the paper lies in its combined performance assessment, using different standards and metrics. The results showed reduced climatization energy requirements with temperature control, but significantly increased artificial lighting energy use. Glare control achieved useful illuminance levels during 74–80% of working hours. Concerning temperature control, working hours within thermal comfort increased (21–43%) under a free-float regime. Moreover, the performance of this glazing was compared to that of a clear glazing with/without a reflective film and a thermochromic glazing for different solar orientations. The electrochromic glazing with glare control showed the highest energy savings (14–36%) for a western orientation, and the lowest negative impact on daylighting for a northern orientation. The best glare reduction was achieved with the reflective film. Considering the free-float regime, the electrochromic glazing, with temperature control, showed the highest increase in working hours within thermal comfort (6–9%) for a western orientation. Full article

Electrochromism induces reversible changes of coloration in specific organic and inorganic materials through electrical charge/discharge reactions. When processed into thin films, electrochromic metal oxides can be integrated into glazing applications such as displays, rearview mirrors, goggles and, most notably, smart windows in energy-efficient buildings. Over the years, the use of spray coating as a liquid-based approach has been acknowledged for its cost-efficient, high-throughput samples production with a low volume consumption. It represents an interesting alternative to vacuum processes and to other wet methods, suitably responding to the current limitations of electrochromic thin films production by offering improved control over deposition parameters and capacities of up-scaling, together with lowered energetic and economic costs. The present review summarizes the main theoretical and practical aspects of spray coating, notably distinguishing room-temperature methodologies from pyrolysis-based, under heating protocols. The main families of functional electrochromic metal oxides are then screened and discussed, establishing how spray processing can challengingly lead to higher levels of optical contrast, commutation kinetics, coloration efficiency and cycling durability, and how low-toxic and environment-friendly precursors can be favored while sustaining large deposition areas. Full article

High-performance glazing technologies are essential for achieving the occupant comfort and building energy efficiency required in contemporary and future buildings. In real-world applications, glazing façades are selected from a steadily increasing number of glazing technologies. However, the authors could not identify a systematic and comprehensive review and classification of glazing technologies in the literature. This creates a barrier when comparing typologically different glazing technologies and combining multiple technologies in a glazing unit. This paper provides a systematic review and classification of established and emerging glazing technologies based on publications from 2001–2022 which were interpreted following the PRISMA methodology. This study reveals that the majority of high-performance glazing systems used in practice are in multi-layer glazing configurations and that the glazing system performance can focus on including additional and multiple functionalities, which aim at improving overall building performance. It was also found that there is a large potential for improvement of multilayer, evacuated, aerogels, electrochromic, and solar cell glazing by incorporating other technologies or innovative materials in multi-layer glazing units for either improving existing technologies or for the development of new ones. However, their longevity, robustness, and cost affordability should be ensured. Full article

This study comprehensively evaluates the energy-saving potential and visual comfort aspects of electrochromic (EC) smart windows in a hot-humid climate office building. Using an advanced building simulation tool, EC windows are compared to conventional low-E glazed windows, considering two control triggers: daylighting level and glare control. The primary objective is to determine energy savings achievable with EC windows while addressing visual comfort. Detailed analysis of the building’s energy performance and indoor environment is conducted. Results show significant energy savings of 23% with EC windows using daylighting control but limited visual comfort in some zones. Conversely, EC windows with glare control achieve 17% energy savings while maintaining visual comfort throughout the building. These findings highlight the potential of EC windows with glare control in saving energy and maintaining visual comfort in hot-humid office buildings. Further research is needed to optimize performance for different building types and climates. In conclusion, this study provides insights into energy-saving capabilities and visual comfort considerations with EC smart windows, emphasizing the importance of appropriate control triggers for maximizing energy savings and occupant comfort. Future investigations should explore EC window performance across diverse building typologies and climates to enhance the benefits of this innovative technology. Full article

A smart window, such as electrochromic or thermochromic windows, may not be able to accomplish at the same time energy efficiency and visual comfort functions, since satisfying one criterium interferes with the other. This recalls to the important issue of establishing precise relationships among parameters affecting energy, glare control, and color rendering tasks and the influence on them of glazing material composition and preparation technique. With this aim, the luminous properties of a number of advanced glazings found in literature and of three home-made electrochromic devices differing by material composition and/or preparation technique are analyzed in this study. The investigation has involved the determination of the CIE (Commission International de l’Eclairage) Color Rendering Index (CIE CRI), the Correlated Color Temperature (CCT), and the luminous transmittance coefficient (τ_V) of the devices which are discussed with regard to their potential in absolving to energy and visual comfort tasks. Results lead to the main conclusion that the CIE CRI, CCT, and τ_V indexes are clearly linked by an exponential correlation. At low τ_V values (τ_V< 0.5), however, the correlation weakens and the variation of the CIE CRI and CCT indexes becomes entirely material dependent. The influence of preparation technique appears to be irrelevant since the color rendering indexes appear to be well correlated to τ_V over all the investigated τ_V range. Full article

The significant increase in construction industry demand with its negative effects on energy consumption is particularly evident in areas with severe climatic factors. Here, the designers aim at providing comfort with the least amount of energy, and consequently have resorted to using different software tools to choose the optimal solution in the early phase of design to avoid time and cost losses. The use of smart innovative technologies such as electrochromic (EC) glazing may provide an important contribution in reducing consumptions while providing good thermal and visual comfort conditions. Nonetheless, as shown in the literature, such glazing should be used and managed carefully to avoid any adverse effects or low performance. Thus, a parametric simulation was carried out using Rhinoceros and Grasshopper to assess the advantages in terms of energy use resulting from use of EC glazing in residential buildings as a function of façade orientation and window-to-wall ratio (WWR) with reference to the city of Biskra, located in the northeastern region of Algeria. Eight main orientations and ten WWR scenarios were investigated in order to evaluate the benefit of using this technology in the selected climatic region. The research results proved the benefit of using EC glazing in all orientations, with energy savings ranging from 35.88% in the northern façade to 60.47% in the southwestern façade. Full article

Adaptive façades are gaining greater importance in highly efficient buildings under a warming climate. There is an increasing demand for adaptive façades designed to regulate solar and thermal gains/losses, as well as avoid discomfort and glare issues. Occupants and developers of office buildings ask for a healthy and energy-neutral working environment. Adaptive façades are appropriate dynamic solutions controlled automatically or through occupant interaction. However, relatively few studies compared their energy and overheating risk performance, and there is still a vast knowledge gap on occupant behavior in operation. Therefore, we chose to study four dynamic envelopes representing four different façade families: dynamic shading, electrochromic glazing, double-skin, and active ventilative façades. Three control strategies were chosen to study the dynamic aspect of solar control, operative temperature, and glare control. Simulations were realized with EnergyPlus on the BESTEST case 600 from the ASHRAE standard 140/2020 for the temperate climate of Brussels. A sensitivity analysis was conducted to study the most influential parameters. The study findings indicate that dynamic shading devices and electrochromic glazing have a remarkable influence on the annual thermal energy demand, decreasing the total annual loads that can reach 30%. On the other hand, BIPV double-skin façades and active ventilative façades (cavity façades) could be more appropriate for cold climates. The study ranks the four façade technologies and provides novel insights for façade designers and building owners regarding the annual energy performance and overheating risk. Full article

Dynamic façades play an important role in enhancing the overall performance of buildings: they respond to the environmental conditions and adjust the amount of transmitted solar radiation. This paper proposes a simulation-based framework to evaluate the energy and comfort performance of different control strategies for switchable electrochromic glazing (EC). The presented method shows the impact of a model predictive control (MPC) on energy savings and on visual and thermal comfort for different orientations compared to other strategies. Besides manual operation and conventional rule-based controls, the benchmark in this study was a simulation-based control (multi-objective penalty-based control) with optimal performance. The hourly results of various control cases were analyzed based on the established performance indicators and criteria. The cumulative annual results show the capabilities and limitations of each control strategy for an EC glazing. For a temperate climate (Mannheim, Germany), results showed that an MPC for EC glazing provides visual and thermal comfort while saving energy of up to 14%, 37%, 37%, and 34% respectively for facing north, east, south, and west relative to the base-case. Full article