Smart dynamic building technologies can help to significantly reduce operational energy and carbon emissions. However, human acceptance remains a significant barrier, particularly for switchable glazing used in smart windows. This study examines how users are affected by the speed and direction of transitions in the transparency of fast switchable glazing, specifically dynamic liquid crystal technology under overcast sky. Perceptual and behavioural data including facial action units, were collected through an experimental campaign in a semi-controlled environment where the glazing transparency was transitioned at two rates (1 and 10 s). It was found that user perception remained consistent regardless of transition speed or direction, but override behaviour was influenced by both factors. In the absence of glare, user overrides were primarily driven by the transition direction, with more users reacting to transitions from dark to clear. Faster transition rates led to an increase in user overrides for both transition directions. Unlike those who did not override, users who overrode the automated glazing control strategy had a negative perception of the visual environment and the window control system. Users directed their gaze more towards the glazing when this was transitioning, suggesting possible distractions. Users were clustered based on their background knowledge and reported preferences. These clusters showed a good correlation with the override delay times. However, the agreement with actual behaviour was low, indicating that a larger number of variables and clusters should be tested to predict user behaviour. Nevertheless, clustering users highlighted the importance of considering individual differences for interaction strategies.@en

The increase in carbon emissions has contributed to rising global temperatures, necessitating higher energy consumption in buildings to maintain thermal comfort during the summer months. The building envelope, as the protective layer of a building, plays a critical role in maintaining indoor comfort and dictating building energy use. However, when assessing the performance of the building envelope, occupant interaction is poorly considered. This study investigates the impact of occupant façade interaction when evaluating alternative façade solutions for thermal comfort in summer season. Occupant behaviour models, specifically window operation models, are identified and implemented to assess their impact on indoor comfort and air quality. This is done by first identifying façade archetypes and generating scenarios with selected occupant behavior models. The results revealed that occupant interaction with windows significantly impact internal air temperatures and thermal comfort, while alternative façade solutions have a relatively lower impact. Largest ventilation areas were associated with lower air temperatures. Consequently, the number of discomfort hours are also lower in scenarios with occupant interaction compared to without. The impact of the façade ventilation area, window-to-wall ratio and thermal mass was more relevant in the scenarios where windows were always closed. The findings of this study can serve as a foundation for the development of strategies that promote occupant interaction with the façade which can lead to reduced building energy demand.@en

The increasing frequency and intensity of heatwaves raises questions about the thermal vulnerability of buildings and, in particular, on how to assess their resilience to extreme heat. In this context, thermal fragility curves, which describe the probability of achieving or exceeding specific temperature thresholds for a building, serve as an effective measure to define the thermal vulnerability of existing buildings and identify tailored retrofit strategies. This study focuses on deriving thermal fragility curves for a case study: a 6-storey residential building constructed in the 1980s with a reinforced concrete structure and masonry infill walls. Dynamic thermal modeling and simulation were conducted over a one-year period using synthetic weather files generated to account for future heatwaves. The simulation results provide useful relationships in particular between: outdoor temperature and indoor Standard Effective Temperature (SET); and between outdoor daily maximum temperature and indoor SET. These relationships were finally analyzed to create and compare fragility curves using maximum likelihood fitting and the so-called Cloud methodology.@en

As cities continue to expand and densify, understanding how buildings affect people’s perception and experience of the acoustic environment in context becomes more relevant. This paper presents a conceptual framework of the influence of façades on the urban soundscape, based on the ISO 12913 series, in order to analyze the three main elements of the soundscape: people, acoustic environment and context, along with façade as a fourth element. The methodology included literature review, as well as an exploration of the ISO 12913 methods for soundscape assessment via soundwalks and laboratory experiments involving a total of forty-three (n = 43) participants. The results provide a promising framework for façade analysis to progress toward the integration of human-centered approaches into the field of façade acoustics and complement current building physics practice.@en

The Smart Readiness Indicator (SRI), introduced by the European Union in 2018, assesses a building’s capacity to accommodate smart-ready services. This evaluation focuses on optimizing energy efficiency, aligning operations with occupant needs, and responding to signals from the grid. Previous studies have evaluated SRI feasibility in various locations and retrofit scenarios, estimating the costs associated with implementing smart technologies in existing European buildings. However, the specific impact of digitizing distinct building services on SRI scores remains unexplored. Particularly, adaptive façade technologies show potential in enhancing overall building performance, being worthy to understand how these services influence the smart readiness rating of buildings. This study investigates the impact of adaptive façade technologies on SRI scores and user satisfaction. A case study of an office building in Delft (The Netherlands) was selected to assess the impact of smart technologies on energy efficiency and comfort. This paper shows preliminary results from the pre-intervention phase, where the SRI was calculated for both the baseline condition and a scenario with the highest possible level of smart services for the building envelope. The results from the SRI methodology showed an increase of approximately 4% in energy efficiency and 15% in terms of energy flexibility. In addition, the SRI predicts similar improvements in user convenience, information, health & well-being, but only 4% in user comfort. This was confirmed by the assessments on user perception and preferences. Users reported to be “slightly satisfied” with several comfort domains. Additionally, several users considered better control of external shadings very important, which was currently reported as very disruptive by users. This preliminary finding shows potential for smart services applied at the façade level to improve user satisfaction if aspects of interaction and convenience are adequately addressed. Post-intervention phase data is now required to confirm these preliminary findings.

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It is a challenge for traditional building control systems to meet occupants’ needs in shared spaces due to the lack of understanding of individual occupant thermal preferences. This is a barrier to balancing energy efficiency and indoor environmental quality (IEQ). Advanced statistical learning methods offer new solutions towards more energy-efficient and user-centric control logics. In this work, a control logic is proposed to optimise the heating, ventilation and air conditioning (HVAC) operation based on thermal comfort archetype preferences, leveraging the ASHRAE Global Thermal Comfort Database II in conjunction with energy simulations. First, we apply the k-means clustering algorithm to categorize occupants into different archetypes regarding their common feedback on the thermal environment. Then, we fit a Bayesian logistic regression model to predict the thermal comfort preferences of different archetypes based on IEQ data. Finally, we identify two occupant-centric control logics to optimize HVAC operation to meet occupants’ requirements: (i) considering a unified response of thermal comfort in the space, and (ii) ensuring the dynamic optimal setpoint when conflicting occupant archetypes are present. Having compared this control logic with a common rule-based logic, our results demonstrate the potential of occupant-centric controls and the importance of multi-objective metrics in accounting for energy efficiency.@en

Control systems in buildings that prioritise occupant preferences have gained attention recently, intending to enhance the acceptability of automated systems. However, effective human-building interaction strategies remain challenging to design due to the lack of understanding of building occupant preferences. This study aims to identify factors influencing occupant satisfaction with building control systems to provide insights for improvement in interaction strategies. Surveys conducted in buildings located in Riga (Latvia) and Delft (The Netherlands) collected data on satisfaction with indoor environmental quality (IEQ), building controls, productivity, control importance, and social-subjective norms. Analysis categorised respondents into high and low satisfaction clusters and identified significant factors influencing satisfaction with IEQ through non-parametric tests. Logistic regression and coefficient analysis were used to assess the relationship between satisfaction and these factors. Findings suggest factors influencing satisfaction with IEQ, personal control, and automation, underscoring the developed methodology's potential. The identification of these factors informs actions that might enhance Human-Building Interaction (HBI) strategies, emphasising tailored approaches and addressing control system limitations. Further research is necessary to evaluate these strategies and understand how insights into human-building interaction strategies can lead to higher satisfaction levels.@en

Rising temperatures are leading to an increase in cooling energy demand and thermal discomfort due to overheating. Despite dynamic switchable glazing being a promising solution for controlling solar radiation while preserving user access to outdoor views, their cost is currently a barrier to their widespread adoption. The recent development of low-cost inkjet-printed switchable glazing offers a cost-effective alternative; however, its performance remains uncertain concerning its contributions to energy efficiency and user satisfaction in terms of thermal comfort and visual experience. This study presents a multi-domain evaluation of the performance of a novel low-cost inkjet-printed glazing with users in terms of their satisfaction with the environment, personal control and interaction. In comparison to a conventional façade with static glazing and external roller blinds, the EC glazing performed better than the conventional façade if the shading is fully down. In this case, higher satisfaction was measured in terms of view clarity, daylight access and colour in the room with the EC glazing. When comparing the performance of the EC glazing at the clearest state with conventional glazing with blinds raised, users’ satisfaction was not significantly different, except for the satisfaction with view clarity. Despite the long transition time of the EC glazing, users were not significantly dissatisfied with the speed of transition. Overall, these preliminary results show that this novel EC glazing is well-accepted by users especially as an alternative to traditional dark roller blinds, but further research is required to investigate its performance during summer.@en

This study assessed the usability of three readily available Personalized Thermal Control Systems (PECS)—an electric blanket, a small personal fan, and a large pedestal fan—among individuals with intellectual disabilities living independently in energy poverty conditions in Chile. The research aimed to identify the primary usability challenges that affect the adoption and operational effectiveness of these technologies and, consequently, their potential to enhance thermal comfort. Results indicated that devices with more advanced control features, i.e. the large pedestal fan, presented the most significant usability challenges, followed by the electric blanket and the small personal fan. Key usability issues included poor visibility, inadequate material choice, ineffective communication, bad affordance, and inadequate levels of touch sensitivity of the control interface in these PECS. The study also showed a large variance in the level of adoption of the PECS among participants, thereby indicating that users have different individual attitudes, ranging from passive acceptance to proactive exploration and use. To conclude, this study advocates for the necessity of developing easily operable PECS that cater to the specific needs of individuals with intellectual disabilities, thereby supporting their autonomy and improving their quality of life in thermally comfortable environments.@en

Façade properties influence human responses in a multidomain manner and these interactions needs to be accounted for effective façades design, particularly to increase resilience to extreme heat. From existing research, it remains unclear whether the glazing colour properties can influence occupant thermal sensation, preferences, and acceptance, or whether higher temperatures affect glare sensation or view perception. This study investigates the combined influence of tinted glazing in façades through a preliminary experimental campaign with human participants exposed to varying glazing hues (neutral and blue) and indoor air temperatures. While previous research has examined the impact of coloured daylight on thermal and glare sensation under thermal conditions close to neutrality, this paper compares occupant responses at neutral and warm thermal conditions by performing repeated measurements.

An experiment was conducted to measure potential differences in human thermal sensation, acceptance, preference, and glare sensation under two thermal conditions (operative temperatures of 25°C and 30°C) and two daylight colours (neutral and blue). Thirty-nine participants were exposed to different combinations of temperature and glazing colour in a randomized order. Data were collected using questionnaires and thermal physiological sensors to capture human responses to these varying conditions. In terms of visual perception, the results demonstrate a distinction between the two visual scenarios, particularly regarding obstruction and glare at a neutral temperature. At the level of thermal sensation, the impact of blue-tinted glazing is not statistically significant with this number of participants. However, a slight difference is observed between the two scenarios at both temperature levels.@en

Facades play a pivotal role in the performance of a building, serving various environmental, structural and operational functions. As climate-induced extreme events become more frequent, developing resilient facades is becoming crucial. Although facades can contribute significantly to the total post-disruption losses, their resilience is not sufficiently addressed in current design approaches. In response to this research gap, this study proposes a multi-criteria decision-making methodology to select optimal facade designs using resilience criteria: resilience loss and economic loss. The framework addresses the complexity of facade design, considering multiple hazards such as earthquakes and heatwaves. For seismic hazard, the facade’s resilience is defined as its ability to mitigate damage. In the case of heat hazard, resilience is assessed based on the ability to keep indoor conditions within a comfortable thermal range. To demonstrate the applicability of the proposed methodology, a case study of an 18-story office building in Izmir (Turkey) is used to compare alternative facade packages. These packages identify the facade design cases, each coupled with a dataset of seismic and thermal fragility curves. Numerical simulations are conducted to derive seismic and thermal resilience curves for each facade package, along with resilience criteria. These criteria are embedded into a practical decision-making process to enable the selection of the optimal design case based on project specifications.@en

Additive Manufacturing with Varying Material Properties enables controlled spatial variation of material properties in 3D-printed components, facilitating custom-tailored characteristics, added functionalities and reduced assembly processes. To promote this approach in building façade applications, this paper presents a novel framework for Additive Manufacturing with varying material properties using a thermosetting reactive polymer, specifically polyurethane. By dynamically changing the polyurethane’s chemical composition, the material properties can be precisely controlled. The framework’s individual aspects, including the material, hardware setup and computational system, are described in detail. Additionally, the research explores the implementation of material transitions with this framework, highlighting three different modes (horizontal, vertical and multi plane) and their impact on print time and material consumption. The paper concludes by discussing the potential of this approach for building façade applications, addressing current challenges and outlining future research directions.@en

Human-Building Interaction (HBI) relies on sensor-actuator networks that are increasingly supported by Artificial Intelligence (AI). This paper presents a novel AI-supported Design-to-Robotic-Production-Assembly and -Operation (D2RPA&O) approach for reconfigurable furniture. It involves a multidisciplinary approach that relies on the integration of various domains such as architecture, robotics, computer, and material science. It contributes to the advancement of HBI by employing spatial reconfiguration relying on AI and lightweight material design, which is of relevance, particularly when the furniture consists of non-identical but similar components that are re−/ configured in a variety of possible combinations.@en

This paper draws attention to the environmental impact of passive smart windows, a novel high-performance glazing technologies that can change their solar transmittance to control the amount of solar gain, thus reducing cooling energy demand. Despite the large influence of building envelope technologies on overall embodied carbon in buildings, the environmental impact of passive smart windows has been inadequately addressed, with a dearth of numerical data on various impact categories beyond energy consumption and Global Warming Potential (GWP). While current literature focuses on the advantages of these technologies in terms of operational energy savings, other critical environmental considerations are currently missing. This paper aims to bridge the existing gap by introducing a novel framework for evaluating the broader environmental impact of passive smart windows through a multi-category LCA method. By analysing the life cycle of these technologies, including production, usage, and disposal, the research seeks to provide a holistic understanding of their contribution to sustainability. The framework is based on systematic literature review on current state-of-art approaches and Interviews with key stakeholders in the dynamic glazing value chain. Literature review and interview results are presented, and then the framework is demonstrated through a case study of a thermochromic technologies for an office building in the Netherlands. Preliminary results show the critical areas where improvements on the methods or on the performance of the technology are required for the achievement of holistically sustainable high-performing glazing.@en

As cities continue to expand and densify, understanding how buildings affect people’s perception and experience of the acoustic environment in context becomes more relevant. This paper presents a conceptual framework of the influ-ence of façades on the urban soundscape, based on the ISO 12913 series, in order to analyze the three main elements of the soundscape: people, acoustic environ-ment and context, along with façade as a fourth element. The methodology in-cluded literature review, as well as an exploration of the ISO 12913 methods for soundscape assessment via soundwalks and laboratory experiments involving a total of forty-three (n = 43) participants. The results provide a promising frame-work for façade analysis to progress toward the integration of human-centered approaches into the field of façade acoustics and complement current building physics practice.@en

The performance of the building envelope is crucial for minimizing operational carbon emissions of buildings and maintaining indoor comfort. Contemporary building envelopes, such as engineered glazed façades, achieve high performance levels but often add a significant amount of embodied carbon. There is therefore an incentive to reduce the thickness of the glass panels, but the minimum thickness possible is often not governed by strength or manufacturing limits but rather by the deflection (serviceability) limits. Despite objective criteria guiding serviceability limits, user acceptance of deformation remains unexplored, leading to conservative designs. This paper introduces a novel method for measuring user satisfaction with glass deformations, aiming to establish acceptance thresholds comparable to objective criteria. The study involves a novel experimental campaign to assess volunteers' levels of perception and acceptance of various glass deformations. The glass was deformed using a bespoke electro-pneumatic system at levels corresponding to below, above, and at the current serviceability limit. The results demonstrate the feasibility of measuring human responses to deformations in the glazing and provide essential data for setting serviceability limits. The experiments and corresponding user satisfaction feedback indicate that the current serviceability limit of L/50, may be relaxed, thereby presenting opportunities for material efficiency, such as the adoption of thinner glass in facades. The methodology effectively captures human responses, revealing that changes in reflection were the primary reason for the perception of movement; leading to a higher perception of glazing movement and a lower acceptance at night. Overall, participants felt safe regardless of their prior knowledge on glass properties, and providing this information to participants did not improve acceptance, which was already sufficiently high. The findings from this research fill an important knowledge gap in understanding user acceptance of glass deformations, crucial for comprehensive user satisfaction assessments and evidence-based reductions in glazing thickness.@en

Heat is a leading weather-related cause of death worldwide and heat waves are increasing globally in terms of frequency, duration, and intensity. Global heat-related deaths could quadruple by midcentury. As with many environmental hazards, numerous factors impact how heat might affect any given person and there are significant gaps in our understanding related to indoor heat and its effect on health. Despite growing interest in establishing standards and guidelines, there is currently no clear consensus on a safe maximum upper limit for indoor temperature. There is conclusive evidence of links between high outdoor temperatures and human health yet research on this correlation does not typically explicitly consider indoor heat exposure. Considerably more research has been completed on healthy, active individuals than for more heat-susceptible populations and the impacts of moderate heat stress on the health of large populations are not well understood.

We conducted a literature review on the impact of indoor thermal conditions on health, recognizing that air temperature alone cannot describe thermal exposure. We introduce the concept of a standardized maximum safe indoor temperature, defined for still air conditions, 50% relative humidity and mean radiant temperature equal to air temperature. Equivalent temperatures with respect to the thermal load on the body can then be calculated for various air velocities, humidities or mean radiant temperatures using the standard effective temperature (SET) model. For U.S. policymakers, we propose adopting a standardized maximum safe indoor temperature of 28 °C. We recognize that the adoption of standardized maximum safe indoor temperatures may vary around the world, but the framework we propose to adjust the standardized upper limit for humidity, air motion, and radiant temperature could be used globally. We also identify important knowledge gaps to guide future research on the relationships between heat and health that could support informed cost-benefit analyses. @en

Visual defects, in particular haze, in glass and façade technologies can significantly impact the aesthetic quality and human experience of daylight and views in buildings. The glass and façade industry increasingly requires methods that can objectively predict and measure the subjective user experience of haze. This is required to appropriately inform the manufacturing process, ensuring optimal functionality and performance, and avoiding material waste and economic losses due to the replacement of defective glazing. Existing methods for measuring haze are not appropriate for assessing large samples, either at manufacturing sites or in-situ. However, haze defects are often only exhibited and visible when glazing is produced in large samples or installed under real luminous conditions. This paper introduces a novel luminance-based method that measures haze by evaluating the halo around a light source that is observed through the glazing. This method is initially tested in a controlled laboratory setting on small glazing samples with varying level of haze. The halo serves as a proxy for haze severity and it is quantified by using luminance-based measurements. In this work, the newly-proposed method is verified by comparing the ranking in haze severity of different samples as performed by means of a standard haze meter and the newly proposed method. Additionally, the paper examines the dependence of this ranking on factors such as camera setup distance and light intensity. It was found that the proposed method was able to effectively ranks samples differing in haze intensity by more than 0.1 orders of magnitude. Positioning the camera closer to the glazing and using higher light intensity yielded more accurate results. However, for haze levels below 1% and differences smaller than 0.1 orders of magnitude, the accuracy is insufficient. To define the expected level of accuracy of methods for haze characterisation in-situ, the sensitivity of the human eye to haze under varying luminous environments and view content needs to be quantified.@en