Pablo Martinez Alcaraz
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16 records found
1
Interface design for lighting and shading controls
Device type, position, and system cues influencing user preference and acceptance
Journal article
(2026)
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P. de la Barra, P. Martinez-Alcaraz, E. Brembilla, G. Brager, K. Exss, A. Luna-Navarro
The integration of smart control systems in office buildings can be disruptive when individual preferences and expectations for control interfaces are overlooked. Understanding how human–building interaction influences environmental comfort and acceptance is essential for creating user-centered designs. This study aimed to evaluate the effectiveness of usability testing as an innovative method for assessing building system control interfaces and user interaction with automation. Specifically, we examined user preferences for shading and lighting controls in a controlled office laboratory, varying by “Type of Device” (analog vs. digital), “Position” (wall, desk, or split), and “System Cues” (information richness). In an experimental setting involving 20 participants, we investigated how these factors influence satisfaction and acceptance of automation. Using an adapted Post-Study System Usability Questionnaire (PSSUQ), we evaluated satisfaction with Ease of Use, Reachability, and Information. Findings show that while participants’ initial expectations favored simple analog controls, preferences shifted toward digital, information-rich systems after hands-on interaction. Ordered logistic regression confirmed that Reachability (β=2.317) and Ease of Use (β=1.831) were the strongest predictors of Overall Satisfaction (p<0.001), placing interface position as the primary design characteristic. However, preferences varied by office type: in shared offices, users preferred wall-mounted controls to facilitate shared access and visibility. These insights offer actionable guidance for designing smart control interfaces that enhance user satisfaction, support personal control, and promote greater acceptance of building automation.
...
The integration of smart control systems in office buildings can be disruptive when individual preferences and expectations for control interfaces are overlooked. Understanding how human–building interaction influences environmental comfort and acceptance is essential for creating user-centered designs. This study aimed to evaluate the effectiveness of usability testing as an innovative method for assessing building system control interfaces and user interaction with automation. Specifically, we examined user preferences for shading and lighting controls in a controlled office laboratory, varying by “Type of Device” (analog vs. digital), “Position” (wall, desk, or split), and “System Cues” (information richness). In an experimental setting involving 20 participants, we investigated how these factors influence satisfaction and acceptance of automation. Using an adapted Post-Study System Usability Questionnaire (PSSUQ), we evaluated satisfaction with Ease of Use, Reachability, and Information. Findings show that while participants’ initial expectations favored simple analog controls, preferences shifted toward digital, information-rich systems after hands-on interaction. Ordered logistic regression confirmed that Reachability (β=2.317) and Ease of Use (β=1.831) were the strongest predictors of Overall Satisfaction (p<0.001), placing interface position as the primary design characteristic. However, preferences varied by office type: in shared offices, users preferred wall-mounted controls to facilitate shared access and visibility. These insights offer actionable guidance for designing smart control interfaces that enhance user satisfaction, support personal control, and promote greater acceptance of building automation.
Conference paper
(2026)
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Eleni Chatzi Nestoros, Pablo Martinez-Alcaraz, Alejandro Fuentes, Juan Diego Blanco Cadena, Michela Turrin, Tiziana Poli, Alessandra Luna-Navarro
Urbanization and climate change have intensified urban heat island effects, significantly affecting outdoor thermal comfort (OTC) in cities. Traditional methods of assessing the influence of urban environments on OTC often rely heavily on computational simulations, neglecting the integration of user-centric data and comprehensive environmental monitoring. This study investigates the relationship between microclimatic conditions, thermal sensation, and human preferences to identify the key factors influencing outdoor thermal comfort. Using the Acquabella district in Milan as a case study, the research adopts a cross-examination approach that integrates qualitative and quantitative assessments to evaluate outdoor thermal conditions. The methodology combines user-centered participatory approaches, including a workshop and an online survey, to identify critical intervention areas and factors contributing to thermal discomfort. Thermal Sensation Votes (TSV) are collected and analyzed in QGIS, highlighting significant environmental and psychological factors influencing user perception. Preliminary simulations using SOLWEIG are employed to cross-examine the results, identifying spaces with varying levels of thermal comfort. This study underscores the value of combining objective and subjective measures to pinpoint areas of critical environmental quality and optimize decision-making processes. By leveraging user data, the methodology reduces computational demands while offering actionable insights for urban health. The approach is scalable to different urban contexts, fostering the development of resilient and climate-adaptive environments.
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Urbanization and climate change have intensified urban heat island effects, significantly affecting outdoor thermal comfort (OTC) in cities. Traditional methods of assessing the influence of urban environments on OTC often rely heavily on computational simulations, neglecting the integration of user-centric data and comprehensive environmental monitoring. This study investigates the relationship between microclimatic conditions, thermal sensation, and human preferences to identify the key factors influencing outdoor thermal comfort. Using the Acquabella district in Milan as a case study, the research adopts a cross-examination approach that integrates qualitative and quantitative assessments to evaluate outdoor thermal conditions. The methodology combines user-centered participatory approaches, including a workshop and an online survey, to identify critical intervention areas and factors contributing to thermal discomfort. Thermal Sensation Votes (TSV) are collected and analyzed in QGIS, highlighting significant environmental and psychological factors influencing user perception. Preliminary simulations using SOLWEIG are employed to cross-examine the results, identifying spaces with varying levels of thermal comfort. This study underscores the value of combining objective and subjective measures to pinpoint areas of critical environmental quality and optimize decision-making processes. By leveraging user data, the methodology reduces computational demands while offering actionable insights for urban health. The approach is scalable to different urban contexts, fostering the development of resilient and climate-adaptive environments.
Conference paper
(2026)
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P. de la Barra, M. S. Khanie, A. Luna-Navarro, P. Martinez-Alcaraz, D. Al Assaad, E. M. Barrett, G. Chinazzo, Z. Deng, B. Dong, More Authors
Buildings are striving to be both energy-efficient and occupant-centered. Personalized systems for lighting and dynamic fenestration systems, e.g., switchable glazing, are emerging as a key solution. These systems, called Personalized Environmental Control Systems (PECS), allow individuals to adjust their immediate environment without impacting others. While PECS initially focused on temperature and air quality, this study explores the potential for the luminous environment, introducing the concept of Visual PECS.
Daylighting and lighting controls build on a long history of personalized systems and methods, from prehistoric torches to adjustable desk lamps. They allow for individual control over (day)light spectrum and intensity, catering to personal needs and promoting circadian health and cellular processes (i.e., photobiomodulation). Additionally, they can reduce glare and improve visual comfort, leading to increased productivity and well-being. Despite this long history, studies formulating “personalized environmental control systems” (PECS) in the daylighting and lighting domain are rare. In this paper, we present preliminary results from a comprehensive review, where 31 papers were identified from an initial pool of 5,238. The findings highlighted two key benefits. First, semi-automated PECS offer the highest energy savings, highlighting the importance of understanding the relationship between users and automation. Secondly, PECS provides improved occupant experience since the ability to control their environment empowers occupants, leading to increased comfort and productivity. Overall, PECS have the potential to facilitate individual control over lighting and visual parameters, ultimately enhancing visual comfort and satisfaction as well as beyond-visual well-being. Our research builds upon the ongoing work of IEA EBC - Annex 87, which investigates the energy and environmental benefits of PECS. ...
Daylighting and lighting controls build on a long history of personalized systems and methods, from prehistoric torches to adjustable desk lamps. They allow for individual control over (day)light spectrum and intensity, catering to personal needs and promoting circadian health and cellular processes (i.e., photobiomodulation). Additionally, they can reduce glare and improve visual comfort, leading to increased productivity and well-being. Despite this long history, studies formulating “personalized environmental control systems” (PECS) in the daylighting and lighting domain are rare. In this paper, we present preliminary results from a comprehensive review, where 31 papers were identified from an initial pool of 5,238. The findings highlighted two key benefits. First, semi-automated PECS offer the highest energy savings, highlighting the importance of understanding the relationship between users and automation. Secondly, PECS provides improved occupant experience since the ability to control their environment empowers occupants, leading to increased comfort and productivity. Overall, PECS have the potential to facilitate individual control over lighting and visual parameters, ultimately enhancing visual comfort and satisfaction as well as beyond-visual well-being. Our research builds upon the ongoing work of IEA EBC - Annex 87, which investigates the energy and environmental benefits of PECS. ...
Buildings are striving to be both energy-efficient and occupant-centered. Personalized systems for lighting and dynamic fenestration systems, e.g., switchable glazing, are emerging as a key solution. These systems, called Personalized Environmental Control Systems (PECS), allow individuals to adjust their immediate environment without impacting others. While PECS initially focused on temperature and air quality, this study explores the potential for the luminous environment, introducing the concept of Visual PECS.
Daylighting and lighting controls build on a long history of personalized systems and methods, from prehistoric torches to adjustable desk lamps. They allow for individual control over (day)light spectrum and intensity, catering to personal needs and promoting circadian health and cellular processes (i.e., photobiomodulation). Additionally, they can reduce glare and improve visual comfort, leading to increased productivity and well-being. Despite this long history, studies formulating “personalized environmental control systems” (PECS) in the daylighting and lighting domain are rare. In this paper, we present preliminary results from a comprehensive review, where 31 papers were identified from an initial pool of 5,238. The findings highlighted two key benefits. First, semi-automated PECS offer the highest energy savings, highlighting the importance of understanding the relationship between users and automation. Secondly, PECS provides improved occupant experience since the ability to control their environment empowers occupants, leading to increased comfort and productivity. Overall, PECS have the potential to facilitate individual control over lighting and visual parameters, ultimately enhancing visual comfort and satisfaction as well as beyond-visual well-being. Our research builds upon the ongoing work of IEA EBC - Annex 87, which investigates the energy and environmental benefits of PECS.
Daylighting and lighting controls build on a long history of personalized systems and methods, from prehistoric torches to adjustable desk lamps. They allow for individual control over (day)light spectrum and intensity, catering to personal needs and promoting circadian health and cellular processes (i.e., photobiomodulation). Additionally, they can reduce glare and improve visual comfort, leading to increased productivity and well-being. Despite this long history, studies formulating “personalized environmental control systems” (PECS) in the daylighting and lighting domain are rare. In this paper, we present preliminary results from a comprehensive review, where 31 papers were identified from an initial pool of 5,238. The findings highlighted two key benefits. First, semi-automated PECS offer the highest energy savings, highlighting the importance of understanding the relationship between users and automation. Secondly, PECS provides improved occupant experience since the ability to control their environment empowers occupants, leading to increased comfort and productivity. Overall, PECS have the potential to facilitate individual control over lighting and visual parameters, ultimately enhancing visual comfort and satisfaction as well as beyond-visual well-being. Our research builds upon the ongoing work of IEA EBC - Annex 87, which investigates the energy and environmental benefits of PECS.
Building automation and control systems (BACS) are central to energy performance and occupant comfort in non-residential buildings. Comfort is inherently multi-domain, including thermal, visual, acoustic, and air quality requirements. Multi-domain BACS involves frequent trade-offs across domains when conflicting control actions arise, such as providing glare control versus daylight availability. Yet existing occupant-centric control research treats building services in isolation, and prior multi-domain comfort reviews rarely examine how multi-domain demands are integrated into BACS decision logic across services. We conducted a systematic review of 43 studies to examine how multi-domain occupant demands are represented and operationalized in BACS. Across the evidence base, thermal comfort is universal, while visual and air quality are frequently included. Acoustics is rarely addressed due controllability constraints. Most studies remain unimodal in their demand representation, even when multiple domains are in scope. Integrated BACS implementations are therefore largely built on within-domain formulations. Multimodal demand models that encode cross-domain and combined effects are uncommon and are rarely implemented in integrated BACS. Rule-based strategies dominate multi-domain controllers. Optimization-based and learning-based controllers are also used, but they often rely on fixed weights or reward terms that make trade-offs difficult to interpret. In addition, actuator choice is rarely made explicit when multiple services can achieve the same target state. Future research should benchmark unimodal and multimodal demand formulations under comparable control contexts, extend bottom-up multimodal models beyond thermal and air quality into integrated BACS, especially for façade control, and develop transparent, preference-aware policy designs that make priorities and service actions understandable.
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Building automation and control systems (BACS) are central to energy performance and occupant comfort in non-residential buildings. Comfort is inherently multi-domain, including thermal, visual, acoustic, and air quality requirements. Multi-domain BACS involves frequent trade-offs across domains when conflicting control actions arise, such as providing glare control versus daylight availability. Yet existing occupant-centric control research treats building services in isolation, and prior multi-domain comfort reviews rarely examine how multi-domain demands are integrated into BACS decision logic across services. We conducted a systematic review of 43 studies to examine how multi-domain occupant demands are represented and operationalized in BACS. Across the evidence base, thermal comfort is universal, while visual and air quality are frequently included. Acoustics is rarely addressed due controllability constraints. Most studies remain unimodal in their demand representation, even when multiple domains are in scope. Integrated BACS implementations are therefore largely built on within-domain formulations. Multimodal demand models that encode cross-domain and combined effects are uncommon and are rarely implemented in integrated BACS. Rule-based strategies dominate multi-domain controllers. Optimization-based and learning-based controllers are also used, but they often rely on fixed weights or reward terms that make trade-offs difficult to interpret. In addition, actuator choice is rarely made explicit when multiple services can achieve the same target state. Future research should benchmark unimodal and multimodal demand formulations under comparable control contexts, extend bottom-up multimodal models beyond thermal and air quality into integrated BACS, especially for façade control, and develop transparent, preference-aware policy designs that make priorities and service actions understandable.
Conference paper
(2026)
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Pedro de la Barra, Pablo Martinez-Alcaraz, Eleonora Brembilla, Alessandra Luna-Navarro
The integration of smart control systems in office buildings often neglects individual expectations and preferences, especially when occupants do not have personal control over their environment. While existing research has advanced personalized comfort models, simulated energy-use behaviors, and quantitative methods for occupant-centric building design, it often overlooks the critical role of personalized control interfaces. These interfaces are essential for integrating occupants into the operable building systems. This study investigates occupant preferences for personal control after experiencing different building control interfaces for lighting and roller shades in an office environment. Using a usability testing approach, 20 participants were involved in brief interaction sessions to evaluate how interface type (digital vs. analogue), position (wall-mounted vs. desk-mounted), and level of information influence occupants’ satisfaction. Additionally, we explored whether participants’ preferences for indoor environmental quality conditions correspond with their reported satisfaction with building control interfaces. Results show that interface placement significantly influences user preference, beyond ease of access. While participants initially favored analogue controls and manual operation, exposure to digital and automated systems led to greater acceptance, particularly when these systems provided clear information and maintained personal control. These findings underscore the importance of actual experiences with system interfaces in understanding occupant preferences and acceptance with building technologies, which is key for occupant-centered design in building control.
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The integration of smart control systems in office buildings often neglects individual expectations and preferences, especially when occupants do not have personal control over their environment. While existing research has advanced personalized comfort models, simulated energy-use behaviors, and quantitative methods for occupant-centric building design, it often overlooks the critical role of personalized control interfaces. These interfaces are essential for integrating occupants into the operable building systems. This study investigates occupant preferences for personal control after experiencing different building control interfaces for lighting and roller shades in an office environment. Using a usability testing approach, 20 participants were involved in brief interaction sessions to evaluate how interface type (digital vs. analogue), position (wall-mounted vs. desk-mounted), and level of information influence occupants’ satisfaction. Additionally, we explored whether participants’ preferences for indoor environmental quality conditions correspond with their reported satisfaction with building control interfaces. Results show that interface placement significantly influences user preference, beyond ease of access. While participants initially favored analogue controls and manual operation, exposure to digital and automated systems led to greater acceptance, particularly when these systems provided clear information and maintained personal control. These findings underscore the importance of actual experiences with system interfaces in understanding occupant preferences and acceptance with building technologies, which is key for occupant-centered design in building control.
Building Automation and Control Systems (BACS) enhance energy efficiency in office buildings but often leave occupants dissatisfied, especially in shared offices with diverse indoor environmental preferences. Personal Comfort Models (PCM) capture individual preferences, yet these models can be difficult to apply in shared environments. This study examines whether a generalized personalized modeling would be necessary, or instead aggregated thermal preferences adequately represent individual needs in shared spaces. By mining the ASHRAE Global Thermal Comfort Database II, we analyzed 11 naturally ventilated office buildings spanning four climate zones, each providing 187 to 568 data points of subjective thermal preferences and concurrent environmental measurements. To capture uncertainties in occupant feedback and monitoring, we developed a Bayesian multinomial logistic framework. We compare an aggregated model (all responses together) with a hierarchical (partial-pooling) model having occupant-specific intercepts, using the No‑U‑Turn Sampler for Hamiltonian Monte Carlo. The Widely Applicable Bayesian Information Criterion confirms that hierarchical approach outperforms the aggregated model in every case. In four of the eleven studies, aggregated air temperature ranges satisfied occupants’ demands within a 95% posterior credible interval. Moreover, in most buildings, these temperature ranges aligned well with the majority of occupant preferences, suggesting that prior knowledge of building conditions or occupant variability might reduce the need for highly customized thermal environment. Future research should explore these findings in conditioned buildings and across other indoor environmental quality domains, where greater variability could exist.
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Building Automation and Control Systems (BACS) enhance energy efficiency in office buildings but often leave occupants dissatisfied, especially in shared offices with diverse indoor environmental preferences. Personal Comfort Models (PCM) capture individual preferences, yet these models can be difficult to apply in shared environments. This study examines whether a generalized personalized modeling would be necessary, or instead aggregated thermal preferences adequately represent individual needs in shared spaces. By mining the ASHRAE Global Thermal Comfort Database II, we analyzed 11 naturally ventilated office buildings spanning four climate zones, each providing 187 to 568 data points of subjective thermal preferences and concurrent environmental measurements. To capture uncertainties in occupant feedback and monitoring, we developed a Bayesian multinomial logistic framework. We compare an aggregated model (all responses together) with a hierarchical (partial-pooling) model having occupant-specific intercepts, using the No‑U‑Turn Sampler for Hamiltonian Monte Carlo. The Widely Applicable Bayesian Information Criterion confirms that hierarchical approach outperforms the aggregated model in every case. In four of the eleven studies, aggregated air temperature ranges satisfied occupants’ demands within a 95% posterior credible interval. Moreover, in most buildings, these temperature ranges aligned well with the majority of occupant preferences, suggesting that prior knowledge of building conditions or occupant variability might reduce the need for highly customized thermal environment. Future research should explore these findings in conditioned buildings and across other indoor environmental quality domains, where greater variability could exist.
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.
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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.
Conference paper
(2025)
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M.V. Davalos Quevedo, Alessandra Luna-Navarro, U. Pottgiesser, P. de la Barra Luegmayer, Pablo Martinez Alcaraz
This paper explores the challenge of gathering occupant feedback in real office environments, focusing on the difference between continuous versus one-time questionnaire methods. Continuous feedback methods are valuable for understanding occupant needs, but they can lead to disengagement and fatigue over time, while one-time questionnaires usually focus on one moment in time and they cannot capture changes or trends over time.
A Pre-Occupancy Evaluation (PrOE) was conducted in a German office before a design intervention. This study compares the data obtained from the German office in a one-time and a continuous questionnaire to evaluate their respective benefits and limitation in informing required design solutions for a pilot area. Both a one-time online questionnaire and a continuous feedback system (implemented using QR codes) were used to collect data on occupant (dis)satisfaction with the office design.
The results of this research show different perception on occupant’s satisfaction between the two surveys. Both surveys show congruency in the dissatisfaction with open offices without partitions than in shared enclosed offices. The one-time survey highlights a lowest satisfaction with the availability of personal control, while the continuous survey presents lowest satisfaction with the acoustic privacy. ...
A Pre-Occupancy Evaluation (PrOE) was conducted in a German office before a design intervention. This study compares the data obtained from the German office in a one-time and a continuous questionnaire to evaluate their respective benefits and limitation in informing required design solutions for a pilot area. Both a one-time online questionnaire and a continuous feedback system (implemented using QR codes) were used to collect data on occupant (dis)satisfaction with the office design.
The results of this research show different perception on occupant’s satisfaction between the two surveys. Both surveys show congruency in the dissatisfaction with open offices without partitions than in shared enclosed offices. The one-time survey highlights a lowest satisfaction with the availability of personal control, while the continuous survey presents lowest satisfaction with the acoustic privacy. ...
This paper explores the challenge of gathering occupant feedback in real office environments, focusing on the difference between continuous versus one-time questionnaire methods. Continuous feedback methods are valuable for understanding occupant needs, but they can lead to disengagement and fatigue over time, while one-time questionnaires usually focus on one moment in time and they cannot capture changes or trends over time.
A Pre-Occupancy Evaluation (PrOE) was conducted in a German office before a design intervention. This study compares the data obtained from the German office in a one-time and a continuous questionnaire to evaluate their respective benefits and limitation in informing required design solutions for a pilot area. Both a one-time online questionnaire and a continuous feedback system (implemented using QR codes) were used to collect data on occupant (dis)satisfaction with the office design.
The results of this research show different perception on occupant’s satisfaction between the two surveys. Both surveys show congruency in the dissatisfaction with open offices without partitions than in shared enclosed offices. The one-time survey highlights a lowest satisfaction with the availability of personal control, while the continuous survey presents lowest satisfaction with the acoustic privacy.
A Pre-Occupancy Evaluation (PrOE) was conducted in a German office before a design intervention. This study compares the data obtained from the German office in a one-time and a continuous questionnaire to evaluate their respective benefits and limitation in informing required design solutions for a pilot area. Both a one-time online questionnaire and a continuous feedback system (implemented using QR codes) were used to collect data on occupant (dis)satisfaction with the office design.
The results of this research show different perception on occupant’s satisfaction between the two surveys. Both surveys show congruency in the dissatisfaction with open offices without partitions than in shared enclosed offices. The one-time survey highlights a lowest satisfaction with the availability of personal control, while the continuous survey presents lowest satisfaction with the acoustic privacy.
Conference paper
(2025)
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P. Martinez-Alcaraz, P. de la Barra, C. P. Andriotis, Y. Wang, A. Luna-Navarro
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.
...
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.
In 2023, Switzerland set a goal of producing 35 TWh per year from renewable sources by 2035 and developed three deployment scenarios to reach it through specific technology mixes of renewable energy production. However, current models do not consider the impact of the cumulative energy demand (CED) of those technologies, accounting for production, transport, installation, performance, maintenance, and disposal. This study integrates CED and its related uncertainty using a 90% confidence interval (CI) to compare net energy across three future energy scenarios. The diverse renewable sources scenario yields a median net production of 29.1 TWh (90% CI: [27.7, 30.2]) and requires 6.24 GW of additional capacity to meet the 35 TWh target. The solar PV-focused scenario, with the highest embodied energy due to battery storage demands, has the lowest net output at 25.2 TWh (90% CI: [23.7, 26.5]), necessitating an extra 11.35 GW. The productivity-maximization scenario achieves the highest net production at 30.8 TWh (90% CI: [29.5, 31.7]), requiring 3.68 GW more capacity. In all energy scenarios, increasing gross renewable targets is essential to reach the net 35 TWh/year goal. Optimizing renewable deployment by prioritizing low CED technologies, such as wind, can maximize net energy production. Policymakers should incorporate embodied energy metrics into planning to ensure sustainable and realistic energy transition strategies.
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In 2023, Switzerland set a goal of producing 35 TWh per year from renewable sources by 2035 and developed three deployment scenarios to reach it through specific technology mixes of renewable energy production. However, current models do not consider the impact of the cumulative energy demand (CED) of those technologies, accounting for production, transport, installation, performance, maintenance, and disposal. This study integrates CED and its related uncertainty using a 90% confidence interval (CI) to compare net energy across three future energy scenarios. The diverse renewable sources scenario yields a median net production of 29.1 TWh (90% CI: [27.7, 30.2]) and requires 6.24 GW of additional capacity to meet the 35 TWh target. The solar PV-focused scenario, with the highest embodied energy due to battery storage demands, has the lowest net output at 25.2 TWh (90% CI: [23.7, 26.5]), necessitating an extra 11.35 GW. The productivity-maximization scenario achieves the highest net production at 30.8 TWh (90% CI: [29.5, 31.7]), requiring 3.68 GW more capacity. In all energy scenarios, increasing gross renewable targets is essential to reach the net 35 TWh/year goal. Optimizing renewable deployment by prioritizing low CED technologies, such as wind, can maximize net energy production. Policymakers should incorporate embodied energy metrics into planning to ensure sustainable and realistic energy transition strategies.
Journal article
(2025)
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Dolaana Khovalyg, Mariya P. Bivolarova, Jun Shinoda, Douaa Al-Assaad, Marika Vellei, Karol Bandurski, Pablo Martinez Alcaraz, P. de la Barra Luegmayer, Alessandra Luna-Navarro, More authors...
Advances in environmental technologies have improved indoor environmental quality (IEQ) by creating steady, uniform conditions. However, these often fail to meet individual thermal comfort and air quality needs, prompting a shift toward adaptive, personalized solutions. Personalized Environmental Control Systems (PECS) aim to enhance comfort, air quality, health, and productivity through user-centered designs. This paper systematically reviews 324 journal articles on PECS from 1988-2023, focusing on thermal and indoor air quality (IAQ) domains. PECS are classified by mobility: building-attached, semi-attached, detached, and wearable. The review assesses their impact on thermal comfort, IAQ, health outcomes (e.g., Sick Building Syndrome, heat stress), and human performance (e.g., cognitive function, productivity). Results show that building-detached PECS often improve thermal sensation, comfort, and acceptability, with combined systems yielding better ratings. Personalized ventilation enhances IAQ by delivering clean air directly to the breathing zone, reducing contaminant exposure. Research on PECS effects on health is limited, mainly focusing on short-term, controlled studies. Evidence for benefits on human performance is sparse but promising. Key challenges include inconsistent performance metrics, limited real-world evaluations, and potential publication bias toward positive results. This review highlights the need for standardized evaluation methods, deeper understanding of combined PECS effects, real-world and long-term testing, and clearer quantification of human performance benefits to advance the field.
...
Advances in environmental technologies have improved indoor environmental quality (IEQ) by creating steady, uniform conditions. However, these often fail to meet individual thermal comfort and air quality needs, prompting a shift toward adaptive, personalized solutions. Personalized Environmental Control Systems (PECS) aim to enhance comfort, air quality, health, and productivity through user-centered designs. This paper systematically reviews 324 journal articles on PECS from 1988-2023, focusing on thermal and indoor air quality (IAQ) domains. PECS are classified by mobility: building-attached, semi-attached, detached, and wearable. The review assesses their impact on thermal comfort, IAQ, health outcomes (e.g., Sick Building Syndrome, heat stress), and human performance (e.g., cognitive function, productivity). Results show that building-detached PECS often improve thermal sensation, comfort, and acceptability, with combined systems yielding better ratings. Personalized ventilation enhances IAQ by delivering clean air directly to the breathing zone, reducing contaminant exposure. Research on PECS effects on health is limited, mainly focusing on short-term, controlled studies. Evidence for benefits on human performance is sparse but promising. Key challenges include inconsistent performance metrics, limited real-world evaluations, and potential publication bias toward positive results. This review highlights the need for standardized evaluation methods, deeper understanding of combined PECS effects, real-world and long-term testing, and clearer quantification of human performance benefits to advance the field.
Photovoltaic panels diffusion in Switzerland
Understanding adopters profiles using clustering methods
Journal article
(2025)
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Pablo Martinez-Alcaraz, Gloria Serra-Coch, Maria Hecher, Claudia R. Binder
The adoption of photovoltaic panels (PV) by households is essential to meet residential Swiss energy transition targets. While previous studies have mostly focused on the factors influencing PV adoption by comparing adopters with non-adopters, few have acknowledged the heterogeneity of adopters and examined how these factors interrelate and differ among them. This study examines how factors associated with PV adoption differ among groups of adopters, and how these differences relate to socio-demographic, household and building characteristics and the geographic context. In 2022, we surveyed 1300 Swiss PV adopters. To segment the adopters, we used factor analysis and clustering methods factors associated with PV adoption. This multi-dimensional approach revealed recommendations for supporting PV adoption: (i) seize opportunity windows, such as renovations, for professionals to act as change agents, (ii) leverage attitude towards energy-conscious behaviour and perceived control over the technology, and (iii) leverage social influence for vertical diffusion.
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The adoption of photovoltaic panels (PV) by households is essential to meet residential Swiss energy transition targets. While previous studies have mostly focused on the factors influencing PV adoption by comparing adopters with non-adopters, few have acknowledged the heterogeneity of adopters and examined how these factors interrelate and differ among them. This study examines how factors associated with PV adoption differ among groups of adopters, and how these differences relate to socio-demographic, household and building characteristics and the geographic context. In 2022, we surveyed 1300 Swiss PV adopters. To segment the adopters, we used factor analysis and clustering methods factors associated with PV adoption. This multi-dimensional approach revealed recommendations for supporting PV adoption: (i) seize opportunity windows, such as renovations, for professionals to act as change agents, (ii) leverage attitude towards energy-conscious behaviour and perceived control over the technology, and (iii) leverage social influence for vertical diffusion.
Review
(2025)
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Douaa Al-Assaad, Ilaria Pigliautile, Jun Shinoda, Rajan Rawal, Maíra André, Siddhi Vashi, Roberto Rugani, Giulia Torriani, Pablo Martinez-Alcaraz, More authors...
Personalized Environmental Control Systems (PECS) can improve both comfort and energy efficiency by shifting indoor climate control toward localized, occupant-tailored comfort, unlike conventional systems that condition entire, partly unoccupied spaces uniformly. . Despite their potential, the absence of standardized assessment and reporting methods, and the diversified PECS technical specifics hinder consistent performance evaluation practices. Conducted in the framework of IEA EBC’s Annex 87, this review, based on the PRISMA statement, provides a comprehensive overview of existing methods and indicators used to evaluate the performance of PECS, specifically targeting thermal and air quality domains. A novel three-layered classification approach was applied to categorize PECS types, and reviewed studies were grouped into four methodological categories: building simulation, CFD, chamber, and field studies. The review identifies methods’ usage trends, benefits, and limitations. Among 302 reviewed papers, more than half (61 %) adopt controlled laboratory tests, while CFD is the most used simulation method (68.6 % of simulation studies). Field studies are a minority, highlighting the limited implementation of PECS in real-world scenarios. Simulations are cost effective in rapidly prototyping and developing PECS. However, the insights they provide into PECS performance are limited by either model resolution constraints or high complexity. Comfort evaluations do not consider individual occupant differences nor behavior inherent to PECS. It is through experiments that knowledge can be gained on realistic occupant responses. However, they can be resource intensive and require careful planning. This review provides best practice guidelines to assist researchers in improving quality reporting of their methods.
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Personalized Environmental Control Systems (PECS) can improve both comfort and energy efficiency by shifting indoor climate control toward localized, occupant-tailored comfort, unlike conventional systems that condition entire, partly unoccupied spaces uniformly. . Despite their potential, the absence of standardized assessment and reporting methods, and the diversified PECS technical specifics hinder consistent performance evaluation practices. Conducted in the framework of IEA EBC’s Annex 87, this review, based on the PRISMA statement, provides a comprehensive overview of existing methods and indicators used to evaluate the performance of PECS, specifically targeting thermal and air quality domains. A novel three-layered classification approach was applied to categorize PECS types, and reviewed studies were grouped into four methodological categories: building simulation, CFD, chamber, and field studies. The review identifies methods’ usage trends, benefits, and limitations. Among 302 reviewed papers, more than half (61 %) adopt controlled laboratory tests, while CFD is the most used simulation method (68.6 % of simulation studies). Field studies are a minority, highlighting the limited implementation of PECS in real-world scenarios. Simulations are cost effective in rapidly prototyping and developing PECS. However, the insights they provide into PECS performance are limited by either model resolution constraints or high complexity. Comfort evaluations do not consider individual occupant differences nor behavior inherent to PECS. It is through experiments that knowledge can be gained on realistic occupant responses. However, they can be resource intensive and require careful planning. This review provides best practice guidelines to assist researchers in improving quality reporting of their methods.
Conference paper
(2025)
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Alessandra Luna-Navarro, Andrea Welti, Pedro de la Barra, Pablo Martinez-Alcaraz, Matteo Porta
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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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.
The 35-35 energy equation
Understanding Switzerland's goal of 35 TWh renewable energy in 2035 through the lens of cumulative energy demand
Journal article
(2025)
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Jair K.E.K. Campfens, Pablo Martinez-Alcaraz, Marc Roca-Musach, Gloria Serra-Coch
In 2023, Switzerland set a goal of producing 35 TWh per year from renewable sources by 2035 and developed three deployment scenarios to reach it through specific technology mixes of renewable energy production. However, current models do not consider the impact of the cumulative energy demand (CED) of those technologies, accounting for production, transport, installation, performance, maintenance, and disposal. This study integrates CED and its related uncertainty using a 90% confidence interval (CI) to compare net energy across three future energy scenarios. The diverse renewable sources scenario yields a median net production of 29.1 TWh (90% CI: [27.7, 30.2]) and requires 6.24 GW of additional capacity to meet the 35 TWh target. The solar PV-focused scenario, with the highest embodied energy due to battery storage demands, has the lowest net output at 25.2 TWh (90% CI: [23.7, 26.5]), necessitating an extra 11.35 GW. The productivity-maximization scenario achieves the highest net production at 30.8 TWh (90% CI: [29.5, 31.7]), requiring 3.68 GW more capacity. In all energy scenarios, increasing gross renewable targets is essential to reach the net 35 TWh/year goal. Optimizing renewable deployment by prioritizing low CED technologies, such as wind, can maximize net energy production. Policymakers should incorporate embodied energy metrics into planning to ensure sustainable and realistic energy transition strategies.
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In 2023, Switzerland set a goal of producing 35 TWh per year from renewable sources by 2035 and developed three deployment scenarios to reach it through specific technology mixes of renewable energy production. However, current models do not consider the impact of the cumulative energy demand (CED) of those technologies, accounting for production, transport, installation, performance, maintenance, and disposal. This study integrates CED and its related uncertainty using a 90% confidence interval (CI) to compare net energy across three future energy scenarios. The diverse renewable sources scenario yields a median net production of 29.1 TWh (90% CI: [27.7, 30.2]) and requires 6.24 GW of additional capacity to meet the 35 TWh target. The solar PV-focused scenario, with the highest embodied energy due to battery storage demands, has the lowest net output at 25.2 TWh (90% CI: [23.7, 26.5]), necessitating an extra 11.35 GW. The productivity-maximization scenario achieves the highest net production at 30.8 TWh (90% CI: [29.5, 31.7]), requiring 3.68 GW more capacity. In all energy scenarios, increasing gross renewable targets is essential to reach the net 35 TWh/year goal. Optimizing renewable deployment by prioritizing low CED technologies, such as wind, can maximize net energy production. Policymakers should incorporate embodied energy metrics into planning to ensure sustainable and realistic energy transition strategies.
Conference paper
(2023)
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P. Martinez-Alcaraz, G. Serra-Coch, C. Alonso-Montolio, H. Coch
Maximizing solar energy production in Switzerland is key to meet energy transition goals. Understanding in detail the current situation, and the potential for expansion is important to develop effective strategies. With this study, we want to contribute to federal and academic efforts to measure solar energy by estimating the net energy produced by photovoltaic (PV) installations when considering their embodied energy. We calculated the values of all energy produced by PV installations across Switzerland from 1991-2021 and subtracted the embodied energy used to manufacture the PV panels and their mounting system. We considered four different types: freestanding, attached-complex, attached-simple and integrated, with progressively decreasing values of embodied energy for the supporting structure. The results show that in 2022, 50% of PV installations were producing net energy, which accounts for an accumulated historical value of 1.000 GWh, implying that 6% of the historical PV generation is net energy. If mounting systems were minimized, the accumulated net energy would reach 23%, showing the importance of integrating PV panels in building elements. These findings suggest that policies to support the diffusion of photovoltaic panels should also ensure long term use of existing installations and consider the mounting systems’ embodied energy for new ones.
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Maximizing solar energy production in Switzerland is key to meet energy transition goals. Understanding in detail the current situation, and the potential for expansion is important to develop effective strategies. With this study, we want to contribute to federal and academic efforts to measure solar energy by estimating the net energy produced by photovoltaic (PV) installations when considering their embodied energy. We calculated the values of all energy produced by PV installations across Switzerland from 1991-2021 and subtracted the embodied energy used to manufacture the PV panels and their mounting system. We considered four different types: freestanding, attached-complex, attached-simple and integrated, with progressively decreasing values of embodied energy for the supporting structure. The results show that in 2022, 50% of PV installations were producing net energy, which accounts for an accumulated historical value of 1.000 GWh, implying that 6% of the historical PV generation is net energy. If mounting systems were minimized, the accumulated net energy would reach 23%, showing the importance of integrating PV panels in building elements. These findings suggest that policies to support the diffusion of photovoltaic panels should also ensure long term use of existing installations and consider the mounting systems’ embodied energy for new ones.