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People's subjective response to any thermal environment is commonly investigated by using rating scales describing the degree of thermal sensation, comfort, and acceptability. Subsequent analyses of results collected in this way rely on the assumption that specific distances between verbal anchors placed on the scale exist and that relationships between verbal anchors from different dimensions that are assessed (e.g. thermal sensation and comfort) do not change. Another inherent assumption is that such scales are independent of the context in which they are used (climate zone, season, etc.). Despite their use worldwide, there is indication that contextual differences influence the way the scales are perceived and therefore question the reliability of the scales’ interpretation. To address this issue, a large international collaborative questionnaire study was conducted in 26 countries, using 21 different languages, which led to a dataset of 8225 questionnaires. Results, analysed by means of robust statistical techniques, revealed that only a subset of the responses are in accordance with the mentioned assumptions. Significant differences appeared between groups of participants in their perception of the scales, both in relation to distances of the anchors and relationships between scales. It was also found that respondents’ interpretations of scales changed with contextual factors, such as climate, season, and language. These findings highlight the need to carefully consider context-dependent factors in interpreting and reporting results from thermal comfort studies or post-occupancy evaluations, as well as to revisit the use of rating scales and the analysis methods used in thermal comfort studies to improve their reliability.

The abbreviated summary is below: Many thermal comfort models are based on the subjective perception of the users in the buildings. The models are created within some limitations and scope. This study aims to contribute to the development of thermal comfort models by comparing the widely used and being developed thermal comfort models with users' actual votes in natural settings. Thermal comfort models were evaluated on the most used religious buildings cases, and suggestions were made for the design and use of religious buildings. For these purposes, thermal comfort measurements were conducted at different zones of prayer areas in churches and mosques in Karlsruhe, Germany. After the events with high participation, a thermal sensation survey was performed on the users. The data were analyzed statistically. According to the results, there are differences between comfort models according to user perception. However, the results of aPMV and ATHB models are closer to user perception than PMV model. [ABSTRACT FROM AUTHOR]

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Recognizing the value of open-source research databases in advancing the art and science of HVAC, in 2014 the ASHRAE Global Thermal Comfort Database II project was launched under the leadership of University of California at Berkeley’s Center for the Built Environment and The University of Sydney’s Indoor Environmental Quality (IEQ) Laboratory. The exercise began with a systematic collection and harmonization of raw data from the last two decades of thermal comfort field studies around the world. The ASHRAE Global Thermal Comfort Database II (Comfort Database), now an online, open-source database, includes approximately 81,846 complete sets of objective indoor climatic observations with accompanying “right-here-right-now” subjective evaluations by the building occupants who were exposed to them. The database is intended to support diverse inquiries about thermal comfort in field settings. A simple web-based interface to the database enables filtering on multiple criteria, including building typology, occupancy type, subjects’ demographic variables, subjective thermal comfort states, indoor thermal environmental criteria, calculated comfort indices, environmental control criteria and outdoor meteorological information. Furthermore, a web-based interactive thermal comfort visualization tool has been developed that allows end-users to quickly and interactively explore the data.

Rising global temperatures have increased the need for research into human adaptability and comfort in buildings. To reduce comfort-related energy demands, low-energy-consumption alternatives for space cooling, such as personal environmental control systems (PECS), are being investigated. The implementation of PECS in office buildings is still underway, and little is known about how occupants' expectations can influence their satisfaction with PECS and indoor environmental quality. This study examines the influence of tailored information and occupants' comfort expectations on their thermal perceptions and satisfaction with a personal ceiling fan. Seventy-six participants completed an online questionnaire and attended a half-day session at 30 °C in a climate chamber in Germany. A manipulation technique to activate personal norms was used to test the influence of information on expectations. Results indicated higher reported thermal comfort in participants with more positive thermal expectations, regardless of their expectations of the building systems. These effects were largely moderated by personal norms, indicating the importance of activating normative motivations to increase thermal comfort. Occupants with negative expectations improved their perceptions of the fan when making personal adjustments to stay comfortable. However, this effect was not moderated by personal norms. Practical implications focus on manipulating occupants' comfort expectations, e.g., by providing occupants with normative messages and individual control, to achieve greater comfort and acceptance of personal building controls in naturally ventilated buildings. [ABSTRACT FROM AUTHOR]

An expected increase in the use of air conditioning by 2050 will significantly increase electricity demand and come at a cost to the environment. Implementing passive cooling strategies and focusing on personal environmental control systems (PECSs) could help to address this issue. While numerous studies have investigated the positive impact of PECSs on thermal comfort and energy savings, their overall economic benefit has been poorly addressed. We present an economic evaluation of personal fans for an office building in Germany. Building performance simulation was used to compare passive and active cooling concepts, and sensitivity analysis was performed for different climate scenarios. A cost-benefit analysis was carried out, including an assessment of investment and operating costs and the monetary value of relative performance. The transferability of comfort and productivity into costs is the novelty of this paper. The results showed that by supplementing night ventilation with personal fans, discomfort hours could be reduced by up to 50%. However, the initial investment of the fan is not compensated by savings in productivity losses compared to night ventilation alone. A reduction in the cost of the technology could help to economically offset the investment. The results contribute to the literature on the economic evaluation of a PECS by proposing a framework to motivate its implementation in buildings. [ABSTRACT FROM AUTHOR]

Given the large amount of time we spend indoors, designing and operating buildings that are safe, comfortable, and conducive to productivity and well-being is essential. To achieve this goal, in the past decades, research has been conducted to investigate the influence of the indoor environment on occupants. Thermal comfort has been the subject of most investigations in this field. However, despite being a consolidated research topic since the 1920s, statistical practices for analysing thermal comfort data often rely on simplified premises, which may be due to several possible factors (e.g., limited computational capabilities and lack of training). Consequently, important aspects of data analysis are often absent or overlooked. Recent statistics and statistical software advances have provided more options for effectively modelling complex issues. However, properly using these tools requires a solid understanding of statistical analysis, increasing the risk of misuse in practice. This paper presents ten questions highlighting the most critical issues regarding statistical analysis for thermal comfort research and practice. The first four questions provide general perspectives concerning statistical data analysis, while the remaining ones address specific problems related to thermal comfort research, but that can extend to all human-centric research in the built environment. Additionally, the last five questions demonstrate the practical significance of analysis pitfalls (i.e., sampling variability, selection bias, variable selection, clustered/nested observations, and measurement error) through examples with synthetic data. This study provides insights into the current statistical 'habits' in thermal comfort research and, more importantly, help researchers better define and conduct their statistical analyses. • Statistical data analysis in human-centric buildings research is critiqued. • Focus is given to statistical data analysis in thermal comfort research. • Causal thinking is highlighted as a key component of statistical analysis. • Simulation examples demonstrate the practical significance of analysis pitfalls. • A companion notebook describing the simulation examples in detail is included. [ABSTRACT FROM AUTHOR]

Occupants' satisfaction had been researched independently related to thermal and visual stimuli for many decades showing among others the influence of self‐perceived control. Few studies revealed interactions between thermal and visual stimuli affecting occupant satisfaction. In addition, studies including interactions between thermal and visual stimuli are lacking different control scenarios. This study focused on the effects of thermal and visual factors, their interaction, seasonal influences, and the degree of self‐perceived control on overall, thermal, and visual satisfaction. A repeated‐measures laboratory study with 61 participants running over two years and a total of 986 participant sessions was conducted. Mixed model analyses with overall satisfaction as outcome variable revealed that thermal satisfaction and visual satisfaction are the most important predictors for overall satisfaction with the indoor environment. Self‐perceived thermal control served as moderator between thermal satisfaction and overall satisfaction. Season had slight influence on overall satisfaction. Random effects explained the highest amount of variance, indicating that intra‐ and interindividual differences in the ratings of satisfaction are more prevalent than study condition. Future building design and operation plans aiming at a high level of occupant satisfaction should consider personal control opportunities and take into account the moderating effect of control opportunities in multimodal interactions. [ABSTRACT FROM AUTHOR]

10.3390/buildings11100459 7 Uddin M.N., Wei H.-H., Chi H.L., Ni M. Influence of Occupant Behavior for Building Energy Conservation: A Systematic Review Study of Diverse Modeling and Simulation Approach. Heating and cooling indoor environments is responsible for the largest share of energy consumption in buildings. Accurately modelling building energy use relies on careful consideration of occupant behaviour. [Extracted from the article]

Understanding the drivers leading to individual differences in human thermal perception has become increasingly important, amongst other things due to challenges such as climate change and an ageing society. This review summarizes existing knowledge related to physiological, psychological, and context-related drivers of diversity in thermal perception. Furthermore, the current state of knowledge is discussed in terms of its applicability in thermal comfort models, by combining modelling approaches of the thermoneutral zone (TNZ) and adaptive thermal heat balance model (ATHB). In conclusion, the results of this review show the clear contribution of some physiological and psychological factors, such as body composition, metabolic rate, adaptation to certain thermal environments and perceived control, to differences in thermal perception. However, the role of other potential diversity-causing parameters, such as age and sex, remain uncertain. Further research is suggested, especially regarding the interaction of different diversity-driving factors with each other, both physiological and psychological, to help establishing a holistic picture. [ABSTRACT FROM AUTHOR]

Current thermal comfort models are fairly inaccurate at predicting occupants' thermal comfort from parameters of indoor environment. The predicted variables, thermal sensation and thermal comfort, are commonly measured using scales. These scales might themselves contribute to the problem of poor prediction due to inter- and intra-individual differences in respondents' interpretation of scales. Until now, it is unclear whether variation in scale use is systematic and potentially statistically controllable. This study investigated (1) whether there are subgroups holding different conceptions of scales and (2) whether these conceptions are associated with different ratings of sensation and comfort under experimental conditions. Sixty-three participants completed a free positioning task that assessed the relative distances between labels belonging to the ASHRAE thermal sensation scale and their distribution along various dimensions (sensation, preference, comfort, pleasantness, acceptability, and tolerability). Subsequently, the participants rated office rooms at cool, neutral, and warm conditions regarding the same dimensions. Latent class regression on the free positioning task revealed subgroups showing distinct and interpretable patterns such as preferences for different temperature ranges. Remarkably, these patterns were mirrored in the participants' ratings under the experimental thermal conditions. The results suggest the existence of different conceptions concerning the relationships between the labels of the ASHRAE scale. The prediction of participants' ratings of thermal conditions in concrete situations can be significantly improved when taking these conceptions into account. [ABSTRACT FROM AUTHOR]

Thermal comfort models can be used to gain insight into important building design variables and predict whether a given design will provide satisfactory thermal conditions. There is a need for better industry standards and awareness towards thermal comfort as a multi-domain construct is increasing. However, despite the research efforts of academics, research outcomes in the field of thermal comfort do not live up to their full potential because they are difficult to scale. In this review, scalability is presented as a construct which characterizes the ability of a thermal comfort model to aid in the understanding and prediction of thermal comfort conditions in real-world practice, and more specifically the design of office buildings. A literature search of recent scientific publications is conducted, resulting in 77 articles on multi-domain thermal comfort modelling. The scoping review identifies current scalability challenges associated with implementing existing thermal comfort models in practice and seeks to steer the research field towards generating more reliable models that contribute to the assessment of thermal comfort in office buildings, with particular focus on the design stage. We propose to do that by identifying potential avenues for future research that are related to several aspects of model scalability, namely, model scope, resolution, and portability. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding humans’ perception of the thermal built environment is one of the prerequisites for designing satisfactory workplaces and related to their energy use. This paper compares the predictive performance of nine thermal comfort indices with respect to the population mean and individual votes together with the effect of false assumptions of metabolic rate, clothing level, and air velocity on this performance. In addition, the potential to customize the indices to the building level,e.g.by means of the coefficient for psychological adaptation, PSYCH, included in the adaptive thermal heat-balance (ATHB) model is analysed. The analysis of field data from two naturally ventilated and four mixed-mode office buildings showed that the ATHB indices outperform the other indices in terms of predicting thermal sensation. The effect of false assumption is larger for predicted mean vote (PMV)-based models compared with standard effective temperature (SET)-based models. In addition, customization revealed no clear distinction between naturally and mixed-mode buildings, which suggests that other factors are more influential. These results are discussed with respect to the potential of the ATHB approach to account for differences in building control characteristics and the way thermal comfort is addressed in related standards. [ABSTRACT FROM PUBLISHER]

Scales are widely used to assess the personal experience of thermal conditions in built environments. Most commonly, thermal sensation is assessed, mainly to determine whether a particular thermal condition is comfortable for individuals. A seven-point thermal sensation scale has been used extensively, which is suitable for describing a one-dimensional relationship between physical parameters of indoor environments and subjective thermal sensation. However, human thermal comfort is not merely a physiological but also a psychological phenomenon. Thus, it should be investigated how scales for its assessment could benefit from a multidimensional conceptualization. The common assumptions related to the usage of thermal sensation scales are challenged, empirically supported by two analyses. These analyses show that the relationship between temperature and subjective thermal sensation is non-linear and depends on the type of scale used. Moreover, the results signify that most people do not perceive the categories of the thermal sensation scale as equidistant and that the range of sensations regarded as ‘comfortable’ varies largely. Therefore, challenges known from experimental psychology (describing the complex relationships between physical parameters, subjective perceptions and measurement-related issues) need to be addressed by the field of thermal comfort and new approaches developed. [ABSTRACT FROM PUBLISHER]

Approaches to provide feedforward information to building occupants about the impact of potential actions on individual thermal comfort levels are scarce. Even less is known about the effect of such information on the decision process of occupants to interact with their built environment and their level of comfort after such decisions. In a naturalistic study, participants (N = 76) were given a choice of four actions to counteract thermal discomfort induced by constantly rising room temperatures: removing a piece of clothing, opening the window, switching on the ceiling fan or switching on the air-conditioning. After receiving information about the potential change in comfort and energy consumption of these options, they had to confirm or revise their choice. The vast majority of participants initially chose to open the windows (N = 28) or remove a piece of clothing (N = 37); only a few chose the ceiling fan (N = 2) or the air-conditioning (N = 9). About one-third (N = 23) revised their choice of action; most of them (N = 15) indicated an influence from the provided information. In conclusion, feedforward information can be a useful tool to combat overheating problems by increasing energy-aware behaviour and thermal acceptance. [ABSTRACT FROM PUBLISHER]

In the adaptive comfort model thermal comfort is described as being influenced by physiological, behavioural and psychological adaptive processes. As psychological variables expectation and habitual adaptation are mentioned. However, the psychological aspects are not sufficiently described yet and related to psychological states rather than personality traits. In this paper, the application of a new questionnaire concerning perceived self-efficacy in the thermal environment is demonstrated. Perceived self-efficacy is in this case the expectation to be able to execute desired actions with respect to the control of indoor thermal conditions. The construct thermo-specific self-efficacy (specSE) was used to analyse differences in the perception of thermal comfort, assumed temperature, perceived control and physiological parameters. Data from field studies in office buildings were compared with data from laboratory experiments. Results showed an influence of specSE on thermal comfort, e.g. people with a low level of specSE feel warmer than people with high specSE. Also perceived control and effectiveness of controls differs between people with high and low specSE. [ABSTRACT FROM AUTHOR]

Agent-based modeling (ABM) allows implementing negotiated behaviors between individual agents. Little is known on how individually preferred behavioral patterns adapt within office spaces used by multiple people. Even less is known about the effect of such negotiated behaviors on the occupants’ satisfaction in terms of preferred indoor thermal conditions and the level of perceived control. In order to gain insights into these processes, an experimental study in a field laboratory was conducted. The 36 subjects worked in the facility for three days: one day in a single person office, one in an office for two people, and one in an office for four people. They were allowed to tilt windows, close blinds, use a ceiling fan, or adjust their clothing levels. The data was analyzed quantitatively and qualitatively. The results suggest that perceived control is negatively affected by the number of people, neutral temperatures are negatively affected by a lack of perceived control, actions on windows are increasing and actions on blinds and fans are decreasing. Based on the results, suggestions for advancements of ABM are given. However, further studies – especially field studies – are necessary before these results can be applied to models applicable for a broader usage. [ABSTRACT FROM AUTHOR]

Few examples studied applicability of exergy analysis on human thermal comfort. These examples relate the human-body exergy consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship between the human-body exergy consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were comparable when applied to data from environments with constant operative temperature. In contrast, when applied to data with temperature transients the prediction of particular models differed significantly and the unsteady-state model resulted in better prediction of mean skin temperature. The results of the present study confirmed previously indicated trends that lowest human body exergy consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body exergy consumption rate. [ABSTRACT FROM AUTHOR]

This paper presents a framework for an adaptive thermal heat balance model (ATHB), which combines the adaptive comfort approach with existing heat balance models. This is done by setting up equations for each of the three adaptive processes (behavioural, physiological, and psychological) individually to modify the input values for the clothing level and metabolic rate of the PMV calculation. The coefficients for these equations are exemplarily derived from empirical data and the exemplary model is evaluated on own data and subsets of the ASHRAE RP884 database. Through the implementation of the three adaptive processes to modify the input variables of the PMV model, the output of the PMV model shows a tight fit to the neutral comfort line of the adaptive comfort model. Beyond the ability of the adaptive and the PMV model, the ATHB allows to compute predicted sensation votes with respect to variations of indoor environmental parameters and the running mean outdoor temperature. The evaluation shows, that the ATHB-model is performing in the same magnitude or better than PMV and adaptive model for naturally ventilated and air conditioned buildings. Future work needs to verify the values for the coefficients and explore the applicability of the model. [ABSTRACT FROM AUTHOR]

The objective of this study is to analyze the effect of different temperature ramps on office workers’ psychological, physiological and behavioral reactions. This paper presents the analysis of the psychological and physiological reactions. The hypothesis is that a steeper ramp leads to more pronounced and earlier reactions. An experimental study in an outdoor facing climate chamber with two fully equipped office spaces was conducted. The results support the hypothesis stated at the beginning, but further in depth analyses especially together with the behavioral reactions need to be done before drawing conclusions for the applicability of light-weight structures. [ABSTRACT FROM AUTHOR]

Indian residences are vulnerable to heat-driven discomfort amid the mounting prevalence of weather extremes, residential design and construction practices, and densifying urbanscapes. Therefore, it is vital to understand the thermal comfort characteristics of nationwide residences. This study proposes an adaptive thermal comfort model based on yearlong field surveys in eight cities located across five climate zones of India – the India Model for Adaptive Comfort - Residential (IMAC-R). The model prescribes the operative temperature bands for 80% and 90% thermal acceptability in correlation with the outdoor reference temperature, applicable to mixed-mode (MM) and naturally ventilated (NV) residences. More than 80% of the Indian residential occupants experienced a neutral thermal sensation in the indoor operative range of 16.3–35 °C in response to a 5.5–33 °C variation in the 30-day outdoor running mean temperature. Comparing the proposed model with the PMV model revealed that the latter underpredicts the thermal adaptivity of Indian occupants. The model was also compared against its predecessor – India Model for Adaptive Comfort for Commercial Buildings (IMAC MM and NV), along with relevant global and regional thermal comfort models. On average, the neutral temperature prescribed by IMAC-R was warmer than the temperatures prescribed by IMAC MM and NV by 2.9 °C and 2.1 °C, respectively; it was also warmer than the temperature prescribed by the recent ASHRAE-55 and EN 16798-1 models by 2 °C and 0.3 °C, respectively. IMAC-R reserves the prospect of addressing the thermal comfort needs of the national population while paving the way for long-term energy savings and climate action. • An adaptive model is proposed for mixed-mode and naturally ventilated residences across the Indian climates. • Indian residential occupants are more adaptive than as predicted by ASHRAE-55, EN 15251, and PMV models. • Fan/window operation and change in clothing insulation were the key adaptive responses. • Comfort modelling is explored in correlation with Universal Thermal Climate Index. [ABSTRACT FROM AUTHOR]

Thermal comfort is fundamental to indoor environmental design and operation as well as indoor thermal environment evaluation. This paper has reviewed the historic evolution of thermal comfort research during the last century using a systematic approach and a particular focus on adaptive thermal comfort studies. A large number of published articles as well as standards and guides were collected and screened based on a rigorous search method to ensure the literature database was both focused and complete. A further evaluation of representative prediction models has been conducted by applying the models to a large database and comparing the differences in their performance. Based on the review analysis, three representative thermal environment assessment approaches were classified as the heat balance approach, the adaptive regression-based approach and the adaptive heat balance approach. The strengths and constraints of each approach were analyzed. Comparisons of different models in the adaptive heat balance approach were conducted using the ASHRAE databases I&II. Thermal comfort theory and approaches have been developed which underpin standards and guidelines in building and engineering system design, operation and evaluation though there are pros and cons of different methods. The heat balance approach features the detailed parameters of design criteria of indoor thermal environments. The adaptive regression-based approach played an important role in raising awareness of adaptive capacities and paved the way towards first implementations into standardization. The adaptive heat balance approach combines the heat balance and the adaptive regression approaches and leads towards future improvements in adaptive comfort modelling. It demonstrates very good performance and its inclusive approach offers potential for further breakthroughs in reducing the limitations of the existing methods. • Comprehensive literature review of the development progress of thermal comfort research. • Three representative thermal environment assessment approaches were classified. • They are the heat balance, the adaptive regression-based, and the adaptive heat balance approaches. • The adaptive heat balance approach bridges the gap of the heat balance and the adaptive regression approaches. [ABSTRACT FROM AUTHOR]

Assessing comfort and predicting occupant behavior in the workplace has been a major topic within built environmental research. Despite the vast knowledge, several studies have reported a performance gap between the predicted and the actual behaviors in buildings, together with a discrepancy between predicted and reported comfort levels of occupants within the working environment. To close these gaps, the inclusion of human behavioral and perceptual theories has been investigated to understand the drivers leading to adaptive behaviors and occupants' comfort preferences. As a result, expectations are hypothesized playing a relevant role in the perception of comfort. However, little is known about the formation of expectations towards the indoor climate and the impact on adaptive behaviors. Therefore, drawing on psychological and comfort theories, we built a research framework to study occupants' expectations in buildings and their influence on comfort-related responses and behaviors. A structural equation model was empirically tested using survey data collected from office workers in Germany. Results showed that occupant's expectations positively influenced comfort and adaptive behaviors. Cognitive mechanisms, such as attitudes, perceived control, self-efficacy, personal norms and thermal history, were needed to capture expectations of the indoor environment. The relationship between the expected interaction with a fan to modify the indoor environment and the current occupant behavior was mediated by occupants' previous experiences with fans. This paper contributes to the assessment of comfort and occupant behavior literature by developing a theoretical framework of behavioral and thermal expectations in the built environment. Findings may have implications on the design of adaptive opportunities to enhance occupant satisfaction with the workplace and to support design strategies to reduce the building energy consumption. • A framework of expectations was proposed to understand comfort and behaviors in the workplace. • The model integrates psychological and comfort theories, such as TPB, NAM and the Self-efficacy theory. • Survey data in Germany was tested through structural equation modeling. • Expectations of the indoor environment influence occupant's perception of comfort and adaptive behaviors. • Expectations and behaviors were mediated by occupants' previous experiences. [ABSTRACT FROM AUTHOR]

Behavioural, physiological and psychological adaptive processes are presumed reasons for the discrepancies between predicted mean vote and observed comfort votes during field studies. However, few are known about the individual portions of these processes. An experimental design was developed, which aims at identifying those portions and is meant for climate chambers with operable windows facing the exterior. This article looks in detail at behavioural and physiological reactions together with their effect on the perceived level of comfort. By means of multivariate regression analyses, these reactions are analysed in order to assess differences due to variations in indoor/outdoor conditions as well as the number of interactive opportunities. One of the results shows that the restriction to keep the window closed is counterbalanced by an increased amount of physiological reactions, such as an increased level of skin temperature, together with an increase of still permitted actions such as drinking. The results highlight the importance of detailed insights into single aspect of adaptive processes for a better understanding of the phenomenon called ‘adaptive comfort’. Such approach is novel and important because a detailed knowledge and quantification of the occupant’s comfort perception in naturally ventilated buildings permits a planning with less uncertainty. [ABSTRACT FROM AUTHOR]

Abstract: Thermally comfortable indoor conditions can be found using the predicted mean vote (PMV)-approach, the adaptive comfort model, or the calculation of the human body exergy consumption (HBx-) rate. Thus, it would be practical either to find a combined model applicable to all conditions or the underlying effects for the observed differences. This paper compares all three approaches by three distinctive procedures: first, conditions leading to temperatures within the adaptive comfort range and those leading to the minimum HBx-rate are compared first based on hourly weather data and second on general assumptions; Third, for the datasets contained in the ASHRAE comfort database, the PMV-value, adaptive comfort temperature, and HBx-rate are calculated and the results compared. According to the first procedure, a linear relationship between adaptive comfort temperature and minimum HBx-rate is found. The exploration of results gained by using the ASHRAE comfort database showed that the minimum HBx-rate corresponds well to the neutral temperature given by the adaptive comfort model. These results can be used as a starting point for a further exploration of differences and similarities between the three approaches, which may lead to a combined model of thermal comfort. Nevertheless, more detailed analyses are necessary to obtain statistically and theoretically assured conclusions. [Copyright &y& Elsevier]

Abstract: Behavioural, physiological and psychological adaptive processes are presumed reasons for the discrepancies between predicted mean vote (PMV) and observed comfort votes during field studies. However, few is known about the individual portions of these processes to this effect. This paper describes the development of an experimental design which aims at identifying those portions and is meant for climate chambers with at least one façade connected to the exterior. The experimental design consists of distinctive settings with respect to variations in outside conditions and the number of control opportunities so that one or more of the three adaptive processes are blocked. The results of a first implementation of this experimental design presented show the ability to analyse the three processes individually with the data gathered by such procedures. As a result, the permission to interact with the built environment by means of using a fan or opening a window alone leads to an increased satisfaction with the thermal conditions. At the same time, the restriction of such behavioural reactions seems to be counterbalanced by an increased amount of physiological reactions such as an increased level of skin moisture and skin temperature. In conclusion, the developed experimental design looks promising in order to reveal the single effects leading to the phenomenon called adaptive comfort, while small adjustments are discussed for further improvements. [Copyright &y& Elsevier]

Immersive virtual reality (IVR) is a promising technology increasingly applied to various research fields, including building science and occupant comfort research. Using immersive virtual environments (IVEs), researchers explore important research questions related to how occupants perceive and interact with their indoor environment in response to different environmental stimuli (e.g., visual, thermal, and acoustic). Despite an increasing number of applications, the literature lacks review efforts of IVE-based comfort research, leaving the current state of such efforts, their shortcomings, and prospects unclear. The current work aims to address this stated gap by presenting a comprehensive review of scholarly articles using IVEs to study occupant comfort and related adaptive behaviors in buildings. The document starts with a review of available IVR technologies and their associated fundamental concepts (i.e., immersion, ecological validity, presence, and user experience), followed by a review of studies that employed IVEs to assess comfort or adaptive behaviors across single or multiple environmental domains. A synthesis is then presented to reflect on the current state-of-the-art, its gaps, and the way forward. Results show that despite significant advancements in IVR technology, IVE-based multi-domain comfort and behavior experiments remain very limited (e.g., considering cross-effects between thermal, visual, and acoustic domains). Furthermore, the use of multi-user IVE is particularly scarce and should be further leveraged in the future to understand how groups of individuals (e.g., co-workers or classmates) collectively respond to environmental stimuli, interact with various building systems, and drive building performance. • Occupant comfort/behavior research using immersive virtual environments (IVEs) is reviewed. • The scope covers IVE concepts, related technologies, visual and thermal comfort experiments. • IVE-based multi-domain comfort and behavior experiments remain overall limited. • Future applications should explore group-level multi-domain comfort and behaviors. • The use of IVE technology in environmental chambers can help address the stated gaps. [ABSTRACT FROM AUTHOR]

Detailed numerical analyses of temperature and air velocity distributions are relevant to assess thermal comfort in a wide range of applications. Until now mainly simulations based on Reynolds-averaged Navier–Stokes equations (RANS) are used, whereby fluctuations as well as anisotropy of the turbulence are represented with insufficient precision. This paper applies a thermal large eddy lattice Boltzmann method (LES–LBM) as an efficient and accurate transient modeling of turbulence. The benchmark case Manikin Heat Loss for Thermal Comfort Evaluation is studied and the model of Predicted Mean Vote (PMV) is applied for estimating thermal sensation. The results for the air velocity, the temperature field and the PMV show a satisfactory agreement with both, the experiment and the results from RANS simulations. The accuracy and the model quality of the simulation are increased further by considering the buoyancy and an inlet seeding. This suggests a successful evaluation of the present model, whereby additional transient flow field data are provided. The obtained transient flow field data, however, motivates future work to study thermal comfort in the present manner. The investigation of the influence of fluctuations on thermal comfort as well as the application to more complex problems seem promising. • LES for transient incompressible thermal flow using a double distribution LBM. • Validation with the benchmark case Manikin Heat Loss for Thermal Comfort Evaluation. • PMV model applied to transient and time averaged data. • LES–LBM results agree well with RANS and experimental reference data. [ABSTRACT FROM AUTHOR]

Research related to personal comfort systems is growing due to their potential to increase an individual's satisfaction with indoor environmental conditions and energy efficiency. At moderately high indoor temperatures, the use of ceiling fans can be a low-energy cooling strategy to enhance comfort in a working environment. This paper studies the performance of a personal ceiling fan and its influence on occupants' satisfaction with the indoor environment, focusing on the effects of personal control, previous experience with fans, variations on participants' activity level and air coming from different directions. In a laboratory study, 41 participants from two age groups were exposed to six different ceiling fan configurations either in sitting or standing positions, with and without control over the ceiling fan speed, and under two thermal conditions (balanced order of in total 24 conditions). Results showed that participants' thermal comfort at indoor temperatures of 28 °C and 31 °C was fulfilled when they used the personal ceiling fan, independent of the direction of the supplied air coming from above. The possibility to control the fan speed showed a significant influence on the thermal perception of participants at a slightly higher activity level compared to fully sedentary. The influence of previous experiences with fans had a positive effect on the rating of the analyzed ceiling fan and thermal comfort. The positive acceptance of personal ceiling fans encourages its use in retrofitted office buildings to increase thermal comfort and motivate energy savings. [ABSTRACT FROM AUTHOR]

In recent years, research has emerged to quantitatively and qualitatively understand occupants' interactions with buildings. However, there has been surprisingly little research on building interfaces and how their design, context (e.g., location), and underlying logic impact their usability and occupants' perceived control, as well as the resulting comfort and energy performance. Research is needed to better understand how occupants interact with building interfaces in both commercial and residential applications; both applications are important to address as there are many differences in interface types, level of control and understanding, and even expectations of engagement. This paper provides a cursory review and discussion of select common building interfaces: windows, window shades/blinds, thermostats, and lighting controls. The goal of this paper is to review literature related to these human-building interfaces to explore interface characteristics, current design and use challenges, and relationships between building interfaces and occupants. Human-building interface interactions are complex, more research is needed to understand design, use, and characteristics. Common themes emerged throughout the literature review to explain occupant interactions (or lack of interactions) with building interfaces, which included thermal and visual comfort, ease and access of control, interface/control placement, poor interface/control design, lack of understanding, and social-behavioral dynamics. • Understanding control interfaces and use of building systems is critical. • Literature indicates drivers of occupant interactions with building interfaces. • Well-designed building interfaces can lead to energy savings and occupant comfort. [ABSTRACT FROM AUTHOR]

• Personal Comfort Systems (PCS) provide thermal comfort at an individual level. • PCS operate on heating, cooling, ventilation and combination modes. • Conventionally, PCS need less than half the energy required for HVAC operation. • This review discusses the results of over 150 published studies on PCS. Conventional heating, ventilation, and air-conditioning (HVAC) systems are designed to condition the entire building volume. In contrast, Personal Comfort Systems (PCS) target conditioning only the occupied zones of the space, while maintaining the remaining volume at a relatively under-conditioned state. PCS offer the occupants the choice of modulating their immediate thermal ambience with local controls. The individual-level control helps in improving the subjective thermal and air quality acceptability with the desired thermal sensation. This review paper details on the various types of heating, cooling, ventilation, heating with ventilation, and cooling with ventilation PCS devices. It summarises the thermal ambience created by the respective PCS devices and the resultant subjective responses of the occupants. This review also identifies the energy saving potential of various kinds of PCS devices, the power use of PCS devices, and discusses their economic viability. [ABSTRACT FROM AUTHOR]

• The concepts of thermal adaptation and alliesthesia lead to antithetic predictions. • An experimental study with 63 participants was conducted. • Adaptation predicts seasonal differences in dimension of thermal sensation. • Alliesthesia predicts seasonal differences in dimension of thermal pleasure. • Optimal thermal conditions depend on dimension, season, sex, and type of analysis. Literature on thermal comfort presents two concepts beyond a static view of perception: adaptation and alliesthesia. Both concepts are typically analyzed separately and consequences for optimal conditions when following one or the other concept are not compared. Predictions concerning preferred conditions in different seasons derived from these concepts are antithetic – while adaptation suggests warmer conditions in summer being closer to neutrality – often equated with comfort – alliesthesia suggests cooler conditions in summer leading to a higher level of pleasantness – also set synonymous with comfort. The objectives of this study were to compare both concepts and the resulting views on optimal thermal conditions experimentally. The experimental study consisted of a between-subject design with two groups of participants experiencing the same three thermal conditions (classified as cool, neutral, warm) each for 50 min in a balanced order in a field laboratory with windows to the outdoors in winter (N = 32) or in summer (N = 31). Participants evaluated their thermal perception on three dimensions: thermal sensation, thermal comfort, and thermal pleasantness at the end of each session. Indoor environmental parameters and subjects' skin temperature were recorded. Statistical analyses with participants' ratings as the dependent, and standard effective temperature, season and sex as independent variables showed that optimal thermal conditions varied significantly between seasons, sex, the dimension of thermal perception, and the applied statistical method. Based on the results, a new type of alliesthesia is proposed to explain such effects: seasonal alliesthesia. Adaptation and alliesthesia focus on different dimensions of thermal perception and lead to distinctive results concerning optimal thermal conditions. Future work in the area of thermal comfort needs to discuss, which dimension is appropriately considered in which context and the consequences drawn for design and operation of buildings. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Thermal expectation together with sensation and comfort is directly assessed • Laboratory and field study data was analysed by ordinal mixed effect regression • Participants' thermal expectations influenced their thermal sensation and comfort • Indoor temperature, location, and day of experiment influenced thermal expectations • Stated expectations were independent of indoor-outdoor temperature difference Thermal expectation is mentioned as one aspect of psychological adaptation to indoor thermal conditions. However, there is a lack of studies in the built environment assessing expectations directly and the relationship between expectations and thermal perception. Therefore, this paper studies potential influences on occupants' expectations of indoor thermal conditions and the implications of their expectations on thermal perception. A combination of data from laboratory and field studies was analysed, where the same 47 participants participated in both of them. Subjects experienced different temperature conditions and were asked directly about the congruence between their thermal expectations and actual experience together with their actual thermal perception. The question regarding participants expectations applied in this study can be considered as the most straightforward way to ask for their expectations. The data was analysed by ordinal mixed effect regression analysis. Results show that there is a significant influence of the level of expectation on thermal sensation and comfort votes for the field and laboratory study. Indoor temperature, the day of experiment (first, second, or third) and the location (laboratory vs. field) show significant influences on thermal expectation. However, participants state their expectation of the indoor environment independent of the outdoor conditions or indoor-outdoor temperature difference. The discussion of implications of these results for adaptive approaches of room conditioning, which relay on the acceptance of higher fluctuations of indoor thermal conditions, suggests to carefully address expectations in future studies. [ABSTRACT FROM AUTHOR]