The accurate prediction of thermal sensation among office workers, at design and post-occupancy stages, is crucial for controlling indoor temperature efficiently and correcting deficiencies in ...workspaces, ensuring healthy and productive working conditions. Traditional analytical comfort models are still the best tool for this purpose given their potential for interpretation. However, their reliability is undermined by their poor accuracy. Based on 304 data series of point-in-time measurements of quantitative and qualitative comfort-related parameters collected in an experimental campaign in three office buildings, one air-conditioned and two in free evolution, in San Luis Potosí (Mexico), this work aims to identify the major error-causing factors of steady and adaptive comfort models. The divergences between predicted and reported thermal sensation were set as a dependant variable of two multiple regressions, one for each model. Eighteen independent demographic, environmental, contextual and subjective variables were considered. No multicollinearity problems were identified. Our findings show that contextual factors and humidity perception were relevant in the adaptive model error. Clothing insulation highly impacted the accuracy of both models while age and body mass were not statistically significant for either of them. Metabolic rate was the factor with the greatest influence in the error of the steady model. Although not covered, other influential factors played a key role in models’ accuracy and further research is needed to integrate these in a new generation of more accurate and flexible analytical models.
•Thermal comfort field assessments were carried out in offices in Mexico.•The aim was to identify main error sources of analytical comfort models.•Regression analysis was applied to errors using 18 independent variables.•Clothing insulation and metabolic rate were relevant in steady-model error.•Clothing, context and perceived humidity were relevant in adaptive error.
Human individual differences widely and markedly affect thermal comfort and should be carefully considered in the design and operation of the built environment. This paper aims to list and examine ...the magnitude and significance of individual difference in the preferred/neutral/comfort temperature through reviewing previous climate chamber and field studies. Causal factors for individual differences are investigated, including sex, age and etc. There is no clear and consistent conclusions as to the significance and size of inter-group differences in thermal comfort (between females and males, or the young and the old). To address the issue of individual difference, a paradigm shift from centralized to personalized air condition is on the way with the following three steps: first, collecting individual physiological and psychological response; second, predict individual comfort with machine learning algorithms; and third, accommodating individual difference with Personalized Comfort Systems.
Occupants’ comfort perception affects building energy consumptions. To improve the understanding of human comfort, which is crucial to reduce energy demand, laboratory experiments with humans in ...controlled environments (test rooms) are fundamental, but their potential also depends on the characteristic of each research facility. Nowadays, there is no common understanding for definitions, concepts, and procedures related to human comfort studies performed in test rooms. Identifying common features would allow standardising test procedures, reproducing the same experiments in different contexts, and sharing knowledge and test possibilities. This review identifies 187 existing test rooms worldwide: 396 papers were systematically selected, thoroughly reviewed, and analysed in terms of performed experiments and related test room details. The review highlights a rising interest in the topic during the last years, since 46% of related papers has been published between 2016 and 2020. A growing interest in non-thermal sensory domains (such as visual and air quality) and multi-domain studies about occupant's whole comfort emerged from the results. These research trends have entailed a change in the way test rooms are designed, equipped and controlled, progressively becoming more realistic inhabitable environments. Nevertheless, some lacks in comfort investigation are highlighted: some continents (like Africa and South America) and climate zones are found to be underrepresented, while involved subjects are mainly students performing office tasks. This review aspires to guide scientists and professionals toward the improved design or the audit of test room experimental facilities, especially in countries and climate zones where human comfort indoors is under-studied.
•Test rooms: environmentally controlled and equipped space to study human comfort.•Systematic review of controlled studies on human comfort (396 papers).•187 test rooms analysed in terms of construction and technical details.•Overview of single and multi-domain comfort experiments conducted in test rooms.•Trends in conducted experiments and test room-related design.
There is little thermal comfort research in residential environments reported from India. Energy consumption in Indian residential buildings is one of the highest, increasing at a phenomenal rate. ...Indian standards advocate two narrow ranges of temperatures for all building and climate types. In this context, a field study in summer and monsoon was conducted following Class-II protocols, for three months in 2008, in naturally ventilated apartment buildings in Hyderabad. Over a 100 subjects involved, giving 3962 datasets. In May, most of the subjects were uncomfortable, preferring a temperature on the cooler side of the neutrality, despite accepting their thermal environments. Thermal sensation, preference and acceptance improved in June and July as temperature receded. Humidity did not affect comfort sensation much, as summer was hot and dry. Conversely, increase in humidity adversely affected the thermal comfort in June. Adaptive use of controls resulted in moderate air movement indoors, adequate for sweat evaporation most of the time. The subjects used traditional ensembles and slowed down their activities adaptively to restore thermal comfort. Clothing adaptation was found to be impeded by many socio-cultural and economic aspects. The comfort band (voting within −1 and
+1) based on the regression analysis was found to be 26–32.45
°C with the neutral temperature at 29.23
°C. This is way above the limits (23–26
°C) set by Indian standards. The PMV was always found to be higher than the actual sensation vote. These findings have far reaching energy implications in a developing country like India.
Students spend a lot of time at school, highlighting the great importance of providing comfortable conditions in educational buildings. Indoor environmental conditions are also related to student ...productivity and well-being, but Literature reviews mainly examine the effects of single parameters on human comfort, lacking in the evaluation of comfort combining different aspects, such as thermal, acoustic, and visual ones. The aim of the paper is to propose an index for the evaluation of the environmental comfort tacking into account thermal, acoustic, and lighting conditions. Seven university classrooms were investigated; measurements of environmental factors were performed including thermal, acoustic, and lighting parameters. Subjective evaluations were also carried out through survey questionnaires purposely elaborated. Three single indexes were proposed basing on the strongest correlation between questionnaire's answer and experimental results: a Predicted Mean Vote Index for the thermo-hygrometric conditions, a Sound Index for the acoustic comfort, and a Visual Index for the lighting conditions. All the indexes are dimensionless and normalized in a 0–1 range: values next to 1 indicate good comfort conditions and values next to 0 indicate bad comfort conditions. On the basis of different weights given for the three aspects, a final combined comfort index was calculated for each classroom and compared with questionnaires results, in order to assess the methodology.
•Analysis of global comfort conditions in seven classrooms was carried out.•Data from many questionnaires were collected and compared to experimental results.•The questions with the best correlation were selected and used as indexes.•A final global index is proposed and compared with questionnaires results.•A new questionnaire was developed to improve the study on global comfort.
India is witnessing unprecedented growth trends in building construction, particularly office spaces. Indian offices are designed to operate at 22.5 ± 1 °C all year round to meet the stringent “Class ...A” specifications outlined by international standards in the absence of an India-specific comfort standard. This paper proposes an India Model for Adaptive Comfort – IMAC – based on the field surveys administered in 16 buildings in three seasons and five cities, representative of five Indian climate zones. A total of 6330 responses were gathered from naturally ventilated, mixed mode and air-conditioned office buildings using instantaneous thermal comfort surveys.
Occupants in naturally ventilated Indian offices were found to be more adaptive than the prevailing ASHRAE and EN models would suggest. According to the IMAC model, neutral temperature in naturally ventilated buildings varies from 19.6 to 28.5 °C for 30-day outdoor running mean air temperatures ranging from 12.5 to 31 °C. This is the first instance where a study proposes a single adaptive model for mixed mode buildings asserting its validity for both naturally ventilated and air-conditioned modes of operation in the building, with neutral temperature varying from 21.5 to 28.7 °C for 13–38.5 °C range of outdoor temperatures. For air-conditioned buildings, Fanger's static PMV model was found to consistently over-predict the sensation on the warmer side of the 7-point sensation scale.
•A single adaptive model is proposed for NV and AC modes of operation.•Indian office occupants are more adaptive than predicted by ASHRAE-55 and EN15251 models.•International comfort standards are not appropriate for Indian office buildings.•Occupants in MM offices are more adaptive than those in AC and less adaptive than those in NV offices.•Fan and window operation, change in clothing are significant adaptive measures in NV offices.
The use of solar gains is one of the most effective passive strategies to reduce the heating energy demand of buildings. However, solar radiation not only affects the thermal balance of the building, ...but also that of the occupants. Several approaches have been developed for including solar effects into steady-state thermal comfort models (i.e. Fanger Model) proposing a correction to the calculation of the Predicted Mean Vote (PMV) and validating it experimentally. One of those approaches incorporates solar radiation as an adjustment of the mean radiant temperature (MRT) used in the calculation of the PMV. In this paper the described approach has been integrated in the calculation of three dynamic thermal comfort indices (i.e. TSENS, TSV and DTS). Results have been compared to the corresponding solar-adjusted PMV. The performance of the comfort models has been assessed on 12 different configurations of a shoebox open plan office, given by the combination of two window sizes and two window orientations in three European locations. Results are presented in detailed spatial and temporal maps for a whole year. Two of the three compared dynamic indices (TSENS and TSV) have been found to perform similar to the solar-adjusted PMV in detecting comfort issues.
•Solar radiation effect has been integrated into dynamic comfort models.•Steady-state and dynamic comfort models have been compared.•Both type of models are suitable for evaluating sun-irradiated spaces.•Three of the four models are able to identify and locate critical situations.•Differences between models are bigger in climates with higher solar radiation.
Climate change and the urgency of decarbonizing the built environment are driving technological innovation in the way we deliver thermal comfort to occupants. These changes, in turn, seem to be ...setting the directions for contemporary thermal comfort research. This article presents a literature review of major changes, developments, and trends in the field of thermal comfort research over the last 20 years. One of the main paradigm shift was the fundamental conceptual reorientation that has taken place in thermal comfort thinking over the last 20 years; a shift away from the physically based determinism of Fanger's comfort model toward the mainstream and acceptance of the adaptive comfort model. Another noticeable shift has been from the undesirable toward the desirable qualities of air movement. Additionally, sophisticated models covering the physics and physiology of the human body were developed, driven by the continuous challenge to model thermal comfort at the same anatomical resolution and to combine these localized signals into a coherent, global thermal perception. Finally, the demand for ever increasing building energy efficiency is pushing technological innovation in the way we deliver comfortable indoor environments. These trends, in turn, continue setting the directions for contemporary thermal comfort research for the next decades.
To investigate the combined effects of thermal, acoustic and visual comfort in open spaces, this study selected five typical spaces on a university campus with five common sounds (broadcasting music, ...running water & birdsong, wind (a gentle breeze) & insects, crowds, and machines) in a cold region of China. 418 volunteers were asked to complete a subjective sensory questionnaire in a randomly combined audio-visual environment while meteorological measures were taken on-site. Four primary outcomes emerged. First, broadcasting music improved individual subjective thermal comfort votes (TCV). Under the moderate heat stress (0.5 ≤ thermal sensation vote TSV ＜ 2.5), a comfortable acoustic environment helped reduce individuals' subjective TSV and increase TCV. Second, the subjective acoustic comfort vote (ACV) of broadcasting music, wind & insect sound and machine noise decreased with the increase of Universal Thermal Climate Index (UTCI); respondents perceived crowds, machines and wind & insects louder when TCV = 2 and −2. Third, under no thermal stress (−0.5 ≤ TSV ＜ 0.5)/moderate heat stress (0.5 ≤ TSV ＜ 2.5), TSV increased with increasing illumination intensity (LUX). Under the strong heat stress (2.5 ≤ TSV ≤ 3), there was no significant difference in TCV among subjective visual comfort vote (VCV) levels. Finally, when the LUX class was neutral/slightly bright, respondents felt darker in thermo-neutrality. Additionally, VCV and TCV were positively correlated under each LUX class.
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•Combined effects of outdoor visual-acoustic-thermal comfort were investigated in Xi'an, China.•Broadcasting music was conducive to improving individual TCV.•Crowd and machine noise were louder when people felt thermally comfortable or uncomfortable.•Visual comfort did not affect TSV and TCV in a hot environment.•Respondents felt darker in thermo-neutrality when LUX was neutral/slightly bright.
Open space comfort significantly affects urban well-being, particularly in dense areas. This study uses drone imagery, climate measurements, and questionnaires to explore acoustic, aesthetic, light, ...thermal and overall comfort in Wuhan's pedestrian street, plazas, and parks, which proposing a hypothesis in both morphological factors and meteorological factors collectively influence comfort senses, and subsequently, overall comfort. The results indicate the sky view factor (SVF) contributes to all the comfort senses. Spaces with SVF over 32.9 % have 170 % higher light comfort and 160 % higher thermal comfort than those below 13.3 %. As SVF change from under 13.3 % to over 32.9 %, mean aesthetic comfort vote increases by 134 %, while acoustic comfort declines by 36 %. With Universal Thermal Climate Index (UTCI) from below 11.5 °C to higher than 21.5 °C, aesthetic comfort's influence weight on overall comfort rises by 85.4 %, while thermal comfort decreases by 32.4 %, indicating a falling importance of thermal but increasing that of aesthetic comfort with warmer environment. Also, the study emphasizes higher “cross-modal effects” between aesthetics and acoustic comfort compared to sunligt and thermal comfort. Research will help inform improvements to outdoor environments in similar climates.
•In winter, sky view factors enhance visual comfort outweighing other effects.•Rising winter UTCI boosts visual/acoustic and weakens sunlight/thermal comfort.•Visual/acoustic comfort's “cross-model effect” surpasses sunlight/thermal comfort.•Original data approach: UAV image modeling combined with traditional methods.
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