Field Study Of Thermal Comfort Research Articles

Variations in Gender Perceptions of Summer Comfort and Adaptation in Colonial Revival-Style Homes

Past investigations have assessed gender variations in thermal comfort and adaptation in different buildings. However, no reported study has evaluated differences in gender perceptions of the thermal environment in US Colonial Revival-style homes. As a result, this study aims to provide an understanding of variations in gender perceptions of summer comfort and adaptation in the buildings. The study evaluated data collected during the field studies of thermal comfort (FSTC), including physical measurements of environmental variables and subjects’ votes. In this study, 67% females and 33% males participated in the field surveys in summertime. The mean neutral temperature of 25.5 °C and preferred temperature of 24.9 °C were noted for females. For males, the mean neutral and preferred temperatures of 25.8 °C and 25.6 °C were observed. Females feel neutral and prefer “no change” to the thermal environment at lower temperatures than males. A difference of 0.3 °C was noted between the average heat indices for females and males. Male respondents who feel warm perceive less air quality more than females. Females and males who perceive being thermally comfortable also perceive good air quality. Females and males who are thermally comfortable rated air humidity to be acceptable. There are similarities and differences between gender perceptions of the thermal environment. The investigation suggests interventions that can help users regulate their skin temperatures and use control measures that are sensitive to clothing insulation. The research also calls for policies that can promote building users’ pivotal adaptive measures to improve their indoor thermal environment. The study enhances our understanding of sustainable indoor environments and how to improve living conditions and adaptive modifications among different groups of occupants in buildings.

Assessment of occupants’ adaptive capacity: a case study in northern Guizhou of China

The thermal comfort of rural residents is a major issue related to people’s livelihood. Due to differences in climatic factors (e.g. local climate) and non-climatic factors (such as building structures, economic and social–cultural levels, living habits and availability of environmental control) between rural and urban areas, participants have different thermal requirements for a given thermal environment. This difference means that thermal comfort standards that consider only urban conditions may not be applicable to rural situations. Therefore, a thermal comfort field study was conducted on the thermal comfort of traditional residential houses with natural ventilation located in rural areas of northern Guizhou, China. This study aims to understand the indoor thermal conditions and perceptions of occupants in rural areas, with a total of 513 subjects that participated in a questionnaire survey. Most survey respondents accept the thermal environment in which they reside, even if the indoor temperature is not within the recommended thermal comfort range specified by international standards such as Ashrae 55. The adaptive predicted mean vote is established using the least-squares method. The adaptive coefficient λ representing the adaptive capacity is twice the recommended coefficient of the Chinese standard, GB/T 50785-2012. This confirms that rural residents have a stronger adaptability to cold conditions in winter. The findings are beneficial for improving thermal comfort and carbon dioxide emission reduction for traditional residential houses in rural areas of northern Guizhou, China.

Enhancement of Indoor Thermal Comfort Using Alternative Building Materials and Construction Technology in Low Income Housing - A Case of Trivandrum, Kerala

In India, rapid urbanisation followed by increased demand for housing has led to higher energy consumption in the building sector and a larger percentage of which is contributed by the housing sector. And the population using affordable housing is higher compared to other developed countries (MOUHA, 2013). The occupants tend to achieve the desired level of thermal comfort by personal adjustments and mechanical means. Using energy intensive methods for comfort is not feasible for a country, like India, with a low energy economy. This study analyses the indoor thermal comfort in low income housing with respect to the building materials and construction technology used. Two typologies of housing were studied which includes a row housing constructed using conventional materials, with hollow brick cement plastered walls and RCC roof slabs, and a vertical stacking multi dwelling constructed using Laurie Baker’s alternative construction technology, with rat-trap bond brick walls and filler slabs. The study explored the current scenario of housing based on a thermal comfort field study using questionnaire survey and onsite measurements (following ASHRAE class II protocol) which was then simulated using Design Builder software changing the wall material used to understand the improvement in indoor thermal comfort. An adaptive thermal comfort model and neutral temperature was generated for both types of housing which was then compared with IMAC Model ranges. The adaptive comfort ranges obtained for both housing were too warm than the acceptable ranges and the PMV values in row housing are hot, while that in vertical stacking is slightly warm to warm. The neutral temperature obtained in vertical stacking housing (28 deg C) is within the acceptable range, whereas that of row housing (28.8 deg C) is greater than the upper limit range of neutral temperature under the IMAC model. The results showed that building material with good thermal performance can cause a significant reduction in indoor temperatures thus improving indoor thermal comfort. Thus indoor thermal comfort in low income housing can be improved by using alternative construction technology, without compromising cost-effectiveness and affordability, and thus contributing to energy efficiency.

Adaptive thermal comfort in naturally ventilated hostels of warm and humid climatic region, Tiruchirappalli, India

• Comfort range for hostel building was found between 26.1 and 32.8 °C. • The desired temperature was found to be 27.8 °C, while neutral temperature was 29.5 °C. • The comfort limit extended by 2.8 °C if air velocity rises from 0.1 to 1.1 m/s. • Sweating Acceptability extended the thermal acceptability limit from 31.8 to 32.4 °C. • At 26.6 °C temperature about 50% of the fans were found switched on. Thermal comfort is an important factor in hostel buildings when the aim is to maximize the productivity of the students. Due to the extreme weather conditions, achieving thermal comfort in a hostel building in a hot and humid climate is even more difficult. Studies conducted in naturally ventilated hostel buildings in warm-humid climates involved the influence of outdoor air temperature only up to 34.4 °C and have been conducted in a specific season. In contrast, the Tiruchirappalli climate is characterized by a higher range of environmental variables. Therefore, to understand the thermal comfort conditions and usage of the environmental controls in naturally ventilated hostel buildings at the higher range of the environmental variables, a thermal comfort field study spread over one year was carried out at the National Institute of Technology, Tiruchirappalli, India, in twenty-seven hostel buildings. This study relies on field observation and thermal comfort responses from 2028 questionnaires collected from the students between September 2019 to August 2020. The analysis revealed a neutral temperature of 29.5 °C and a comfort range from 26.1 °C to 32.8 °C, indicating a wide range of thermal adaptation than suggested by the National Building Code of India and ASHRAE standard 55. The preferred temperature was 27.8 °C, indicating that students preferred a cooler environment. Acceptability with sweating conditions extended the upper limit of thermal acceptability from 31.8 °C to 32.4 °C. The use of a mosquito net can increase the probability of opening a window. Results indicated that overall behavioral adjustment could extend the comfort limits. The study results would be helpful to develop guidelines and designs for naturally ventilated hostel buildings in warm and humid climates that will contribute to reducing energy demand.

Evaluating thermal comfort and neutral temperature in residential apartments in hot and dry climate: A case study in Shiraz, Iran

Determination of thermal comfort, as one of the main goals of climate design, is of great importance due to its direct impact on human productivity and health, the interior space quality, and the energy consumption reduction, regarding the fact that most of the human activities take place in the house. Though providing crucial design information, determination and analysis of the thermal comfort range is a challenging issue due to variety of climatic, physiological, and cultural influencing factors, which in turn, necessitate field studies. Considering the critical need of determining thermal comfort range for each climate, this research aimed to describe field study of thermal comfort conducted in mid-rise residential apartments with open courtyards in hot and dry climate of Shiraz, Iran to provide neutral temperature, thermal comfort range, and the relationship between neutral temperature and indoor as well as outdoor temperature. The data and information needed, based on the experimental and field methods, were collected using the two main methods of questionnaire and measurement and the results were discussed with analytical and inferential description. In addition to a positive correlation between indoor air temperature and PMV as well as AMV, the findings of survey and regression analysis reveals a good relationship between neutral temperature and indoor temperature and also, between indoor comfort and outdoor conditions. Furthermore, a neutral temperature of 27.18 °C and the comfort band (23.2–30.8 °C) vindicated that respondents achieve comfort at a higher indoor air temperatures compared with the recommendations of international standards such as ISO7730. Moreover, the regression equation between the preferred and neutral temperature suggests that the neutral temperature can be used as a suitable criterion for predicting indoor temperature.

A systematic review on thermal environment and thermal comfort studies in Chinese residential buildings

Amid the backdrop of the energy crisis, thermal comfort is crucial to achieve energy savings. Residential buildings are characterized by a wide range of adaptive comfort opportunities. However, there has been a lack of systematic refinement and review of residential thermal comfort field studies in China to provide valuable recommendations for energy conservation. We systematically reviewed studies on thermal environment and thermal comfort in Chinese residential buildings published in peer-reviewed journals up to 2020. A total of 34 studies were deemed to have provided sufficient information on both the thermal environment and thermal comfort. We found that in winter, there were obvious differences between urban and rural dwellings in Severe Cold (SC) and Cold (C) zones, with regard to their indoor air temperature (urban: 19.8 ∼ 25.0 °C v.s. rural: 11.3 ∼ 17.8 °C) and neutral temperature (urban: 17.6 ∼ 25.1 °C v.s. rural: 11.9 ∼ 23.45 °C). While in summer, the indoor air temperature in urban dwellings were slightly lower than those in rural areas due to their prevalent use of air conditioner (urban: 26.1 ∼ 28.9 °C v.s. rural: 29.5 ∼ 34.9 °C). Indoor air temperature and neutral temperature varied considerably in different climate zones in winter. In SC zones, the indoor environment was overheated, which could lead to energy wastage and overheating discomfort for residents. Residents in Hot-Summer and Cold-Winter (HSCW) zone were the most tolerant to the variation of thermal environment (the median coefficient of MTS or TSV equation: SC: 0.18; C: 0.20; HSCW: 0.13; HSWW: 0.23).

Adaptive thermal comfort of residential buildings in the composite climatic region of India: a field study

ABSTRACT This paper presents the results of an adaptive thermal comfort field study conducted in the naturally ventilated residential buildings in the composite climate type of India over three main seasons i.e. monsoon, winter, and summer using ASHRAE’s class II field measurements protocols. 768 measurements were collated wherein subjective thermal comfort sensation, preference, and acceptance for indoor environment variables were thoroughly explored along with the adaptive actions of the users for four different times during a day. Correlation analysis helped decipher the relationship between subjective votes and thermal comfort evaluation parameters. Thermal environment acceptance during monsoon season and morning time was highest however the same was found lower during summers and afternoons. The middle age group had the lowest acceptance and well-acclimatized non-native participants had a good thermal acceptance. Education also affects thermal acceptance and it decreases with increasing education level. The comfort temperature and adaptive comfort equation were also studied and results were compared with national and international thermal comfort standards. This study predicted a wider thermal comfort range of 12.23–34.45°C and indicated revising TSI, the first thermal comfort index for Indian Subjects.

A Review of Thermal Comfort in Residential Buildings: Comfort Threads and Energy Saving Potential

Residential buildings instigate a vital role in creating a safe and comfortable indoor living environment. The phenomenon of overheating, an impact of climate change, can cause a negative effect on residents’ productiveness and heat-related illnesses and can even force high pressure on electricity generation by increasing the risk of power outages due to excessive peak cooling and heating requirements. Various issues on building thermal comfort are being evolved and discussed in review articles. However, there are few articles that review the current condition of adaptive thermal comfort studies and the potential for energy savings in residential buildings. Therefore, the aims for this paper are to: identify comfort temperature ranges in residential buildings, investigate the correlation of comfort temperature with indoor and outdoor temperatures with the aid of ‘comfort threads’, and clarify the effect of adaptive measures on residential energy saving potential. This study obtained a large variation of residential comfort temperatures, which mostly depend on the climate and operation modes of the building. ‘Comfort threads’ explains that people are adapting to a large variation of indoor and outdoor temperatures and the wide range of comfort temperature could provide significant energy savings in residential buildings. This review provides insight on and an overview of thermal comfort field studies in residential buildings.

Thermal Comfort in the Design Classroom for Architecture in the Cold Area of China

A field study of thermal comfort in a design classroom for teaching architecture and dormitory rooms in a cold area of China was conducted to provide a better understanding of the thermal comfort of students, and to clarify the energy saving potential of such building spaces. Respondents were the same for both the classroom and dormitories field survey, with a total of 89 students majoring in architecture. The students’ subjective thermal responses and their environmental parameters for two months before and after heating were collected and compared, and the results showed that when respondents adjusted their clothing it was not necessarily to adapt to the thermal environment but may have been due to habituation. The thermal neutral operative temperature was determined to be 23.1 °C in the design classroom and the thermal sensation was maintained at neutral-cool in the dormitory rooms. Although there were significant differences between the thermal environments in the classroom and dormitories, thermal acceptability was close to 100%. In the design classroom, the PMV (Predicted Mean Vote) predicted the indoor thermal environment relatively accurately, while in dormitory rooms, the PMV underestimated the thermal sensations. Students can tolerate lower temperatures, showing adaptability to the environment.

Field study of seasonal thermal comfort and adaptive behavior for occupants in residential buildings of Xi’an, China

Field study of seasonal thermal comfort and adaptive behavior for occupants in residential buildings of Xi’an, China

Evaluation of thermal comfort in library buildings in the tropical climate of Kumasi, Ghana

Adaptive comfort considerations and passive design are crucial in tropical, hot and humid climates where the straightforward response to discomfort in this climate, such as in Ghana, has been the adoption of air conditioners and mechanical cooling. This approach, along with following the provisions of current international comfort standards, has resulted in higher electricity demand and excessive emissions of greenhouse gases into the atmosphere. This paper presents an adaptive thermal comfort field study in library buildings in the tropical Aw climate of Kumasi, Ghana considering naturally-ventilated (NV) and air-conditioned (AC) buildings. The proposed models in this study are compared with existing studies and current international standards. Using the Griffiths coefficient of 0.5, the mean neutral temperature of 27.4 °C and 30.3 °C were predicted for AC and NV mode, respectively. Although Fanger's predicted mean vote (PMV) method overestimates the extent of changes in thermal sensation votes (TSV) by indoor operative temperature in AC mode, the neutral temperature predicted from PMV (27.8 °C) is analogous to the one estimated using TSV. The adaptive equations for Kumasi's hot and humid climate predict higher slopes of 0.17 K−1 and 0.41 K−1 in AC and NV modes, respectively, than the standards; this indicates that the Ghanaian respondents were more sensitive to the outdoor temperature changes. The average difference of 2.1 °C in AC mode and 1.8–3.3 °C in NV mode were estimated when comparing the proposed model with those in the international standards

Thermal comfort evaluation in architectural studio classrooms – A summer study in a warm to moderate Indian climate

This paper reports the findings from a thermal comfort field study conducted in institutional studio classrooms in the warm-to-moderate climate of Tumkur in Karnataka, India. A total of 506 datasets were obtained in the questionnaire survey consisting of students of architecture. The survey was carried out during the hot-dry months of March, April and May 2019 using subjective questionnaires during which indoor environment variables were measured simultaneously in accordance with ASHRAE Standard 55 Class II protocols. A comfort temperature of 30.4°C was obtained using Griffith’s method, and the comfort band was found to be between 25.0°C to 32.5°C on the central sensation scale for 80% acceptability for the summer (hot-dry) season. Subjects showed greater tolerance and adaptation to warmer conditions with the main means of adaptation by opening windows, wearing lighter clothing, use of ceiling fans, drinking of cold water and use of curtain blinds. Comparison of the field study results with international standards shows that the standards failed to capture the comfort limits and adaptations of subjects in tropical climates of India. Findings of the present study bear significance in developing guidelines for thermal comfort for institutional buildings in the warm-to-moderate climate of India.

Field Study of thermal comfort of indoor fitness places in cold region

A healthy body is the foundation of everything. The indoor environment comfort of fitness places has been paid more and more attention. However, there is a lack of relevant standards for the thermal environment of indoor sports and fitness venues in China, especially the research on the indoor thermal environment in different seasons. Therefore, in our study, physical environment parameters such as indoor temperature and humidity, black ball temperature, air flow rate and CO2 concentration in 9 indoor fitness places in Xi ‘an in different seasons were measured on site. At the same time, a subjective questionnaire survey was conducted on thermal sensation and acceptability of the people who were exercising in the fitness places. Through subjective questionnaire analysis, respondents generally have a high degree of satisfaction and acceptance of temperature, and the average thermal comfort vote is the highest when the indoor temperature is 17.9-23.9°C. In addition, the thermal comfort of different sports in the same space also has certain differences. The fitness people indoor have lower satisfaction with air flow and air quality. Based on the study of the factors affecting indoor thermal comfort, this paper puts forward the improvement strategies for improving indoor thermal comfort, and provides scientific basis for the design and operation of fitness venues.

Predicting thermal satisfaction as a function of indoor CO[formula omitted] levels: Bayesian modelling of new field data

In the pursuit of mitigating the performance gap between model-predicted thermal comfort and measurements of perceived thermal comfort, recent studies have investigated the multi-domain nature of thermal comfort and IEQ. This paper presents an update to a recent work that applied Bayesian logistic regression to examine possible independent correlations between perceived thermal comfort of building occupants and metrics of indoor environmental quality (IEQ) such as CO2 concentrations. The prior work made use of the COPE dataset, a 20-year-old field database of objective and subjective IEQ measurements collected from approximately 800 occupants of open-plan offices in large Canadian and US cities. This study updates that work with a new IEQ field study of 141 workstations carried out at the University of British Columbia across 2019 and 2020. In addition, a new, hierarchical (multi-level) Bayesian logistic regression model is formulated and applied. The new results not only increase the credibility of observing measurements of CO2 concentrations to improve predictions of thermal satisfaction in the original COPE dataset, but that the credibility of this evidence is strengthened on the addition of the new data. At indoor temperatures of 23.5 °C, the probability of an occupant feeling thermally satisfied at measured CO2 levels of 550 ppm was 0.62 [0.54 - 0.69, 95% CrI]. This decreased to 0.28 [0.17-0.42, 95% CrI] at 750 ppm.This study does not suggest these observations are generalizable outside the COPE and UBC datasets, nor does it suggest that CO2 must be affecting occupants physiologically or psychologically to cause these observations. However, it is suggested that CO2 levels may remain overlooked as a contextual, or latent variable for the real-time prediction of perceived thermal comfort in buildings. For instance, prior research has observed a relationship between indoor CO2 levels and perceived air quality as well as a relationship between multiple perceptual factors of IEQ, such as air quality and thermal comfort. If the findings of this paper continue to be found in future studies, measurements of CO2 concentrations may be used to improve the accuracy of thermal comfort prediction models. The core recommendation for future work is therefore to expand measurements in future thermal comfort field studies to include, at least, measurements of indoor CO2 levels. A greater dataset is needed to determine whether the findings of this study are possibly universally applicable, and/or whether knowledge of indoor CO2 concentrations may improve personalized models of thermal comfort that are building- and context-specific.

Comfortable and partial warm environment increases salivary S-IgE concentration in healthy adults

An indoor thermal environment stimulates the human endocrine system, thermoregulation system, and nervous system, which significantly affects immunity. However, the effect of environmental temperature on immunity was not included in the field study of thermal comfort. To achieve this, we considered three different temperatures (18, 24, and 30 °C). Skin surface temperature, unstimulated whole saliva, thermal sensation vote, and thermal comfort vote from ten subjects under each condition were acquired simultaneously. The same subjects and experiment were repeated once in different years. Salivary secretory immunoglobulin E (S-IgE) concentration was measured using an enzyme-linked immunosorbent assay. Our results indicate that environmental temperature significantly affected salivary S-IgE concentration (P = 0.015), When the environmental temperature increased from 18 to 24 to 30 ℃, the IgE concentration in saliva gradually increased. The S-IgE concentration was the highest when the thermal sensation and thermal comfort were close to neutral and comfortable, which was 143.7% higher than the very uncomfortable. The S-IgE concentration was significantly positively correlated for thigh, back, forehead temperature, and average skin temperature (P = 0.023, P = 0.045, P = 0.021, P = 0.018, respectively). A comfortable and warm environment may enhance oral mucosal immunity by increasing the concentration of S-IgE in the saliva.

ASHRAE Likelihood of Dissatisfaction: A new right-here and right-now thermal comfort index for assessing the Likelihood of dissatisfaction according to the ASHRAE adaptive comfort model

The assessment of local and short-term thermal discomfort in buildings has been widely investigated, and different metrics are available in the literature to predict the likelihood of dissatisfied people. These metrics are named right-here and right-now discomfort indexes and constitute the basis for evaluating long-term thermal comfort conditions in buildings. Well-known examples are the Predicted Percentage of Dissatisfied (PPD) part of the Fanger comfort model included in the ISO standard 7730 and the Overheating risk index (NaOR), built upon the EN adaptive thermal comfort model. This study proposes a new index for use with the ASHRAE adaptive thermal comfort model to fill a gap in the literature and standard. It is called the ASHRAE Likelihood of Dissatisfaction (ALD) and is obtained from a logistic regression of the right-here and right-now thermal comfort field data contained in the 1990s ASHRAE RP-884 database. The recent release of another, more extensive database of thermal comfort field studies, the ASHRAE Global Thermal Comfort Database II, provides an opportunity to validate ALD with an independent dataset and assess its generalisability. The successful external validation of ALD and its agreement with NaOR give support to the reliability of the novel right-here and right-now index and open to the possibility to use it for assessing short-term thermal comfort conditions in buildings, calculating long-term thermal comfort indices based on the ASHRAE adaptive model, optimising both the design of new buildings and renovations and for assessing the operational thermal comfort performance of existing buildings.

A field study on adaptive thermal comfort in Spanish primary classrooms during summer season

The assessment of indoor thermal comfort in schools has become an essential object of study; however, applying existing thermal comfort criteria would assume children and adults have a similar range of thermal comfort, without considering discrepancies regarding their level of activity or their behavioural adaptation. Therefore, the objective of the present study was to investigate the thermal comfort in a school building based on an adaptive thermal comfort field study in Seville, in the southwest of Spain, during a summer season. In this study, 2 free-running and 1 air-conditioned classroom were analysed; 67 students aged 10–11 years participated and 2010 thermal questionnaires were collected. A discrepancy was observed between the predicted mean vote and the thermal sensation vote, showing the former is not a good predictor of thermal perception. Thermoneutrality was not always the desired sensation for children; a preference for coolness was detected. A neutral temperature was observed at an average indoor temperature of 24–27 °C and a widening in the thermal comfort range was detected compared with international standards. Regarding adaptive strategies, they showed a preference towards opening windows and doors over using fans or changing clothes. The results suggest that the application of the current models for adults would not be suitable for estimating the thermal comfort of children, and these data could be used to promote natural strategies for assessing thermal comfort over conditioning systems in schools, with the aim of both space ventilation and energy efficiency.

Adaptive thermal comfort study of workers in a mini-industrial unit during summer and winter season in a tropical country, India

Providing a comfortable thermal environment to workers for better health and productivity is one of the necessary conditions for sustainable industrial development. However, there is a dearth of field studies on the thermal comfort status and adaptation of workers in naturally ventilated industrial buildings across the world. Therefore, an adaptive thermal comfort field study in a mini-industrial unit factory, located in the composite climate of India, was conducted in the hot summer and cold winter seasons. Overall, 1276 valid subjective responses were collected from 325 factory workers during the field measurements and survey. We found a seasonal comfort temperature variation of more than 9.5°C with a mean comfort temperature of 32.2°C. The mean preferred temperature was observed about 2.5°C lower than their mean comfort temperature. The adaptive comfort relation suggested that surveyed factory workers had a high thermal adaptation owing to the combined effect of behavioural adjustments and elevated airspeed. A logistic regression analysis was carried out to predict the fan use behavior by the workers during the hot summer season. Since the study duration also lies in the COVID-19 pandemic period, an effort has been made to quantify the psychological and behavioural changes of workers due to the COVID-19 pandemic situation at their workplace through a questionnaire-based study.

Field investigation on thermal comfort of passengers in an airport terminal in the severe cold zone of China

Numerous airport terminals are being constructed in China. However, the current Chinese standards do not specify an indoor comfort zone for airport terminals. Therefore, this study aims to understand the thermal comfort demand of passengers and provide references for designing an indoor thermal environment in airport terminals. We selected typical periods in May 2019, August 2019, and January 2020 to conduct a thermal comfort field study in an airport terminal in the severe cold zone of China. 640 valid questionnaires were collected in the departure lounge during different seasons, and 625 valid questionnaires from different functional zones during winter were analysed. The neutral Top of passengers was 25.6 °C, 23.7 °C, and 17.7 °C in the departure lounge in summer, transition season, and winter, respectively. The 80% and 90% acceptability ranges of passengers in the departure lounge in transition season and winter were wider than in summer, indicating that passengers were easily adaptable to the indoor environment. Differences are observed in the thermal comfort demands of passengers with different dwell times. Because of the difference in metabolic rates, the preferred temperature in the baggage reclaim (16.2 °C) was lower than in the check-in hall and departure lounge (20.3 °C and 20.7 °C, respectively) during winter. This indicates that different design parameters should be developed according to the characteristics of the metabolic rate and dwell time in different functional zones. The findings from this study show excellent energy-saving potential in airport terminals in winter.

A thermal comfort field study on subway passengers during air-conditioning season in Beijing

With the massive increase of subway passengers in large Chinese cities, thermal comfort in the subway has become an important topic. The thermal comfort of subway passengers is different from that in above-ground buildings and has its own particularities, as the subway comprises of underground semi-closed buildings. Moreover, the thermal environment experienced by passengers is dynamic. Considering these reasons, this study adopts a dynamic thermal comfort study method for investigating thermal sensations in the subway. The field study was conducted in two Beijing subway stations in May 2016 and June–July 2017, and a total of 628 samples were obtained. Variations in thermal sensation and thermal comfort were analyzed. The results showed that the thermal sensations of subway passengers change dramatically through the entire process, and alternate between hot and cold. For the station hall and platform, although the temperature and the relative humidity were beyond the standard range of the "Code for Design of Metro in China" (GB50157- 2013), passengers find them acceptable. The study also provides reliable basic data for the design and operation management of ventilation and air-conditioning systems in the subway station, so as to create a comfortable thermal environment for subway passengers.