Thermal Comfort Studies Research Articles

Thermal comfort and gender affirmation: A virtual ethnography of extreme heat among trans women in Rio de Janeiro

The multisensory experience of feeling hot, breathless, sweaty, and weak during heat spells among transgender people is a critically understudied area in both medical anthropology and thermal comfort research. This article contributes to the anthropology of heat and humidity by intersecting with health and thermal comfort studies. Through virtual ethnography with three trans women in Rio de Janeiro in 2021 and 2022, the research reveals that trans women in the city face heightened risks of heat stress and thermal discomfort due to unsafe living conditions, side effects of gender-affirming modifications, and social discrimination. These findings highlight the urgent need to address the specific challenges transgender individuals face in accessing thermal safety and underscore the importance of considering their unique needs.

Revaluation of Vernacular Architecture in a Hot Humid Climate in Villa Rica - Peru: A Study of Thermal Comfort Compared to Confined Masonry

Revaluation of Vernacular Architecture in a Hot Humid Climate in Villa Rica - Peru: A Study of Thermal Comfort Compared to Confined Masonry

Comparative study of outdoor thermal comfort: Residents vs. tourists at Xi'an Ming Dynasty Ancient city wall scenic area

This study explores the thermal perceptions and comfort of residents and tourists at the Xi'an Ming Dynasty Ancient City Wall Scenic Area, addressing a gap in comparative outdoor thermal comfort studies in historical settings. Meteorological measurements and questionnaires collected between July 2019 and March 2021 analyze physical, individual, social, and psychological factors influencing thermal sensation, comfort, and acceptability across seasons. The RayMan model calculates Physiological Equivalent Temperature (PET), with data analyzed using SPSS 27.0. Results show Neutral PET (NPET) values of 17.1 °C for residents and 18.6 °C for tourists, and Preferred PET (PPET) values of 18.4 °C and 20.8 °C, respectively. Thermal Acceptability Ranges (TAR) are 13.5 °C–26.7 °C for residents and 15 °C–24.1 °C for tourists. Whether the measurement space contains water sources significantly affects temperature and humidity, while vegetation impacts wind speed. Physical factors predominantly affect perceptions, with individual factors becoming more important for tourists in winter. The findings provide insights for optimizing the thermal environment in scenic open spaces to enhance the comfort of both residents and tourists.

Investigation of thermal comfort and preferred temperatures among rural elderly in Weihai, China: Considering metabolic rate effects

As the population ages, the thermal environment indoors for the elderly has garnered extensive attention. However, current research on thermal comfort for the elderly is not comprehensive, particularly for rural elderly individuals who experience unique thermal perceptions and adaptation behaviors due to physical changes. Moreover, metabolic rates, which are often overlooked in thermal comfort studies for the elderly, play a crucial role. A year-long survey of thermal comfort was conducted in the rural areas of Weihai, a coastal city in China's cold region, collecting 203 questionnaires. Three different values of metabolic rates (recommended values, estimated values, and values calculated using Basal Metabolic Rate and Physical Activity Ratio) were analyzed. The results demonstrate that the Basal Metabolic Rate and Physical Activity Ratio method provides predictions of thermal sensation that more closely align with actual thermal sensations. The adaptive coefficient of the aPMV model was found to be −0.38 in colder environments and 0.272 in warmer ones. Additionally, using PMV regression, TSV regression, and Griffiths' method, we calculated the local elderly's comfort temperatures to be 18.9 °C (15.43–22.57 °C), 19.3 °C (15.16–22.75 °C), and 21.63 °C (21.34–23.49 °C) respectively. This study introduces a straightforward method for calculating metabolic rates in elderly individuals, offering new insights for research on thermal comfort in the elderly and expanding the database for thermal comfort studies. It lays a foundation for future design and standardization of housing for rural elderly populations.

Approach on enhancing the air conditioning system to improve the winter thermal environment in Eastern China Region's airport terminals

Passengers typically spend much time in commercial zones of terminals for retail, meals, and other services. Enhancing the study of thermal comfort in this local space is necessary. The climate in the Eastern China Region is variable and complex, making it more challenging to maintain the indoor thermal environment. This study conducted field measurements in winter in a commercial zone of one terminal to assess the thermal environment. Numerical simulations and PMV-PPD analyses were performed using the Computational Fluid Dynamics (CFD) program The results showed that the overall humidity in the commercial zone was low. There were notable differences in the temperatures and velocities of supply air among different air vents on the commercial island. Based on these initial conditions obtained by measurements, the simulations showed that localized areas under the breathing plane are either too hot (24°C and above) or too cold (18°C and below). The dissatisfaction percentage of the population exceeds 27%. This paper proposed that through enhancements in the air vent dimensions, layout, and air supply conditions, the temperature can be maintained in the range of 20-24°C. Furthermore, the PMV could be controlled within the range of -0.5 to 0.5. PPD was below 10%, reflecting compliance with Class I heating standards. Overall, findings from this study provide a less costly modification for thermal comfort improvement in commercial zones, and serve as a reference for the design and operation of air-conditioning systems to ensure thermal comfort in airport terminals’ commercial zones.

Thermal insulation provided by chairs with various clothing ensembles

The thermal insulation provided by chairs significantly influences human thermal comfort. On the one hand, it modifies the heat exchange mechanism at the contact points between the body and the chair surface. On the other hand, an increase in local thermal insulation can exacerbate differences in thermal insulation across various areas of the body, impacting overall comfort. However, the thermal insulation data for chairs are decades old and thus need to be updated to reflect modern designs and materials. Six typical office chairs were tested using a thermal manikin dressed in five typical clothing ensembles (ranging from summer to winter). The effective thermal insulation of the chairs varied between 0.04 and 0.14 clo when tested in the nude. The added values ranged from 0.04 to 0.30 clo when tested with different clothing ensembles. Higher clothing levels correspond to higher added chair thermal insulation. Therefore, a simple weighing method was developed to adjust the seasonal coefficient of the mean chair insulation value (0.75 in summer, 1.0 in transition, and 1.25 in winter). Furthermore, a simple model was established for calculating the overall clothing level for a seated person. The model was validated using data measured in this experiment and other external sources, with a minimum prediction mean error of 1.4 %. This study provides a reference for accurately acquiring the thermal insulation value of chairs for a seated person in thermal comfort studies.

Study of indoor local thermal comfort for impinging jet ventilation combined with ductless personalized ventilation under different cooling loads

Excessive temperature stratification and draught are two prominent drawbacks for impinging jet ventilation (IJV). Using IJV together with ductless personalized ventilation (DPV) (i.e., IJV + DPV) has been proved to be an effective way to reduce temperature stratification, but the draught rate around occupant would be increased. In the current work, an in-depth study on the characteristics of indoor local thermal comfort for IJV + DPV operating with different scenarios is done. Predictive models for the local thermal comfort indicators are developed to optimize the operating parameters (including supply velocity of IJV (Vs) and intake airflow rate of DPV (Df)) with different room cooling loads (Q). The results show that the application of IJV can be extended to spaces with high cooling loads (e.g., larger than 60 W/m2) by using together with DPV, but the risk of thermal discomfort increases. To avoid local thermal discomfort, the combination relationship between Vs and Df should be properly matched and this relation becomes more stricter with the increase of Q. It also obtains that the maximum cooling load that IJV + DPV can eliminate is less than 170 W/m2. At last, to ensure the IJV + DPV create a good local thermal comfort environment, design chart about the feasible ranges of Vs and Df are established for different values of Q. On the whole, the current study not only can provide a basis for the application of IJV + DPV in spaces with high cooling load, but also can provide theoretical guidance for the operation control and optimization design of the IJV + DPV.

Progress and Future Prospects of Habitat Thermal Comfort Research

This paper is a comprehensive study in the topic of human environment and thermal comfort. Firstly, it introduces the concept of thermal comfort and its key role in human environments, and describes the influence of different factors on thermal comfort; secondly, it discusses the commonly used methods of thermal comfort assessment and the assessment indexes in different hot and humid environments; furthermore, it discusses the technologies and strategies to improve thermal comfort, such as the design of ventilation and air-conditioning systems as well as the green building materials, and so on. This paper intends to give a complete literature review for the study of human environment and thermal comfort, and to provide references and recommendations for future research and practice in related domains.

Study of thermal comfort in some standard school buildings: A case of Madagascar island

Study of thermal comfort in some standard school buildings: A case of Madagascar island

WRF-Comfort: simulating microscale variability in outdoor heat stress at the city scale with a mesoscale model

Abstract. Urban overheating and its ongoing exacerbation due to global warming and urban development lead to increased exposure to urban heat and increased thermal discomfort and heat stress. To quantify thermal stress, specific indices have been proposed that depend on air temperature, mean radiant temperature (MRT), wind speed, and relative humidity. While temperature and humidity vary on scales of hundreds of meters, MRT and wind speed are strongly affected by individual buildings and trees and vary on the meter scale. Therefore, most numerical thermal comfort studies apply microscale models to limited spatial domains (commonly representing urban neighborhoods with building blocks) with resolutions on the order of 1 m and a few hours of simulation. This prevents the analysis of the impact of city-scale adaptation and/or mitigation strategies on thermal stress and comfort. To solve this problem, we develop a methodology to estimate thermal stress indicators and their subgrid variability in mesoscale models – here applied to the multilayer urban canopy parameterization BEP-BEM within the Weather Research and Forecasting (WRF) model. The new scheme (consisting of three main steps) can readily assess intra-neighborhood-scale heat stress distributions across whole cities and for timescales of minutes to years. The first key component of the approach is the estimation of MRT in several locations within streets for different street orientations. Second, mean wind speed and its subgrid variability are downscaled as a function of the local urban morphology based on relations derived from a set of microscale LES and RANS simulations across a wide range of realistic and idealized urban morphologies. Lastly, we compute the distributions of two thermal stress indices for each grid square, combining all the subgrid values of MRT, wind speed, air temperature, and absolute humidity. From these distributions, we quantify the high and low tails of the heat stress distribution in each grid square across the city, representing the thermal diversity experienced in street canyons. In this contribution, we present the core methodology as well as simulation results for Madrid (Spain), which illustrate strong differences between heat stress indices and common heat metrics like air or surface temperature both across the city and over the diurnal cycle.

Investigating the impact of a large river and its surrounding contextual conditions on pedestrians’ summer thermal perceptions in a Cfa-climate city

Thermal comfort studies are usually employed to find subjective thermal responses [indicated by neutral temperature (NT), i.e. the temperature with no thermal stress] of residents from a region towards thermal environments. According to the recently published works in the literature, NTs are affected by many factors, such as geographical location and microenvironments. To elucidate the origins of these effects, the impact of microenvironment elements around a water surface on pedestrians’ thermal perceptions was systematically investigated in this work. The Fujiang River (FJR) in Mianyang City was taken as the sample site. The municipal meteorology station is located next to the site by around 2.5 km. By performing meteorology measurements combining questionnaires, it was found that the riverside NT (indicated by physiologically equivalent temperature, PET) of Mianyang in the summer of 2023 was 21.4 °C. The relationship between the distance from the water (DFW) and NT was quadratic linear. The same phenomenon took place by using either PET or Universal Thermal Climate Index (UTCI) indexes. Meanwhile, the meteorological contexts also affected NTs, including relative humidity (RH) and air velocity (Va). Regarding RH, the NPET increased from 15.2 °C (RH = 50%) to 26.9 °C (RH = 90%). In contrast, the NPET dropped from 23.0 to − 50.6 °C when the Va increased from 0.2 to 2.5 m/s, respectively. From our analysis, it was demonstrated that human thermal responses are significantly affected by both the microenvironmental and meteorological backgrounds around the water surface. Our work provides valuable insights for the proper use of water surfaces in urban design for adjusting thermal comfort.

A Systematic Review of Outdoor Thermal Comfort Studies for the Urban (Re)Design of City Squares

In the upcoming period, city squares’ urban redesign will be crucial in achieving sustainable development goals. This study presents a systematic review of OTC-related studies for the urban design of city squares using the PRISMA 2020 methodology. A review included a total of 173 papers from 2001 to 2023. The results identified five study types—clusters based on four pre-defined criteria: study approach, data collection methods, time duration, and primary objectives. The clusters indicate that more than half of all studies are related to the comparison of thermal comfort and heat mitigation measures. Most of the case studies were located in one of three climate zones: temperate oceanic (Cfb) (58 studies), hot summer Mediterranean (Csa) (40 studies), or humid subtropical (Cfa) (28 studies). The most common geometry of the analyzed urban square is medium-sized, is rectangular, and has dominant axel orientation south–north. Also, based on all five clusters, several research gaps were identified, appropriate for future research: the majority of studies related to the traditionally considered climate areas, no typology of urban square geometry configuration based on OTC assessment, and the lack of a local design model for assessing and improving the thermal comfort of city squares.

Numerical study of thermal comfort and energy efficiency about electrically heated footwear under a cold environment

PurposeThe paper aims to reveal the relationship among energy efficiency, thermal comfort and thermal regulation of electrically heated footwear and to investigate influencing factors on the energy efficiency and thermal comfort.Design/methodology/approachA finite volume model was proposed to simulate the two-dimensional heat transfer in electrically heated footwear (EHF) under an extremely cold condition. The model domain consists of three-layer footwear materials, a heating pad, a sock material, an air gap and skin tissues. Model predictions were verified by experimental data from cold-contact exposure. Then the influencing factors on the energy efficiency and thermal comfort were investigated through parametric analysis.FindingsThe paper demonstrated that the skin temperature control (STC) mode provided superior thermal comfort compared to the heating pad temperature control (HPTC) mode. However, the energy efficiency for the HPTC mode with a heating temperature of 38 °C was 18% higher than the STC mode. The energy efficiency of EHF while reaching the state of thermal comfort was strongly determined by the arrangement and connection of heating elements, heating temperature, thickness and thermal conductivity of footwear materials.Originality/valueThe findings obtained in this paper can be used to engineer the EHF that provides optimal thermal comfort and energy efficiency in cold environments.

Thermal Comfort Assessment of UPM Engineering Library in Tropical Climate Conditions

Thermal comfort is the study of indoor comfort level feel by the occupant in a room. This paper presents the study of thermal comfort that had been carried out in the library of engineering faculty at Universiti Putra Malayia in Serdang, Malaysia. The study was made in 4 days from 9 am to 11 am on October and November. This study was carried out to assess their thermal conditions during the occupants’ study hours. Thermal comfort variables were measured during study hours too. Qualitative and Quantitative data analysis showed that engineering library meet the requirement of comfort zone thermal conditions of ASHRAE standard 55 and ISO 7730. The result shows the environmental condition of the library is neutral to slightly warm in 4-point ASHRAE scale. The linear regression between Predicted Mean Vote and Operative Temperature reveals that the maximum acceptable temperature in this field of study is 26.5ºC.

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.

Thermal comfort study of urban waterfront spaces in cold regions: Waterfront skyline control based on thermal comfort objectives

In waterfronts, thermal comfort is affected by climate and urban morphology. Existing studies on waterfront thermal comfort have mainly focused on warm and hot regions, focusing on the cooling effects of water and vegetation during the summer. The research methods are mostly questionnaire surveys and simulations, whereas the urban form and climate characteristics of cold regions are rarely considered, and the results of these studies are seldom applied to design practices. This study focused on the thermal comfort of waterfronts in cold regions. Computational Fluid Dynamics, Mean Radiant Temperature, and the Universal Thermal Climatic Index were used to examine the effects of tree–water features (winter river ice and tree defoliation) on thermal comfort in cold regions, and correlation analyses were combined to screen for relevant urban morphology factors for waterfront thermal comfort. Regression analyses were conducted to understand the influence of six factors, namely, building orientation, floor area ratio, open space ratio, building height to distance between river and building ratio, standard deviation of the first building row, and vegetation concentration, on waterfront thermal comfort. After training and comparing the four thermal comfort prediction models, a genetic algorithm combined with an artificial neural network was applied to optimize the design of the urban morphology of the six waterfront blocks. The optimization improved the waterfront thermal comfort performance by 22%, 7%, 77%, 106%, 3%, and 3%, respectively.

The Study of Thermal Comfort in a Common Commercial Car Cabin: Looking at Malaysia’s Perspective

Assessing thermal comfort in vehicles poses unique challenges compared to buildings. The in-car environment is characterized by specific factors such as sunlight exposure, poor clothing insulation, non-uniform average radiant temperature, and limited time to establish comfort parameters. To address these challenges, this study aims to evaluate thermal comfort in different branded car cabins by analyzing temperature distribution, air velocity, relative humidity, and dew point temperature. A comprehensive review of literature was conducted, focusing on various aspects including airflow regimes, factors influencing thermal comfort, measuring instruments, and comfort indices. Understanding these factors is crucial for developing comprehensive methodologies to assess thermal comfort and indoor air quality in vehicle cabins. The results of the study indicate that MPV cars offer superior comfort levels within the optimal range of -1 to +1, surpassing sedans and compact cars. These findings are instrumental in guiding design and engineering decisions to improve passenger comfort in vehicles. Tailoring the design of different car types to meet the specific comfort requirements can lead to enhanced overall comfort and satisfaction. In conclusion, this study provides valuable insights into assessing thermal comfort and indoor air quality in vehicle cabins. By addressing the unique challenges posed by the in-car environment, it offers guidance for designing and engineering vehicles that prioritize passenger comfort and well-being.

A systematic review of microclimate and outdoor thermal comfort studies in Australia and New Zealand

PurposeGiven the distinct and unique climates in these countries, research conducted in other parts of the world may not be directly applicable. Therefore, it is crucial to conduct research tailored to the specific climatic conditions of Australia and New Zealand to ensure accuracy and relevance.Design/methodology/approachGiven population growth, urban expansions and predicted climate change, researchers should provide a deeper understanding of microclimatic conditions and outdoor thermal comfort in Australia and New Zealand. The study’s objectives can be classified into three categories: (1) to analyze previous research works on urban microclimate and outdoor thermal comfort in Australia and New Zealand; (2) to highlight the gaps in urban microclimate studies and (3) to provide a summary of recommendations for the neglected but critical aspects of urban microclimate.FindingsThe findings of this study indicate that, despite the various climate challenges in these countries, there has been limited investigation. According to the selected papers, Melbourne has the highest number of microclimatic studies among various cities. It is a significant area for past researchers to examine people’s thermal perceptions in residential areas during the summer through field measurements and surveys. An obvious gap in previous research is investigating the impacts of various urban contexts on microclimatic conditions through software simulations over the course of a year and considering the predicted future climate changes in these countries.Originality/valueThis paper aims to review existing studies in these countries, provide a foundation for future research, identify research gaps and highlight areas requiring further investigation.

Impact of Energy-Consuming Air Conditioning Systems on People's Thermal Comfort and Preferences: Comparative Study of Iraq and Gulf Cooperation Council Countries

This study investigates the impact of the intense usage of air-conditioning systems on the thermal comfort requirements of building occupants. It compares the thermal comfort requirements of building occupants in Iraq and Gulf Cooperation Council (GCC) countries. Iraqis have limited usage of air-conditioning units, whilst people in GCC countries intensely operate these systems. Research work underpinning this article involved undertaking a year-long thermal comfort survey in Iraq, and an intensive analysis of thermal comfort studies conducted in GCC countries. Results show that, in Iraq, people experience a 2–50 °C annual indoor temperature range, and their annual comfort range is 14–35 °C. In GCC countries, due to the intense usage of air-conditioning systems, the widest recorded annual indoor temperature range is 17.2–31.0 °C, and the widest annual comfort range is 20.0–27.8 °C. These results demonstrate the significant impact of air-conditioning systems on narrowing the thermal comfort limits of building occupants leading to high energy consumption. This study presents a novel comparison between two cases highlighting the impact of air-conditioning systems on the thermal comfort requirements of building occupants. The results of this study can be used to inform the development of thermal comfort standards that better consider people’s adaptation capabilities to help reduce energy consumption for heating and cooling purposes.

A Systematic Review on the Studies of Thermal Comfort in Urban Residential Buildings in China

There have been fruitful publications on thermal comfort of urban residential buildings in China. However, there is a lack of reviews on this topic to perform a comprehensive analysis and find opportunities to meet occupants’ thermal comfort needs while improving building energy efficiencies. This paper addresses this issue by presenting a systematic review on the advancements in research on thermal comfort in urban residential buildings in China. Firstly, two common thermal comfort research approaches, i.e., field studies and laboratory studies, are discussed. Secondly, eleven main thermal comfort evaluation indicators are summarized. Finally, this paper analyzes the thermal comfort survey data from different researchers, discusses the impacts of adaptive behaviors on human thermal comfort, and provides recommendations for future research on urban residential thermal comfort. It was found that people have higher and higher requirements for their indoor thermal environment as time goes by, especially in the winter; the thermoneutral temperature is higher in warmer climate regions in the summer but lower in the winter than in colder climate regions; the thermoneutral temperature tends to increase with the indoor air temperature due to an adaptation to the indoor thermal environment. The outcomes of this paper provide valuable information on thermal comfort behaviors of urban residents in different climate zones in China, which can serve as a resource for the academic community conducting future research on thermal comfort and assist policymakers in enhancing building energy efficiencies without compromising the occupants’ comfort.