Thermal Comfort Assessment Research Articles

An assessment of Users’ Satisfaction with the Thermal Comfort of Selected Lecture Theatres in Ahmadu Bello University Zaria, Nigeria

Thermal discomfort in lecture theatres can create unsatisfactory conditions for effective learning. Achieving a thermally comfortable indoor environment in any building is of great importance for all building users. However, this has become a complex task in educational buildings. This study assessed the thermal comfort parameters in 6 lecture theatres of the main campus of Ahmadu Bello University, Zaria. The study adopted both the objective and subjective approach of thermal comfort assessment. Checklist was used to characterize lecture theatres while measuring devices were used to collect data on air temperature, relative humidity, and air velocity. A total 510 questionnaire was used to collect data on users’ perception on thermal sensation. Findings from the objective assessment for morning and afternoon sessions, showed that the indoor air temperature, relative humidity, and air velocity were in the range of 27.53oC to 35.59oC, 35.29% to 55.34%, and 0.01 m/s to 1.23 m/s respectively. Findings from the subjective assessment showed the thermal sensation vote to be 28.4% and 18.6% for morning and afternoon votes respectively. Results from the inferential statistical analysis showed significant differences (p≤0.05) in the mean value of the thermal comfort parameters measured across all the theatres. The study recommended that natural ventilation should be adequately augmented with sufficient mechanical ventilation systems in the lecture theatres to enhance the thermal condition of the indoor spaces. Also, future designs of lecture theatres should comply with accepted standard for achieving optimum thermal comfort.

Optimization design of waterfront tour routes under thermal comfort assessment in summer—a case study of West Lake in Hangzhou, China

ABSTRACT The existing research on waterfront tour route planning suggests that thermal comfort assessment has a direct impact on people’s outdoor tour experiences. It contributes to understanding the thermal comfort regulation mechanisms of landscape nodes and the scientific planning of tour routes. However, the research in this area is relatively limited and faces complex issues in data processing and analysis. This study takes the West Lake waterfront tour route in Hangzhou, China, as an example. Through empirical research, it validates the feasibility of tour route planning guided by thermal comfort. It employs field surveys, on-site measurements, and data analysis methods primarily based on the Rayman software to explore the relationship between urban outdoor waterfront spaces and microclimates. The study reveals the following findings: (i) Extensive water bodies surrounding an area positively regulate local microclimates. The closer one is to the water and the more water surrounds the area, the stronger the microclimate effect. (ii) Factors such as spatial openness, waterfront orientation, prevailing monsoons, etc. all have certain impacts on the microclimates of the lake and lakeside spaces. (iii) Air temperature has significant variability in its impact on human thermal comfort, with different PET (Physiological Equivalent Temperature) values at each measurement point during different time periods. The study combines the actual human thermal comfort conditions at eight measurement points around the lake with existing tour routes. It proposes two practical tour route optimization designs based on real tour microclimate factors. These designs employ thermal comfort assessment methods to effectively enhance and improve human thermal comfort during tours. This research carries social value and provides new insights for mitigating urban waterfront space microclimates, enhancing tour comfort, and improving landscape environments.

Design strategies for renovation of public space in Beijing's traditional communities based on measured microclimate and thermal comfort

This paper proposes design strategies for renovating traditional communities in Beijing based on measured microclimate and thermal comfort and preserving historical authenticity to empower residents to make autonomous decisions about the renovation process. Based on the collected data from 11 hutongs and 102 courtyards in Dongcheng District, 4 representative courtyards and 2 representative hutongs are summarized. Microclimate data were collected in the representative months of January and September 2022. The design guidelines for 4 courtyards and 2 hutongs design guidelines, including 20 renovation modes, are proposed through on-site measurement and thermal comfort analysis. Due to the difference in microclimate, the proposed design guidelines can only be applied to the public space of traditional communities in Beijing but not to the public space in traditional villages in the suburbs. The application of the results also faces two challenges: the willingness of the public to participate in the renovation work and the demolition of illegal buildings. This study emphasizes human comfort as a factor to be considered in renovation projects. This study provides a standardized method for public space renovation in historic districts through microclimate analysis and thermal comfort assessment.

Thermal Comfort Assessment in University Classrooms: A Discriminant Analysis for Categorizing Individuals According to Gender and Thermal Preferences

The concern with the well-being of users in buildings has become increasingly essential, covering aspects related to health, energy efficiency, and productivity. The thermal environment evaluation in buildings has become more frequent due to the time people spend inside them. In this context, this study aimed to analyze thermal comfort in classrooms at a Brazilian University. During the autumn, 50 measurements were performed, resulting in 519 valid responses. The results of the linear regression analysis revealed that the thermal comfort range for females was 20.39–22.19 °C, while for males it was 19.47–22.56 °C. Through discriminant analysis, participants were classified based on their thermal sensation vote (TSV), predicted mean vote (PMV), and thermal preference votes (PREF), achieving a success rate of 76.1% for females and 81.6% for males in forming the groups, which demonstrates the effectiveness of discriminant functions in predicting thermal comfort for both groups. These results highlight the importance of considering gender differences in the search for thermal comfort conditions and providing guidelines that promote the well-being of occupants and the conscious use of energy. This implies adjusting the thermal conditions according to the specific needs of males and females in classrooms, always seeking to provide a suitable environment for activities, and considering energy efficiency and users’ productivity.

Thermal Comfort Assessment in Urban Green Spaces: Contribution of Thermography to the Study of Thermal Variation between Tree Canopies and Air Temperature

Understanding the thermal effects of different urban patterns that constitute today’s urban landscapes is critical to the development of urban resilience to climate change. This article aims to assess the efficiency of urban green spaces in thermal regulation. Through thermography, we explored the interaction between air temperature and the spatial components within these environments. Through comparative analysis involving a UAV, we studied the relationship between air temperatures at varying altitudes and the temperature within tree canopies. The results revealed significant differences in the thermal distribution between impervious urban areas with buildings and green spaces. These findings provide important information for assessing thermal comfort and the efficiency of urban green spaces in mitigating the impact of extreme heat events. During the summer months, green spaces, due to shade and the enhanced absorption of solar radiation by trees, exhibited lower temperatures compared to impervious areas. However, in winter, urban areas displayed higher temperatures, attributable to their heat retention capacity. This study contributes to the existing knowledge base by providing an in-depth examination of the thermal efficiency of urban green spaces across different layers of their lower atmosphere. Our results underscore the crucial role of tree cover in thermal comfort regulation, offering valuable information for sustainable urban planning. These insights are particularly relevant for the design of more comfortable and resilient environments in response to climatic variations and for the crafting of a tree-planting strategy in Mediterranean climate cities, an area where the impacts of climate change are becoming increasingly apparent.

From Building Information Model to Digital Twin: A Framework for Building Thermal Comfort Monitoring, Visualizing, and Assessment

The existing building stock is globally responsible for 17.5% of greenhouse gas emissions due to their operation to achieve occupant satisfaction, thus requiring a vast intervention. However, reducing building stock emissions and optimizing building energy performance cannot be considered independently by the users’ well-being. The thermal comfort conditions and their monitoring represent a central issue that could optimize building energy usage while achieving good indoor environmental conditions. This document describes the first findings of ongoing research focused on the development of a building monitoring system, based on the integration of Building Information Modeling tools and sensor technology through Dynamo Visual Programming. Starting from the development of an Asset Information Model, which represents the virtual replica of a building that currently hosts the administrative offices of the municipality of Cagliari, the first step presented in this contribution shows a thermal comfort monitoring system, scalable and modular, that allows effective gathering and elaboration of data about comfort levels in each of the building’s rooms. The system proves to be a helpful support for facility managers to control building thermal comfort conditions and HVAC systems to assure their best operative status or plan suitable interventions to achieve it.

Assessment of thermal comfort in the traditional and contemporary houses in Byblos: A comparative study

This paper presents a comparative study on the thermal comfort of traditional and contemporary houses in Byblos, Lebanon. With climate change affecting indoor environments and potentially leading to increased energy consumption, achieving optimal thermal comfort is a crucial issue for building research. The study analyzes several environmental parameters and conducts an occupancy survey to assess thermal comfort in both types of houses. The questionnaire used in the survey consists of 46 questions divided into three parts: “Who are you?”, “The environment of your house?”, and “Architectural characteristics of the house.” The results show that traditional houses perform better than contemporary ones in terms of thermal comfort, due to their use of natural and passive methods. However, both types of houses have room for improvement in terms of energy efficiency. This study provides insights into potential solutions for improving indoor thermal comfort while reducing energy consumption in traditional and contemporary houses.

A Novel Data-Driven Model for the Effect of Mood State on Thermal Sensation

Thermal comfort has an important role in human life, considering that people spend most of their lives in indoor environments. However, the necessity of ensuring the thermal comfort of these people presents an important problem, calculating the thermal comfort accurately. The assessment of thermal comfort has always been problematic, from past to present, and the studies conducted in this field have indicated that there is a gap between thermal comfort and thermal sensation. Although recent studies have shown an effort to take human psychology into account more extensively, these studies just focused on the physiological responses of the human body under psychological disturbances. On the other hand, the mood state of people is one of the most significant parameters of human psychology. Thus, this paper investigated the effect of occupants’ mood states on thermal sensation; furthermore, it introduced a novel “Mood State Correction Factor” (MSCF) to the existing thermal comfort model. To this aim, experiments were conducted at a mixed-mode building in a university between 15 August 2021 and 15 August 2022. Actual Mean Vote (AMV) and Profile of Mood States (POMS) were used to examine the effect of mood state on thermal sensation. The outcomes of this study showed that in the mood states of very pessimistic and very optimistic, the occupants felt warmer than the calculated one and the MSCFs are calculated as −0.125 and −0.114 for the very pessimistic and very optimistic mood states, respectively. It is worth our time to note that the experiments in this study were conducted during the COVID-19 Global Pandemic and the results of this study could differ in different cultural backgrounds.

A novel method for calculation of the CO2 concentration impact on correlation between thermal comfort and human body exergy consumption

The majority of studies dealing with the correlation between human body exergy consumption and thermal comfort use adopted, constant values of metabolic rate for appropriate activity level. Taking into account correlations between metabolic rate and the occupant’s exhaled CO2 volumetric flow rate, this study proposes a novel method for the calculation of metabolic rate using measured CO2 concentration in the indoor air. Using measured values of the air and radiant temperature, relative humidity and air velocity, and calculated values of metabolic rate, the human body exergy consumption rate and corresponding Predicted Mean Vote (PMV) are calculated. Moreover, a novel polynomial relation between them is proposed. Results show that metabolic rate values vary in the range of 0.97 to 1.54 met which leads to significantly wider range of PMV and human body exergy consumption rate comparing to the assumed value of 1.2 met for sedentary school activity. According to the obtained relation, the minimal value of the human body exergy consumption rate occurs for PMV = − 0.02. Results of this study imply that treating CO2 concentration as variable does have an impact on the thermal comfort assessment, providing enhanced correlations between thermal comfort and human body exergy consumption rate.

Effects of natural ventilation on indoor thermal comfort in a residential house constructed with reinforced concrete wall

This study aims to investigate the effect of natural ventilation on the thermal performance of a double-story end-lot unit residential house constructed with reinforced concrete walls and structure in Kluang, Johor. Field measurement was conducted in the master bedroom of the house. Five ventilation cases were investigated which are night ventilation (case 1), no ventilation (case 2), day ventilation (case 3), day ventilation with fan (case 4), and night ventilation with fan (case 5). The measured data were indoor air temperature, outdoor air temperature, indoor relative humidity, outdoor relative humidity, and globe temperature. Then, the thermal comfort assessment was conducted based on the adaptive thermal comfort equation for hot-humid climate for all cases. The results show that the mean indoor temperature for all cases is in the range of 29°C to 31.5°C which indicates a high indoor air temperature. Furthermore, the analysis of air temperature difference between outdoor and indoor (out-in) for different natural ventilation modes showed that the indoor thermal conditions of the master bedroom were not significantly different when compared between cases. In the thermal comfort assessment, the night ventilation case (case 1) provided the most comfortable hours during the measurement with a range of 11 to 35.4 %, thanks to the lower outdoor climate conditions at night compared to the other cases. Overall, in this study, the effect of natural ventilation modes on the indoor thermal condition of a master bedroom in a residential house with concrete walls and structures was found not significantly different in the performance of air temperature reduction and comfort hour improvement when compared between cases.

Experiments on Microclimatically adapt a courtyard to climate change

Climate change impacts biodiversity, the use of public spaces, as well as building energy demand, and health in Mediterranean cities. The courtyard is a common typology of private/public open space in the area, which, according to previous research, is substantially affected by climate change. The main reasons are to be found in limited ventilation and the significant amount of radiation received by upper surfaces. A preliminary microclimate, simulation-based evaluation of mitigation strategies to adapt and capitalize on climate changes is here performed through the assessment of a series of analyses using reference year 2020 and 2080. The study addresses a representative courtyard, San Sepolcro cloister (Parma, Italy). One mitigation strategy is explored, limiting direct solar radiation. The shading system, which reduces solar radiation, arises from a process of morphogenesis based on solar parameters and exploits a strategy with vertical structures typical of some cacti, following the biomimicry approach of imitating natural strategies. In this case, the imitation regards both form and function, as well as the generative process. The research was conducted through parametric and generative design in Rhino-Grasshopper and environmental analysis in ENVI-Met. The Universal Thermal Climate Index (UTCI) was the reference index for the assessment of thermal comfort. The shading system allows for improving thermal comfort, through protection from the sun’s rays and the non-obstruction of the vertical ventilation of the courtyard.

Assessment of thermal environment and thermal comfort in a typical composite ice shell building

Composite ice shell buildings are a special type of architecture found in severe cold regions and have played an important role in ice and snow tourism in recent years owing to their ability to offer tourists a romantic and novel experience. We conducted a field study to examine the thermal environment of a typical composite ice shell building in Harbin, China. In the unheated hall and separate small room, the indoor air had an average temperature and relative humidity of −20.64 °C and 76.94%, and −17.71 °C and 79.57%, respectively. Surface heat flux measurement of the north-facing building envelope revealed that the thermal properties of composite and plain ice differed significantly, suggesting that composite ice may have a lower thermal conductivity. The natural ventilation rate of 48,041 m3/h corresponded to an air change rate of 6.86 h−1, making the thermal environment highly susceptible to outdoor meteorological conditions. In addition, we conducted a questionnaire survey to study the thermal sensation and thermal comfort of the tourists. The results showed that the mean thermal sensation for the foot and head were approximately “cold " and “slightly cool”, respectively. The overall and mean thermal sensation for the hand were both between “cool” and “cold”, and the mean thermal comfort was approximately “slightly uncomfortable”. An adaptive thermal sensation prediction model suitable for composite ice shell buildings was developed through the study. These findings can assist in the design and construction of thermal environments that are better suited for short-term stays and specialty tourism.

Equivalent contact temperature (ECT) for personal comfort assessment – analytical description and definition of comfort limits

This paper introduces the equivalent contact temperature (ECT) model for local thermal comfort assessment in contact areas for non-uniform environmental conditions. It aims to complete the comfort evaluation scheme of the equivalent temperature approach included in ISO 14505-2 by the contact areas back and buttocks that are currently neglected in the standard. For the assessment of local and overall thermal comfort of seated persons, these contact areas are of great importance, especially if exposed to personal comfort systems. Person-oriented climatization systems, such as seat heating and ventilation, are much more energy efficient than conventional HVAC systems and allow to incorporate the human individual into the system’s control loop. The ECT-approach is formally defined, analytically as well as mathematically derived and validated by a subject study. The results of the subject study (air temperature of 26 °C and 29 °C) confirm the cooling effect due to the seat ventilation and show fundamental correlations between ECTs and body part specific mean thermal votes for buttocks and back. Practitioner summary:The equivalent contact temperature model for local thermal comfort assessment in contact areas for non-uniform environmental conditions is formally defined, analytically as well as mathematically derived and validated by a subject study. It completes the existing equivalent temperature comfort scheme by both contact areas back a nd buttocks to improve thermal comfort assessment.

Techno-economic analysis and optimization of near-zero energy and emission neighborhoods using biomass waste

The present study aims to simulate and design a near-Zero Energy neighborhood in one of the most significant industrial cities for reducing greenhouse gas emissions. For this building, biomass wastes are used for energy production, and also energy storage is provided using a battery pack system. Additionally, the Fanger model is used to assess the passengers' thermal comfort, and information on hot water usage is given. The transient performance of the aforementioned building is tested for one year using TRNSYS software, which was employed for this simulation. Wind turbines are considered electricity generators for this building, and any extra energy generated is stored in a battery pack for usage when the wind speed is insufficient and electricity is needed. Hot water is created using a biomass waste system and is kept in a hot water tank after being burned using a burner. A humidifier is utilized to ventilate the building, and a heat pump provides both the building's heating and cooling needs. The produced hot water is used to supply the residents' hot water. In addition, The Fanger model is considered and used for the assessment of occupants' thermal comfort. Matlab software is a powerful software used for this task. According to the findings, a wind turbine with a 6 kW generation capacity may supply the building's power needs while also charging the batteries beyond their initial capacity, and the building will have zero energy. Additionally, biomass fuel is used to give the building the required water which should be hot. On average, 200 g of biomass and biofuel are used per hour to maintain this temperature.

InfraRed Thermography and 3D-Data Fusion for Architectural Heritage: A Scoping Review

Comprehensive documentation is the foundation of effective conservation, repair and maintenance (CRM) practices for architectural heritage. In order to diagnose historic buildings and inform decision making, a combination of multi-disciplinary surveys is fundamental to understanding a building’s heritage and performance. Infrared thermography (IRT), a non-contact, non-invasive and non-destructive imaging technique, allows both qualitative and quantitative assessments of temperature to be undertaken. However, the inherent low spatial resolution of thermal imaging has led recent work to fuse thermographic and geometric data for the accurate 3D documentation of architectural heritage. This paper maps the scope of this emerging field to understand the application of IRT and 3D-data fusion (IRT-3DDF) for architectural heritage. A scoping review is undertaken to systematically map the current literature and determine research gaps and future trends. Results indicate that the increasing availability of thermal cameras and advances in photogrammetric software are enabling thermal models to be generated successfully for the diagnosis and holistic management of architectural heritage. In addition, it is evident that IRT-3DDF provides several opportunities for additional data integration, historic building information modelling (H-BIM) and temporal analysis of historic buildings. Future developments are needed to transform IRT-3DDF findings into actionable insights and to apply IRT-3DDF to pressing climate-related challenges, such as energy efficiency, retrofitting and thermal comfort assessments.

Thermal comfort assessment during summer in rural Indian kitchens in tropical regions

ABSTRACT Several past studies have shown that occupants in a house generally feel more uncomfortable during the summer season. In kitchens, which are an integral part of the rural household, the environment inside is usually warmer than the room temperature. In the present work, a thermal comfort survey and experimental data collection have been conducted simultaneously in several residential kitchens in the rural areas of Raipur, India, during the summer season to assess the thermal comfort conditions of the subjects. A linear regression analysis has been done to determine the comfort band which is then compared with past data available in the literature. The results highlight the lack of proper airflow motion, insufficient ventilation, location of the cooking platform, and small sizes of the kitchen as some of the main design drawbacks of rural household kitchens. The current study conducted will help researchers to formulate design strategies to enhance the thermal comfort condition of subjects in such kitchens.

Thermal comfort assessment in the modern passenger car under actual operational conditions

Abstract People’s ever-increasing needs encourage designers of various vehicles to search for solutions that will provide the most comfortable internal environment conditions. Currently, partly due to the COVID-19 threat, many people use their individual cars to travel to work, college, shops, trips, and holidays. Proper internal air parameters that need to be maintained in vehicles are critical in the summer. The article discusses the thermal comfort of four passengers of a modern car produced in 2017 to verify if contemporary production technology can successfully meet the thermal needs of people under actual conditions in the Polish climate. For this purpose, five temperature values were tested: 20°C, 22°C, 24°C, 26°C, and 28°C for the car located in the shade and sun. In addition, the Testo 400 meter was used to control and measure the internal parameters, and questionnaires were used to find out about the thermal impressions of the respondents. The research was carried out in July when the air temperature in Poland was high.

Assessment of Thermal Comfort and Indoor Air Quality in Library Group Study Rooms

Human performance and health are among the most relevant topics in modern society, especially at young ages, when academic performance is indispensable. Thus, as humans spend most of their life inside a building, thermal comfort and indoor air quality are essential aspects of a room. The aim of the current study is to numerically evaluate the main thermal comfort parameters such as PMV and PPD as well as indoor air quality, i.e., CO2 concentration, in library group study rooms at the University of Gävle in Sweden. Rotroninc Measurement Solutions CL11 sensors were utilized for temperature measurements. Simulation models were created and validated based on building data as well as temperature measurements. Several simulations were conducted throughout the year, covering different periods. The results show that even though the ventilation system, with only temperature control, works as intended for maintaining thermal comfort, the CO2 concentration rises above 1000 ppm when more than one student occupies the rooms, which is not recommended by different thermal comfort ruling institutions. Consequently, a modification to the ventilation system control is recommended, changing it from temperature control to CO2 and temperature control.

Effect of Spatial Proximity and Human Thermal Plume on the Design of a DIY Human-Centered Thermohygrometric Monitoring System

Wearable devices have been introduced for research purposes and especially for environmental monitoring, with the aim of collecting large amounts of data. In a previous study, we addressed the measurement reliability of low-cost thermohygrometers. In this study, we aim to find out how human thermal plume could affect the measurement performance of thermohygrometers. For this purpose, we used a Do-It-Yourself device that can be easily replicated. It consists of 10 iButtons with 3D-printed brackets to position them at different distances from the body. The device was attached to the user’s belt in a seated position. We considered two scenarios: a summer scenario with an air temperature of 28 °C and a clothing thermal resistance of 0.5 clo and an autumn scenario with an air temperature of 21 °C and a clothing thermal resistance of 1.0 clo. The results show that the proximity of the measurement station to the body significantly affects the accuracy of the measurements and should be considered when developing new wearable devices to assess thermal comfort. Therefore, we recommend that at least two thermohygrometers be considered in the development of a new wearable device if it is to be worn on a belt, with one positioned as close to the body as possible and the other at least 8 cm away, to determine if and how the standard thermal comfort assessment differs from the user’s personal perception and whether spatial proximity might also play a role.

The Effect of Airflow Velocity through a Laminar Airflow Ceiling (LAFC) on the Assessment of Thermal Comfort in the Operating Room

Forced ventilation is applied in clean rooms, specifically operating rooms, to ensure the health of both the patient and the medical staff. Ventilation reduces the risk of patient contamination, and its parameters are legally prescribed. In addition to preventing contamination, the ventilation system also ensures the creation of a comfortable environment for personnel who spend a large amount of working time in the operating room. This research focuses on the appropriate design of the air flow rate from the distribution element to the operating room. The PMV and PPD indexes were used to evaluate thermal comfort for human beings. The measurements of parameters determining thermal comfort took place in a laboratory with an accurate model of the operating room, including equipment and HVAC system, during the summer months, in cooling mode. Discharge speeds in the range of 0.15–0.175 m/s were evaluated as the most comfortable, with the PPD index ranging up to 22%. There was a significant increase in user dissatisfaction up to the limit of 70% at higher discharge speeds.