Thermal Comfort Analysis Research Articles

Computational Simulation and Analysis of Local Thermal Comfort and Indoor Air Quality in Space with Displacement Ventilation

Computational Simulation and Analysis of Local Thermal Comfort and Indoor Air Quality in Space with Displacement Ventilation

Bibliometric analysis and literature review of occupant thermal comfort in naturally ventilated buildings (1995-2021).

This paper presents the global research landscape and scientific progress on occupant thermal comfort in naturally ventilated buildings (OTC-NVB). Despite the growing interest in the area, comprehensive papers on the current status and future developments on the topic are currently lacking. Hence, the publication trends, bibliometric analysis, and systematic literature review of the published documents on OTC-NVB were examined. The search query "Thermal Comfort" AND "Natural Ventilation" AND "Buildings" was designed and executed to recover related documents on the topic from the Elsevier Scopus database. Results showed that 976 documents (comprising articles, conference papers, reviews, etc.) were published on the topic from 1995 to 2021. Further analysis showed that 97.34% of the publications were published in the English language. Richard J.de Dear (University of Sydney, Australia) is the most prolific researcher on OTC-NVB research, while Energy and Buildings has the highest publications. Bibliometric analysis showed high publications, citations, keywords, and co-authorships among researchers, whereas the most occurrent keywords are ventilation, natural ventilation, thermal comfort, buildings, and air conditioning. Systematic literature review demonstrated that OTC-NVB research has progressed significantly from empirical to computer-based studies involving complex mathematical equations, programs, or software like artificial neural networks (ANN) and computational fluid dynamics (CFD). In general, OTC-NVB research findings indicate that physiological, social, and environmental factors considerably influence OTC in NVBs. Future studies will likely employ artificial intelligence or building performance simulation (BPS) tools to examine relationships between OTC and indoor air/environmental quality, human behavior, novel clothing, or building materials in NVBs.

Research and thermal comfort analysis of the air conditioning system of the Ferris wheel car based on thermoelectric cooling

To solve the problem of thermal discomfort caused by the lack of cooling facilities on the Ferris wheel and to investigate the effect of the coupling effect of thermoelectric modules on the thermoelectric cooling (TEC) system, this paper proposes a two-module thermoelectric cooling and air-conditioning system that can be applied to the Ferris wheel. Firstly, the experimental platform was established to test the performance parameters of the TEC system and reveal the influence of the thermoelectric module (TEM) coupling effect on the system performance. Then, the thermal environment inside the Ferris wheel was simulated using the CFD method and human thermal comfort was evaluated. The results show that when the voltage of TEM1 and TEM2 is 10V and 6V respectively, the thermoelectric cooling and air-conditioning system has the best working performance, and the coefficient of performance (COP) is 0.43. And the human thermal comfort deviation AEQT is 0.29, which is in a comfortable state under the action of the air-conditioning system.

Environmental and energy analysis of the renovation of social housing buildings under various climate change scenarios and user profiles

The renovation of social housing buildings, a priority for the European Union, must be assessed under a Climate Change (CC) context. This work, centred on the user and the environmental impact, analyses the climate resilience of the renovation of the social housing building stock of the Basque Country, located in Northern Spain. In this region, characterised by cold winters and mild summers, CC projections indicate a moderate warming even in the worst-case scenario. The assessment of passive renovation actions indicates that reducing heating demand is key no matter the CC scenario. The reduction achieved in heating demand with deep passive renovations is up to 82.2 % when the worst CC scenario is considered. Indeed, since low-income tenants occupy these buildings, it has been found that global warming would help users achieve indoor standard conditions in a more effective way than with passive renovation actions. Consequently, to improve indoor conditions independently of the CC scenario, active renovation measures must also be considered. Furthermore, the thermal comfort analysis proved that the risk of overheating in this region is negligible, with less than 4 % of the yearly hours above 26 °C. Finally, the Life Cycle Impact Assessment shows that the environmental impact of the renovation is short when compared to the impact of the operational stage. The use of conventional or ecological materials during renovation would save up to 6.5 % of Non-Renewable Primary Energy Consumption and 3.7 % of CO2 emissions during the life-cycle of the building.

A Comprehensive Analysis of Thermal Comfort and Steam Protective Performance of Fabric Systems Containing a 3D Spacer Layer

A Comprehensive Analysis of Thermal Comfort and Steam Protective Performance of Fabric Systems Containing a 3D Spacer Layer

Analysis of Thermal Comfort of the Building Envelope Using an Earth-Air Heat Exchanger

The constructive elements of a building influence the demand for electrical energy, and optimal decisions can be assessed with the support of software that measures this building's demand more accurately. The objective of this research is to assess the thermal behavior of a residential dwelling located in bioclimatic zone 2 in the southern region of Brazil, seeking energy sources that contribute to improving thermal comfort. The study utilizes parameters that reduce the thermal demand for cooling and heating by installing an earth-air heat exchanger (EAHE) in the prolonged occupancy enviroments (POEs) within the building. The results obtained in the EnergyPlus software show that the adaptive comfort of the model with the Earth-Air Heat Exchanger (EAHE), compared to without it, reduces cold discomfort by 5.4% and increases thermal comfort in the building by 5.2%. Analyzing the annual temperatures of the spaces with the EAHE, it is observed that the outlet temperature of the EAHE duct remains at an average of 23.6°C and 23.8°C for the living room and bedrooms, respectively. From an energy perspective, the electrical energy consumption of the building was reduced by 29.8% when using the EAHE.

Nanotechnology for thermal comfort and energy efficiency in educational buildings with a simulation and measurement approach in BSh climate

Educational buildings have a large share and impact on urban development. While research shows a significant portion of non-industrial energy consumption in these buildings, obtaining optimal thermal comfort in educational buildings remains one of the main concerns in achieving the grounds to promote students’ best performance and efficiency. Extensive research has been done in this field, however, this research presents a new approach to the diverse use of nanotechnology techniques which improve its properties and components in the buildings, aiming to reduce energy consumption and increase thermal comfort. In this paper, thermal comfort and energy consumption are evaluated in a 12-class elementary school located in Shiraz City. Aeropan and nano-Phase change materials (nano-PCMs) is used in the window glass and walls of the studied case. This evaluation presents the simulation and experimental analysis of thermal comfort (PMV) and energy consumption of three classroom alignments in the school building including the Linear-shape (LS), the Integrated Linear-shape (ILS), and the U-shaped (US) alignment. The simulation was performed using EnergyPlus 9.6 software, while the experimental data was collected using TESTO 425 device. The result of this research shows that after applying nano-PCM and Aeropan techniques in window glass and walls, the US alignment has the highest reduction in energy consumption (monthly average of 11.80%) compared to LS and ILS alignments. This alignment includes an energy consumption reduction of 12.03% in the coldest, and, 11.66% in the hottest day of the year in addition to increasing the monthly average thermal comfort of school by the use of nanomaterials.

Učinak naprednih izolacijskih materijala i strategija pasivne optimizacije na toplinsku udobnost u tradicionalnim kućama tijekom zime

This study proposed an interior thermal comfort test to enhance the interior thermal comfort of traditional houses in the Guan Zhong region of the Shaanxi Province during winter. The study was conducted in Xiaoliu village by employing field tests and a questionnaire survey. The field tests and analysis revealed that the thermal comfort of traditional houses in this region is poor, the spatial layout of the houses is unsuitable for conserving heat, the thermal properties of the enclosure walls are inadequate, and the mode of heating is inefficient. The heat transfer parameters, heat lost and gained through fabrics, and thermal properties of nanomaterials have been used to improve the thermal comfort analysis. Combined with the local economic conditions, passive design strategies such as optimizing the spatial layout, improving the thermal insulation performance of the enclosure walls, and using solar energy were implemented. The simulation results indicate that energy consumption can be significantly reduced, and the indoor thermal comfort of traditional houses can be enhanced by reasonably dividing the indoor space, increasing the thermal insulation performance of the enclosure walls, and making better use of solar energy and natural ventilation. Therefore, to improve thermal comfort and reduce the energy load of traditional houses in the Guan Zhong region, it is necessary to adopt passive optimisation strategies.

Improving kitchen thermal comfort in summer based on optimization of airflow distribution

To quantitatively analyze the comfort of kitchen environment, this paper presents a thermal comfort analysis method for kitchen with air-conditioned range hood. It corrects the deficiency in the original comfort formula involving humidity, thereby reasonably quantifying the impact of the cooling airflow from air-conditioning, including humidity, on kitchen thermal comfort. By adjusting the structural parameters of the air conditioning system, the airflow distribution in the kitchen space during summer has been optimized, thereby further enhancing its thermal comfort. This method employs Fluent analyses and its User-Defined Functions (UDF) to analyze the indoor flow field, temperature, humidity, and the distribution of PMV-PPD within the kitchen equipped with air-conditioned range hood. Additionally, experimental data are applied to validate the accuracy and effectiveness of the simulation model. The results indicate that under high temperature climate conditions in summer, air-conditioned range hood significantly enhances the thermal comfort of kitchen environment during cooking. Moreover, optimal thermal comfort for both the kitchen space and local respiratory area of the human body is achieved when the air supply angle is set at 45°, the air conditioning outlet flow rate is 5.5 m3/min and the air supply temperature is set at 21 °C. Compared to the initial operating conditions, Human thermal sensitivity weighted PMV decreased by 98.17 %, and the weighted PPD decreased by 82.07 %. This study provides valuable insights for the design and operation of air-conditioned range hoods, contributing to improved thermal comfort and energy efficiency in residential kitchens.

Experimental study on condensation-free radiant cooling panel with low-temperature for local cooling in vehicles - Part 1: Design process and feasibility evaluation with performance test

Although radiant cooling has significant advantages (high efficiency and thermal comfort), insufficient cooling capacity and condensation risk limit the practical application. In this study, a novel condensation-free radiant cooling panel (RCP) with high cooling capacity is proposed. The performance of proposed RCP was experimentally evaluated at different operating conditions. The transparent cover and surface-painting spray materials of the RCP were examined using Fourier-transform infrared spectroscopy to analyze their transmittance and absorptivity. The total cooling heat flux of the proposed RCP ranged between 2019.5 and 3824.5 W m–2, which are significantly higher than those of previous studies (70–1457 W m–2), owing to low surface temperatures. The radiant heat flux decreased by 13.5% when the distance between the cooling surface and the heater increased from 10 cm to 20 cm, and decreased by 52% when evaporating temperature increased from –40 °C to –20 °C. However, the heater and ambient temperatures showed insignificant effect. The results of this study report feasibility of the proposed RCP and parameters that influence performance. The target application of the proposed RCP is local cooling systems in vehicles to enhance thermal comfort, which is given in succeeding research, Part 2: Demonstration with passengers for thermal comfort analysis.

On-site measurement and mediation analysis of physiological parameters and thermal comfort under different outdoor microclimates in a cold region

This study examined the physiological responses and thermal comfort of ten subjects (five females and five males) across five outdoor locations on the campus of Hebei University of Technology during winter. Physiological parameters, including heart rate, LF/HF values from ECG, and α, β, θ values from EEG, were assessed. It revealed significant differences in microclimatic parameters and physiological responses among measurement points. Mean heart rate variations reached up to 5.72 (6.72 %) and mean β values differed by up to 0.05 (26.32 %), 0.08 (47.06 %), and 0.10 (43.48 %) during T1, T2, and T3 periods. HR, α, and θ values positively correlated with TCV, with coefficients of 0.131 (p < 0.01), 0.081 (p < 0.01), and 0.018, while LF/HF and β showed negative correlations, with coefficients of −0.109 (p < 0.01) and − 0.024 (p < 0.01). Changes in TCV from 0 to −2 corresponded to HR, LF/HF, α, β, and θ variations of 6.69 %, −3.5 %, 12.5 %, −9.38 %, and 7.14 %, respectively. Regarding microclimatic parameters' impact on thermal comfort, β in EEG signals showed greater mediating effects than other physiological parameters. This study is useful for providing guidelines for outdoor activities in winter and developing more accurate physiological parameter monitoring and comfort assessment methods.

Identification and application of the best-suited machine learning algorithm based on thermal comfort data characteristic: A data-driven approach

Integrating machine learning (ML) techniques in thermal comfort analysis is pivotal in contemporary research. This study systematically evaluates and applies ML algorithms for predicting thermal comfort parameters, emphasizing data imputation, parameter-specific behaviour analysis, and the development of an Independent Parameterised Modelling Ensemble (IPME) framework. A data-driven approach addresses missing values in the ASHRAE Global Thermal Comfort Database II using ML algorithms tailored to each thermal comfort (TC) parameter. Performance metrics, such as coefficient of determination (R2) for numerical data and accuracy for categorical data, guide the selection process, resulting in optimised ML-TC pairs for imputation. The analysis reveals parameter-specific behaviours, with numerical parameters exhibiting varying correlations with environmental conditions and parameters related to individual preferences posing challenges. ML models show improved performance with categorical data, potentially because of their ability to capture subjective aspects effectively. The IPME framework was proposed to address the conventional ML limitations by employing a hybrid ensemble strategy that selects tailored TC parameter-specific ML algorithms. This approach aims to enhance prediction accuracy by acknowledging the uniqueness of parameters and harnessing diverse ML capabilities. Future research directions include further exploration of the IPME framework and post-imputation retraining of ML models to capture actual behaviour. This study underscores the potential of ML in enhancing thermal comfort analysis, offering insights into imputation strategies, parameter-specific behaviours, and ensemble modelling approaches for more reliable predictions in building environments.

Analysis of thermal comfort in traditional architecture, focused on digital simulations

Analysis of thermal comfort in traditional architecture, focused on digital simulations

Thermal comfort and mechanical analysis of vigorous diamond and diaper weaves; warp, weft and balanced float fabrics with equal thread densities

Diamond (pointed twill) and diaper (herringbone twill) woven assemblies are considered ideal for applications where thermal insulation, heat retention, wrinkle resistance, strength, softness, and breathability attributes are crucial. Limited research has been found on the optimization of thermal comfort and mechanical performance of warp face, weft face and balanced float diaper and diamond woven assemblies. In this work six different woven assemblies have been engineered using cotton (cellulosic yarn) on a dobby machine, having warp face (4/2) weft face (2/4) and balanced float (3/3) based diamond and diaper weave designs with equal number of thread densities. Thermal comfort (dry fluid transmission, thermal resistance, stiffness, and overall wet fluid management capability) and mechanical (tensile, puncture and tear strength) tests were performed for developed woven fabrics. The results of diamond warp face sample showed the highest dry fluid transmission and volume porosity. Diamond weft face specimens showed the highest thermal conductivity behavior and diaper weft face exhibited the highest overall wet fluid management capability behavior. Stiffness was the highest in diamond balanced float. Diamond warp faced fabric showed the highest tearing durability and diaper weft face showed the highest tensile resilience in mechanical performance attributes.

Effect of layering outerwear on innerwear and air gap between the two layers on thermal comfort properties of knitted fabrics

PurposeIn everyday life, people generally wear two layers of clothes (a knitted vest and a knitted t-shirt) during the summer. It is essential to understand which types of innerwear and outerwear maximize comfort. The primary objective of this research is to investigate the influence of layering outerwear on innerwear, as well as the air gap between two layers, on thermal comfort properties.Design/methodology/approachIn this study, a total of 12 combinations were created from four vest fabrics and three T-shirt fabrics. The thermal properties (thermal conductivity, thermal resistance, thermal absorptivity, thermal diffusion and peak heat flow) were evaluated for the individual inner and outer layers. Each inner layer was layered with an outer layer to observe the effect of layering on the thermal properties. An air gap of 2 mm was introduced between the inner and outer layers to study the effect of air gap on thermal properties.FindingsTencel fibre exhibits higher thermal conductivity and absorptivity than cotton and polyester. Upon layering an outer layer on an inner layer, the thermal conductivity and thermal absorptivity increase to a slight extent, thermal resistance and diffusion increase drastically and the peak heat flow reduces. With an air gap between the two layers, the thermal conductivity did not improve, the difference in thermal resistance among all the combinations reduced, the thermal absorptivity of the combination textiles was lower than that of the innerwear alone, the thermal diffusion increased and the peak heat flow diminished for all the combinations.Practical implicationsIn practice, this comprehensive thermal comfort analysis provides specific combinations of inner and outer articles of clothing that are most appropriate for enhancing comfort during the summer season.Originality/valueThough there are many studies on the effect of multilayer fabrics on thermal properties, no extensive research analyses the influence of innerwear and outerwear combinations on thermal comfort properties.

Impact of Climate on Ecotourism in the Muthanna Desert

This research addresses the measurement and statistical analysis of thermal comfort in the desert of Al Muthanna, aiming to identify the most influential climatic elements on human comfort in the study area. Additionally, it seeks to determine the most suitable climatic criteria that align with the climate and reality of the study area. The research has led to the following key conclusions: 1. The months (June, July, August, September) recorded values of (H-) indicating extreme discomfort according to the Thermal Comfort Index (THI), whereas the months of December and February experienced values of (C-) denoting discomfort. Extreme discomfort (H) was recorded in October and April, while relative comfort was noted in November and March, with THI values between 17 and 18. 2. The months (June, July, August) were recorded as (H+) indicating very hot conditions, while the months (May, September, October) recorded a value of (H), and ideal comfort was observed in December and January. The values of (P) indicating ideal warmth were recorded during the months (February, March, April, November.

Evaluating the effects of different tree species on enhancing outdoor thermal comfort in a post-industrial landscape

A frequently emphasized strategy to reduce the burden of heat in cities across the world is the implementation of street trees. Here, we examine the effects of deciduous and coniferous tree deployment on meteorological variables and pedestrian thermal comfort through analysis of the new dynamic thermal comfort (dPET) index, using the latest version of the computational fluid dynamics model ENVI-met. We performed on site observational measurements of air temperature (Ta), relative humidity (Rh), wind speed (Ws), and mean radiant temperature (MRT) at five different locations on the hottest day of summer 2023, in a post-industrial urban landscape located in Tehran, Iran. Observations were used to evaluate ENVI-met simulation performance and served as a baseline against which sensitivity experiments—based on a minimum (35%) and maximum (75%) intervention scenario for deciduous and coniferous trees—were compared against. Our analysis indicates that 35% and 75% deployment reduced Ta by 1.2 °C and 4.2 °C, respectively, for deciduous tree species, compared to a 0.9 °C and 3.1 °C reduction for coniferous species, during the hottest day of summer 2023. The maximum deployment scenario decreased MRT by approximately 60 °C and 43 °C for deciduous and coniferous tree deployment, respectively. The maximum tree deployment scenario decreased dPET by nearly 16 °C and 14 °C for deciduous and coniferous trees, respectively, during the time of day that diurnal heating is maximized. Our findings highlight micrometeorological and personalized thermal comfort effects associated with variable tree species type and extent through examination of a pedestrian’s ambulatory experience across diverse urban microclimates in a region of the world that is particularly understudied.

Efficiency Assessment on Roof Geometry and Trombe Wall Shape for Improving Buildings’ Heating Performance

It is crucial to consider structural design issues in Trombe wall (T-wall) buildings to promote more suitable indoor climates and thermal comfort standards. Therefore, the present study examined the impact of two different T-wall designs and six different roof types on the energy and operational efficiency of a building located in a low-temperature and high-humidity winter climate. Ansys-CFX 15.0 software was employed to simulate the thermal and fluid dynamics behavior of the T-wall system, and flow, thermal comfort, energy, and exergy analyses were conducted. Three-dimensional simulation results and the pertinent literature data showed a good level of agreement, and the accuracy of the model was ensured. Outcomes revealed an average air velocity variation of 0.186 m/s and maximum average indoor air temperature variation of 3.3 °C between the six roof geometries. The highest air speed (0.988 m/s) was recorded for the gambrel roof while the lowest one (0.802 m/s) was recorded for the typical flat roof. The shed roof right with a rounded T-wall was more comfortable for standing and sitting activity than the others for the two T-wall shapes, and, at Y = 0.6 m and Y = 1.1 m, the average predicted percentages of dissatisfied (PPD) values were 31 and 28%, respectively. Furthermore, it was determined in the study that solar radiation intensity and T-wall and roof geometries had a significant effect on energy and exergy efficiency, and high energy and exergy efficiencies were achieved at higher solar intensity values. The best energy and exergy efficiencies were obtained for the butterfly and shed roof configurations. This study can serve as a reference for the thermal environment design of buildings with T-walls.

Assessing the Relationship Between Land Surface Temperature and Air Temperature for Thermal Comfort Analysis in Can Tho City: Implications for Sustainable Spatial Planning

This study aims to assess the relationship between land surface temperature (LST) and air temperature (Tair) and thermal comfort analysis in Can Tho City. LST is derived from the Landsat thermal band, while Tair is measured using 15 monitoring stations. A Temperature Humidity Index (THI) is employed as a preferred metric for analyzing the thermal comfort level, calculated based on a combination of Tair and relative humidity (RH). Besides quantitative data collection, the study also survey residents in high heat risk areas to acquire insights into their current experiences and perceptions heat. The results reveal that individuals in high SUHI areas experience discomfort across varying temperature ranges, influenced by particular working conditions and personal characteristics. Moreover, the findings highlight a significant correlation between LST and Tair, reaching a coefficient of 0.73, indicating the applicability of land surface temperature in large-scale temperature calculations. These results underscore the need for further research on the extent of heat-related health effects and the development of strategies for heat stress mitigation. Understanding of thermal comfort and the impacts of SUHI is crucial for addressing climate and societal challenges and enhance the well-being of urban populations.

Use of passive cooling techniques and super cool materials to minimize cooling energy and improve thermal comfort in Brazilian schools

Standardized replicable buildings can cause discomfort and increased air conditioning usage. Besides, super cool coatings are effective passive solutions. Therefore, this study evaluates thermal comfort in a standardized Brazilian public school in 8 climates, verifies suitable super cool coatings and identifies optimal additional passive techniques to meet regulatory requirements without active air conditioning, a topic worthy of investigation. Methods include pilot simulations with DesignBuilder, thermal comfort analysis considering ASHRAE 55 adaptive model; JEA Algorithm optimization simulations; identification of most influential passive strategies by sensitivity analyses; and evaluation of the ideal opaque envelope through heat balance. Results showed that current model do not meet the Brazilian normative. Thus, different super cool coatings are recommended: thermochromic for heating-dominated; spectrally selective for cooling-dominated dry and high broadband emissivity for extreme-cooling-dominated humid zones. Regarding opaque envelope, thermal mass flat roofs and insulated walls are advised. In 7 of 8 climates, super cool roof was most effective followed by natural ventilation. Optimal combinations include super cool envelope, window shading and natural ventilation 24 hours 7 days a week with 95 % of free-aperture for extreme-cooling-dominated zones; super cool roofs, medium reflectivity walls and 5 % of free-aperture for cooling-dominated; thermochromic roof and dark walls with natural ventilation during occupancy with 5 % of free-aperture for heating-dominated.