Thermal Sensation Vote Research Articles

Effects of indoor temperature on office workers’ performance: an experimental study based on subjective assessments, neurobehavioral tests, and physiological measurements

Indoor temperature has a critical impact on the performance of office workers. This study aimed to evaluate the effect of indoor temperature on work performance through subjective assessments, neurobehavioral tests, and physiological measurements. The experiment was conducted in a controlled office environment. Under each temperature condition, participants voted on their perception of thermal sensation, thermal satisfaction, and sick building syndrome (SBS) symptoms. Participants were given neurobehavioral tests based on a ten-item task, and their body temperature, blood pressure, heart rate, and blood oxygen saturation were measured before and after the tests. The study showed that the effect of indoor temperature on the test tasks varied greatly and depended on the task type. The indoor temperature, thermal sensation votes, and body temperature for optimum work performance were 17 °C, −0.57, and 36.4 °C, respectively. Work performance was positively correlated with thermal satisfaction votes and negatively correlated with sleepiness intensity. Practitioner summary: Work performance is closely related to indoor temperature. This study evaluated the effect of indoor temperature on work performance through subjective assessments, neurobehavioral tests, and physiological measurements. The relationships between work performance and indoor temperature, perceived votes, and physiological parameters were established, respectively.

The analysis and optimization of thermal sensation of train drivers under occupational thermal exposure.

Prolonged exposure of train drivers to thermal discomfort can lead to occupational safety and health (OSH) risks, causing physical and mental injuries. Traditional method of treating human skin as a wall surface fail to observe accurate skin temperature changes or obtain human thermal comfort that adapts to the thermal environment. This study employs the Stolwijk human thermal regulation model to investigate and optimize the thermal comfort of train drivers. To minimize the time-consuming design optimization, a pointer optimization algorithm based on radial basis function (RBF) approximation was utilized to optimize the train cab ventilation system design and enhance drivers' thermal comfort. The train driver thermal comfort model was developed using Star-CCM+ and 60 operating conditions were sampled using an Optimal Latin Hypercube Design (Opt LHD). We analyzed the effects of air supply temperature, air supply volume, air supply angle, solar radiation intensity and solar altitude angle on the local thermal sensation vote (LTSV) and overall thermal sensation vote (OTSV) of the train driver. Finally, the study obtained the optimal air supply parameters for the Heating Ventilation and Air Conditioning (HVAC) in the train cabin under extreme summer conditions, effectively improving the thermal comfort of the driver.

A Prospective Study of Thermal Comfort in Users in Technical Institution TVET: Workshop Facilities Space

Thermal comfort is a part of indoor environmental quality that should be considered to ensure the occupants' well-being. Unconducive buildings not only bring occupants discomfort but also tend to affect health, disrupt the process of teaching and learning, and reduce work productivity. Thus, this study determines the thermal condition of existing workshop buildings used in Technical and Vocational Education and Training (TVET) implementation. Evaluations of comfort are based on occupant surveys and environmental measurements. A total of 257 people completed a questionnaire distributed at three technical institutions in Kedah, Malaysia. According to the findings, the average thermal sensation vote is 1.85, which leads to 66.5% of respondents feeling discomfort. Meanwhile, the adaptive model analysis showed that the workshop environmental conditions were out of the comfort zone and did not comply with the ASHRAE 55 standard. Hence, the thermal discomfort factors from the occupants' perspective were identified and widely discussed. As a result, the research findings will benefit parties involved in new building construction or existing building renovations to improve indoor air quality.

Thermal comfort analysis and improvement of outdoor sports spaces in universities: a case study of Xi'an Jiaotong University.

This article investigates the potential impact of thermal comfort on university teachers' and students' outdoor exercise via a case study of the thermal comfort of outdoor sports at the two campuses of Xi'an Jiaotong University-Xingqing Campus and Innovation Harbour Campus. Thermal comfort analysis is a crucial topic of urban environmental studies, but it has not yet been integrated with research on the improvement of outdoor sports spaces. This article is an attempt to fill this gap, using meteorological data gathered from a weather station and questionnaires gathered from the respondents. With collected data, the present research then uses linear regression to probe into the relationship between Mean Thermal Sensation Vote (MTSV), Mean Thermal Comfort Vote (MTCV), and MPET, to demonstrate general trends and display the PET values when TSV is most ideal. The results show that the significant differences in thermal comfort between the two campuses exert little impact on people's will to exercise. Under the ideal thermal sensation, the calculated PET values for the Xingqing Campus and Innovation Harbour Campus were 25.55°C and 26.61°C respectively. The article ends with concrete suggestions on practical strategies to improve the thermal comfort of outdoor sports spaces.

Evaluation of the Effects of Airflow Patterns on Human Thermal Perception

Recently, greenhouse gas emissions have led to irreversible climate change, and in order to mitigate the changes, more and more research is focusing on energy efficiency and environmental protection in the building sector. Improving indoor ventilation airflow as a feasible solution for energy conservation as well as improving human thermal comfort. This study aims to provide reference for optimizing the thermal perception of occupants in indoor ventilation design. This research evaluates the effect of heat perception on students in a stable indoor environment (28 ℃, RH 50%) under two airflow patterns (dynamic and constant). The use of airflow was found to have a positive impact on thermal sensation vote (TSV) and thermal pleasure vote (TPV). There was non-significant difference in the effects of heat perception between airflow modes. This finding is consistent with the findings of Parkinson and de Dear's study. It is worth noting that differences in experimental results may be due to other personal factors (e.g., gender, age, and weight). Further studies are therefore needed to demonstrate the influence of these factors on the thermal perception effect of air movement.

Association between physiological and perceptual heat strain while wearing stab-resistant body armor

In this study, we explored the association between physiological and perceptual heat strain while wearing stab-resistant body armor (SRBA). Human trials were performed on ten participants in warm and hot environments. Physiological responses (core temperature, skin temperature, and heart rate), and perceptual responses (thermal sensation vote, thermal comfort vote, restriction of perceived exertion (RPE), wetness of skin, and wetness of clothing) were recorded throughout the trials, and subsequently, the physiological strain index (PSI), and perceptual strain index (PeSI) were calculated. The results indicated that the PeSI showed a significant moderate association with the PSI, and was capable of predicting PSI for low (PSI = 3) and high (PSI = 7) levels of physiological strain with the areas under the curves of 0.80 and 0.64, respectively. Moreover, Bland-Altman analysis indicated that the majority of the PSI ranged within the 95% confidence interval, and the mean difference between PSI and PeSI was 0.14 ± 2.02 with the lower 95% limit and upper 95% limit being −3.82 to 4.10, respectively. Therefore, the subjective responses could be used as an indicator for predicting physiological strain while wearing SRBA. This study could provide fundamental knowledge for the usage of SRBA, and the development of physiological heat strain assessment.

폭염저감기술에 따른 외부공간의 기온 저감에 대한 연구 : 쿨링포그의 더위 저감효과 검증을 위한 실증실험

To provide Social Overhead Capital (SOC) for daily human lives, local governments are preparing various measures against heat waves, such as supplying Heat Wave Mitigation Facilities and supporting the vulnerable. Cooling Fog is a recent trend of Heat Wave Mitigation Facilities, but South Korea has limited data on reducing body temperature through direct application of cooling matter on the body, and most research on Cooling Fog has addressed technical aspects. In this study, to confirm the effect of Cooling Fog on the human body, experiments were conducted. First, the change of environmental factors in the space around the Cooling Fog was compared with an unaffected area. Second, a survey was conducted targeting people who use Cooling Fog to review its sensory effects. Finally, the effect of Cooling Fog was quantitatively verified by linking and analyzing related data. The air temperature and radiation temperature were lower in the area of Cooling Fog, but humidity was high. The sensory survey confirmed that Cooling Fog produced a sensation of cooler temperature compared to the area without Cooling Fog, as assessed using Thermal Sensation Vote (TSV), Heat Score, and Apparent Temperature (AT). In addition, the area of Cooling Fog was reported to have higher Thermal Comfort than the area without.

Influencing assessment of different heating modes on thermal comfort in electric vehicle cabin

Electric vehicle (EV) is more environmental-friendly than gasoline vehicle because the main power is not petrol. For the heating system, the waste heat generated by engines is recycled to heat the cabin of gasoline ones, while the EV need extra electric energy consumption for heating the cabin which decreases the driving range. Personal comfort system (PCS) has been reported that it is an alternative technique to improve occupant thermal comfort and indirectly save building heating energy. This study aims to investigate the occupants’ thermal sensation under four heating modes in the EV cabin in winter, including no heating, only PCS, only air conditioning, and both air conditioning and PCS. The field survey is conducted in a parked EV with 12 subjects. Three thermal comfort indexes (PMV, SET*, and operative temperature Top) are used and assessed for their applicability in the thermal environment of the EV. Results show that the thermal environment in the cabin is non-uniform and dynamic with the air conditioning mode, while the PCS mode just slightly affects the temperature differences inside. Meanwhile, the subjects’ thermal sensations cannot maintain neutral or warmer under the PCS mode only. The results of PMV are lower than the subjects’ actual thermal sensation votes (TSV), while the results of SET* and Top show significant linear relationships with the TSV for the correlation coefficients above 0.80. Compare to the air conditioning mode, the neutral SET* and neutral Top are decreased by 2.7 °C and 1.6 °C under the mode with PCS and air conditioning, respectively. The findings indicate that PCS not only has a positive effect on improving the cabin environment and occupant's thermal sensation but also has the potential to lower the setting temperature of air conditioner of EVs in winter.

Field investigation of the heat stress in outdoor of healthcare workers wearing personal protective equipment in South China.

Since the advent of coronavirus disease 2019 (COVID-19), healthcare workers (HCWs) wearing personal protective equipment (PPE) has become a common phenomenon. COVID-19 outbreaks overlap with heat waves, and healthcare workers must unfortunately wear PPE during hot weather and experience excessive heat stress. Healthcare workers are at risk of developing heat-related health problems during hot periods in South China. The investigation of thermal response to heat stress among HCWs when they do not wear PPE and when they finish work wearing PPE, and the impact of PPE use on HCWs' physical health were conducted. The field survey were conducted in Guangzhou, including 11 districts. In this survey, HCWs were invited to answer a questionnaire about their heat perception in the thermal environment around them. Most HCWs experienced discomfort in their back, head, face, etc., and nearly 80% of HCWs experienced "profuse sweating." Up to 96.81% of HCWs felt "hot" or "very hot." The air temperature had a significant impact on thermal comfort. Healthcare workers' whole thermal sensation and local thermal sensation were increased significantly by wearing PPE and their thermal sensation vote (TSV) tended towards "very hot." The adaptive ability of the healthcare workers would decreased while wearing PPE. In addition, the accept range of the air temperature (T a) were determined in this investigation. Graphical Abstract.

Dynamic thermal responses and showering thermal comfort under different conditions

This study conducted a series of human subject experiments on shower thermal comfort to investigate the dynamic thermal responses under different conditions. Questionnaires (including thermal sensation votes, thermal comfort votes, sweating sensation votes, and mood-related votes) and physiological parameters (including skin temperature, core temperature, heart rate, blood pressure, and brain waves) were collected from 27 subjects. The results showed that the subjects’ comfort-related votes changed dynamically during the pre-, mid-, and post-showering phases. The changes in thermal sensation, thermal comfort, fatigue relieving, and sweating sensation during the 10-min shower were 0.7 ± 0.8, 0.9 ± 1.2, 0.9 ± 1.0, and 0.9 ± 0.9, respectively. After a 10-min shower, 16 mood-related questions were answered toward positively. The heart rate and mean skin temperature of the subjects increased by approximately 10% and 8%, respectively. The body temperature tended to be more uniform, with smaller temperature differences between the trunk and extremities. The changes in core temperature, blood pressure, and brain waves were less significant because the reference test condition (25 °C air temperature, 40 °C showering water temperature, and 10-min duration) was not intensive. Further analyses indicated showering water temperature and duration were the most significant factors affecting the mid-showering thermal comfort. The ambient temperature and airspeed were the most significant factors affecting post-showering thermal comfort. The initial thermal status primarily affects thermal comfort before showering. No significant difference was observed between the elder and the younger subjects under moderate conditions.

Analysis of Thermal Environmental in Buildings with Water and Landscape Elements as Microclimate Modifiers in Hot and Humid Tropical Climates

Thermal conditions in buildings are influenced by climatic conditions and are determined by the thermal performance of the building itself. The thermal condition is caused by the transfer of heat flow between the environment and the building. This study aims to analyze the value of temperature, humidity, solar radiation, and wind speed with the presence of the water element as a modifier of the microclimate in the building as well as thermal comfort for the adaptation of visitor behavior. The research focus is on the water element and the sensation of the thermal environment with public building objects. Field research based on ASHRAE 55 2020 and ISO 7730 standards. Four environmental parameters were measured, namely temperature, humidity, solar radiation, and air velocity. Data were obtained through field measurements using quantitative methods through analysis of the Predicted Mean Vote (PMV) thermal comfort index, Predicted Percentage of Dissatisfied (PPD), and Standard Effective Temperature (SET). The data is processed using a statistical approach and then simulated with 2-dimensional numerical data using the Thermal Comfort Tool (CBE) software after which it is compared with the thermal comfort index. PMV, PPD, and SET are generated and refer to the ASHRAE 55-2020 standard. Meanwhile, the sensation of the thermal environment based on behavioral adaptation was analyzed based on the results of the questionnaire answers using the thermal sensation vote (TSV). The results show that the analysis of the thermal environment in the context of the microclimate in the building, thermal comfort as well as water and landscape elements are important potentials that can provide positive values, improve quality, and maintain microclimate stability at the building scale and regional scale and need to be controlled and taken action. adaptive in buildings such as setting water elements and ventilation systems in buildings to provide a passive cooling effect on buildings.

A thermal comfort evaluation model based on facial skin temperature

This study realized a Fisher discriminant analysis method for thermal comfort evaluation based on facial skin temperature. These models directly determine whether an individual is in a neutral state through neutral facial skin temperature thresholds and have physiological significance. The implementation of the models was based on climate-controlled experimental data. The air temperatures considered included 12, 15, 18, 21, and 24 °C (winter) and 24, 26, 28, 30, and 32 °C (summer). During the experiments, the thermal sensation votes of 40 participants were documented using subjective questionnaires, and facial skin temperatures were continuously measured using high-precision corrected iButtons. The results show that the highest precision of the evaluation model was 80%, and the corresponding false-negative rate (FNR) was 27%. The neutral facial skin temperature ranges were higher during summer than during winter. After 15 min of exposure, the models exhibited higher reliability. The average skin temperature from multiple facial parts was more suitable for evaluating neutral thermal sensations than that from a single facial part. The average skin temperature of the nose, cheeks, and chin is the most appropriate index for future applications of infrared thermal imaging. To a certain extent, the models were further improved by sex. Considering air-conditioning energy conservation, this study provides expanded evaluation models. The recommended average skin temperature exhibited a higher evaluation performance: the highest precision was 86%, and the FNR was 19%. These results provide a theoretical basis for the future use of the facial skin temperature as a feedback signal for air conditioners.

The Challenge of Multiple Thermal Comfort Prediction Models: Is TSV Enough?

Classroom thermal comfort has a direct effect on student health and educational outcomes. However, measuring thermal comfort (TC) is a non-trivial task. It is represented by several subjective metrics e.g., Thermal Sensation Vote, Thermal Comfort Vote, Thermal Preference Vote, etc. Since machine learning (ML) is being increasingly used to predict occupant comfort, multiple TC metrics for the same indoor space may yield contradictory results. This poses the challenge of selecting the most suitable single TC metric or the minimal TC metric combination for a given indoor space. Ideally, it will be a metric that can be used to predict all other TC metrics and occupant behavior with high accuracy. This work addresses this problem by using a primary student thermal comfort dataset gathered from 11 schools and over 500 unique students. A comprehensive evaluation is carried out through hundreds of TC prediction models using several ML algorithms. It evaluates the ability of TC metrics to predict (a) other TC metrics, and (b) the adaptive behavior of primary students. An algorithm is proposed to select the most suitable single TC metric or the minimal TC metric input combination. Results show that ML models can accurately predict all TC metrics and occupant-adaptive behavior using a small subset of TC metrics with an average accuracy as high as 79%. This work also found Thermal Sensation Vote to be the most significant single TC predictor, followed by Thermal Satisfaction Level. Interestingly, satisfaction with clothing was found to be as equally relevant as thermal preference. Furthermore, the impact of seasons and choice of ML algorithms on TC metric and occupant behavior prediction is shown.

Summer weather perception and preferences in Powsin Culture Park (Warsaw, Poland)

Green areas situated inside the city play a very important role for many aspects. Among other, from the social point of view, they have a positive impact on the life of city habitants: directly improve well-being and health, reduce noise, provide opportunities for activity and recreation, improve the tourist attractiveness of the city, etc. The objective of this study was to assess thermal sensations and preferences of people staying outdoors for recreational purposes in the area of the city park during summer 2019, as well as to identify how bioclimate perceptions are modified by personal factors (physical and physiological). In order to determine the optimum thermal zone for recreation and urban tourism during the summer, the regression model for mean thermal preferences (MTPV) every 1 °C in PET value intervals was calculated, and according to this procedure, the preferable spectrum of thermal conditions for tourism and recreation in Warsaw which is related to the PET value range between 27.3 and 31.7 °C. All age groups indicated the highest frequency of neutral thermal sensation vote, which decreased with feeling more extreme thermal conditions. In the case of classification by the gender, the men more than the women indicated the thermal conditions as neutral, “slightly warm,” and “warm.” Studies have shown that women were more sensitive than men to extreme thermal sensations especially “hot” and men more often than women indicated greater acceptance for comfortable and warmer thermal conditions.

Meta-learning of personalized thermal comfort model and fast identification of the best personalized thermal environmental conditions

The model of personalized thermal comfort can be learned via various machine learning algorithms and used to improve the individuals’ thermal comfort levels with potentially less energy consumption of HVAC systems. However, the learning of such a model typically requires a substantial number of thermal votes from the considered occupant, and the environmental conditions needed for collecting some votes may be undesired by the occupant in order to obtain a model with good generalization ability. In this paper, we propose to use a meta-learning algorithm to reduce the required number of personalized thermal votes so that a personalized thermal comfort model can be obtained with only a small number of feedback. With the learned meta-model, we derive a method based on the backpropagation of neural networks to quickly identify the best environmental and personal conditions for a specific occupant. The proposed identification algorithm has an additional advantage that the thermal comfort, indicated by the mean thermal sensation value, improves incrementally during the data collection process. We use the ASHRAE global thermal comfort database II to verify that the meta-learning algorithm can achieve an improved prediction accuracy after using 5 thermal sensation votes from an occupant to make adaptations. In addition, we show the effectiveness of the fast identification algorithm for the best personalized thermal environmental conditions with a thermal sensation generation model built from the PMV model.

Impact of Pandemic Safety Measures on Students’ Thermal Comfort—Case Study: Romania

The indoor environmental quality of a building has attracted everyone’s attention since a worldwide pandemic was declared and forced people indoors. After several months, people were able to return to their usual activities, but with strict safety measures added due to the circumstances. This paper focuses on the impact of safety measures on students’ thermal comfort, a case study performed in a continental climate zone, during the winter. The methodology used involved the collection of both quantitative and qualitative data. Descriptive statistics and frequencies alongside correlations and cross-tabular methods were used to analyze the collected data. The results indicated that the predicted mean vote (PMV) underestimated students’ thermal perception. A difference of 1.5 °C was found between the operative neutral temperature of the PMV and students’ thermal sensation votes while wearing masks. Likewise, a lower neutral operative temperature was found for students wearing masks than for those without masks. Students wearing masks preferred a slightly cooler environment and a significant difference was found (p = 0.001) between students’ thermal comfort votes. All of these findings indicate that there is a potential for energy savings without affecting students’ thermal comfort.

Comparative Analysis of Comfort Temperature of School Children and Their Teachers

Thermal comfort in learning environments influences the student’s focus and learning productivity. This study aims to evaluate and compare the adaptive thermal comfort of schoolchildren and their teachers in naturally ventilated primary schools in some selected cities in Imo State Nigeria. To achieve these objectives, the study analyzed the data collected from 330 pupils and 44 teachers in six surveyed classrooms in two types of classroom buildings. The recorded data in the surveyed classrooms consisted of four environmental factors and two personal factors. At the same time, the subjects filled out the questionnaires asking them about thermal sensation and thermal preferences against the classrooms’ thermal requirements. The results of the measurements showed that the indoor mean air temperature, relative humidity, and air velocity were 29.1°C, 71.2%, and 0.19m/s, respectively. The mean thermal sensation votes of the children were +0.16 while that of their teachers was +0.58. The preferred temperatures were 27.4°C and 29.4°C for the schoolchildren and the teachers, respectively. Furthermore, the comfort range of the students was between 25.8°C - 31.6°C, and that of the teachers was between 28.0°C - 29.9°C. Based on the results of this study conducted in primary school buildings located in warm and humid climates, the thermal comfort perception of children and adults differ. This information will serve as a guide to professionals in the built environment, especially architects when designing primary school buildings in the warm and humid climates.

The Right Activities at Right Spaces: Relationships between Elderly Adults’ Physical Activities and Thermal Responses

In this study, the physiological and thermal responses of 54 healthy elderly adults during horticultural activities with various intensities (low, moderate, and high) in three typical open spaces were investigated through meteorological measurements, questionnaires, and physiological monitoring. Physiological equivalent temperature (PET), blood pressure, heart rate, oxygen saturation, and ear canal temperature were used as physiological evaluation indices. The results showed that: (1) the proportional changes before and after thermal sensation vote (TSV) and thermal comfort vote (TCV) activities were positively correlated with the spatial characteristics and metabolic levels of outdoor activities in summer; (2) physiological indices were almost constant during low-intensity horticultural activities and significantly different before and after moderate-intensity and vigorous-intensity horticultural activities; (3) when the intensity of horticultural activities changed from low to moderate, the neutral PET (NPET) decreased to 25.29 and 26.82 °C, respectively, whereas the NPET increased to 23.97 °C during vigorous intensity; (4) heart rate (HR) and diastolic blood pressure (SBP) were positively correlated with metabolic rate for the elderly; (5) a moderate sky view factor space was more suitable for the elderly to participate in during outdoor horticultural activities in summer.

Climate chamber investigation of the effect of indoor thermal histories on thermal adaptation in different seasons

The indoor thermal history of residents in the hot summer and cold winter climate zone in China have undergone a significant change in recent years, which also changes their seasonal thermal adaptations and this has formed feed-back effects to the increasing usage of air conditioning units in this area. To study the seasonal variations of thermal adaptation, the thermal comfort experiments were conducted on two groups of participants. Each groups included 20 participants who had indoor history mainly with natural ventilation (NV group) and air-conditioning (AC group), respectively. The results demonstrated that the thermal sensation vote (TSV) in warm environments did not differ between AC and NV subjects in summer. However, the TSV of AC subjects were much lower than that of NV subjects in the same standard effective temperature and skin temperature in a cold environment in winter. Overall, the participants who spent most of their time in AC space in winter showed a low level of thermal adaptation with a narrower acceptable skin temperature range of 32.6 – 33.5 °C. Thus, this study presents the basic information regarding the seasonal effects on human thermal adaptation due to different long-term indoor thermal histories.

Hierarchical and K-means clustering to assess thermal dissatisfaction and productivity in university classrooms

The thermal environment is one of the main factors that influences Thermal Comfort and, consequently, the productivity of the occupants. The poor quality of the indoor environment in classrooms can be a risk to the health and productivity of students. This study evaluated the relationship between thermal dissatisfaction and productivity in university classrooms through a cluster analysis by hierarchical and non-hierarchical (k-means clustering) methods to verify how thermal dissatisfaction influences students' productivity. Two methods were adopted for determining the actual percentage of dissatisfaction (APD1 and APD2) and productivity (PROD1 and PROD2). After all calculations, 4 clusters were obtained; from the dendrogram, it was observed that clusters 2, 3, and 4 had the solutions with the highest stability. With the formation of clusters and their subsequent characterization, it was possible to observe the relationship between the two productivity methods and other variables, such as thermal dissatisfaction. The most significant variable for separating the clusters was PROD2. A discriminant analysis was performed to confirm that the clusters formed were effective, obtaining a 95.4% success ratio. Thus, when comparing the two most populous clusters, it was found that if self-perceived productivity is the highest, then thermal dissatisfaction based on thermal sensation votes will be the lowest. Also, it is suggested that there was a relation between the time of day and self-perceived productivity. Cold sensation is related to lower self-perceived productivity, while thermal neutrality is related to higher self-perceived productivity.