scholarly journals Investigating Thermal Comfort for the Classroom Environment using IoT

2018 ◽  
Vol 9 (1) ◽  
pp. 157 ◽  
Author(s):  
Nurshahrily Idura Ramli ◽  
Mohd Izani Mohamed Rawi ◽  
Ahmad Zahid Hijazi ◽  
Abdullah Hayyan Kunji Mohammed
Keyword(s):  
Environmental Factors ◽  
Metabolic Rate ◽  
Thermal Comfort ◽  
Classroom Environment ◽  
Thermal Sensation ◽  
Influencing Factor ◽  
Physiological Factors ◽  
Clothing Insulation ◽  
Air Movement ◽  
Radiant Temperature

<p>In this modern century where fine comfort is a necessity especially in buildings and occupied space, the study to satisfy one aspect of human comfort is a must. This study encompasses of exploring the physiological and environmental factors in achieving thermal comfort which specifically considering the clothing insulation and metabolic rate of students as well as the deployment of dry-bulb temperature, mean radiant temperature, humidity, and air movement in order to obtain the level of comfort students are experiencing in class. The level of comfort are detected by using ASHRAE 55 to determine the average thermal sensation response through the Predicted Mean Vote (PMV) value. An android application were developed to read input of recognizing clothing level (thickness of clothing) and capturing metabolic rate to cater the inputs for physiological factors, while radiant temperature, humidity and air movement are captured through static sensors set up in the classroom space. This paper analyses both the physiological and environmental factors in affecting students in class and further determine their comfort levels that is a major influencing factor of focus in learning. Through cross referencing collected data from IoT enabled nodes, it is found that both physiological and environmental factors, and the combination of them greatly influence in getting the most comfortable state with PMV value of 0.</p>

scholarly journals Objective and subjective thermal comfort evaluation in Hungary

2017 ◽  
Vol 21 (3) ◽  
pp. 1409-1418 ◽  
Author(s):  
Laszlo Kajtar ◽  
Jozsef Nyers ◽  
Janos Szabo ◽  
Laszlo Ketskemety ◽  
Levente Herczeg ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Evaluation Method ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Climatic Conditions ◽  
Temperate Climate ◽  
Clothing Insulation ◽  
Winter Time ◽  
Radiant Temperature ◽  
S Model

Thermal comfort sensation can be predicted in the most exact way based on Fanger?s predicted mean vote (PMV) model. This evaluation method takes all the six influencing factors into consideration: air temperature and humidity, air velocity, mean radiant temperature of surrounding surfaces, clothing insulation, and occupants? activities. Fanger?s PMV method was developed for temperate climate and European people, with the participation of university students as subjects. Many researchers had investigated its validity in different geographic locations (i. e. climatic conditions, people) and under non-laboratory circumstances. The results were summarised by van Hoof which had been published in the scientific references. The articles gave us the idea to elaborate the former measurement results. During the last decades thermal comfort was evaluated by our research team using subjective scientific questionnaires and applying the objective Fanger?s model in several office buildings in Hungary. The relation between the PMV and actual mean vote values were analysed based on these results. Investigations were carried out under steady-state conditions in winter time. We performed objective thermal comfort evaluations based on instrumental measurements using the PMV theory. Parallel to this we assessed the subjective thermal sensation using scientific questionnaires. The mathematical relationship between the actual mean vote and PMV was defined according to the evaluated thermal environment: AMV = PMV + 0.275, (arg. ?1.7 ? PMV ? +0.5).

scholarly journals The Effects of a Passive Exoskeleton on Human Thermal Responses in Temperate and Cold Environments

2021 ◽  
Vol 18 (8) ◽  
pp. 3889
Author(s):  
Yang Liu ◽  
Xiaoling Li ◽  
Jiarui Lai ◽  
Aibin Zhu ◽  
Xiaodong Zhang ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Thermal Comfort ◽  
Thermal Sensation ◽  
Thermal Response ◽  
Clothing Insulation ◽  
Ambient Temperatures ◽  
Cold Environments ◽  
Significant Difference ◽  
Passive Exoskeleton ◽  
Package Handlers

The exoskeleton as functional wearable equipment has been increasingly used in working environments. However, the effects of wearing an exoskeleton on human thermal responses are still unknown. In this study, 10 male package handlers were exposed to 10 °C (COLD) and 25 °C (TEMP) ambient temperatures while performing a 10 kg lifting task (LIFTING) and sedentary (REST) both with (EXO) and without the exoskeleton (WEXO). Thermal responses, including the metabolic rate and mean skin temperature (MST), were continuously measured. Thermal comfort, thermal sensation and sweat feeling were also recorded. For LIFTING, metabolic heat production is significant decrease with the exoskeleton support. The MST and thermal sensation significantly increase when wearing the exoskeleton, but thermal discomfort and sweating are only aggravated in TEMP. For REST, MST and thermal sensation are also increased by the exoskeleton, and there is no significant difference in the metabolic rate between EXO and WEXO. The thermal comfort is significantly improved by wearing the exoskeleton only in COLD. The results suggest that the passive exoskeleton increases the local clothing insulation, and the way of wearing reduces the “pumping effect”, which makes a difference in the thermal response between COLD and TEMP. Designers need to develop appropriate usage strategies according to the operative temperature.

scholarly journals Clothing Insulation Rate and Metabolic Rate Estimation for Individual Thermal Comfort Assessment in Real Life

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 619
Author(s):  
Jinsong Liu ◽  
Isak Worre Foged ◽  
Thomas B. Moeslund
Keyword(s):  
Metabolic Rate ◽  
Thermal Comfort ◽  
Real Life ◽  
Activity Level ◽  
Tracking Accuracy ◽  
Classification Rate ◽  
Clothing Insulation ◽  
Activity Intensity ◽  
Bounding Box ◽  
Tracking By Detection

Satisfactory indoor thermal environments can improve working efficiencies of office staff. To build such satisfactory indoor microclimates, individual thermal comfort assessment is important, for which personal clothing insulation rate (Icl) and metabolic rate (M) need to be estimated dynamically. Therefore, this paper proposes a vision-based method. Specifically, a human tracking-by-detection framework is implemented to acquire each person’s clothing status (short-sleeved, long-sleeved), key posture (sitting, standing), and bounding box information simultaneously. The clothing status together with a key body points detector locate the person’s skin region and clothes region, allowing the measurement of skin temperature (Ts) and clothes temperature (Tc), and realizing the calculation of Icl from Ts and Tc. The key posture and the bounding box change across time can category the person’s activity intensity into a corresponding level, from which the M value is estimated. Moreover, we have collected a multi-person thermal dataset to evaluate the method. The tracking-by-detection framework achieves a mAP50 (Mean Average Precision) rate of 89.1% and a MOTA (Multiple Object Tracking Accuracy) rate of 99.5%. The Icl estimation module gets an accuracy of 96.2% in locating skin and clothes. The M estimation module obtains a classification rate of 95.6% in categorizing activity level. All of these prove the usefulness of the proposed method in a multi-person scenario of real-life applications.

Required temperature distribution based on clothing insulation and metabolic rate survey in Japan

2019 ◽  
Vol 29 (6) ◽  
pp. 775-782
Author(s):  
Masanari Ukai ◽  
Tatsuo Nobe
Keyword(s):  
Physical Activity ◽  
Temperature Distribution ◽  
Metabolic Rate ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
Metabolic Rates ◽  
Clothing Insulation ◽  
Office Environment ◽  
Temporal And Spatial ◽  
Temperature Side

In this study, the authors evaluated clothing insulation and changes in the metabolic rate of individuals in an office environment to determine thermal comfort. Clothing was evaluated using a questionnaire completed by 1306 workers in nine offices. The metabolic rates of 86 workers in three offices were measured using a physical activity meter. The distribution of the temperature at which a person in the room perceived a neutral thermal sensation was then calculated from the determined metabolic rates and clothing insulation values. The results demonstrate a noticeable difference between the average and most frequent values during the summer. Moreover, the required temperature distribution is not normal; rather, it is broad and skewed to the low-temperature side. Therefore, even if a thermally uniform environment is provided at the average required temperature by preventing temporal and spatial variations in the thermal environment, complaints of an unacceptably hot thermal environment are more likely to occur than complaints of an excessively cold thermal environment.

Influence of sinusoidal airflow and airflow distance on human thermal response to a personalized ventilation system

2016 ◽  
Vol 27 (3) ◽  
pp. 317-330 ◽  
Author(s):  
Yongxin Xie ◽  
Sauchung Fu ◽  
Chili Wu ◽  
Christopher Y.H. Chao
Keyword(s):  
Thermal Comfort ◽  
Thermal Sensation ◽  
Human Subjects ◽  
Ventilation System ◽  
Thermal Response ◽  
Joint Effect ◽  
Experimental Conditions ◽  
Movement Perception ◽  
Air Movement ◽  
Personalized Ventilation

Since the concept of personalized ventilation was introduced in the late 1990s, many studies on thermal comfort have been conducted and a number of parameters identified. In this research, the influence of three parameters, the airflow speed, airflow fluctuating period and a parameter which has drawn less attention in previous studies – the airflow distance between the human subject and the nozzle of the personalized ventilation device on air movement perception, thermal sensation and thermal comfort – are studied. The combinations of fluctuating period and airflow amplitude were selected based on the Power Spectrum Density method. Then 25 human subjects participated in the thermal comfort experiment, each of them underwent 54 tests of different experimental conditions and expressed their thermal feelings by completing the survey questionnaire. Our findings showed that a longer airflow distance could lead to cooler thermal sensation, but not cause any difference in thermal comfort. Changing the fluctuating period of the sinusoidal airflow from 10 s to 60 s did not cause an influence on thermal sensation, but a shorter fluctuating period could result in a higher air movement perception. When dealing with thermal comfort issues, a joint effect with airflow speed and fluctuating period occurs and this should also be considered.

A Data-Driven Thermal Sensation Model Based Predictive Controller for Indoor Thermal Comfort and Energy Optimization

2014 ◽  
Author(s):  
Xiao Chen ◽  
Qian Wang
Keyword(s):  
Thermal Comfort ◽  
Thermal Sensation ◽  
Energy Optimization ◽  
Data Driven ◽  
Air Velocity ◽  
Comfort Index ◽  
Indoor Thermal Comfort ◽  
Occupant Feedback ◽  
Predictive Controller ◽  
Radiant Temperature

This paper proposes a model predictive controller (MPC) using a data-driven thermal sensation model for indoor thermal comfort and energy optimization. The uniqueness of this empirical thermal sensation model lies in that it uses feedback from occupants (occupant actual votes) to improve the accuracy of model prediction. We evaluated the performance of our controller by comparing it with other MPC controllers developed using the Predicted Mean Vote (PMV) model as thermal comfort index. The simulation results demonstrate that in general our controller achieves a comparable level of energy consumption and comfort while eases the computation demand posed by using the PMV model in the MPC formulation. It is also worth pointing out that since we assume that our controller receives occupant feedback (votes) on thermal comfort, we do not need to monitor the parameters such as relative humidity, air velocity, mean radiant temperature and occupant clothing level changes which are necessary in the computation of PMV index. Furthermore simulations show that in cases where occupants’ actual sensation votes might deviate from the PMV predictions (i.e., a bias associated with PMV), our controller has the potential to outperform the PMV based MPC controller by providing a better indoor thermal comfort.

Thermal comfort analyses of naturally ventilated university classrooms

2016 ◽  
Vol 34 (4/5) ◽  
pp. 427-445 ◽  
Author(s):  
Baharuddin Hamzah ◽  
Muhammad Taufik Ishak ◽  
Syarif Beddu ◽  
Mohammad Yoenus Osman
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Thermal Environment ◽  
Thermal Sensation ◽  
National Standard ◽  
Content Type ◽  
Thermal Environments ◽  
Neutral Temperature ◽  
Radiant Temperature ◽  
University Classrooms

Purpose The purpose of this paper is to analyse thermal comfort and the thermal environment in naturally ventilated classrooms. Specifically, the aims of the study were to identify the thermal environment and thermal comfort of respondents in naturally ventilated university classrooms and compare them with the ASHRAE and Indonesian National Standard (SNI); to check on whether the predicted mean vote (PMV) model is applicable or not for predicting the thermal comfort of occupants in naturally ventilated university classrooms; and to analyse the neutral temperature of occupants in the naturally ventilated university classrooms. Design/methodology/approach The study was carried out at the new campus of Faculty of Engineering, Hasanuddin University, Gowa campus. A number of field surveys, which measured thermal environments, namely, air temperature, mean radiant temperature (MRT), relative humidity, and air velocity, were carried out. The personal activity and clothing properties were also recorded. At the same time, respondents were asked to fill a questionnaire to obtain their thermal sensation votes (TSV) and thermal comfort votes (TCV), thermal preference, and thermal acceptance. A total of 118 respondents participated in the study. Before the survey was conducted, a brief explanation was provided to the participants to ensure that they understood the study objectives and also how to fill in the questionnaires. Findings The results indicated that the surveyed classrooms had higher thermal environments than those specified in the well-known ASHRAE standard and Indonesian National Standard (SNI). However, this condition did not make respondents feel uncomfortable because a large proportion of respondents voted within the comfort zone (+1, 0, and −1). The predictive mean vote using the PMV model was higher than the respondents’ votes either by TSV or by TCV. There was a huge difference between neutral temperature using operative temperature (To) and air temperature (Ta). This difference may have been because of the small value of MRT recorded in the measured classrooms. Originality/value The research shows that the use of the PMV model in predicting thermal comfort in the tropic region might be misleading. This is because PMV mostly overestimates the TSV and TCV of the respondents. People in the tropic region are more tolerant to a higher temperature. On the basis of this finding, there is a need to develop a new thermal comfort model for university classrooms that is particularly optimal for this tropical area.

scholarly journals Experimental Evaluation of Radiant Heating Ceiling Systems Based on Thermal Comfort Criteria

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2932 ◽  
Author(s):  
M. Safizadeh ◽  
Marcel Schweiker ◽  
Andreas Wagner
Keyword(s):  
Low Temperature ◽  
Thermal Comfort ◽  
Thermal Sensation ◽  
Building Envelope ◽  
Building Energy Efficiency ◽  
Radiant Heating ◽  
Heating Systems ◽  
Radiant Temperature ◽  
Temperature Asymmetry ◽  
Comfort Criteria

Low-temperature radiant heating systems can be considered as suitable candidates for the refurbishment of old heating systems. These systems are proven to save energy, however, their drawback is their impact on the creation of radiant temperature asymmetry and local thermal discomfort, especially in old buildings where the temperatures of surfaces (for example external walls with a low level of insulation and large windows) are low. This study aims to evaluate the potential application of low-temperature radiant ceiling heating systems (28–38 °C) in old and energy-renovated buildings, based on subjective experiments and thermal comfort criteria such as thermal sensation, comfort, satisfaction, and sensation asymmetry votes. Later, in the Discussion section, the guideline for the radiant temperature asymmetry for the warm ceiling presented in ASHRAE Standard-55 is corrected for relatively low air temperatures and different surface temperatures corresponding to “about neutral” conditions for winter clothing. Findings of this research show that the radiant ceiling heating system operating at low temperatures (33–38 °C) can provide fairly neutral thermal sensation and satisfactory comfort at the majority of body-parts, if the building envelope satisfies advanced building energy-efficiency regulations. Additionally, the experimental analyses imply that limitation of 5% suggested by ASHRAE-55 for the percentage of dissatisfied occupants feeling uncomfortable due to overhead radiation can be elevated to 10%.

Effects of temperature, air movement and initial metabolic rate on thermal sensation during transient state in the tropics

2019 ◽  
Vol 155 ◽  
pp. 70-82 ◽  
Author(s):  
Kuniaki Mihara ◽  
Chandra Sekhar ◽  
Kwok Wai Tham ◽  
Yuichi Takemasa ◽  
Bertrand Lasternas
Keyword(s):  
Metabolic Rate ◽  
Thermal Sensation ◽  
Transient State ◽  
Air Movement ◽  
Effects Of Temperature ◽  
The Tropics
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