Ergonomics of the thermal environment. Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria

2006 ◽  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Analytical Determination ◽  
Local Thermal Comfort ◽  
Comfort Criteria

Some evidence of a time-varying thermal perception

2021 ◽  
pp. 1420326X2110345
Author(s):  
Marika Vellei ◽  
William O’Brien ◽  
Simon Martinez ◽  
Jérôme Le Dréau
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Time Of Day ◽  
Time Varying ◽  
Thermal Perception ◽  
Indoor Thermal Environment ◽  
Human Circadian Rhythm ◽  
Comfort Criteria

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.

Enhanced effects of footwarmer by wearing sandals in winter office: A Swedish case study

2020 ◽  
pp. 1420326X2091397 ◽  
Author(s):  
Bin Yang ◽  
Zhe Li ◽  
Bin Zhou ◽  
Thomas Olofsson ◽  
Angui Li
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Heating Temperature ◽  
Whole Body ◽  
Thermal Stimulus ◽  
Body Parts ◽  
Heating Effects ◽  
Localized Heating ◽  
Cooling Devices ◽  
Local Thermal Comfort

Human-centred thermal environment conditioning can guarantee thermal comfort needs of human occupants in their micro-environments by using localized heating/cooling devices. Meanwhile, less intensified thermal conditioning of unoccupied surrounding environments can achieve heating/cooling energy efficiency. The concept was originated from task/ambient conditioning, which was developed for personal comfort systems. Most of the localized heating/cooling devices are workstation based or chair based. Task conditioning would become more closely to targets (human bodies) by using special clothing materials or thermoelectric elements. From thermal physiological viewpoints, thermal stimulus to thermally sensitive body parts may generate better results for not only local thermal comfort but also for whole body thermal comfort. Thermal stimulus to the extremities (feet) has demonstrated good thermal comfort effects. Scandinavians are accustomed to outdoor harsh environments and prefer wearing heavy shoes' outdoors in winter. They have the habit of changing heavy shoes to sandals when entering offices, which give the opportunity to enhance localized heating effects of footwarmers by reducing shoes’ thermal resistance. Climatic chamber tests with 32 Nordic subjects were performed under different indoor ambient heating temperatures with/without the aid of footwarmers. With footwarmers and sandals, indoor heating temperature at 16°C was acceptable, which achieved energy efficient thermal comfort.

scholarly journals Effect of thermochromic coatings on the indoor thermal behavior of a case study building

2021 ◽  
Vol 238 ◽  
pp. 06003
Author(s):  
Claudia Fabiani ◽  
Anna Laura Pisello
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Positive Impact ◽  
Central Italy ◽  
Research Work ◽  
Research Field ◽  
Building Envelope ◽  
Local Boundary ◽  
Local Thermal Comfort

Passive systems and solutions aimed at improving local thermal comfort conditions represent a cutting-edge research field in building applications. However, only a few investigations were performed by taking into account the local distribution and spatial variability of the airflow generated by the application of both traditional and innovative passive strategies. The present research work is aimed at bridging such gap by modelling the indoor thermal environment of a case study prototype building, i.e. test-room, situated in central Italy, by taking into account the indoor heat transfer phenomena. In particular, a CFD model of the building is elaborated and used to predict the indoor thermal effect of an adaptive thermochromic envelope, compared to more traditional solutions. The simulation results are post-processed in terms of (i) indoor temperature and (ii) indoor airflows. The main findings confirm a non-negligible and positive impact of the thermochromic building envelope on the local indoor thermal comfort conditions in both summer and winter conditions, due to its capability of selectively tailor the absorption of heat gains and a function of the local boundary conditions.

scholarly journals A Comparative Study on Cooling Period Thermal Comfort Assessment in Modern Open Office Landscape in Estonia

2019 ◽  
Author(s):  
Martin Kiil ◽  
Raimo Simson ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Ventilation System ◽  
Work Environments ◽  
Office Buildings ◽  
Indoor Climate ◽  
Cooling Period ◽  
Actual Usage ◽  
Air Ventilation ◽  
Local Thermal Comfort

Local thermal comfort (TC) and draught rate (DR) has been studied widely. There has been more meaningful research performed in controlled boundary condition situations than in actual work environments involving occupants. TC conditions in office buildings in Estonia have been barely investigated in the past. In this paper, the results of TC and DR assessment in five office buildings in Tallinn are presented and discussed. Studied office landscapes vary in heating, ventilation and cooling (HVAC) system parameters, room units and elements. All sample buildings were less than six years old, equipped with dedicated outdoor air ventilation system and room conditioning units. The on-site measurements consisted of TC and DR assessment with indoor climate questionnaire (ICQ). The purpose of the survey is to assess the correspondence between HVAC design and the actual situation. Results show, whether and in what extent the standard-based criteria for TC is suitable for actual usage of the occupants. Preferring one room conditioning unit type or system may not guarantee better thermal environment without draught. Although some HVAC systems observed in this study should create the prerequisites for ensuring more comfort, results show that this is not the case for all buildings in this study.

scholarly journals A Comparative Study on Cooling Period Thermal Comfort Assessment in Modern Open Office Landscape in Estonia

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 127 ◽  
Author(s):  
Martin Kiil ◽  
Raimo Simson ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Cooling System ◽  
Ventilation System ◽  
Office Buildings ◽  
Indoor Climate ◽  
Cooling Period ◽  
Actual Usage ◽  
Air Ventilation ◽  
Local Thermal Comfort

Local thermal comfort and draught rate has been studied widely. There has been more meaningful research performed in controlled boundary condition situations than in actual work environments involving occupants. Thermal comfort conditions in office buildings in Estonia have been barely investigated in the past. In this paper, the results of thermal comfort and draught rate assessment in five office buildings in Tallinn are presented and discussed. Studied office landscapes vary in heating, ventilation and cooling system parameters, room units, and elements. All sample buildings were less than six years old, equipped with dedicated outdoor air ventilation system and room conditioning units. The on-site measurements consisted of thermal comfort and draught rate assessment with indoor climate questionnaire. The purpose of the survey is to assess the correspondence between heating, ventilation and cooling system design, and the actual situation. Results show, whether and in what extent the standard-based criteria for thermal comfort is suitable for actual usage of the occupants. Preferring one room conditioning unit type or system may not guarantee better thermal environment without draught. Although some heating, ventilation and cooling systems observed in this study should create the prerequisites for ensuring more comfort, results show that this is not the case for all buildings in this study.

scholarly journals Evaluating the Connection between Thermal Comfort and Productivity in Buildings: A Systematic Literature Review

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 244
Author(s):  
Ana Maria Bueno ◽  
Antonio Augusto de Paula Xavier ◽  
Evandro Eduardo Broday
Keyword(s):  
Literature Review ◽  
Thermal Comfort ◽  
Systematic Literature Review ◽  
Thermal Environment ◽  
Final Analysis ◽  
Personal Factors ◽  
Exclusion Criteria ◽  
Environment Variables ◽  
Main Factors ◽  
Combination Of Methods

The thermal environment is one of the main factors that influence thermal comfort and, consequently, the productivity of occupants inside buildings. Throughout the years, research has described the connection between thermal comfort and productivity. Mathematical models have been established in the attempt to predict changes in productivity according to thermal variations in the environment. Some of these models have failed for a number of reasons, including the understanding of the effect that several environment variables have had on performance. From this context, a systematic literature review was carried out with the aim of verifying the connection between thermal comfort and productivity and the combinations of different thermal and personal factors that can have an effect on productivity. A hundred and twenty-eight articles were found which show a connection between productivity and some thermal comfort variables. By means of specific inclusion and exclusion criteria, 60 articles were selected for a final analysis. The main conclusions found in this study were: (i) the vast majority of research uses subjective measures and/or a combination of methods to evaluate productivity; (ii) performance/productivity can be attained within an ampler temperature range; (iii) few studies present ways of calculating productivity.

scholarly journals Development of a Deep Neural Network Model for Estimating Joint Location of Occupant Indoor Activities for Providing Thermal Comfort

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 696
Author(s):  
Eun Ji Choi ◽  
Jin Woo Moon ◽  
Ji-hoon Han ◽  
Yongseok Yoo
Keyword(s):  
Neural Network ◽  
Thermal Comfort ◽  
Deep Neural Network ◽  
Mean Squared Error ◽  
Thermal Environment ◽  
The Body ◽  
Estimation Accuracy ◽  
Accurate Estimation ◽  
Body Parts ◽  
Joint Location

The type of occupant activities is a significantly important factor to determine indoor thermal comfort; thus, an accurate method to estimate occupant activity needs to be developed. The purpose of this study was to develop a deep neural network (DNN) model for estimating the joint location of diverse human activities, which will be used to provide a comfortable thermal environment. The DNN model was trained with images to estimate 14 joints of a person performing 10 common indoor activities. The DNN contained numerous shortcut connections for efficient training and had two stages of sequential and parallel layers for accurate joint localization. Estimation accuracy was quantified using the mean squared error (MSE) for the estimated joints and the percentage of correct parts (PCP) for the body parts. The results show that the joint MSEs for the head and neck were lowest, and the PCP was highest for the torso. The PCP for individual activities ranged from 0.71 to 0.92, while typing and standing in a relaxed manner were the activities with the highest PCP. Estimation accuracy was higher for relatively still activities and lower for activities involving wide-ranging arm or leg motion. This study thus highlights the potential for the accurate estimation of occupant indoor activities by proposing a novel DNN model. This approach holds significant promise for finding the actual type of occupant activities and for use in target indoor applications related to thermal comfort in buildings.

scholarly journals How Can We Adapt Thermal Comfort for Disabled Patients? A Case Study of French Healthcare Buildings in Summer

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4530
Author(s):  
Youcef Bouzidi ◽  
Zoubayre El Akili ◽  
Antoine Gademer ◽  
Nacef Tazi ◽  
Adil Chahboun
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Linear Regression Analysis ◽  
Environmental Parameters ◽  
Physical Parameters ◽  
Mean Radiant Temperature ◽  
Operative Temperature ◽  
Neutral Temperature ◽  
Radiant Temperature

This paper investigates adaptive thermal comfort during summer in medical residences that are located in the French city of Troyes and managed by the Association of Parents of Disabled Children (APEI). Thermal comfort in these buildings is evaluated using subjective measurements and objective physical parameters. The thermal sensations of respondents were determined by questionnaires, while thermal comfort was estimated using the predicted mean vote (PMV) model. Indoor environmental parameters (relative humidity, mean radiant temperature, air temperature, and air velocity) were measured using a thermal environment sensor during the summer period in July and August 2018. A good correlation was found between operative temperature, mean radiant temperature, and PMV. The neutral temperature was determined by linear regression analysis of the operative temperature and Fanger’s PMV model. The obtained neutral temperature is 23.7 °C. Based on the datasets and questionnaires, the adaptive coefficient α representing patients’ capacity to adapt to heat was found to be 1.261. A strong correlation was also observed between the sequential thermal index n(t) and the adaptive temperature. Finally, a new empirical model of adaptive temperature was developed using the data collected from a longitudinal survey in four residential buildings of APEI in summer, and the obtained adaptive temperature is 25.0 °C with upper and lower limits of 24.7 °C and 25.4 °C.

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