scholarly journals The Effect of Ceiling Heating and Mechanical Ventilation on Thermal Comfort

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3712
Author(s):  
Balázs András-Tövissi ◽  
László Kajtár ◽  
Árpád Nyers
Keyword(s):  
Mechanical Ventilation ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Mechanisms Of Action ◽  
Public Buildings ◽  
Predicted Mean Vote ◽  
Radiant Temperature ◽  
Temperature Asymmetry

In the case of public buildings with ceiling heating and mechanical ventilation, radiant temperature asymmetry caused by the warm ceiling and draught occur simultaneously. The currently available literature does not offer an exhaustive description of the comfort conditions resulting from such a thermal environment. This research focuses on complementing the available knowledge, using instrumental measurements, as well as subject measurements carried out on 20 individuals. Relying on these measurements, the purpose of the research is to support the understanding of the combined mechanisms of action of the two local discomfort parameters. The main result of this research is that, if the predicted percentage dissatified is less than 6%, the radiant temperature asymmetry is in an interval of 5–15 °C, and the draught rate is 15% or 25%, the actual mean vote and the predicted mean vote values differ significantly, and the actual mean vote is always lower, with a few exceptions. In addition, the research highlights the changes of the actual mean vote caused by raising the draught rate from 15% to 25%, in the presence of radiant temperature asymmetry caused by warm ceilings.

scholarly journals Experimental Investigation of Adaptive Thermal Comfort in French Healthcare Buildings

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 551
Author(s):  
Zoubayre El Akili ◽  
Youcef Bouzidi ◽  
Abdelatif Merabtine ◽  
Guillaume Polidori ◽  
Amal Chkeir
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Winter Season ◽  
Environmental Parameters ◽  
Physical Parameters ◽  
Predicted Mean Vote ◽  
Adaptive Thermal Comfort ◽  
Important Research Topic ◽  
Radiant Temperature ◽  
The Relationship

The thermal comfort requirements of disabled people in healthcare buildings are an important research topic that concerns a specific population with medical conditions impacted by the indoor environment. This paper experimentally investigated adaptive thermal comfort in buildings belonging to the Association of Parents of Disabled Children, located in the city of Troyes, France, during the winter season. Thermal comfort was evaluated using subjective measurements and objective physical parameters. The thermal sensations of respondents were determined by questionnaires adapted to their disability. Indoor environmental parameters such as relative humidity, mean radiant temperature, air temperature, and air velocity were measured using a thermal microclimate station during winter in February and March 2020. The main results indicated a strong correlation between operative temperature, predicted mean vote, and adaptive predicted mean vote, with the adaptive temperature estimated at around 21.65 °C. These findings highlighted the need to propose an adaptive thermal comfort strategy. Thus, a new adaptive model of the predicted mean vote was proposed and discussed, with a focus on the relationship between patient sensations and the thermal environment.

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.

scholarly journals Field Study Of A Radiant Heating System For Sleep Thermal Comfort And Potential Energy Saving

2021 ◽  
Author(s):  
Christopher L. K. Wang
Keyword(s):  
Potential Energy ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Energy Savings ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Thermal Conditions ◽  
Heating System ◽  
The Body ◽  
Radiant Temperature

As sleep is unconscious, the traditional definition of thermal comfort with conscious judgment does not apply. In this thesis sleep thermal comfort is defined as the thermal condition which enables sleep to most efficiently rejuvenate the body and mind. A comfort model was developed to stimulate the respective thermal environment required to achieve the desired body thermal conditions and a new infrared sphere method was developed to measure mean radiant temperature. Existing heating conditions according to building code conditions during sleeping hours was calculated to likely overheat a sleeping person and allowed energy saving potential by reducing nighttime heating set points. Experimenting with existing radiantly and forced air heated residential buildings, it was confirmed that thermal environment was too hot for comfortable sleep and that the infrared sphere method shows promise. With the site data, potential energy savings were calculated and around 10% of energy consumption reduction may be achieved during peak heating.

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 ANALISIS PENGARUH BENTUK SERAMBI MASJID TERHADAP KENYAMANAN TERMAL ADAPTIF

2020 ◽  
Vol 4 (3) ◽  
pp. 261
Author(s):  
Abdul Qodir ◽  
Erni Setyowati ◽  
Suryono Suryono
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Thermal Conditions ◽  
Temperature Range ◽  
Adaptive Thermal Comfort ◽  
Environment Variables ◽  
Average Condition ◽  
Radiant Temperature ◽  
Thermal Preferences ◽  
Neutral Conditions

This study examines the effect of the porch on the adaptive thermal comfort of mosques by taking 2 mosques that have different porch shapes with the specific purpose of obtaining data on the neutrality, acceptability and preferences of the mosque respondents' thermal conditions in the framework of developing adaptive thermal comfort standards for Indonesia. Measurement of physical environment variables is done by taking data on temperature, humidity, air velocity, and mean radiant temperature (MRT) at 2 mosques and at the same time the impression and thermal preference questionnaire data are taken, examination of clothing types and activities, and list of thermal environment controls to 40 respondents in each mosque. Data of thermal neutrality and thermal preferences were analyzed by regression analysis using SPSS 19 software, while thermal acceptance was analyzed based on the results of the questionnaire answers. The analysis showed that the neutrality value at Ulul Albab mosque was Tdb = 28.47 OC, ET * = 30.11 OC, SET * = 23.11 OC, TSENS = 1.17, DISC = -1.06, and PMV = -0.65, this data shows that the neutral condition desired by respondents is slightly below the average condition, while the neutrality in Nurul Ilmi mosque at Tdb = 30.27 OC, ET * = 31.65 OC, SET * = 29.05 OC, TSENS = 1.03, DISC = 1.68, and PMV = 1.22, this data also shows that the neutral conditions desired by respondents are slightly below average conditions. While the preference value at Ulul Albab mosque is Tdb = 22.25 OC, ET * = 28.62 OC, SET * = 24.24 OC, TSENS = 0.23, DISC = 0.23, and PMV = -0.60 and preference conditions at Nurul Ilmi mosque at Tdb = 29.11 OC, ET * = 31.17 OC, SET * = 28.50 OC, TSENS = 1.04, DISC = 1.45, and PMV = 1.03. As many as 92% of respondents in the Ulul Albab mosque can accept local thermal conditions in the temperature range of 27oC - 31oC. While 90% of respondents in the Nurul Ilmi mosque can accept local thermal conditions in the temperature range of 27oC-32oC. The results of the neutrality, acceptance and preference analysis show that the Ulul Albab mosque is better than the Nurul Ilmi mosque.

scholarly journals Evaluasi Kenyamanan Termal Ruang Sekolah SMA Negeri di Kota Padang

2016 ◽  
Vol 12 (1) ◽  
pp. 310 ◽  
Author(s):  
Lusi Susanti ◽  
Nike Aulia
Keyword(s):  
Thermal Comfort ◽  
Climatic Factors ◽  
Thermal Conditions ◽  
Comfort Level ◽  
Air Humidity ◽  
Student Body ◽  
Predicted Mean Vote ◽  
Individual Vote ◽  
The Individual ◽  
Radiant Temperature

This research aims to determine thermal conditions and sensation of thermal comfort in classrooms of high schools in Padang. This study was conducted in 11 State Senior High School (SMA) represented 11 districts in Padang. About 10% of total student body in each schools were participated in this study to vote thermal comfort questioners. To determine thermal comfort level in this study, PMV (Predicted mean Vote) and PPD (Predicted Percentage of dissatisfied) method were used according to standard of thermal comfort in ASHRAE 55-2005 and ISO 7730. PMV method is used to determine scope of situation in the environment that scaled from +3 for very hot until -3 for very cold, and PPD is a method to calculate the number of human (in percentage) dissatisfied with the environment. Calculated PMV and PPD were compared with PMV and PPD resulted from individual vote from questionnaires. Result showed that in general, thermal conditions in classrooms had air temperature and radiant temperature from 27oC – 30oC, air humidity from 68% - 80%, and wind speed of 0 m/s. Calculated PMV from this condition were ranging from +1 slightly warm) until +2 (warm) while PPD calculated greater than 20%. Compared with calculated PMV and PPD values, the individual vote showed values from +0,5 (neutral) until +1 (slightly warm) while PPD values of individual vote greater than 20% except for SMA 2 and SMA 11 Padang. It is concluded that improvements of indoor thermal conditions have to make inside classrooms as well as landscape outside in order to improve thermal comfort level of students during learning and teaching.Keywords: Thermal Comfort, PMV (Predicted Mean Vote), PPD (Predicted Percentage ofDissatisfied), climatic factors, SMA

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%.

scholarly journals Research on Indoor Thermal Comfort and Age of Air in Qilou Street Shop under Mechanical Ventilation Scheme: A Case Study of Nanning Traditional Block in Southern China

2021 ◽  
Vol 13 (7) ◽  
pp. 4037
Author(s):  
Xianfeng Huang ◽  
Chen Qu
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Thermal Comfort ◽  
Thermal Environment ◽  
Southern China ◽  
Air Conditioner ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Circulation Mode ◽  
Ventilation Scheme

In hot summers, air conditioning (AC) and mechanical ventilation (such as fans) are used as cooling modes that strongly influence the resultant indoor environment, like thermal comfort and air quality in the shops of a Nanning arcade street (qilou). The air circulation mode in shops greatly affects the indoor thermal environment and level of air freshness. The approaches for effectively improving the indoor thermal comfort and air quality are developed in qilou street shops with air-conditioner in a humid and hot region in southern China. Consequently, the purpose of this study is to assess different ventilation schemes in order to identify the best one. By using two indices, i.e., the predicted mean vote (PMV) and the age of air (AoA), in situ measurement and numerical simulation are conducted to investigate humans’ thermal comfort in extreme summer. Then, the indoor thermal comfort and AoA levels in summer under three different ventilation schemes (upper-inlet–upper-outlet, upper-inlet–bottom-outlet, and side-inlet–side-outlet) are comparatively analyzed through numerical computations of the indoor thermal environment. The results show that the upper-inlet–upper-outlet mode of the AC ventilation scheme led to the creation of a favorable air quality and comfortable thermal environment inside the shop, which will help designers understand the influence of the ventilation scheme on the indoor thermal comfort and health environment.

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