Experimental study on coupling effect of indoor air temperature and radiant temperature on human thermal comfort in non-uniform thermal environment

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

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An Interactive Task Conditioning System Featuring Personal Comfort Models and Non-Intrusive Sensing Techniques: A Field Study in Shanghai

Technologies ◽

10.3390/technologies9040090 ◽

2021 ◽

Vol 9 (4) ◽

pp. 90

Author(s):

Siliang Lu ◽

Erica Cochran Hameen

Keyword(s):

Thermal Comfort ◽

Field Study ◽

Air Temperature ◽

Indoor Air ◽

Thermal Environment ◽

Thermal Sensation ◽

New Paradigm ◽

Dynamic Task ◽

Current Task ◽

Open Plan

Heating, ventilation and air-conditioning (HVAC) systems play a key role in shaping office environments. However, open-plan office buildings nowadays are also faced with problems like unnecessary energy waste and an unsatisfactory shared indoor thermal environment. Therefore, it is significant to develop a new paradigm of an HVAC system framework so that everyone could work under their preferred thermal environment and the system can achieve higher energy efficiency such as task ambient conditioning system (TAC). However, current task conditioning systems are not responsive to personal thermal comfort dynamically. Hence, this research aims to develop a dynamic task conditioning system featuring personal thermal comfort models with machine learning and the wireless non-intrusive sensing system. In order to evaluate the proposed task conditioning system performance, a field study was conducted in a shared office space in Shanghai from July to August. As a result, personal thermal comfort models with indoor air temperature, relative humidity and cheek (side face) skin temperature have better performances than baseline models with indoor air temperature only. Moreover, compared to personal thermal satisfaction predictions, 90% of subjects have better performances in thermal sensation predictions. Therefore, personal thermal comfort models could be further implemented into the task conditioning control of TAC systems.

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Experimental study on dynamic thermal environment of passenger compartment based on thermal evaluation indexes

Science Progress ◽

10.1177/0036850420942991 ◽

2020 ◽

Vol 103 (3) ◽

pp. 003685042094299

Author(s):

Liang Zhang ◽

Liangkui Qi ◽

Jianhua Liu ◽

Qingqing Wu

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Prediction Accuracy ◽

Thermal Environment ◽

Temperature Model ◽

Equivalent Temperature ◽

Vote Model ◽

Evaluation Indexes ◽

Human Thermal Comfort ◽

Experimental Values

In this article, the thermal environment and the human thermal comfort of car cabin under different driving states in summer were studied experimentally. The weighted predictive mean vote model and the weighted equivalent temperature model were used for calculation and compared with the experimental values. The experimental results show that the air temperature and relative humidity distribution in cabin are affected by the space position and driving state. The temperature of the cabin seat, which is affected by solar radiation and crew, in the heating stage is slightly higher than the air temperature, while the cooling rate in the cooling stage is much lower than the air temperature. The predictive mean vote model and the equivalent temperature model are basically consistent with the actual thermal comfort of human body under the idle and driving conditions with the change of time. The prediction accuracy of the two models under the idle condition is higher than that under the driving condition, and the overall prediction accuracy of the equivalent temperature model is higher than that of the predictive mean vote model.

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Thermal comfort analyses of naturally ventilated university classrooms

Structural Survey ◽

10.1108/ss-12-2015-0055 ◽

2016 ◽

Vol 34 (4/5) ◽

pp. 427-445 ◽

Cited By ~ 11

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.

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The effects of building layouts and envelope on indoor thermal environment of Hui style traditional buildings in Wuyuan

E3S Web of Conferences ◽

10.1051/e3sconf/202019405013 ◽

2020 ◽

Vol 194 ◽

pp. 05013

Author(s):

Xiaowei Hong ◽

Guangjin Zhang ◽

Yufeng Zhang

Keyword(s):

Quantitative Analysis ◽

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Thermal Environment ◽

Field Investigation ◽

Indoor Thermal Environment ◽

Adaptive Thermal Comfort ◽

Thermal Comfort Model

Indoor thermal environment of Hui style traditional houses is depended on surrounding environments, building layouts and envelope. Quantitative analysis of the effects of building layouts and envelope on indoor thermal environment is of great significance for preventions of traditional houses and design of new archaized houses. A field investigation was conducted on thirty-six traditional houses from nine villages in Wuyuan, and the typical buildings’ layout and envelope were determined. Four traditional buildings in different location in Wuyuan were selected for continual recording. The four buildings with four types of building layouts and envelope were analyzed by using local adaptive thermal comfort model, and the effects of building layouts and envelope of traditional buildings were clearly revealed. The most crucial way to improve indoor thermal environment in Hui style traditional buildings was raising the indoor air temperature.

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Thermal comfort analysis of radiant cooling panels with dedicated fresh-air system

Indoor and Built Environment ◽

10.1177/1420326x20961142 ◽

2020 ◽

pp. 1420326X2096114

Author(s):

S. Y. Qin ◽

X. Cui ◽

C. Yang ◽

L. W. Jin

Keyword(s):

Relative Humidity ◽

Surface Temperature ◽

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Area Ratio ◽

Human Thermal Comfort ◽

Air Supply ◽

Radiant Cooling ◽

Air System

Radiant system has been increasingly applied in buildings due to its good thermal comfort and energy-saving potential. In this research, a simplified predicted mean vote (PMV) model and sensible cooling load equation were proposed based on human thermal comfort. Simulations were carried out using Airpak to explore relationships among thermal comfort characteristics, design and operation parameters. Results show that radiant surface temperature, fresh-air supply temperature and the area ratio are correlated approximately linearly with the indoor air temperature, while the relative humidity has little effect on the indoor air temperature. The indoor air velocity in the simulated environment was no more than 0.15 m/s, satisfying the requirements of limit values in the occupied zone. The results indicate that the optimum radiant surface temperature ( tc) is 19°C to 23°C when fresh-air supply temperature ( ts) is 26°C. The relative humidity ( φ) should be maintained at 50% to 70%, and the area ratio of radiant panels to total surfaces ( k1) should be kept within 0.15 to 0.38 when the radiant surface temperature is 20°C and the fresh-air supply temperature is 26°C. The simplified PMV model and the sensible load equation can provide reference for panel design based on characteristics of radiant cooling panels with a dedicated fresh-air system.

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Field Survey on Occupant Thermal Comfort of Cold Regions in Transition Season

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.805-806.1620 ◽

2013 ◽

Vol 805-806 ◽

pp. 1620-1624 ◽

Cited By ~ 2

Author(s):

Wan Ying Qu

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Field Survey ◽

Thermal Environment ◽

Thermal Sensation ◽

Residential Buildings ◽

Cold Regions ◽

Indoor Thermal Environment ◽

Transition Season

A thermal comfort field study was investigated in residential buildings of cold regions in transition season during which the indoor thermal environment conditions are measured, the thermal sensation value of the occupants is questioned and recorded. A seven-point thermal sensation scale was used to evaluate the thermal sensation. The statistical method was used to analyze the data and the conclusions are as follows in transition season: clothing increase in 0.1clo when the indoor air temperature is lowered by 1°C; and clothing will be a corresponding increase in 0.06clo when the outdoor air temperature is lowered by 1°C; clothing also varies with gender, age, weight and thermal history and other related; the measured thermal neutral temperature is 21.3°C; and the minimum accepted temperature is 11.4 °C in transition season in cold regions. Most people choose to change clothes, switch and other passive measures, and occasionally take active measures of heater, electric fans and others.

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An Investigation of the Behavioral Characteristics of Higher- and Lower-Temperature Group Families in a Condominium Equipped with a HEMS System

Buildings ◽

10.3390/buildings9010004 ◽

2018 ◽

Vol 9 (1) ◽

pp. 4 ◽

Cited By ~ 3

Author(s):

Rajan KC ◽

Hom Rijal ◽

Masanori Shukuya ◽

Kazui Yoshida

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Energy Use ◽

Thermal Environment ◽

Indoor Thermal Environment ◽

Home Energy Management ◽

Temperature Group ◽

Higher Temperature ◽

Lower Temperature

A home energy management system (HEMS) shows the energy used indoors so that the energy waste can be easily identified and reduced. Thermal comfort is related to the trend of energy use in buildings. We conducted a survey in a condominium equipped with a HEMS to determine the indoor thermal environment and various behaviors of the occupants taken for thermal comfort adjustment. The results showed that there is a large variation of indoor air temperatures according to season, floor and flat. We categorized families into two groups, one with higher and the other with lower average indoor temperatures. The indoor air temperature of the higher temperature group in summer was found to be higher than the recommended indoor temperature during the summer season in Japan. The higher temperature group tended to adopt behaviors, such as window opening and using a fan more often, than the lower temperature group. Due to the moderately high insulating levels in the building surveyed, the indoor air temperature of both groups was not low in winter. Heating was used less and irregular. The overall results indicate that the groups of families behaved differently to adjust the indoor thermal environment even though they were equipped with the same HEMS system.

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Influence of indoor air temperature on human thermal comfort, motivation and performance

Building and Environment ◽

10.1016/j.buildenv.2013.06.012 ◽

2013 ◽

Vol 68 ◽

pp. 114-122 ◽

Cited By ~ 88

Author(s):

Weilin Cui ◽

Guoguang Cao ◽

Jung Ho Park ◽

Qin Ouyang ◽

Yingxin Zhu

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Indoor Air ◽

Human Thermal Comfort ◽

And Performance

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Impact of ventilation system type on indoor thermal environment and human thermal comfort in a ceiling cooling room

Thermal Science ◽

10.2298/tsci210108277w ◽

2021 ◽

pp. 277-277

Author(s):

Xiaozhou Wu ◽

Genglin Liu ◽

Jie Gao ◽

Shuang Wu

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Thermal Environment ◽

Thermal Sensation ◽

Ventilation System ◽

Physical Parameters ◽

Curtain Wall ◽

Indoor Thermal Environment ◽

Human Thermal Comfort ◽

System Type

A ceiling cooling (CC) system integrated with a mechanical ventilation system is an advanced HVAC system for the modern office building with glass curtain wall. In this paper, considering the influence of heat transfer of external envelope, the indoor thermal environment and human thermal comfort were objectively measured and subjectively evaluated in a ceiling cooling room with mixing ventilation (MV) or underfloor air distribution (UFAD). Indoor physical parameters and human skin temperatures were measured as the chilled ceiling surface temperature and supply air temperature were 17.1?C-17.6?C and 22.2?C - 22.6?C. Simultaneously, 16 subjects (8 males and 8 females) were selected to subjectively evaluate the thermal environment. The results showed that the difference between mean radiant temperature and air temperature in the occupied zone was 0.8?C with CC+MV and 1.2?C with CC+UFAD, and the indoor air velocity was 0.17m/s with CC+MV and 0.13m/s with CC+UFAD. In addition, the calculated and measured thermal sensation votes with CC+MV were all slightly less than those with CC+UFAD. Therefore, ventilation system type had a slight impact on the indoor thermal environment and human thermal comfort in the ceiling cooling room.

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