Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort
Thermal comfort (TC) and CO<sub>2</sub> concentration significantly influence the overall indoor comfort sensations of building occupants. However, few studies have focused on educational buildings regarding both TC and CO<sub>2</sub> concentration in tropical regions, and th...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-11-01
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| Series: | Buildings |
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| Online Access: | https://www.mdpi.com/2075-5309/12/11/1921 |
| _version_ | 1797468825486098432 |
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| author | Lin-Rui Jia Qing-Yun Li Xi Chen Chi-Chung Lee Jie Han |
| author_facet | Lin-Rui Jia Qing-Yun Li Xi Chen Chi-Chung Lee Jie Han |
| author_sort | Lin-Rui Jia |
| collection | DOAJ |
| description | Thermal comfort (TC) and CO<sub>2</sub> concentration significantly influence the overall indoor comfort sensations of building occupants. However, few studies have focused on educational buildings regarding both TC and CO<sub>2</sub> concentration in tropical regions, and they also lack guidelines for short-term evaluation, which is essential for university classrooms. In this study, a mechanically ventilated university classroom was selected to investigate the 5 min-averaged comfort ranges for indoor parameters and the impacts of TC and variation of CO<sub>2</sub> on student overall comfort. The real-time indoor environmental parameters were monitored, including indoor air temperature (<i>T</i><sub>a</sub>), mean radiant temperature (<i>T</i><sub>m</sub>), relative humidity (<i>RH</i>) and CO<sub>2</sub> and air velocity (<i>v</i><sub>a</sub>); the operative temperature (<i>T</i><sub>op</sub>) was calculated. Moreover, an online-based questionnaire survey related to thermal sensation (TS) and CO<sub>2</sub>-related air sensation (AS) was carried out. Linear and nonlinear regression models of comfort sensation predictions were obtained based on the questionnaires and corresponding measured indoor environmental data. The 5 min-averaged comfort ranges for <i>T</i><sub>op</sub>, CO<sub>2</sub> and <i>RH</i> are 21.5–23.8 °C, <1095 ppm and 47–63.5%, respectively. The comfort range of the TS and AS are 2.3–3.1 and 1–1.55, respectively. The result shows that students prefer a relatively cold indoor environment, as this improves their ability to tolerate bad indoor air quality (IAQ) with high CO<sub>2</sub>. A regression analysis indicated that AS is the most critical aspect, with a weight of 0.32, followed by TS, with 0.18. Finally, it was also found that individual weighting coefficients were not equivalent and differed across geographical locations and building types. Thus, obtaining the prediction models for a particular building is necessary. The results can give meaningful suggestions to adopt the appropriate operations for HVAC and improve indoor environmental quality in university buildings in tropical regions. |
| first_indexed | 2024-03-09T19:12:52Z |
| format | Article |
| id | doaj.art-076bcc72f54e4aec8e3818875b41fba8 |
| institution | Directory Open Access Journal |
| issn | 2075-5309 |
| language | English |
| last_indexed | 2024-03-09T19:12:52Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
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| series | Buildings |
| spelling | doaj.art-076bcc72f54e4aec8e3818875b41fba82023-11-24T03:59:48ZengMDPI AGBuildings2075-53092022-11-011211192110.3390/buildings12111921Indoor Thermal and Ventilation Indicator on University Students’ Overall ComfortLin-Rui Jia0Qing-Yun Li1Xi Chen2Chi-Chung Lee3Jie Han4School of Science and Technology, Hong Kong Metropolitan University, Hong Kong 999077, ChinaTeaching and Learning Centre, Lingnan University, Hong Kong 999077, ChinaDepartment of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong 999077, ChinaSchool of Science and Technology, Hong Kong Metropolitan University, Hong Kong 999077, ChinaSchool of Science and Technology, Hong Kong Metropolitan University, Hong Kong 999077, ChinaThermal comfort (TC) and CO<sub>2</sub> concentration significantly influence the overall indoor comfort sensations of building occupants. However, few studies have focused on educational buildings regarding both TC and CO<sub>2</sub> concentration in tropical regions, and they also lack guidelines for short-term evaluation, which is essential for university classrooms. In this study, a mechanically ventilated university classroom was selected to investigate the 5 min-averaged comfort ranges for indoor parameters and the impacts of TC and variation of CO<sub>2</sub> on student overall comfort. The real-time indoor environmental parameters were monitored, including indoor air temperature (<i>T</i><sub>a</sub>), mean radiant temperature (<i>T</i><sub>m</sub>), relative humidity (<i>RH</i>) and CO<sub>2</sub> and air velocity (<i>v</i><sub>a</sub>); the operative temperature (<i>T</i><sub>op</sub>) was calculated. Moreover, an online-based questionnaire survey related to thermal sensation (TS) and CO<sub>2</sub>-related air sensation (AS) was carried out. Linear and nonlinear regression models of comfort sensation predictions were obtained based on the questionnaires and corresponding measured indoor environmental data. The 5 min-averaged comfort ranges for <i>T</i><sub>op</sub>, CO<sub>2</sub> and <i>RH</i> are 21.5–23.8 °C, <1095 ppm and 47–63.5%, respectively. The comfort range of the TS and AS are 2.3–3.1 and 1–1.55, respectively. The result shows that students prefer a relatively cold indoor environment, as this improves their ability to tolerate bad indoor air quality (IAQ) with high CO<sub>2</sub>. A regression analysis indicated that AS is the most critical aspect, with a weight of 0.32, followed by TS, with 0.18. Finally, it was also found that individual weighting coefficients were not equivalent and differed across geographical locations and building types. Thus, obtaining the prediction models for a particular building is necessary. The results can give meaningful suggestions to adopt the appropriate operations for HVAC and improve indoor environmental quality in university buildings in tropical regions.https://www.mdpi.com/2075-5309/12/11/1921indoor air qualityventilation indicatorthermal comfortuniversity classroomquestionnaire surveyregression analysis |
| spellingShingle | Lin-Rui Jia Qing-Yun Li Xi Chen Chi-Chung Lee Jie Han Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort Buildings indoor air quality ventilation indicator thermal comfort university classroom questionnaire survey regression analysis |
| title | Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort |
| title_full | Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort |
| title_fullStr | Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort |
| title_full_unstemmed | Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort |
| title_short | Indoor Thermal and Ventilation Indicator on University Students’ Overall Comfort |
| title_sort | indoor thermal and ventilation indicator on university students overall comfort |
| topic | indoor air quality ventilation indicator thermal comfort university classroom questionnaire survey regression analysis |
| url | https://www.mdpi.com/2075-5309/12/11/1921 |
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