ZEMCH 2019 International Conference Proceedings April.2020 | Page 170
Figure 6. Dv by CO₂ Concentration
Figure 7. Average Dv by CO₂ Concentration
4. Conclusion
This study compared the differences in Dv (bias between PMV and TSV) for each carbon dioxide
concentration to assess the impact of carbon dioxide concentration on TSV. The findings are as follows.
(1) During non‐exam periods, the carbon dioxide concentration did not surpass 1,500 ppm, but the
average carbon dioxide concentration during exam periods was 2,258 ppm, peaking at 4,328 ppm. Such
levels are much higher than recommended indoor carbon dioxide concentration, indicating a need for
a ventilation strategy for rooms with high occupant density like library reading room.
(2) Out of all respondents, 28.57% said the temperature is pleasant (neutral), and 55.76% said they
felt warm thermal sensation (1, 2, 3). The average values of PMV and TSV were respectively ‐0.25 and
0.61, with TSV higher by about 0.86. The TSV distribution formed at higher than PMV, which indicates
that the occupants felt a warmer thermal sensation than PMV. These results imply that PMV alone is
insufficient to make an accurate prediction of TSV.
(3) The higher the carbon dioxide concentration, the lower the Dv distribution. Especially at the
carbon dioxide concentration of over 2,000 ppm, 96% of Dv was negative. Average Dv for each carbon
dioxide concentration segment decreased as the segment increased, and the average Dv between
segments 2,500 and 4,500 ppm was ‐1.42, showing a thermal sensation difference by over 1 scale. This
shows that carbon dioxide concentration affects TSV and it is necessary to consider the carbon dioxide
concentration for thermal comfort assessment.
Author Contributions: Hakjong Shin analyzed the results and wrote the full manuscript; Minho Kang, Sunhye
Mun, and Younghoon Kwak discussed the results; Jung‐ho Huh advised all tasks and double‐checked the results
and the whole manuscript.
Acknowledgments: This work was supported by the National Research Foundation of Korea (NRF) grant funded
by the Korea government (no. NRF‐2017R1A2A2A05001443, NRF‐2019R1C1C1010956).
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