Ventilation efficiency and improvements for displacement ventilation systems during heating: A case study of a ward with vertical induction units

Sheng, Shaoyu; Yamanaka, Toshio; Kobayashi, Tomohiro et al.

Building and Environment, 2024, 266, 112037

アクセス数:367件（2025-10-06 23:27 集計）

固定URL: https://hdl.handle.net/11094/98333

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タイトル
Ventilation efficiency and improvements for displacement ventilation systems during heating: A case study of a ward with vertical induction units
著者
著者名
Sheng, Shaoyu
NRID
1000080182575 1000080182575
researchmap permalink
read0014081 read0014081
著者名
Yamanaka, Toshio
NRID
1000090580952 1000090580952
ORCID
0000-0003-4956-1274 0000-0003-4956-1274
researchmap permalink
tkoba_0151426 tkoba_0151426
Scopus Author ID
55724294200 55724294200
著者名
Kobayashi, Tomohiro
著者名
Chou, Nobukazu
キーワード等
CFD simulation
Displacement ventilation
Full-scale experiment
Heating
Hospital ward ventilation
Induction unit
内容
Sheng S., Yamanaka T., Kobayashi T., et al. Ventilation efficiency and improvements for displacement ventilation systems during heating: A case study of a ward with vertical induction units. Building and Environment 266, 112037 (2024); https://doi.org/10.1016/j.buildenv.2024.112037.
抄録
This study investigates the ventilation mechanism and effectiveness of a displacement ventilation (DV) system under heating conditions. A method to maintain ventilation efficiency by indirectly achieving DV was proposed. A four-bed hospital ward with prototype wall-mounted induction units (IUs) and ceiling exhaust served as the case study. Full-scale experiments assessed indoor temperature and tracer gas distribution, adjusting parameters such as cubicle and window curtains, window heaters, and window heat loss. Results showed that while the vertical temperature gradient was established, downdrafts near windows disrupted DV's stratification, leading to quasi-displacement ventilation with a normalized contaminant concentration of around 0.7 near patients. To counter this, using curtains to limit air exchange between the near-window and near-bed spaces effectively prevented the horizontal movement of contaminants toward the window. This allowed the downdraft to remain clean and diffuse along the floor, thereby reducing the normalized concentration to approximately 0.3–0.5 b y indirectly achieving DV. CFD numerical studies further examined this method under varied temperature conditions and airflow patterns. Additionally, the infection risk in this ward was evaluated for reference, showing that indirect DV can reduce infection probability by one-third compared to quasi-DV. Moreover, window heat loss valued at 50–100 W/m2 achieved the best ventilation, while smaller values generated insufficient downdraft to achieve indirect DV and larger values resulted in high floor-level velocity that accelerated contaminant dispersion.
出版者
Elsevier Ltd
収録物名
Building and Environment
巻(号)
266
ページ
112037
刊行年月
2024-12-01
言語
英語
ハンドルURL
https://hdl.handle.net/11094/98333
PISSN
03601323
関連情報 (isIdenticalTo)
DOI (出版社版)
https://doi.org/10.1016/j.buildenv.2024.112037
アクセス権
open access
権利情報
This article is licensed under a Creative Commons Attribution 4.0 International License.
出版タイプ
Version of Record
カテゴリ
学術雑誌論文 Journal Article