Droplet fate and infection risk under ceiling fan integrated air conditioning: cough and speech scenarios
- 1College of Civil Engineering, Taiyuan University of Technology, Taiyuan 030024, China
- 2Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
- 3College of Civil Engineering, Taiyuan University of Technology, Taiyuan 030024, China; Low-Carbon Building Shanxi Provincial Laboratory, Taiyuan 030024, China; Corresponding author.
Abstract
Ceiling Fan-Integrated Air Conditioning (CFIAC) is a coupling configuration of air conditioning ventilation systems and ceiling fans that combines fresh air supply (from the air conditioning system) with indoor airflow distribution adjustment (via ceiling fans). This study employed Computational Fluid Dynamics to simulate the transient respiratory droplet dispersion under CFIAC systems. By combining infection risk for the exposed person and droplet fate indicators (suspension, sedimentation, escape), the impacts of different ventilation configurations, ceiling fan speeds, and exhalation types on droplet transmission were investigated. Ceiling fan activation was found to either mitigate local infection risk or enhance airflow circulation: downward operation at 72 rpm reduced local infection risk by 96.6 %, while upward rotation decreased the fraction of suspended droplets by 39.29 % (boosting droplet escape by 10.88-fold relative to fan-off conditions). Excessively high fan speeds (122 rpm) negated these benefits, increasing infection risk by 4.25-fold compared to the 72 rpm condition. CFIAC systems exhibited more effective control over coughing droplets than over speaking droplets, with the infection risk associated with speaking being 15.5 % higher than that of coughing. Among the tested configurations, upper-supply and ceiling-exhaust ventilation excelled in reducing local infection risk, while upper-supply and lower-exhaust ventilation optimized overall respiratory droplet control. These results provide practical guidance for optimizing CFIAC operation and formulating targeted infection prevention strategies.
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BibTeX
@article{kang2026droplet,
title = {{Droplet fate and infection risk under ceiling fan integrated air conditioning: cough and speech scenarios}},
author = {Liming Kang and Xinghui Zhang and Cong Zhang and Bin Cao and Yingxin Zhu and Xinyu Jia},
journal = {Energy and Built Environment},
year = {2026},
month = oct,
doi = {10.1016/j.enbenv.2026.02.002},
url = {https://doi.org/10.1016/j.enbenv.2026.02.002},
note = {CC BY},
}
RIS
TY - JOUR
TI - Droplet fate and infection risk under ceiling fan integrated air conditioning: cough and speech scenarios
AU - Liming Kang
AU - Xinghui Zhang
AU - Cong Zhang
AU - Bin Cao
AU - Yingxin Zhu
AU - Xinyu Jia
PY - 2026
DA - 2026/10/30
JO - Energy and Built Environment
DO - 10.1016/j.enbenv.2026.02.002
UR - https://doi.org/10.1016/j.enbenv.2026.02.002
AB - Ceiling Fan-Integrated Air Conditioning (CFIAC) is a coupling configuration of air conditioning ventilation systems and ceiling fans that combines fresh air supply (from the air conditioning system) with indoor airflow distribution adjustment (via ceiling fans). This study employed Computational Fluid Dynamics to simulate the transient respiratory droplet dispersion under CFIAC systems. By combining infection risk for the exposed person and droplet fate indicators (suspension, sedimentation, escape), the impacts of different ventilation configurations, ceiling fan speeds, and exhalation types on droplet transmission were investigated. Ceiling fan activation was found to either mitigate local infection risk or enhance airflow circulation: downward operation at 72 rpm reduced local infection risk by 96.6 %, while upward rotation decreased the fraction of suspended droplets by 39.29 % (boosting droplet escape by 10.88-fold relative to fan-off conditions). Excessively high fan speeds (122 rpm) negated these benefits, increasing infection risk by 4.25-fold compared to the 72 rpm condition. CFIAC systems exhibited more effective control over coughing droplets than over speaking droplets, with the infection risk associated with speaking being 15.5 % higher than that of coughing. Among the tested configurations, upper-supply and ceiling-exhaust ventilation excelled in reducing local infection risk, while upper-supply and lower-exhaust ventilation optimized overall respiratory droplet control. These results provide practical guidance for optimizing CFIAC operation and formulating targeted infection prevention strategies.
SN - 2666-1233
ER -