Intermittent personalized ventilation coupled with mixing ventilation for occupant protection against active and passive contaminants and energy savings D. Al Assaad, C. Habchi, K. Ghali and N. Ghaddar   2018/04/20

Abstract

An intermittent personalized ventilation PVMmodule (PVMM) coupled with a conventional mixing
ventilation system (MV) was studied to investigate its ability in protecting occupants from indoor contaminants. This study examines the intermittent PVM operating frequency range that minimizes active and passive contaminant concentration near the occupant and nearby surfaces. A 3D CFD model of a typical office space was developed for this study and validated through experiments done in a climatic chamber. Simulations were performed under different typical indoor frequencies (0.3 Hz, 0.5 Hz and 1 Hz) and a typical personalized ventilation average flow rate (7.5 L/s). The space was considered to be infected with CO2 and particles of diameter 1 ìm. Results showed that under a frequency range of [0.78 Hz – 0.94 Hz], the intermittent PVM was able to provide good occupant protection with a satisfactory ventilation efficiency of around 77%, intake fraction range of
[11.8 %, 26.8 %] and a deposition fraction range of [7.5 %, 8.75 %]. Moreover, the system was able to reduce energy costs by 16.1 % compared to steady state personalized ventilator.

Authors and affiliations

D. Al Assaad1, C. Habchi2 K. Ghali1 and N. Ghaddar1
1. Department of Mechanical Engineering. American University of Beirut. Lebanon
2. Department of Mechanical Engineering. Lebanese University, Branch II. Roumieh, Lebanon

Key words

Personalized ventilation, mixing ventilation, intermittent, contaminants

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