Ceiling personalized ventilation combined with desk fans for reduced direct and indirect cross-contamination and efficient use of office space

Habchi, Carine; Ghali, Kamel; Ghaddar, Nesreen; Chakroun, Walid; Alotaibi, Sorour

doi:10.1016/j.enconman.2015.12.067

Cited by 53 publications

(29 citation statements)

References 37 publications

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“…Habchi et al (2014) studied the cross-infection between occupants in the room with a mathematical multi-plume multi-layer transport model. Habchi et al (2016) investigated the direct and indirect cross-contamination in office space with ceiling personalized ventilation combined with desk fans. He et al (2011) investigated the exhaled droplet cross-transmission between occupants in a typical office room with different ventilation strategies.…”

Section: Introductionmentioning

confidence: 99%

Person to person droplets transmission characteristics in unidirectional ventilated protective isolation room: The impact of initial droplet size

Yang

Zhao

2016

Build. Simul.

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Person to person droplets/particles or contaminant cross transmission is an important issue in ventilated environment, especially in the unidirectional ventilated protective isolation room (UVPIR) where the patient's immune system is extremely low and easily infected. We simulated the dispersion process of the droplets with initial diameter of 100 μm, 10 μm and gaseous contaminant in unidirectional ventilated protective isolation room and studied the droplets dispersion and cross transmission with different sizes. The droplets with initial size of 100 μm settle out of the coughing jet quickly after coming out from mouth and cannot be carried by the coughing jet to the human thermal plume affecting (HTPA) zone of the susceptible manikin. Hence, the larger droplets disperse mainly in the HTPA zone of the source manikin, and the droplets cross transmission between source manikin and susceptible manikin is very small. The droplets with initial size of 10 μm and gaseous contaminant have similar dispersion but different removal process in the UVPIR. Part of the droplets with initial size of 10 μm and gaseous contaminant that are carried by the higher velocity coughing airflow can enter the HTPA zone of the susceptible manikin and disperse around it. The other part cannot spread to the susceptible manikin's HTPA zone and mainly spread in the source manikin's HTPA zone. The results from this study would be useful for UVPIR usage and operation in order to minimize the risk of cross infection.

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Section: Introductionmentioning

confidence: 99%

Person to person droplets transmission characteristics in unidirectional ventilated protective isolation room: The impact of initial droplet size

Yang

Zhao

2016

Build. Simul.

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“…Another study redesigned a round movable panel (RMP) [127], used in several review studies [38,80,92]. The commonly used PV type also includes ceiling-mounted personalized ventilation (CMPV) [88,89], chair-based personalized ventilation (CBPV) [29,37], desk-mounted personalized ventilation (DMPV) [120], desk fan (DF) and/or chair fan (CF) [103,104], and bed-based task/ambient air conditioning (BTAC) [105,109,110]. Figure 2 shows the commonly used PV types.…”

Section: Pv Types With Background Hvac Systemsmentioning

confidence: 99%

A Review of CFD Analysis Methods for Personalized Ventilation (PV) in Indoor Built Environments

et al. 2019

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Computational fluid dynamics (CFD) is an effective analysis method of personalized ventilation (PV) in indoor built environments. As an increasingly important supplement to experimental and theoretical methods, the quality of CFD simulations must be maintained through an adequately controlled numerical modeling process. CFD numerical data can explain PV performance in terms of inhaled air quality, occupants’ thermal comfort, and building energy savings. Therefore, this paper presents state-of-the-art CFD analyses of PV systems in indoor built environments. The results emphasize the importance of accurate thermal boundary conditions for computational thermal manikins (CTMs) to properly analyze the heat exchange between human body and the microenvironment, including both convective and radiative heat exchange. CFD modeling performance is examined in terms of effectiveness of computational grids, convergence criteria, and validation methods. Additionally, indices of PV performance are suggested as system-performance evaluation criteria. A specific utilization of realistic PV air supply diffuser configurations remains a challenging task for further study. Overall, the adaptable airflow characteristics of a PV air supply provide an opportunity to achieve better thermal comfort with lower energy use based on CFD numerical analyses.

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“…For this reason, the number of tracked particle trajectories should be high enough to insure statistically stable results [13,15]. The particle source in-cell (PSI-C) scheme was used to correlate between particle concentration and trajectories within each computational cell [16,17]. It was found that 200,000 particle trajectories allowed obtaining a stable solution for the concentration field [17].…”

Section: B Modeling Of Particle Transportmentioning

confidence: 99%

“…The particle source in-cell (PSI-C) scheme was used to correlate between particle concentration and trajectories within each computational cell [16,17]. It was found that 200,000 particle trajectories allowed obtaining a stable solution for the concentration field [17].…”

Section: B Modeling Of Particle Transportmentioning

confidence: 99%

“…As in indoor environments airflow velocities are much lower than the ones needed for particle detachment [20], particle re-suspension can be neglected. In order to model particle deposition, the "trap" treatment of the Lagrangian technique was selected at walls [17]. At the outlet, the "escape" treatment was adopted to end the particle trajectory.…”

Section: Boundary Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Chair Fans as Energy Efficient Strategy to Aid Localized Ventilation

Habchi¹,

Ghali²,

Ghaddar³

2016

REPQJ

Self Cite

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Abstract. Nowadays, the air conditioning industry is deviating from the conventional mixing ventilation technique towards localized ventilation. Displacement ventilation and ceiling personalized ventilation are localized systems presenting a high potential in insuring good indoor air quality while reducing the energy consumption compared to mixing ventilation. In this work it is proposed to enhance their performance by assisting them with chair fans controlling the behavior of occupants' convective plumes.Computational fluid dynamics models were developed to simulate office spaces ventilated by displacement ventilation and ceiling personalized ventilation equipped with chair fans. The Lagrangian technique was adopted to track particle trajectories to determine particle behavior after generation from occupant respiratory activity. A parametric study was conducted to assess the effect of chair fan flow rate on each system performance in terms of indoor air quality.Recommendations were given to reduce cross-infection between occupants for both types of localized systems studied with reduced energy consumption. The total chair fans flow rate was optimized for both cases to insure acceptable indoor air quality resulting in significant energy savings. It was found that the optimal total chair fans flow rate per occupant was approximately

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Ceiling personalized ventilation combined with desk fans for reduced direct and indirect cross-contamination and efficient use of office space

Cited by 53 publications

References 37 publications

Person to person droplets transmission characteristics in unidirectional ventilated protective isolation room: The impact of initial droplet size

Person to person droplets transmission characteristics in unidirectional ventilated protective isolation room: The impact of initial droplet size

A Review of CFD Analysis Methods for Personalized Ventilation (PV) in Indoor Built Environments

Chair Fans as Energy Efficient Strategy to Aid Localized Ventilation

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