Studying the features of air flow induced by a room ceiling-fan

Bassiouny, Ramadan; Korah, Nader S.

doi:10.1016/j.enbuild.2011.03.034

Cited by 51 publications

(28 citation statements)

References 2 publications

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“…Electric fans used for air induction are common household appliances, especially in less developed countries (Bassiouny and Korah, 2011). Fans do not in fact, cool the air, but actually work by evaporative cooling of the sweat on our bodies, and by increasing heat convection into the surrounding air, due to the airflow from the fan.…”

Section: Introductionmentioning

confidence: 99%

Statistical Characteristics and Frequency Spectrum Analysis of Fan Induced Airflow Compared with Natural Winds

Gao

Zhang

et al. 2015

International Journal of Ventilation

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Electric fans used for cooling or local ventilation are common household appliances around the world, especially in developing countries. They offer many advantages such as low cost and energy savings, as well as easy implementation. However, the airflow from fans is often considered to be less comfortable than the sensations produced by natural winds. In order to avoid the draught induced by fans, and to investigate dynamic airflow characteristics of household fans, an anemometer was utilized to measure the corresponding time series of the air velocity. Statistical parameters, wavelet transforms and power spectrum exponents of air velocity signals from different types of fans were analyzed.The results show that the standard deviation of actual, natural wind velocity profiles is slightly greater than that of mechanically produced wind. More importantly, we found that statistical parameters involving mean air velocity, standard deviation, skewness and kurtosis are insufficient to indicate completely, all the characteristics of mechanical wind. Power spectrum density exponent (β) also shows the frequency characteristics of airflow. Finally, based on the comparison of β with a variety of fans, it was found that inducing surrounding air can enhance β, and reduce the draught.

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Section: Introductionmentioning

confidence: 99%

Statistical Characteristics and Frequency Spectrum Analysis of Fan Induced Airflow Compared with Natural Winds

Gao

Zhang

et al. 2015

International Journal of Ventilation

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“…For example, the rotating blades of a ceiling fan induce swirl to the main flow stream [3]. In fact, the flow structures in a swirling flow are governed by the ratio between the tangential and axial momentums.…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of turbulent flow and mass transfer in far-field of swirl diffusers

Tavakoli

Hosseini

2013

Energy and Buildings

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“…Jain et al [14] experimentally developed quantitative profiles, qualitative descriptions, and visualizations for flow in a closed room with a ceiling fan. Bassiouny and Korah [15] developed an analytical and computational model to predict the airflow from a ceiling fan operating at different speeds. All of these studies were characterizing the flow from a single ceiling fan operating in an empty room.…”

Section: Introductionmentioning

confidence: 99%

Ceiling fan air speeds around desks and office partitions

Gao

Zhang

Arens

et al. 2017

Building and Environment

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Ceiling fans may cool room occupants very efficiently, but the air speeds experienced in the occupied zone are inherently non-uniform. Designers should be aware of several generic flow patterns when positioning ceiling fans in a room. Key to these are the fan jet itself and lateral spreading near the floor. Adding workstation furniture redirects the jet's airflow laterally in a deeper spreading zone, making room air flows more complex but potentially increasing the cooling experienced by the occupants. This paper presents the first evaluation of the effects of tables and workstation partitions on a room's generic air flow and comfort profiles. In a test room with a ceiling fan, we moved five anemometers mounted in a "tree" at heights of 0.1, 0.6, 0.75, 1.1, and 1.7 m to sample a dense measurement grid of 7 rows and 6 columns. We tested five different table and partition configurations and compared them to the empty room base case. From the results we propose a simplified model of room airflow under ceiling fans, useful for positioning fans and workstation furniture. We also present comfort contours measured in two ways that have comfort standards implications. The measured data are publicly available on the internet. Keywords: Ceiling fan; air speed; furniture; comfort cooling; corrective power Highlights 1. We performed high resolution measurements of ceiling-fan-induced air flow in an empty room; 2. We compare this reference case to air flow profiles measured in the room with five different table and partition configurations. The data are included as publicly available supplementary material; 4. The initial ceiling fan flow in the room could be modeled as a free jet; 5. The subsequent room circulation, with and without tables and partitions, may be represented by an intuitive model for designers who are placing fans and furniture; 6. The extent of comfort cooling provided by the fan air flow can be represented by the metric 'corrective power'. Corrective power equates the cooling effect of the fan as an ambient temperature reduction, ºC. We present the corrective power distribution in the room in two ways--with and without the air speed at ankle level--to evaluate air speed cooling effect. This evaluation is significant for thermal comfort standards.

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Studying the features of air flow induced by a room ceiling-fan

Cited by 51 publications

References 2 publications

Statistical Characteristics and Frequency Spectrum Analysis of Fan Induced Airflow Compared with Natural Winds

Statistical Characteristics and Frequency Spectrum Analysis of Fan Induced Airflow Compared with Natural Winds

Large eddy simulation of turbulent flow and mass transfer in far-field of swirl diffusers

Ceiling fan air speeds around desks and office partitions

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