New paper: Ceiling fan air speeds around desks and office partitions

It is the first work to evaluate the effects of tables and workstation partitions on a room’s generic air flow and comfort profiles. Check more details about the study (here).

Background:

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.

We performed high resolution measurements of ceiling-fan-induced air flow in an empty room.

Highlight:

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.

The initial ceiling fan flow in the room could be modeled as a free jet.

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.

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.

The effect of indoor layout on airflow distribution

Indoor airflow pattern might be quite different with the indoor layout.  Furniture, partitions, and even occupants can influence airflow speed and directions, resulting in complex indoor air distribution. We examined airflow distribution when considering furniture (e.g., table), partitions attached to a table, and an occupant using a thermal manikin sitting in front of a table.

How might a table affect ceiling fan-driven flow?

When a table is positioned under a ceiling fan, this is how airflow looks like.

                         Front view                                                        Side view

How might a table with partition affect ceiling fan-driven flow?

                         Front view                                                        Side view

How airflow looks like around a person sitting under a ceiling fan?


Note: There is no heat generated by the manikin.