Computational Fluid Dynamics Study of a Diffuse Ceiling Ventilation System through Sound-absorbing Ceiling Panels

Abstract

The Diffuse Ceiling Ventilation (DCV) is one of the promising concepts to satisfy ventilation and thermal comfort requirements in modern buildings. This solution allows the injection of a high amount of ventilation air at lower speed and with a more even distribution than traditional air injection solutions. Office buildings often present a suspended ceiling realised with perforated sound-absorbing panels that are suitable to be used as air diffusers. However, fresh air is normally injected in the plenum through a duct or through one of the vertical surfaces of the plenum, causing an uneven velocity distribution in the air jets leaving the diffuser, which can lead to local thermal discomfort issues. The aim of this work is to use CFD as a tool to find a suitable perforation pattern, within the boundaries of existing, commercially available panels, to achieve a uniform air distribution in the room with low velocity. Three commercially available panel designs were considered. Three-dimensional steady state CFD calculations were repeated on different configurations to find an optimal perforation rate and distribution. The optimal distributions were identified and simulations repeated for a room section. This ventilation strategy proved a positive influence on the indoor comfort, ensuring the injection of an adequate ventilation air without drafts due both to the air injection and the resulting velocity field in the room.