An Experimental study of diffuse ceiling ventilation with symmetrical and asymmetrical heat load distributions

Strength and location of heat loads have a significant effect on air distribution. Symmetrical and asymmetrical heat load distributions were studied at 40 W/floor-m2 (C40) and at 80 W/floor-m2 (C80) with diffuse ceiling ventilation. Experiments were carried out in a test chamber (5.5x3.8x3.2 m3, LxWxH) by conducting experiments with omnidirectional anemometers. In the symmetrical case (SC), cylindrical heat sources were located evenly on the floor. In the asymmetrical case (AC), double office layout including a seated-dummy with a laptop and a monitor was conducted next to warm window panels in the perimeter area. The results show that AC produces stronger circulating airflow pattern that SC from perimeter area to opposite corridor side, because heat load was equally distributed in SC. In AC, the air temperature was higher (0.5°C, 0.9°C) and the air speed was lower (0.02 m/s, 0.04 m/s) in the perimeter area than in the corridor side regarding the seated person zone at C40 and C80,
respectively. In SC, significant horizontal temperature difference was not obtained between the perimeter and corridor sides. Thermal environment is classified as the category B defined by the EN ISO 7730:2005 for common heat load conditions and category C for peak load conditions.