Flow Pattern Effects on Night Cooling Ventilation

Passive cooling techniques such as night time cross ventilation can potentially provide substantial cooling energy savings in warm climates. The efficiency of night cooling ventilation is determined by three main factors: the external airflow rate in the room, the flow pattern and the thermal mass distribution. The aim of this paper is to analyse the effect of the enclosure shape and the situation of inlet/outlet openings on the total cooling energy stored in the structure. This analysis presents a comprehensive sample of typologies to generate guidelines which can help the designer with the distribution of the thermal mass and inlet/outlet openings in the enclosure. The approach combines a theoretical analysis which characterizes the enclosure charge/discharge time constants and storage efficiencies with simulation studies based on computational fluid dynamics software (CFD).