Performance evaluation and design guidelines for stratum ventilation

This paper evaluates the performance of stratum ventilation systems for small to medium individual offices, open offices, classrooms, and retail shops operated under elevated room temperatures according to governmental guidelines. With proper design, stratum ventilation can maintain a thermally comfortable environment that has a horizontal airflow at head level, a small and reverse temperature gradient between the head and foot levels, and a high air distribution performance index. Because the supply air enters the breathing zone directly, the supply air path is shortened. Therefore, the mean age of air is younger, the ventilation effectiveness is higher and indoor air quality is better in the breathing zone. This air distribution method uses the cooling effects of both temperature and velocity of the supply air. Therefore, for a specific application, stratum ventilation needs smaller capacity. This leads to smaller system size, space occupation, initial cost and energy consumption. This paper presents guidelines for designing stratum ventilation. © 2011 Elsevier Ltd.