An experimental investigation into stratum ventilation for the cooling of an office with asymmetrically distributed heat gains

The performance of stratum ventilation in an office with a glazed façade was investigated. An electric heating film, hung on a side wall of the test chamber, was employed to simulate the heat gain via a glazing curtain wall. In total, 13 experimental cases were conducted by adjusting the heat generation of the heating film, the temperature and the airflow rate of supply air. The performance of stratum ventilation was evaluated by examining the distributions of temperature, velocity and dimensionless carbon dioxide (CO2) concentration, effective draft temperature for stratum ventilation (EDTS), predicted mean vote index (PMV), and efficiencies of heat and contaminant removals. The experimental results demonstrated that stratum ventilation performed well in heat removal and contaminant removal. Quality inhaled air for the occupants was provided in all experimental cases. It was found that the glass wall temperature had a significant influence on thermal comfort of occupants. When the inner surface temperature of glass wall closed to 40 °C, the PMV values approached the upper bound of the comfort zone. For every case wherein the cooling load was 90 W/m2 or below, and the supply air temperature was 19-21 °C, thermal comfort of the occupants was provided. Both the efficiencies of heat removal and of local contaminant removal improved with increasing airflow rate at constant supply air temperature. Therefore, stratum ventilation could perform well in cooling offices with highly asymmetric distribution of heat gains.