Wind induced ventilation of light well in high rise apartment building - influence of bottom opening condition on airflow rate.

The light well is often designed in the center of high-rise apartment buildings in Japan. This light well is an empty space without ceilings or floors from the bottom to the top, and this well is called "Void" in Japan. In this well, the exhaust from the kitchen and the gas water heater is sometimes discharged to the corridors surrounding Void, and the exhaust can pollute the air in Void. To keep the air quality in Void clean, the natural ventilation is usually depended on. The authors have made many model experiments on the natural ventilation of Void to clarify the basic ventilation characteristics such as airflow patterns, airflow rates and temperature distributions. In this paper, we investigated the effect of the size and number of bottom openings with intention to supply fresh air on the airflow rate. If two openings are located on both sides at the bottom of Void, it can be anticipated that the airflow passes through from the windward to the leeward, and the airflow rate of Void can decrease as compared with the case of only one opening. The wind tunnel test was conducted to examine this phenomenon in the wind-induced ventilation under the various conditions of the size of bottom openings and the wind directions. As a result, the airflow rates of Void with two bottom openings are obviously smaller than those with only one bottom opening.