An experimental study on human sensation to airflow in naturally ventilated rooms

Abstract

During two summers, the authors conducted experiments on the effect of cross-ventilation, the most traditional and popular passive cooling means in Japan, on thermal sensations of people. Five male and five female subjects of college age were exposed to airflow for 60 to 90 minutes in the cross-ventilated room of the dwelling units and voted on their thermal sensations, including comfort sensation and airflow sensation. Airflow sensation of the whole body has a high correlation with comfort sensation, especially for females: airflow plays an important role in promoting the thermal comfort of people. A comparison between males' and females' frequency in changing their votes on comfort sensation implies that females are thermally more sensitive than males are. Airflow sensation of the whole body is related to airflow velocity. Females recognize low airflow more sensitively than males do. Among the parts of the body, airflow sensation at the shanks facing to the wind has the best correspondence with that of the whole body. Sensations about airflow speed, strength, and fluctuation have high correlations with each other and airflow sensation of the whole body. These three airflow characteristics influence comfort sensation in a cross-ventilated room. The relationship between temperature sensation resulting from airflow with air temperature shows a different tendency by two ranges of airflow velocity; voting temperature sensation in the cool range requires lower air temperature for the low velocity range (less than 1 m/s) than for the high velocity range (over 1 m/s).