New Passive Cooling as a Technique for Hot Arid Climate

Abstract

Cooling of buildings is an essential target for engineers and builders in the hot arid climate of Egypt. New cooling system was integrated into a single room built in Assiut University (El-Gorib site) in Assiut, Egypt. A passive cooling technique was integrated inside a short wind tower made from expanded paper (wet pad) 0.1 m thick. A water tube was installed on the top of the expanded paper with small nozzles. The results show that outlet air temperature from the wind tower is 27.3°C. The calculated predicted mean vote (PMV) is within the recommended range (−0.5 < PMV < +0.5). This indicates that occupants remain satisfied with indoor thermal environment after using the passive cooling system and the difference is nearly 6-7 K between outdoor and indoor. The system achieves the acceptable airflow rate with an average of 450 ppm for CO 2 concentration during daytime. The relative humidity did not exceed 57% most of the time. The maximum airspeed inside the solar chimney was 3.5 m/s under the effect of a high solar radiation of 890 W/m 2 . The findings show that solar chimney with passive cooling tower design (SCPC) system achieves comfortable thermal conditions with a significant improvement in building energy conservation.