Effect of fenestration geometrical factors on building energy consumption and performance evaluation of a new external solar shading device in warm and humid climatic condition

Glazed facades are being increasingly used in modern buildings in order to improve the daylight availability in the interiors, offer better external views and also add to the architectural beauty of the building. However this increased usage of glazed facades is leading to higher solar gain inside the building which is becoming a major issue in hot climatic regions. External shadings are thus used to protect the buildings from direct solar radiation which cause high solar gain as well as discomfort due to glare. The present study summarizes the effect of geometrical factors like window to wall ratio (WWR) and window positioning on the heating, cooling and lighting energy consumption of a South facing building cell in warm and humid climate. The performances of different commonly used external solar shading devices have been compared. The study also proposes the design of an external shading device which, when compared with the existing shading designs, leads to reduction in annual energy consumption of the building. The simulations were carried out using building energy simulation program EnergyPlus for the warm and humid climate of Kolkata, India. In order to validate the applicability of the new shading in other locations experiencing similar climate, the performance of the proposed shading was also evaluated for two other locations-Naples in USA and Hanoi in Vietnam. In both of these cases the new shading offered better performance than the other existing shading designs.