Thermal and lighting performance of 5 complex fenestration systems in a semiarid climate of Chile

Abstract

Overheating, high cooling energy demand and glare are common concerns in office buildings in Santiago de Chile. Complex Fenestration Systems (CFS), which include an external shading device, represent a means to control these problems, reducing cooling energy demand and enhancing visual comfort. The present paper evaluates and compares the thermal and lighting performance of 5 different types of CFS (3 with horizontal louvers and 2 with vertical louvers) through laboratory experiments.Experiments were made using two calorimetric test-rooms emulating the size of a small office for three orientations: North, Northeast and Northwest. A Coefficient of Performance was calculated for each CFS by comparing the radiation entering the room in both test-rooms. A useful daylight illuminance factor was calculated to evaluate visual comfort.Horizontal louvers consistently performed better than vertical louvers for all orientations tested. Results for vertical louvers, clearly show which combination of louver alignment and façade orientation does not provide an effective solar protection. For horizontal louvers, although the ones that completely block the passage of direct light, not allowing an outside view, perform better than the ones permitting a view to the outside, the difference is not significant (less than 10%). So two cases of louvers allowing an outside view are recommended for office buildings. These results may help designers to make more informed decisions in the early building design stages.