Some Investigations of External Shading Devices on Thermal and Daylighting Performance of a Building

Abstract

Solar heat gain through windows is a significant factor in determining the cooling load of buildings. External shading devices are extensively used in buildings to reduce the cooling load. However, use of shading devices reduces illuminance level inside the room which in turn increases the use of artificial lighting. A case study is carried out to study the impact of four different types of shading devices on solar gain, cooling load, lighting gain and illuminance level in four rooms facing west facade at hostel building located in coastal area near Mumbai. A computerized simulation tool (IES ) is used to carry out the investigations. The results indicate that egg-crate and diagonal fins shading devices perform better compared to other shading devices. Peak cooling load is reduced by about 28% with egg-crate shading device with 500 lx illuminance level.