Conference article

The daylight factor model given by Charted Institute of Building Services Engineers (CIBSE) was modified in this paper to incorporate time variations with respect to zenith angle (?z) and vertical height (h) of working surface above ground surface which was normalized with central height (H) of skylight dome. The modified model contains constant exponents which are determined using linear regression analysis based on hourly experimental data of inside and outside illuminance for each month of the year 2007–2008. The prediction of modified model is found in good agreement with experimental observed inside illuminance data on the basis of values of root mean square percentage error (e) and correlation coefficient (r). The annual average daylight factor values for big and small dome skylight rooms are determined as 2.3% and 4.4% respectively. The energy saving potential of skylight rooms for selected climatic locations in India is also presented in this paper. This paper also investigates embodied energy of an existing eco-friendly and low embodied energy adobe house with dome shape roof located at Solar Energy Park inside IIT Delhi campus in New Delhi (India). Based on embodied energy analysis; the energy payback time for the adobe house was determined as 18 years. The embodied energy per unit floor area of reinforced cement concrete (R.C.C.) building (3702.3 MJ/m²) is quiet higher as compared to adobe house embodied energy (2298.8 MJ/m²).

Skylight; Dome shape roof; Daylight Factor; Illumination; Mud house