Daylight Optimization in Classrooms under Composite Climates: Simulation Insights

One of the fundamental criteria architects consider when designing schools, colleges, or educational buildings is the daylight in the classrooms. It is desirable to provide more usable daylight in buildings, not only to conserve energy, but also to improve the performance and productivity of the occupants. Daylight systems can reduce the artificial lighting requirements of a building while achieving appropriate illumination levels inside the space. In this study, classroom models were designed as per Indian Standard: 8827-1978, considering the room size in the ratio 1:1.5, a window on one side of the wall with an opening equal to 20% of the floor area, and a work desk at 0.80 m above the floor level. The study was conducted to investigate the illumination performance in the composite climatic zone of Central India using a computer simulation tool for various combinations, such as window opening, shading devices, months, and timings. The design sky illumination was set at 12,000 lux under an overcast sky condition. The simulation results exhibited that the shading devices are very effective in restricting the excessive illumination levels in accordance with Indian Standard: 8827-1978. Shading for the south-facing windows reduced the illumination levels from 708 lux to 392 lux in April and from 5873 lux to 3645 lux in December, preventing the glare and overheating. Shading for the north-facing windows provided 310 to 351 lux in April and August, making them perfect for a classroom under daylight. These results highlight the importance of orientation-specific shading strategies for classrooms, which are relevant in the composite climate of Central India.