A solar PV (photovoltaic) rooftop generation unit with 35 KWP of electricity meets 100 percent of the building’s basic electricity needs directly from solar energy, for computers, lighting, fans, and mechanical ventilation. Energy generated from renewable energy is 13.8 percent, (Rs. 1,24,500 for energy generation of 24,900 kWh) of the total energy cost of Rs 9,04,290 for 1,30,744 kWh of electricity consumption per annum and 171 MBtu).
Heating, ventilation, and air conditioning (HVAC) energy cost savings have been realized from the Phase-II building with the use of a cool radiant slab system that reduces the need for cooling by reducing fan energy and space cooling energy (thus accounting for 9 percent of the total ~41.6 percent energy cost savings).
Innovative shading devices that prevent sunlight from hitting the glass windows account for 5 percent of total energy savings by improving the U value of the wall (0.079 against the baseline 1.24 Btu/ft2.F.h), well-designed shading devices and double-glazed glass (0.49 as against 1.27 Btu/ft2.F.h) reduce the overall building load. Ceiling fans reduce the need for air conditioning. Natural light is maximized by placing offices, classrooms, board rooms, and exhibition areas in proximity to courtyards.
Rainwater harvesting, groundwater recharge, and zero waste begin with collecting rainwater from the rooftop for reuse and groundwater recharge. An underground storage tank holds 800,000 liters of harvested water. Harvested water fulfils water requirements for the cooling tower of the air-conditioning system. Annual rainwater collection can last at least 97 days for building use. Gray and black water is treated onsite and recycled for irrigation and flushing. Low-flow fixtures and 100 percent gray water treatment reduces the use of potable water by 77 percent. No potable water is used to irrigate the landscape (comprised of native plants). Using treated water for landscape irrigation saves 8,657 liters. With zero runoff from the site, on an average rainfall day, almost 41,900 liters of discharge is collected, filtered, and guided to recharge the aquifers.
The ecological footprint and carbon dioxide emissions are minimized due to the choices of building materials and the use locally sourced materials. Wood was used instead of aluminum for doors, windows, and AC grills. The use of burnt brick was limited. Excavated soil was reused for making in-situ bricks for the building itself, resulting in about 30 percent reduction in CO2 emissions as compared to similar-size buildings. Using leftover materials in creative ways helped to reduce waste. The overall result is cost-effective, creative, simple, and sustainable.