When Debabrata Dutta, a senior technical manager with Wipro Technologies, and wife Arunima finally settled down in Kolkata after postings in the US and Bangalore what they wanted was a home that combined the luxury of a bungalow with the security of a housing complex. They got both, with a bonus: being part of India’s first solar housing project.

Today, the couple are the proud owners of a “dream house” in Rabirashmi Abasan christened thus by Chief Minister Buddadeb Bhattacharjee himself, for rabirashmi means sunrays.

• A “Grid Interactive Solar PV” means the buildings and community centre are connected with a “grid” or supply network of power utilities, says S P Gon Chaudhuri, Director, WBREDA.

• The complex’s own hydro-pneumatic water pump starts working when there is a reduction of pressure inside the pipes caused by opening of taps, flushing cisterns etc. The pump has a varying frequency so that it operates only up to the speed which is needed to get full pressure, thereby saving energy. It operates at maximum capacity only when all the taps are opened.

• Each bungalow has own “power plant” on the rooftop, comprising a solar photovoltaic panel with a capacity of two kilowatts. Household gadgets and electric installations can run on solar power during the day. Post sunset, with the generation dwindling, the system automatically switches to conventional electricity.

• The PV system also has an in-built power back-up system, which stores around 3 kilowatts of power. So, in case of an emergency at night, say during power cuts, one can switch to the back-up to harness stored power. An inverter helps the “switchover” post-sunset. All residents have been advised to opt for LEDs and CFLs.

• Each house is fitted with a solar heater on the rooftop connected to kitchen and bathrooms. The small water tank in the solar heater has a thermal insulation which provides round-the-clock hot water supply.

• There is a swimming pool heated by solar energy.