Kolkata boasts of India’s first solar
housing complex
Kolkata’s New Town, which has already gained in reputation as a
computer engineering and IT hub, now has a new feather in its cap—Rabi
Rashmi Abasan—India’s first solar powered residential complex.
The “carbon-neutral” housing was conceived of about six years
ago by S P Gon Chowdhury, a specialist in renewable energy systems and
2003 Green Oscar recipient. The project was executed on a 0.4 hectare
plot of land by Bengal DCL—a state housing board and Development
Consultants Group joint venture enterprise, following a proposal by
West Bengal Renewable Energy Devlopment Corporation (of which Gon
Chowdhury was the then director).
The 25 villas and community hall in this high-end housing use building
integrated photovoltaic (BIPV) technology and have “solar passive”
architecture which reduces the buildings’ energy requirements by
meeting its daily cooling and lighting needs through maximum use of
natural light and proper ventilation.
The houses are structurally identical. Each takes up a 720 square-foot
plot, has a mezzanine and first floor and a small lily pool out in
front. Water in the pool cools the breeze flowing into the house
through adjustable louvres above it—a natural draft circulation process
called “the chimney effect,” explains Mihir Dey, the project’s design
and engineering supervisor. The walls have built-in air cavities that
act as insulators and help maintain the temperature balance within the
house.
The tiled, sloping roofs are fitted with solar panels and the buidings
have 100-litre solar water heaters. Solar panels are also integrated
into the glazing of the windows using BIPV technology, which basically
uses photovoltaic panels as part of a building’s outer structure so
that they serve simultaneously as building ‘envelope’ material and
power generator. This is the first time BIPV technology is being used
in homes in India.
The solar energy yield per building is an estimated 2 kilowatts per
hour (KWH), which accounts for 40 percent of the power needed to run
standard household appliances, says Gon Chowdhury. The
temperature-regulated swimming pool at the community centre too, is
packed with solar roof panels and BIPV double glazed surface panels.
These can collectively generate nearly 8 KWH. Even the streets in the
housing complex, are lit by solar lamps that function according to the
intensity of surrounding light.
Electricity generated by the solar power systems will be fed into a
grid that also gets regular power supply from the New Town Electric
Supply Corporation Limited (NESC). The difference in the power
generated and consumed will be adjusted in the residents’ electricity
bill. The solar energy system also provides a powerful back up for the
complex, enabling alternative power supply for as long as 24 hours at a
stretch.
The project received only 10 per cent funding from the West Bengal
state government and was paid for mainly the future residents, who
shelled out an extra Rs 6 lakh for the BIPV technology. Priced at Rs 45
lakh, the homes here cost a bit more than similar upmarket houses in
the area. But buyers, who are to move in, in October, were willing to
shoulder the extra cost since they expect to save on power bills in the
long run.
“It is a novel architectural concept in today’s time and I mainly
bought a house here because of the promise of reduced pollution and a
healthy living environment,” says Jyoti Poddar, a Kolkata-based
businessman and future resident. “With the constant hike in electricity
bills nowadays, a complex with its own source of energy is also a
welcome prospect for us. We intend to spend a few weekends there at the
onset because the surroundings haven’t developed too much yet. But we
hope to shift in permanently quite soon.”
It is too early, however, to assess if Rabi Reshmi is indeed
“carbon neutral” as Gon Chowdhury asserts. “The full extent of its (the
housing’s) success can only be determined a year after its
construction” says Madhumita Roy, a green buildings expert and
professor at Jadavpur University’s department of architecture. Roy does
point out one possible flaw. All the houses are symmetrical, which
means they won’t necessarily receive the same amount of sunlight and
thus there may be a difference in the amount of energy each home
produces.
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