A bottle full of light

Children assembling the solar bulb light. PHOTO: IIT POWAI   | Photo Credit: de04LOL2

An empty plastic bottle, litre of water, few spoons of bleach -- that's all that the students of IIT Powai needed to bring light to the homes of slum dwellers in Gowandi.

Inspired by Isang Litrong Liwanag's campaign carried out successfully by the My Shelter Foundation in the Philippines, students of the department of metallurgical engineering and material science decided to bring light to the dingy rooms of Mumbai slums. “We saw the simplicity of the solar bottle bulb and wondered why we couldn't implement it to lighten up slums in Mumbai,” explains the group that worked for over four months to bring the simple yet ingenious idea to life -- “litre of light”.

A Solar Bottle Bulb is a clear water bottle filled with tap water and a little bleach, this bottle is then embedded into the roofs of houses, with part of the bottle outside, and part of it inside. “The water inside the bottle makes the light omni directional, mimicking an electric light bulb. The bleach keeps the water clear for years,” Jaydeep Soni, third year student and member of the team, said.

The group in their field trips visited slum areas in Andheri and Govandi. “The rooms were so close to each other that even the passage between them had close to no light even during the day time. Inside the room at least one tube or bulb was required all through the day, pushing their electricity bills to Rs 400-600 each month.” The students constructed few samples of the solar water bottle bulbs to show the residents how they worked, “We couldn't just drill a hole in their roofs, we needed them to like the idea and after seeing how simple, clean and cheap it is everyone liked the concept,” Soni said.

“It is a very simple procedure, and very simple things are used but each is very important, without the bleach, the water would quickly turn green with algae. Without the water, there would be a bright spot on the floor, without the sealant there could be seepage or worse, bottle could drop from the roof. So we are seeking volunteers to help us in assembling the parts,” Sahil Dhingra, another member of the group, added.

“The only drawback of the solar water bulb is that it is functional only from sunrise till sunset, even then the electricity is saves during the day time is reason enough for slum dwellers to use it,” another volunteer says as he meticulously places a water bottle inside the circular cut out of a metal sheet.

”We aim to implement this simple, sustainable technology in the slums of Mumbai at a large scale, with pilots already in place,” said Dhingra. Currently busy with gathering enough volunteers to install 500 such bulbs in slums, the group of 17 students are also working closely with development organisations to find out other areas where the ‘litre of light' can be of help. The students created the sample as a part of Padarth 2012, the Materials Science festival of IIT Bombay.

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Printable version | Jan 25, 2021 3:10:25 AM | https://www.thehindu.com/sci-tech/energy-and-environment/a-bottle-full-of-light/article2960029.ece

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