In many of the worlds slums, people are packed into every available space. Home are built next to each other with no windows to let in light. People live in darkness 24 hours a day. Electricity for lights is either unavailable, sporadic, or too expensive leaving millions in darkness at high noon. Simple recycled plastic waste bottles are bring light to to the darkness. Filling discarded plastic or glass bottles with water and a small amount of bleach and placed in holes in the roof is providing light. This is far safer than candles or kerosene lanterns and far cheaper than battery powered lights. They can be made with minimal skills, last for years, and utilize common material. The bulbs commonly use 2 liter bottles but can be made with almost any plastic or glass bottle. A sealant is used to attach it to the roof and keep out rain water. These simple “lights” capture the sun and disuse it into their homes. In full sun they product about as much light as a typical 60 watt incandescent light bulb. They are amazingly bright. Even in homes with electricity these lights can reduce the electrical bill. If 1 million water lights were installed replacing 60 watt bulbs, the energy saving would be over 100,000 tons of coal over a year.
A Filipino man has installed hundreds of these in his neighborhood. Developed by MIT students and inspired by the Appropriate Technology Collaborative, the “bulb” is made from a one-liter soda bottle that is filled with purified water and bleach, then inserted tightly into the roof of a home. The bulbs are called Isang Litrong Liwanag in the local filipino language which translates as A Liter of Light.
The bulbs reduce demand on the electrical grid, provide light to those without electricity, reduce fires from candles and other open flame lights, reduce the amount of plastic trash, may reduce birth rates, and improves the quality of lives.
Some of the locals have turned bottle lights into a business generating money for their families and reducing trash.
Watch the video. It will warm your heart and inspire you.
2 minute version
6 minute version
To read more visit: http://gb-sb.blogspot.com/2011/12/how-solar-bottle-bulbs-works-and-liter.html