Liter of Light is a global open source movement with the aim to provide an ecologically sustainable and free-of-cost source of interior light to rooms in simple dwellings with a thin roof. The device is simple: it is a transparent 1.5-2l plastic bottle, as typically used for carbonated drinks, filled with water plus a little bleach to inhibit algal growth, fitted through the roof of a house. During daytime the water inside the bottle refracts sunlight, delivering about as much light as a 40- to 60-watt incandescent bulb to the interior. A properly installed solar bottle can last up to 5 years.
The use of plastic bottles in this way to provide indoor lighting from daylight was developed by Alfredo Moser of Brazil in 2002. Using the technology as a social enterprise was first launched in the Philippines by Illac Diaz under the MyShelter Foundation in April 2011. In order to help the idea to grow sustainably, the Foundation implemented a “local entrepreneur” business model whereby bottle bulbs are assembled and installed by local people, who can earn a small income for their work. Within months, one carpenter and one set of tools in one community in San Pedro, Laguna, expanded the organization to 15,000 solar bottle bulb installations in 20 cities and provinces around the Philippines, and began to inspire local initiatives around the world. MyShelter Foundation also established a training center that conducts workshops with youth, business companies, and other groups who are interested in volunteering their time to build lights in their communities.
In less than a year since inception, over 200,000 bottle bulbs were installed in communities around the world. Liter of Light has a goal to light up 1 million homes by the end of 2015.
About the MyShelter Foundation
MyShelter Foundation was established by Illac Diaz in 2006 to create a system of sustainability and reliability through its capability-building and employment-generating projects. Based on the concepts of social enterprise, appropriate low-cost technologies, and alternative construction in the Philippines, MyShelter Foundation has pioneered projects such as the Pier One Seafarer’s Dormitory, the Design Against the Elements (DAtE) competition, and the Bottle School Project.
The Solar Bottle Bulb, as it has also been called, is installed in the roof of homes with the purpose of refracting sunlight in order to light up a room. The project’s innovation lies in its utilization of cheap, durable and readily available materials to produce high quality natural lighting enabling the urban poor to have access to an affordable, environmentally friendly long-term alternative to electric light for use during the day.
Most of the plastic bottles used are recycled 1.5 liter bottles. After being filled with water and a little bleach, the bottle is pushed through a steel sheet that serves as a metal lock to prevent it from slipping. It is then embedded into a corrugated iron roof. A small part of the bottle is left outside while the rest of it protrudes into the house. Sealant is put around the hole made in the roof to keep it weather proof. The refractive properties of water ensures that the light from the sun that reaches the inside of the bottle becomes omni-directional mimicking an electric light bulb and emitting the same amount of light as a 40-60 W incandescent bulb depending on the amount of solar insolation available. Adding bleach to the water prevents it from turning green with algae and ensures a high quality light keeping the water clear for a longer time. In order to facilitate use of the invention through open source mechanisms, step-by-step guides on materials and installation are available online.
The Liter of Light is a zero-carbon-emitting alternative to the daytime use of electric or hydrocarbon-burning (kerosene, gas) illumination. The materials used in the technology are readily available, the plastic bottles as scrap, needing no additional manufacturing resources. This inexpensive technology allows most slum households to install it with the assistance of entrepreneurs from their communities. Once installed, the bottle is estimated to last about five years before being replaced. The electrical power consumed, at significant cost in carbon dioxide emission and money, by an electric bulb producing comparable light (say 55W incandescent or 20W CFL) is substantial.
Using an appropriate durable, leak-proof, space-filling glue is one of the main challenges for the solution. Many local groups are experimenting with different glues to find the best solution for both costs and quality. It was usually found that silicone-based or polyurethane glues work best. Inventor Moser, wrapping his face in a cloth, makes a hole in a roof tile with a drill, then pushes the bottle up into the hole, he says « You fix the bottle in with polyester resin. Even when it rains, the roof never leaks – not one drop. »
Source : Wikipedia