I have highlighted before the innovative solar tubes (closet lighting ideas) which brings in natural lighting through the roof during the day. A cheaper and simpler option, a 1.5 liter solar bottle light, is being used in rural and poor areas around the world.
For a lot of people around the world, just turning on one light bulb can be a major expense. Their homes are not well designed, so it can be a dark place even during the day. Now they can have an inexpensive lighting solution during the day (costing $1 to install in the Philippines). A 1.5 liter soda bottle is filled with water and a little bit of chlorine or bleach. A hole is then cut into the roof where these bottles can sit.
The water reflects the sun light in all directions (it is equivalent to a 50-60 watt light bulb), whereas just a hole in the roof works as a spotlight and doesn’t light up the whole area. The Chlorine or bleach prevents algae or bacteria growing in the water.
Creating Light and Green Jobs In The Philippines
Solar Bottles in Uganda
More posts on the importance of lighting: