A Liter’s Worth of Indoor Light

Isang Litrong Liwanag (in English, the phrase means “A Liter of Light”)  is a Philippines-based organization aiming to build indoor lighting in one million homes throughout the country by 2012. Ambitious plans are par for the course when it comes to humanitarian efforts, but this group is a little bit different. They’re not installing electrical outlets or building power plants. Instead, they’re illuminating these homes with a contraption that would impress MacGyver himself: The solar water bottle.

Here’s the setup: The plastic water bottles are cleaned, filled with water and bleach, and tucked snugly into holes cut into a roof. When sunlight hits the bottle, the water refracts the light and provides about as much illumination as a 50-watt light bulb.

Sure, this isn’t perfect, and the disadvantages are obvious. Solar water bottles of this type can’t store energy, so they can’t work at night. Although the bleach prevents algae from dimming the water, the bottles must be replaced about every five years. Yet the benefits are equally apparent: In homes without electricity, any sort of illumination is incredibly useful. These solar lights don’t require expensive parts, expert upkeep or a power source. They don’t produce harmful pollutants, and they’re nowhere near as dangerous as the faulty electrical systems that may be found in these informal settlements.

The concept comes from students at MIT, who based their design on the principles of the appropriate technologies movement.

Organizations in the Middle East and Brazil are also working with this technology, and I wouldn’t be surprised if it spreads throughout the developing world. Check out the video below for more information, and let me know if you have any ideas for similar inventions.