There has been much buzz about the water-purifying machine that Segway inventor Dean Kamen has been working on. You toss anything that looks wet into the Slingshot and it comes out as perfect distilled clean water. Obviously gasoline, diesel and paraffin are not part of this wet family.
The Slingshot can supply 1000 liters of clean water per day. You can use practically any water source; ocean, puddle, domestic waste water. The slingshot uses vapor compression distillation and takes only 2 percent of the power needed by a typical distillers. There are no filters and no charcoal to replace.
The Slingshot can utilize waste heat (450 watts) from a sterling engine electrical generator (prototype being developed by Dean Kamen) to boil water. The heat put into the water is recovered through a “counter-flow heat exchanger” and recycled to heat the next batch of water. This sterling engine which can run on anything that burns (propane or cow dung), can generate 1 kilowatt, energy enough to power 70 high efficiency light bulbs.
Inventing something that is great is often only half the solution. The other half is putting the technology in the hands of the people who need it most. An estimated 1.1 billion people in the world don't have access to clean drinking water, and an estimated 1.6 billion don't have electricity. Those figures add up to a big and important pair of problems for the world and an equally big opportunity for entrepreneurs.
Africa, especially sub-Saharan Africa is just the place for portable water and energy solutions. The real invention needed here is a financial model that enables the access of both the Slingshot and the sterling electrical generator to millions of thousands of parched and dim households.
I think 500,000 one-kilowatt electrical generates would create both light and wealth for rural households, as opposed to low quality public works employment and public debt from 500-megawatt hydropower built using a loan from the Peoples Republic of China. Similarly, investment in one million Slingshots that supply 1,000 litres per day could deliver real water and entrepreneurs as opposed to the millions of aid dollars spent on water sector reforms in Kenya that generate more bureaucracy, public debt and less water.