Engineering a Better World

Five low-tech innovations making high-impact changes across the globe

Sport Solar Oven
Taking the heat out of the kitchen.

Potable water, electricity, medications—these are some of the things we know people often lack sufficient access to in the developing world. But the United Nations’ Food and Agriculture Organization estimates that more than 2.4 billion people also lack adequate cooking fuels. In places like Haiti and Nepal, less than two percent of original forests remain; where wood can be scrounged, the smoke generated from cooking fires can contribute to lung and eye ailments.

Using nothing but the sun’s heat, the Sport Solar Oven can cook an entire meal in two to four hours. Similar to a conventional crock-pot, this simple solution is ideal for families in low-income countries with sun-rich environments where the oven can reach cooking temperatures as high as 350 degrees Fahrenheit. The Solar Oven Society (SOS) has distributed the ovens—which are constructed from recycled plastic pop bottles, aluminum and insulation—to over 42 countries to date, including Afghanistan, Nicaragua and Mexico.

Two to four hours before meal time, food is placed within a black pot in the oven which faces the direction of the sun. The oven can be left alone to cook almost anything: meat, fish, chicken, vegetables, bread, cakes, rice and pasta, with little effort. While solar cooking has been researched and tested for the past 25 years, it was only in 2003 that SOS and other companies began manufacturing and distributing the ovens on a worldwide scale.

The Sport is shipped as a complete ready-to-cook kit and includes two cooking pots, a thermometer, an instruction book with recipes and a Water Pasteurization Indicator for $60 USD. SOS accepts donations from individuals and organizations to help reduce this cost and also puts all proceeds from North American sales toward projects in the developing world. While production is currently taking place in the United States, an oven manufacturing plant is being built in Ethiopia, which is expected to stimulate the local economy and improve availability of the oven.

The Play Pump
Fetching water has never been so fun.

Even when clean water is available in rural African communities, young girls are often obliged to walk a few miles each day to access it, or dedicate valuable time and energy to using hand pumps which frequently break down. The constant struggle for potable drinking water consumes time these girls could be spending at school or playing with friends.

Enter the PlayPump, a merry-go-round that pumps clean, safe drinking water from the ground every time a joyful child spins around and around. While children play on the carousel, water is pumped from the ground through a closed system into a 2,500 litre water tank that stands seven metres above the ground; it can produce up to 1,400 litres of water per hour based on a rate of 16 rotations per minute. Water is accessed through a simple tap, and the excess is diverted back into the system to ensure its purity.

PlayPumps International has partnered with local governments and NGOs to bore new wells near school grounds and equip them with these carousel pumps. Seven hundred pumps have been installed to date, providing free drinking water to over one million people in South Africa, Mozambique and Swaziland.

“Water is the biggest problem we’ve got,” says one of the PlayPump’s creators, South African Trevor Field. Yet the PlayPump generates more than just water, as it frees up time for schoolchildren who can worry less about daily survival and focus more on their education. Gender equality is cleverly promoted as boys are now involved in the “work” with the PlayPump. Messages promoting HIV/AIDS awareness are disseminated on the above-ground water tanks. The advertising space is also sold to raise money for system maintenance.

Solar Rental Service
A small price for a huge potential.

Solar power systems are the ideal solution for rural communities that lack access to electricity, but they remain prohibitively expensive even by North American standards.

In Laos, Sunlabob Rural Energy Systems has established a solar rental service that enables off-the-grid households and enterprises to power lights, televisions, radios, refrigerators, water pumps, heaters and battery chargers without large upfront investments.

For one single family in Laos to access solar power in their home, it costs between $2 and $10 per month, depending on the size of the system required. Since the initial pilot project in Ban Sorg village in 2003, Sunlabob has installed over 5,600 systems in more than 450 villages throughout the country.

Sunlabob is funding distribution of the solar power systems through a capital fund created from various private investors. As rent is collected from users, it is also placed back into this fund, generating resources for continuous solar power distribution. The unique thing about the rural electrification system is that all actors in the supply chain are motivated by personal interest, maintaining a standard of commercial viability.

Local technicians are trained to install and service the solar equipment. If the system should malfunction, the technicians are already there and renters don’t have to pay until the problem is fixed. The dilemma is generally remedied right away, too, since payments do not start up again until the energy begins to flow.

Currently, the demand in rural Laos is far outstripping Sunlabob’s supply. The organization is seeking additional capital to fund the purchase of more technology, with long-term strategy of helping the country achieve its development goals.

The Kanchan Arsenic Filter
How rusty nails are preventing cancer.

While access to potable water is a problem in many developing countries, some communities face an added the glitch—about 150 million people are affected by water containing arsenic, a poisonous metalloid that causes skin disease and cancer.

In Nepal, one of the regions most burdened by arsenic poisoning, a team of researchers from the Massachusetts Institute of Technology (MIT) has partnered with two local NGOs in the rural Terai region to develop a low-cost spin on the traditional sand filter. The Kanchan Arsenic Filter (KAF), from the Nepali word meaning “mountain spring water,” strips the poison directly from the source using rusty iron nails in a filter of sand and gravel held in a plastic bucket and washbasin, attached to a PVC pipe.

“The iron nails in the KAF are like the cartridge in a Brita water filter,” explains Susan Murcott, an engineering lecturer at MIT. The nails act as an “adsorption media”—rust, when exposed to water and oxygen, attracts the arsenic and removes the poison from the water. Even before this occurs, several harmful pathogens have already been removed through the sand and gravel filter.

Slow sand filters were first developed in the 1820s, but the idea was revisited in the 1980s. It was not until 2003, however, that the technology was adapted to remove arsenic, when MIT Masters student Tommy Ngai thought to integrate the sand and rust filtration systems.

The KAF is as low-tech as it gets: the filter does not require any external power source and the only maintenance required is the replacement of the rusty nails every three years. At a one-time cost of $10 USD, the filter produces plenty of arsenic-free water (15 litres per hour) for the average Nepali family of six.

Murcott hopes to expand the current distribution of 3,000 filters to 5,000 worldwide by the end of 2007. MIT has left the filter as an open source product, hoping that others will adapt this technology and implement it in different areas of the world that are plagued unneccesarily by arsenic poisoning.

Sugarcane charcoal
A sweet and healthy solution.

In Haiti , where 98 percent of the country is deforested, gathering wood for cooking fires is nearly impossible. And when wood actually is burned, smoke levels are so concentrated that they frequently cause respiratory and heart illnesses.

For years, wood-based charcoal has been used as an alternative to firewood as it is smokeless and produces more heat per unit weight than wood alone; but in denuded places like Haiti this is hardly an option. Amy Smith and her team of researchers at MIT have taken the age-old idea of charcoal briquetting and substituted the wood input for something more abundant in Haiti: sugarcane waste.

In the small fishing village of Petit Anse in northern Haiti, sugarcane charcoal is being introduced this month using the dried out bagasse (waste) from the stripped sugarcane plant. According to Smith, when bagasse is heated in an oil drum kiln (a low oxygen environment) charcoal dust is created, which is then mixed with cassava flour and shaped into briquettes by hand. After baking in the sun for about a week, the charcoal briquettes are ready for smokeless and woodless burning.

Tests have shown that the energy density of sugarcane charcoal is much higher than wood charcoal and can be produced for about a third of the price. Smith suggests that entrepreneurs with little startup capital can afford the $10 oil drum and the cassava root for briquette production, since the actual bagasse is a waste product and should be available at no cost.

After a micro-enterprise has been established to sell the briquettes, demand may require faster production than hand-formation can keep up with. Smith and the team at MIT are working to design a briquette press that would use locally available skills and materials—increasing the selling potential of sugarcane fuel.

This entry was posted on Monday, October 22nd, 2007 at 2:17 pm and is filed under Volunteer. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a comment, or trackback from your own site. Add to del.icio.us.