Sun-Powered System Could Provide Electricity, Heat, and Cooling to Rural Schools And Clinics.
A startup company established by a team of MIT students and alumni aims to change how electrical energy is provided to clinics in remote and isolated parts of Africa.
The team has developed a patented technology that uses a mirrored parabolic trough to capture sunlight, heating fluid in a pipe along the centerline of the mirror. The fluid then powers what is called “a sort of air conditioner in reverse: Instead of using electricity to pump out cold air on one side and hot air on the other, it uses the hot fluid and cold air to generate electricity. At the same time, the hot fluid can be used to provide heat and hot water.”
A system prototype has been installed at a small clinic in the southern African nation of Lesotho. By next year, the team plans to have five fully operational systems installed in isolated clinics and schools there for field-testing. The key element of the system is a device called a scroll expander. It is used to convert the heat to power — a process that is described in a coming paper to be published in the ASME Journal of Engineering for Gas Turbines and Power.
Matthew Orosz, PhD, is the lead author of the paper. In a press announcement, he says the idea for the project began years ago, when he spent two years working in a village in Lesotho as a Peace Corps volunteer — with no access to electricity or hot water. He says some 60,000 clinics worldwide have similar situations. He returned to MIT determined to provide a solution.
Working with fellow student Amy Mueller, their thesis advisor Harold Hemond, the William E. Leonhard Professor of Engineering at MIT, and others, Orosz set up a nonprofit company called Solar Turbine Group (now known as STG International) to develop the solar technology he envisioned as a practical alternative for these off-the-grid facilities.
Orosz explains there are only two viable options today to provide electricity for such places: a solar photovoltaic (PV) array or a diesel generator. Both are somewhat less expensive to install than his company’s solar trough system, but when the costs of replacement parts and fuel are factored in, he estimates the solar trough system will be substantially cheaper over its lifetime.
The pilot system, which Orosz and colleagues built at Lesotho’s Matjotjo Village Health Clinic in 2008, provided the initial proof of principle, even though it took years to get all the parts working properly in the remote location.
The clinic in Lesotho, now closed for renovations, is expected to reopen early next year, when the team plans to return to the site and begin full-time operations with the newly automated setup. Over the course of the year, they plan to install four more systems at other schools and clinics in that country, with help from Lesotho’s ministries of health and education and three local engineers who are members of the STG team.
From a business perspective, the team hopes to create a local source of jobs and revenues; the systems will be built, owned and operated by local companies set up for that purpose, Orosz says.
Here’s a video on it all:
Africa will be a welcome home to energy innovations like what is being developed by STG International as it leapfrogs dirty fossil fuels for clean energy opions.
Source: MIT news , STG International
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