Bringing Power to the People — and Heat as Well
Sun-powered system developed by MIT students could provide electricity, heat, and cooling to rural schools and clinics
In some isolated clinics in parts of Africa, the electricity needed to power lights and medical devices is generated by expensive imported diesel fuel; the water supply can be so cold in winter that health workers can’t even wash their hands properly. But a startup company established by a team of MIT students and alumni aims to change that.
The patented technology they developed uses a mirrored parabolic trough to capture sunlight, heating fluid in a pipe along the mirror’s centerline. This fluid then powers 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 — or, by adding a separate chiller stage, to produce cooling as well.
The Solar ORC setup in Lesotho. Photo courtesy of STG International
A prototype of the system has been installed at a small clinic in the southern African nation of Lesotho; next year, the MIT team plans to have five fully operational systems installed in isolated clinics and schools there for field-testing. The key element of the system — a device called a scroll expander, used to convert the heat to power — is described in a paper to be published in the ASME Journal of Engineering for Gas Turbines and Power.