Solar Energy: Rays of Hope
How will the world's developing countries provide for electrical power as they move from having no, or very little electricity, to one where citizens are on the grid? Conventional methods to generate electricity rely on burning coal, oil, or natural gas, all of which produce carbon dioxide, the most important greenhouse gas.
A new, innovative solar collector is now installed at Eckerd College in front of the marine science laboratory. This is a demonstration pilot project developed by MIT students Matt Orosz and Amy Mueller. They have developed a small, self-contained and inexpensive system to generate electricity and hot water.
This system is less expensive and more reliable than a conventional diesel generator, is relatively simple, and is carbon free.
How does it work?
Two 130 foot arrays of parabolic solar collectors made from reflective aluminum collect and concentrate energy from the sun to heat a thermal fluid similar to anti-freeze in a car. The heated thermal fluid passes through a heat exchanger (boiler) where it heats the working fluid, similar to freons found in refrigerators and A/C units. The working fluid vaporizes into a gas and as it expands turns a turbine, which produce electricity.
The working fluid goes into another heat exchanger, where the remaining heat produces hot water. Finally, the working fluid goes through a condenser, similar to a car radiator, where it turns back into a fluid, and is pumped back to the boiler.
This process is known as an Organic Rankine cycle (ORC), well known to industrial engineers, which allows heat recovery from relatively low temperature sources.
The system has an output of ~ 3kW, the amount of electricity used by a large house in the United States. The purpose is to demonstrate the concept of a solar thermal system, and to serve as a U.S. based test bed for field trials of a similar unit in a health clinic in Lesotho, in southern Africa.
Benefits of Solar Power in Africa
This project is designed for countries such as Lesotho, Africa, where less than one out of nine people have access to electricity. While a system such as this can't provide each household with power, it can provide electricity for essential programs including health clinics, community centers, schools, and small businesses in rural areas, which have no access to the electrical grid.
Solar thermal panels will provide the people of Lesotho, and other developing countries with a clean, dependable source of domestic energy, so as to limit their dependence on outside production.
As global temperatures continue to increase, it is crucial to find ways for these countries to leapfrog over the old, carbon based technology to innovative, sustainable, ways to produce electricity and hot water.
Meet the designer:
During his Peace Corps duty in Lesotho, Matt Orosz lived in a rural mountain village without electricity or running water. Impressed by the simplicity of a locally-constructed solar bread cooker, Matt began to experiment with ideas for converting solar energy to produce hot water and electricity. He returned to the U.S. to pursue a graduate degree in engineering at MIT where these ideas were slowly formed into designs, experiments, and prototype technologies. Several awards and fellowships later, Matt and his team have focused on continued technology development, monitoring of field installations in Lesotho, and promotion of local technology development in Lesotho. A graduate of Dartmouth and MIT, Matt is currently pursuing a doctorate in Environmental Engineering at MIT in energy systems integration. In 2009 he was appointed a Fulbright Scholar.