I've been hearing about an MIT (student) project to build low-cost solar concentrators using off the shelf materials since January when the project was part of the Independent Activities Period. (IAP happens in January and anyone from a professor emeritus to a student to a janitor can offer a non-credit course. It is a hold-over from the student demonstration days of the Sixties™ but less and less of interest is happening during IAP as the years go by.)

Yesterday, I went to see their prototype. Their breakthrough is not in technology but in materials. They use standard mirrors that sit in a frame so that they "sag" into a shallow parabolic shape and focus up to 1000 suns on a black coil which can then heat water to as high as 400º F. This is "low" temperature steam, capable of providing process heat but not enough to run a steam turbine. The machinery that moves the concentrator to track the sun is an off the shelf TV satellite dish motor. The model I saw does not yet have an automatic tracking system but, again, off the shelf components are available. It is an impressive machine.



Another discovery is the scale of this concentrator. The concentrator is about 12 feet across. It's big but it's not huge. The designer of the system, Doug Wood, a long-time solar concentrator experimenter who holds the patent on this design, found that this size worked better and was less susceptible to wind damage. Bigger is not always better.

I talked with Matthew Ritter, an Olin College student who is working on the project, and found that he had also worked on the recent MIT entry in the Solar Decathlon and previously had worked on a summer workshop at MIT building alternative fuel vehicles, probably the last time we talked.

The students have formed a company to develop and market this design and will be moving to California to become Raw Solar. They will be leaving behind their prototype on the lawn by Memorial Drive. They do not know whether MIT will continue to experiment with and use this gift but are trying hard to find faculty support for the project.

About thirty years ago, I helped a group of MIT students build a solar greenhouse about a block away from where the concentrator now stands. It was a project of the then Appropriate Technology Club of MIT and was built by two students, Tom Coradetti (sp?) and Tom Zimmerman, the inventor of the DataGlove, and me. The faculty advisor was Tim Johnson whose specialty was high-tech windows. It stayed on that site for a year and was eventually torn down to make way for an experimental solar building, a high-tech wonder designed by Tim Johnson, that was little used and lasted maybe a decade before being torn down. Leaving the concentrator, I biked past that old site and saw that now it is a parking lot for trucks and bulldozers. The 'Tute has never been interested in low tech, in my experience. The students almost always are. Too bad that MIT doesn't recognize and harness that interest.

In addition, this concentrator reminds of the work my friend Tim Harkness did. He experimented with using hydraulics to form parabolic dishes and used to come to local solar events like the upcoming Boston Solar Day with his large, modular dish and cook chicken stew. I have one of his scale model prototypes that I take out from time to time to display to the public. Tim died of cancer a few years ago, much too young. He would have loved this development and have offered improvements.