Published on August 30th, 2009 | by Susan Kraemer13
Backyard Solar Dish Melts Steel
We’re all familiar with the vast solar thermal power stations in the desert that use mirrors to make steam to drive turbines. Giant solar thermal arrays are already making electricity in the desert in Spain and California. But what if we could have just one of these units in the backyard, just for our own use?
That’s what motivated a team of MIT students to find the way to make the cheapest solar power station out there. Mass produce it for the home user and market it under their own new start up RawSolar.
Sure, it melts steel. But even more practically for the home owner, it makes steam in a flash:
By directing the dish at the more typical target for solar thermal power stations – water – you create steam instantly. Steam that could drive your own little turbine, making your own little supply of electricity. Or you could direct it to supplying heat for a floorboard radiator setup or a radiant flooring system. Initially the team is not using the steam to make electricity, like the desert arrays. But that will be next, I’m sure.
Solar thermal power stations are far more inexpensive and efficient than solar pv, because they’re just made of mirrors held up in a metal structure. The energy of typical sunlight can be concentrated by a factor of 1,000.
The team assembled this 12-foot dish in several weeks. The design is exceedingly simple and inexpensive. The frame is composed of aluminum tubing and mirrors are attached to it. The steam is relatively low temperature steam – at about 212 to 400 degrees Fahrenheit; not the 700 degrees steam the desert arrays make.
The team comprised Spencer Ahrens, a MIT mechanical engineering graduate, Sloan MBA Micah Sze, UC Berkeley mechanical engineering grad Eva Markiewicz, Olin College student Matt Ritter and MIT materials science student Anna Bershteyn.