Harvesting the Sun

Solar mirrors shed both light and heat for sustainability.

January 23, 2007

Physics professor Hans Pfister and Sean Diamond ’08 carefully set the solar mirrors that will harness the sun’s energy.

It seems like something ingenious that the professor from Gilligan's Island would build to help the castaways live better. The solar-mirrors system, designed and built by physics professor Hans Pfister, technician Rick Lindsey, electronics-design engineer Bill Giewont and physics major Sean Diamond '08, combines 46 inexpensive mirrors from a local building-supply store with a car radiator, axle and windshield-wiper motor to produce hot water.

The mirrors move in sync with the sun's movement across the sky and focus its rays onto a car radiator, which acts as a heat exchanger, converting the solar energy into thermal energy and heating up the water with an 83-percent efficiency rate.

"We're not living sustainably," says Pfister. "So I thought about positive ways that we could get additional energy without depleting our resources and adding to greenhouse gases."

Pfister's creative use of basic physics and off-the-shelf parts brings an "aha" moment to even casual observers when they see the system and realize how much energy can actually be generated from such a simple process.

Diamond, who worked with Pfister on the project, says, "We saved hundreds of man hours by designing the system out of reusable parts. A major challenge was to get it all working smoothly."

After being moved from its current location on Tome Hall, the system will provide hot water for residents of the Center for Sustainable Living (Treehouse).