- Associated Press - Saturday, January 18, 2014

DENVER (AP) - Aaron Brown has built water heaters for schools in Costa Rica and done charity work all around the world, but the Metropolitan State University of Denver professor says some of the most rewarding work he’s ever done is happening right now in Denver’s Westwood neighborhood.

Brown, who teaches mechanical engineering at Metro State, is working with students, as well as a local nonprofit organization, Revision International, to build solar powered furnaces for homes in the neighborhood. With empty soda cans as one of the main parts of the design, the furnaces cost around $30 to make and are expected to save about the same amount in monthly energy costs.

Anderson said the electricity used by the fans costs about two cents a day. Cool air is drawn into the unit’s base and then heated as it travels up through drilled holes in the 144 aluminum cans, which have been heated by the sun. The air then exits through ventilation holes at the top of the unit.

Joseph Teipel, the director of operations and co-founder of the project, held a series of meetings in the community. And while Revision had previous successes there in areas like backyard gardens and urban farms, some people were still leery.

“You talking about soda cans being glued together, so it’s not something that just comes to people’s minds, but the initial installations were key. Now that they’ve seen it and see how well it works, they’re really excited,” Teipel said.

While there has to be a supplemental source for heat at night, the units can reach about 170 degrees during the day. In one of the units installed in November, Anderson said, a room that was about 60 degrees increased to 90 degrees within 20 minutes.

In November, the group installed two of the heaters in homes, with more installations scheduled for later this month.

An initial effort yielded a furnace that cost about $60, but Brown thought the price could be lowered. That was the challenge he posed to his students at Metro State, tasking them with making the units faster, cheaper and more efficient and reliable.

“You have to be really creative,” said Richard Anderson, a Metro State senior who’s part of the project team. “Right now, the unit will last for about a winter without any maintenance. If you bumped up the cost to about $100, it would last three or four times longer.”

The success has helped temper some of the initial skepticism from some members of the neighborhood. There were doubts that the unattractive, simple contraptions would actually work.

When organizers started their backyard gardening initiative in 2009 there were seven families involved. By the end of 2013 there were 200 families, and Teipel said another 100 are expected to join this year.

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Information from: The Denver Post, http://www.denverpost.com