Sunday, February 12, 2012

Solar Thermal Advocates say Colorado is Perfect for Taking the Heat

And now for a radical idea: Use the sun to heat water and air.

OK, perhaps it isn't a radical idea, but it is an underused one in Colorado and one that a group of solar-energy businesses and renewable-energy advocates want to boost.
Chris Meehan, left, and Brian Ellingson check out newly
installed solar thermal panels at the Mulroy complex.

The aim is to expand the Colorado market from $16 million in 2010 sales to $677 million in 2030, according to the "road map" released Tuesday by the group, the Solar Thermal Alliance of Colorado.

"Colorado has the perfect mix for thermal solar," said Neal Lurie, executive director of the Colorado Solar Energy Industries Association, a trade group and alliance member.

That mix is strong, abundant sunshine; warm days and cold nights; cold groundwater; and heavy heating loads, Lurie said.

The combination allows solar thermal systems in Colorado to perform better than in any state in the country, according to a study by the Florida Energy Center and the National Renewable Energy Laboratory.

Most of the solar-energy focus has been on high-tech photovoltaic, or PV, panels that turn sunlight into electricity.

In contrast, solar thermal panels are more low-tech — pipes, with fins to gather more heat, running through a boxlike panel with a piece of glass on top and insulation on the bottom.

As modest as it may appear, it is very efficient.

"A solar thermal panel gathers 70 to 80 percent of the sun's energy, while a PV panel gets maybe 17 percent of the energy," said Laurent Meillon, director of Lakewood-based Capitol Solar Energy, a thermal-unit installer.

The hot water, or in some cases heating fluid, is carried away from the panels and used to preheat water or air before going to a water heater or furnace.

A thermal unit at the Denver Housing Authority's Mulroy complex takes water that comes from Denver Water at about 35 degrees Fahrenheit and warms it to 76 degrees. The complex's boiler then heats it to about 129 degrees.

"In the first year of operation, we saved about 20 percent on our gas bill, about $4,500," said Chris Spelke, DHA program manager.

The systems are also cheaper than PV systems — about $2 a watt compared with $4 a watt for photovoltaics, Meillon said.

The price for a residential hot-water system ranges from $8,000 to $10,000 — with federal tax credit available that cuts the cost by 30 percent, Meillon said. Commercial systems range from $40,000 to $100,000.

A first step in the road map is to get the technology in front of consumers.

"People need to know that there is solar that isn't PV," said Tony Frank, executive director of the Colorado Renewable Energy Society.


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