Henrico man installs unusual solar system

Who says there's nothing new under the sun?

The solar-heating system that businessman Dave Stets installed at his eastern Henrico County house is a first, experts say.

Stets' system collects solar heat year-round and stores it underground, where it can be tapped in winter.

"People use similar systems, but not like this," said Stets as he showed off the glistening solar panels behind his white ranch house in the Marion Hill area.

"What Dave is doing is forging new ground," said Bob Ramlow, a prominent solar-heat consultant in Amherst, Wis.

Stets, 63, is co-owner of Richmond BySolar, which builds solar projects. A jovial man with reddish hair combed straight back, Stets is part idea guy and part salesman.

Stets came up with the idea for the system, and he got help with the design from James T. McLeskey Jr., an associate professor of mechanical engineering at Virginia Commonwealth University, and Marshall L. Sweet, a VCU graduate student.

Stets hopes his unusual solar-heat system will evolve into a product he can sell. He calls the system a prototype. McLeskey calls it an experiment.

Eight solar panels, 8 feet tall and 4 feet wide, collect the sun's warmth in Stets' backyard, just beyond the patio and bird feeder.

That heat warms a nontoxic form of antifreeze in the panels. Moved by a pump, the hot liquid leaves the panels in a pipe that runs underground. That heat warms a 15-cubic meter bed of sand.

The sand bed "is like an oven in the ground," Stets said.

The hot sand warms a separate, water-filled pipe, which runs to Stets' house and provides heat under the floor.

The key is the sand, which holds heat like a battery holds electricity. That addresses a long-time solar-heat challenge — how to obtain sufficient warmth in winter, when daytimes are short and there is less sun.

Similar designs are working around the world. One used on a few homes in the U.S. sends heat from solar panels directly to a bed of sand under the house.

That design is "elegantly simple," having fewer parts, but it's harder than Stets' system to add to an existing house, said Ramlow, the consultant.

"There isn't one that's better or worse," Ramlow said. "They're just different."

Stets got his system running in October, so it hasn't had time to build up heat for long. That means it's too soon to know how effective the system is.

"I'd say it's definitely providing heat to the house, but we won't see the full potential until next year," said VCU's Sweet.

Sweet made the system the subject of his 2010 master's thesis. He is now pursuing a doctorate in mechanical engineering.

Using a computer model, or simulation, Sweet determined that a solar system like Stets', in a house similar to Stets', could shave more than 70 percent off heating bills.

But it would take more than 27 years to recoup more than $29,000 in upfront costs, Sweet's analysis showed.

Some people might be reluctant to spend that much for a payback so far down the road, Sweet said. And some people might be reluctant to try new technology.

"Scientifically, we know it does pay off, but there is a lot more than just science affecting our society right now," Sweet said.

Solar heat can reduce emissions linked to global warming. People who opt for solar heat, Sweet said, are like people who buy a Prius — they are doing it for more than the money.

"They are the ones who care and are environmentally friendly," Sweet said.

It's wrong to think of solar systems in terms of "how quick do I get my money back," said Ramlow, the consultant.

People don't envision a payback point when they buy a normal heating system, Ramlow said.

Stets has other sources of winter warmth, including a heat pump.

Stets was reluctant to reveal financial details of his solar system, saying he's still refining it. He noted that his 1,200-square-foot house is smaller than the home in Sweet's example, so the heating system would cost less.

"It's not really a research project," Stets said. "We know it works."

rspringston@timesdispatch.com

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