Posted on Mon, Sep. 14, 2009

Someday, you might unplug your air conditioner and cool your house on a 110- degree afternoon by cranking up the heat from the sun.

In his laboratory at the University of California at Merced, physicist Roland Winston says he is nearing a breakthrough that could make that scenario happen in the next several years.

Winston, an innovator in amplifying sunlight for energy, is putting the finishing touches on a solar-concentration array that heats oil to 400 degrees. The oil's heat will be used to power a chilling unit that produces cold water for air conditioners.

He expects to announce a collaboration with a private company within the next several months to produce a solar air-conditioning unit.

"We want to make it economic and practical," said Winston, who heads a research team at UC Merced. "The key is collecting solar energy no matter where the sun is in the sky. The San Joaquin Valley is the perfect place to do it."

Sun powers a move west

Valley sunshine was his main reason for moving to Merced in 2003 from the University of Chicago. Winston, 73, spent nearly four decades in Chicago making a name for himself in particle physics as well as solar research. He has dozens of patents collected in a lifetime of research.

His peers in the research community say he could have remained in Chicago and finished his career as physics department chairman, a position he had held for several years. But he knew the sunny San Joaquin Valley was a perfect incubator for solar technology.

Jerry Olson, a principal scientist for 31 years at the National Renewable Energy Laboratory in Denver, said he admires Winston's move to UC Merced.

"Over the years, Roland has really made some very significant contributions," Olson said. "But he really wants this world in a better place, so he moved for solar research."

Winston is the director of the California Advanced Solar Technologies Institute, which received a $2.25 million grant from the UC Office of the President last month to fund solar research over the next five years. The institute includes researchers at UC campuses at Berkeley and Santa Barbara.

Their goal is to make solar energy more affordable and widespread.

UC Merced officials said they were fortunate to land a professor of Winston's stature.

"Roland is a major research presence in the field of solar energy research," said Jeff Wright, dean of the School of Engineering. "His efforts at UC Merced have already produced groundbreaking innovations."

Solar power has long been coveted as pollution-free energy from a virtually limitless source. But sunlight is not intense enough to generate large amounts of electricity without massive solar panels.

In his work on energizing particles in the 1960s, Winston found a way to amplify sunlight. He concentrated it by using "nonimaging optics," or mirrors that magnify and focus solar energy.

Initial skepticism

Winston today is widely accepted as the researcher who invented the field of nonimaging optics. But his ideas were initially met with skepticism until continued research erased the doubts of the scientific community.

The next task was to develop efficient ways to use the amplified sunlight. Winston and others adapted nonimaging optics for use with photovoltaic cells, converting the energy into electricity.

In the past few years, he has worked at finding ways to channel the energy into devices that heat water or oil, so-called thermal processes.

Thermal energy -- heat -- is used to power conventional air conditioners. They start by heating fluid first. Ordinarily, electricity or natural gas provides the fuel. Winston's approach taps sunlight instead.

Other researchers and companies are trying to adapt the technology for air conditioning. For instance, Southern California Gas Co. engineers are installing a prototype concentrator unit on the company's building in Downey to power the air conditioning. The sun will heat water, which then will power a thermal energy process to create cold water for air conditioning.

The gas company's rooftop unit costs about $200,000, including mirrors, pipes and computer-automated solar trackers. The trackers move the mirrors as the sun crosses the sky each day to capture sunlight.

No trackers needed

Winston's design does not require trackers. His mirrors are curved to capture the sun's light from almost any angle.

"They never move," he said. "Whenever you get moving parts for tracking, you have maintenance and wear. But with this design, there's no need for tracking, no matter where the sun is."

He uses oil instead of water, he said, because oil can be heated to higher temperatures without boiling. Winston said his goal is to make the process more efficient.

It probably will take several years to produce affordable solar air-conditioning units, Winston said. But he thinks people would be willing to pay a little extra money in the beginning so they could unplug from the electricity grid powered by fossil fuel.

The solar air conditioner could be designed to fit on the ground next to a home, he said.

Bernadette Del Chiaro, clean energy advocate for the nonprofit Environment California, said she thinks many people would welcome such a breakthrough.

"We burn tons of fossil fuels, pollute the air, warm our climate and drive energy prices up to cool our homes," she said. "I think people would love to tap into the valley's famous sunshine."