Clouds, or not, sun's energy harnessed

Sep 29 - McClatchy-Tribune Regional News - Yesenia Amaro Merced Sun-Star, Calif.

Researchers at UC Merced have created a new kind of solar thermal system that generates high temperatures and efficiency levels without having to track the sun.

The system, which works all day, uses specially made collector tubes to collect sunlight. Using existing technology, the heat generated from the collectors can then be transformed for cooling and heating, among other potential uses, researchers said Wednesday.

Solar collectors usually have to move and track the sun to achieve full energy production and require additional equipment that can be costly and difficult to maintain, researchers said.

"What makes (the collector tubes) so unique is that they don't have to track the sun," said Heather Poiry, a mechanical engineering student who works with UC Merced Professor Roland Winston, who pioneered the system. "This is the only one of its kind that doesn't have to move to track the sun."

The system had been in the works for the past two years. The group was able to get it up and running this summer with the help of many other UC Merced students, some of whom volunteered their time.

The system and a double-effect absorption chiller are being used to provide air conditioning for a trailer office in the back of the UC Merced facility at Castle. A double-effect absorption chiller is a machine that converts heat into cold, Winston said.

The solar thermal system produces temperatures of up to 400 F, and it works on cloudy days, unlike tracking systems that work only on sunny days, Poiry said. Inside the trailer, the group has a computer that monitors the environment outside.

"The Valley is a great place for solar because we have so much of it," said Ron Durbin, executive director of the University of California Advanced Solar Technologies Institute.

It not only reduces the amount of greenhouse gases, but the electricity costs, too, he added.

The team plans to take the project even further. "We are looking at using this kind of technology to produce electricity in the future," Winston said.

This kind of technology would be useful, especially in parts of third-world countries where there's no electricity, Durbin said.

The research team has high expectations for the system, Winston said. "This is a lower-cost alternative to tracking systems," he said. The system, designed for industrial settings, can be mounted on rooftops and on the sides of buildings, Durbin said.

Christopher Thomas, a research assistant, said helping with the research gave him the hands-on experience that he would never get inside a classroom. He said this is probably one of the top engineering research projects going on at UC Merced.

Bennett Widyolar, a graduate student, agreed. "It's been really fun," he said. "This is the only place where we get to see how it works."

Bruce Johnston, program manager for UC Solar, has traveled to various places to showcase the research and the system. People have already shown interest, he said.

The group said they'll continue to make improvements to the system.

Reporter Yesenia Amaro can be reached at (209) 385-2482 or yamaro@mercedsunstar.com.