Follow the sun: Sandia solar-tracking technology fuels global business

by Nancy Salem

In the 1980s Tim Leonard was busy programming computers at Sandia, unaware that just down the hall work was going on that would change his life.

 Tim was in the wind energy group, steps away from the people in solar energy. One of them was Alex Maish, starting his pet project, a low-cost, high-precision tracking technology to continuously move solar panels into the best possible position to catch sunlight and generate energy.

“I met Alex, but I didn’t really know what he was working on,” Tim says. “I would visit, say hi, and go back.”

Years later, after leaving the Labs, Tim ran into Alex at a local nursery. He filled Alex in on his business - programming and electronic upgrading of gaming machines - and confided that it wasn’t challenging.

Alex mentioned his solar-tracking technology. “He said it was being licensed but that none of the interested companies had been able to commercialize it. He needed someone to make some prototype [circuit] boards for an industry client,” Tim says. “I told him I’d take a look.”

Tim helped Alex with electronics and programming, and liked the technology so much he licensed it himself in the mid-1990s. He built a business, Precision Solar Technologies Corp., and placed trackers around the world. Among Tim’s customers is Sandia, where the technology was developed and where many solar devices are fitted with his trackers, including at the National Solar Thermal Test Facility.

“We’re now into 16 years of commercial use and thousands of unit-hours of performance,” Tim says.

Celestial equations

Alex’s goal was to develop affordable precision tracking for solar energy research, development, and production. His technology - trademarked SolarTrak by Sandia, which holds the patent - is a software program in a computer chip that sits on an electronic circuit board that controls the tracker.

Unlike sensor-based controllers, SolarTrak uses celestial equations to calculate the exact position of the sun at any time, anywhere on the planet, regardless of cloud cover. “This can be critical in partly cloudy situations where the bright edge of a cloud can fool a sensor,” Tim says.

SolarTrak determines the sun’s location, makes decisions based on its angle, and turns on machinery that moves solar equipment into position. It factors wind speed and other external information into performance.

“The computer uses electronic feedback to monitor where the machinery is in its range of motion. With that information and the position of the sun, it makes the two coincide,” Tim says. “It’s a simple process. It’s prudent to hook up a PC every few months and check the clock, but mostly it runs and runs.”

SolarTrak technology has been used in commercial, industrial, residential, and research applications. Precision Solar Technologies has put controllers to work in heliostat projects, solar furnace applications, solar trough facilities, photovoltaics, and fiber optic daylighting research, bringing natural light deep into the interiors of buildings.

Hundreds of SolarTrak controllers are in commercial use in 18 countries and have been used in research projects at Sandia and Oak Ridge national laboratories, Rensselaer Polytechnic Institute in New York, Walt Disney Imagineering, the University of Loughborough and the University of Reading in the United Kingdom, US universities, and private-sector entities including Emcore, Amonix, and Los Alamos Research Associates.

“I’ve put a SolarTrak controller on everything I know of that moves and has to point at the sun,” Tim says.

An offer from Sandia

Tim grew up in Washington, D.C., and moved to Albuquerque in 1973 to attend the University of New Mexico. He studied architecture and learned computer programming in engineering courses included in the curriculum. He continued to study mechanical engineering after earning a bachelor’s degree in 1977.

Tim went to work as a programmer for the Civil Engineering Research Facility, CERF, that was part of UNM’s engineering department. “One day a fellow from CERF came in, sat on my desk, asked a few questions about programming and engineering structures, and asked if I wanted to be a contractor at Sandia working on their mainframe computers and doing structural analysis on the vertical axis wind turbine,” he says. “Suffice it to say I said yes.”

Tim joined the Labs’ wind energy program as a contractor in 1977. He left nine years later and was quickly hired back as Labs staff by his supervisor Dick Braasch. “I went back to my old office and not a piece of paper or pencil had been moved since I left three months earlier,” Tim says. “Dick brought me back in, and it was a great feeling of belonging.”

He stayed another five years, working in a variety of areas as his old friends in the wind group moved on to other projects.

Using the programming, assembly, and structural skills he developed at Sandia, Tim was hired by companies in the early 1990s to work on video gaming machines. That work taught Tim electronics. “I started designing digital boards and creating more elaborate games,” he says.

Tim ran into Alex in early 1995 and licensed the solar tracking technology about a year later. Alex was still working on the project at

Sandia, and he and Tim fine-tuned the technology to get it commercialized. “Alex was eight years into it when we started working together,” he says. “It became a joint venture.”

Tim built the business through word of mouth and a website. His first customer was a researcher at the University of Australia in Canberra. Other early customers included Arizona Public Service and Amonix, where Tim installed his first high-powered, large piece of tracking equipment, on a 30- by 40-foot, 19,000-pound array.

Tim’s signature product is the Prospector, a stand-alone solar weather station to measure solar and atmospheric environments.

In addition to the station, Precision Solar produces other full systems that include motors, gear drives, mechanical arms, and frames that hold and move the solar arrays for power production or research. The company does new systems and retrofits older ones. Tim works from a home base in Tijeras with an electronics and assembly workshop, forklift, and loading dock to send trackers to far-off places.

Energy savings

Tim says doing work for Sandia helped him develop the business. “Sandia wanted a lower-cost tracker for their sun sensors, and that led to the Prospector,” he says. “I also did a solar data acquisition system for another person at Sandia as well as other ancillary projects.  Each time they approached me with a niche project it became a potential product line.”

Rich Diver, a retired Sandian and solar engineering consultant, says Tim’s trackers are cost-effective and “very robust.” “The Prospector is a really nice product,” he says. “It works well.”

 Santa Fe resident Ricardo Sanchez remembers going to Sandia, where his dad worked, and looking up at the solar tower. “I was amazed at what it could do,” he says. “I was really psyched to have that type of technology on my home.”

About five years ago, Sanchez installed 13 fixed solar thermal panels on his roof, but they didn’t generate enough heat. “I met Tim and went with his mirror heliostat tracker that reflects sunlight onto the panels. It took my system from something that didn’t work to something that worked,” he says. “I used to have a $500 a month heating bill in the winter. Now it’s $700 for the whole season. The tracker is perfect. I don’t do a thing. It just works.”

Tim says he’s never regretted taking on the business. “I grew up with Erector sets and Lincoln Logs and was making things that moved since I was very young. Then I learned computers and electronics,” he says. “This business has brought together every single aspect of everything I have learned either in school or on my own.”

Alex died in 2005 after a lifelong struggle with cystic fibrosis. He lived to see the beginnings of a business founded on his technology. Tim says he and Alex became best of friends and that he believes Alex would have been proud of the growth of the business and that it accomplished his goal of bringing down the once-astronomical cost of precision solar tracking.

“To this day, every (circuit) board I make says ‘Originally developed at Sandia Labs’,” Tim says. “Alex gets the credit. I’m still looking for my first opportunity to dedicate a precision solar field in his name.”

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An ideal companion for biofuels

by Patti Koning

When Aristotle said that the whole is greater than the sum of its parts, he probably wasn’t thinking of engines and biofuels. But his famous quote applies perfectly to the synergy between Leaner Lifted-Flame Combustion (LLFC) and oxygenated biofuels. Each technology has its own limitations, but combining the two may create something much greater - a cleaner, more efficient, lower cost diesel engine that runs on domestic, renewable fuels.

Lyle Pickett and Chuck Mueller (both 8362), working in partnership with Ford Motor Co. and the University of Wisconsin’s Engine Research Center, are investigating how oxygen-rich biofuels might enable low-emissions diesel engines.  

“The cost of advanced engine and aftertreatment technologies can be a barrier to improving fuel economy,” says Lyle. “Clean-diesel cars are more fuel efficient than regular gasoline cars but they haven’t been adopted widely, in part because they are more expensive. The interplay between LLFC and the right biofuel may produce a high-efficiency combustion strategy that can also reduce costly aftertreatment and overcome that barrier.”

An alternative combustion strategy

LLFC is an alternative combustion strategy developed by Sandia with the potential for soot-free emissions. With LLFC, the fuel spray mixes with air inside the cylinder before reaching the flame. The distance from the fuel injector to the flame is the “lift-off length.”

“With enough oxygen mixed into the fuel, you go from an orange, soot-producing flame to a blue flame that burns cleanly,” explains Lyle. Other methods to reduce emissions in diesel engines are being pursued, but they are difficult to control because fuel injection occurs long before combustion is initiated. LLFC offers a control advantage because fuel injection occurs simultaneously with combustion.

LLFC has been demonstrated in lab tests; however, the conditions are hard to reproduce in an engine using typical diesel fuel. The system needs low ambient temperature, something hard to sustain in an engine, and small nozzle holes to increase air entrainment, which may be incompatible with engine power requirements. An oxygen-rich fuel could overcome these difficulties.

“Every strategy has its tradeoffs. For example, LLFC with conventional diesel fuel may require high injection pressure, which can be costly,” says Chuck. “But using an oxygenated fuel could reduce that need.”

Since many biofuels are oxygenates, they should naturally enable LLFC. In addition, renewable biofuels should have lower greenhouse gas emissions over their life-cycle and would count toward the federal Renewable Fuel Standard. The potential synergy between an advanced combustion strategy and a renewable fuel is one of the main attractions of this project.

To meet current emission standards, modern diesel engines use a particulate filter. The black soot that in the past could be observed coming from the tailpipe of a bus or 18-wheeler is now trapped on the filter. The filter is periodically heated to consume the soot, but this requires more fuel, resulting in lower overall efficiency and fewer miles per gallon. LLFC may allow a diesel engine to meet emissions standards without the use of a particulate filter, thus avoiding this penalty.

“Even though biofuels have less energy per volume than regular diesel, if you can eliminate the particulate filter, overall efficiency improves, somewhat offsetting its lower energy content,” says Lyle. In addition, removing the particulate filter would reduce the pumping work of the engine as well as the weight and cost of the vehicle. In fact, aftertreatment can cost as much as the powertrain for some engines.

The project has four main goals: to identify fuel properties that can be used to enable controllable LLFC; to increase fundamental understanding of LLFC; to identify and test possible fuels; and to enhance combustion models to capture the effects of key fuel properties on combustion in advanced combustion regimes. The work is sponsored by DOE’s Vehicle Technologies Program.

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Sandia/California honors young women for outstanding achievement in math and science

by Patti Koning

Last month, the Sandia Women’s Connection (SWC) honored 18 young women from area high schools for their achievement in math and science. Now in its 21st year, the Math & Science Awards event is designed to both encourage the young women to continue studying math and science and to create mentoring opportunities.

For the second year in a row, the event was held at Sandia’s Combustion Research Computation and Visualization (CRCV) building at the Livermore Valley Open Campus (LVOC).

“The world is wide open to you,” said Div. 8000 VP Rick Stulen. “It may sound trite, but you will end up in places you can only imagine today. Keep up the enthusiasm and curiosity that got you here today. I can tell you that it only gets better from here. It gets harder, for sure, but it also gets better.”

Teachers from nine high schools in Livermore, Dublin, Pleasanton, Tracy, and Manteca nominated two students, one for outstanding achievement in math and one for outstanding achievement in science. The award is given to young women in their junior year of high school so they can include it on their college and scholarship applications.

“Although women have made tremendous strides in math and science, there is a lack of women in very high levels of related industries, including engineering, mathematics, and physics,” said Cathy Branda (8623), the event’s chair. “The decisions that women make not to pursue careers in STEM [science, technology, engineering, and math] fields seem to be made very early. Our objective is to highlight for you that you can aim your sights on any career option and to give you a flavor of what some of those career options could look like.”

Before the awards ceremony began, the awardees and their families met their Sandia hosts, women with careers in math and science. Donna Djordjevich (8116) explained her Ground Truth program, an interactive gaming platform used to simulate critical homeland security activities. Yanli Liu (8621) shared her research on the use of a microfluidic device to study cellular signaling at sub-cellular resolution.

“This is really wonderful and encouraging for these girls,” says Elizabeth Lopez, a science teacher at Granada High School. “Even today, engineering, math, and science are still considered ‘boy’ subjects. Meeting all of these successful women reminds them that they can do whatever they set their minds to.”

The challenge for Rachel Sowa, winner of the science award for Livermore High School, is narrowing down her interests. She’s considering computer science, architecture, civil engineering, and now sound engineering, after running the sound board for her school’s spring musical, “Hairspray.” “She’s always been a builder,” says her mother, Genevieve Getman-Sowa. “She’s worked hard and it’s paying off.”

For her father Erik, the awards ceremony was also a return to his roots - he worked at Sandia with Rick Stulen early in his career. “I couldn’t be happier for Rachel to be included in this group of young women,” he says. “It’s important for her to be surrounded by people with the same intellectual values.”

To start off the awards ceremony, computer scientist Janine Bennett (8953) and systems analyst Julie Fruetel (8114) shared their personal stories. Both women said that in high school, they could not have envisioned their current professional success.

Janine is a computer scientist who builds mathematical and computer software tools to identify, characterize, and track features of interest in large-scale data. “When I was your age, I had no idea I would end up working at a national lab as a scientist in a research group,” she says. “I spent a lot of time agonizing about picking a major and a college when I didn’t know what I was going to do with the rest of my life.”

She shared three pieces of advice that she wished she’d known back then: make careful, thoughtful decisions and then relax and go with it; enjoy what you do; and partner well in life. Janine advised the young women to identify both professional and personal support networks.

“If you decide to pursue a PhD, make sure you have a good advisor with whom you communicate well. That can be almost as important as the actual technical work,” she said. “And make sure you partner well in life. I stressed a lot about the work-life balance, but my husband and I really value each other’s careers. We have a 20-month-old son and while we do make sacrifices, we are making it work together.”

Julie told the students that initially she was interested in journalism and didn’t consider engineering until her junior year of high school. “I went to my high school guidance counselor and we made a plan of what I needed to do to apply to colleges with the best engineering programs,” she said. “His message to me was ‘You can do this,’ and that was very meaningful to me.”

That plan included taking chemistry, physics, and calculus in her senior year. Julie earned a bachelor of science degree in chemistry from Harvey Mudd College and then went on to earn a doctorate in pharmaceutical chemistry at the University of California, San Francisco. In both cases, she aimed high, attending the best schools she could.

At Sandia, Julie first worked in microfluidics on MicroChemLab, a handheld device to bring benchtop laboratory analysis methods into the field, and then moved into systems analysis. “There is no right or wrong path,” she says. “No one could have predicted the arc I took.”

In closing, Cathy told the awardees to keep up the good work, but also to keep in touch. “When you excel in math and science, doors open but it may not always be obvious what those doors are. Internships are a great way to explore career options,” she said. “Sandia is a wonderful place to do those internships because of the breadth and kind of work that we do.”

Julie’s remarks hit home with Selena Chang, the Granada High School recipient for math. “I’m reconsidering the AP classes to take next year,” she says. “I think I’ll probably add AP chemistry.”

 Award winners

Outstanding Achievement in Mathematics

• Alysse Ketner, Amador High School
• Alexandra Brown, Dublin High School
• Alejandra Nieves, East Union High School
• Selina Lao, Foothill High School
• Selena Shang, Granada High School
• Lynn Hao Tran, Livermore High School
• Amanda Christensen, Manteca High School
• Danielle Nghiem, Merrill F. West High School

Emily Spencer, Tracy High School

Outstanding Achievement in Science

• Da Eun Kim, Amador High School
• Nancy Zhou, Dublin High School
• Britney Johnston, East Union High School
• Victoria Liu, Foothill High School
• Meagan White, Granada High School
• Rachel Sowa, Livermore High School
• Brooke Mejorado, Manteca High School
• Chloe Pounds, Merrill F. West High School
• Lucy Cui, Tracy High School

Special thanks to the Sandia hosts and Math & Science Awards Committee:

Sandia Hosts

• Amanda Askin (8112)
• Julie Fruetel (8114)
• Mary Gonzales (8250)
• Yalin Hu (8135)
• Tammy Kolda (8966)
• Jina Lee (8116)
• Kirsty Leong (8651)
• Kari Neely (85151)
• Stacy Nelson (8259)
• Jacquieline O’Connor (8632)

Committee

• Glenn Kubiak (8600), director champion, SWC
• Cathy Branda (8623), Chair
• Donna Blevins (8953), co-chair
• Marilyn Hawley (8116), co-chair
• Seanna Crouch (8942)
• Deneille Wiese-Smith (8128)

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