Researcher builds solar collector for algae feedstock

• WARNING: Resize helper couldn't find requested file: /datadrive/websites/biodieselmagazine.com/app/webroot/uploads/posts/web/1290-1294330214.jpg

Web exclusive posted August 20, 2008 at 10:19 a.m. CST

An industrial technology researcher at Sul Ross State University in Alpine, Texas, is designing and building a solar collector that can be used to process and distribute light and heat to grow algae feedstock for biodiesel. The system will also produce solar and steam-generated electricity.

Keith Klein, an assistant professor in the university's Industrial Technology Department, is working on a shoestring budget to fabricate an insulated algae propagation tank that includes a parabolic mirror with a refractor that will concentrate the plant-feeding part of the light spectrum on algae and the remaining light on solar cells and a boiler.

"We're capturing light, we're processing it, and doing with that processed light what is most beneficial to be done with it," Klein said. "I think with this approach, we should get twice the energy out of the light beam. Now that sounds sort of stupid, but we're taking the part that the plants want and we're shining that on the plants and we're taking the part that wants to make electricity and we're putting that on the [solar cells]. With a great big one, we could be boiling water and running a steam turbine."

Klein said because plants only use blue and red light for photosynthesis, that part of the spectrum will be supplied to the algae. The infrared light will be used to produce electricity from solar cells and a boiler.

Because the device includes an insulated tank for the algae, Klein said his device will allow the feedstock to grow in more disparate climates. The tank will prevent water from evaporating in warm weather, he said, adding that it will also allow the algae to grow in cold weather. The framework that will hold the mirror is a set of hoops and ribs that will allow the mirrors to rotate and face the sun throughout the day.

"When it wakes up in the morning, it's obviously going to have to turn around and face east and the parabola is going to have to lean up to focus the light," he said. "And then during the day, the computer is going to have to turn and face it into the sun. I think it will be rather easy, but it's going to be a lot of head-scratching."

The current framework for the device measures 24 feet in length with a 12 foot diameter, but Klein said the device could conceivably be built to be 100 feet long and 40 feet in diameter.

Klein said his project began with a $4,000 grant from the Associated General Contractors of America to develop a fireproof roof that uses solar energy to heat water. "It worked really good," he said, "but you know, nobody really wants much hot water, because they already got hot water." That project evolved into making a roof with parabolic solar collectors that track the sun. Now the project has turned into creating an environment for growing algae feedstock for biodiesel.

Having just returned from the "Efficient Conversion of Solar Energy to Electricity and Fuels: Critical Research Directions and Tutorial" workshop that was hosted Aug. 13-15 by the University of Colorado in Boulder and sponsored by the U.S. DOE and the Colorado Renewable Energy Collaboratory, Klein said he's inspired to keep moving forward with the project.

"I think it's an interesting idea," he said. "If I wasn't teaching four classes and all of those other things and if somebody gave me money to hire 10 people, I could really move along faster with it." The project recently received two additional $6,000 grants from the university.

Klein said he's looking for a collaborator to supply him with oil-producing algae, but at this point any algae will do. "We may just find a pond out here and get some scum off the top of it," he quipped. "It's a T. Boone Pickens plan without the windmills."