Solar power system has a bright future
16-08-2012 00:00
Solar panels erected on poles with tracking mechanisms manage to follow the sun's path during the day and produce more energy than a stationary rooftop panel.
But a nanotechnology researcher in Madison aims to one-up today's conventional tracking technology.
Following nature's lead, Hongrui Jiang studied the sunflower and came to develop a nanocomposite that can follow the sun because, like the flower, it responds to the light -- and heat -- the sun gives off.
The goal is to mimic nature's inner workings to help boost energy output and, ultimately, reduce the cost of producing power from the sun.
"We know the sunflower and other plants, either their leaves or their flowers or both, can move along with the direction of the sun to get higher lighting perception," Jiang said.
The results of his research were recently published in the journal Advanced Functional Materials and mentioned in the journal Nature.
But an interest in solar energy drove him to consider a nanotech alternative that mimics the sunflower's tracking abilities.
"Solar has a bright future, but there are many challenges that need to be solved before it can have a greater impact," he said.
Researchers are looking at a variety of ways to boost the output from solar power to help bring the costs down. The Department of Energy has funded a variety of research projects, though not Jiang's, through a SunShot initiative to make solar power cost-competitive by 2020.
The polymer-based system Jiang's team has developed uses carbon nanotubes in combination with a liquid crystalline elastomer to absorb light. The movement of the solar system would take place as heat generated by the sunlight prompts the polymer to contract.
The difference from conventional solar tracking systems is that the nanotech system would function more automatically than today's trackers, which require motors and gears to shift panels' direction toward the sun during the day. Those motors and gears require energy, reducing the net output from the solar panels.
"Carbon nanotubes have a very wide range of absorption, visible light all the way to infrared," Jiang said. "That is something we can take advantage of, since it is possible to use sunlight to drive it directly."
The next step in the process, with an eye toward commercial development, would be to deploy the technology at a larger system than the small contraption Jiang's team assembled and tested on campus in Madison. Jiang is a professor of electrical and computer engineering and head of the UW Micro-Nano Sensors and Actuators Lab.
His nanotech lab is focused on micro-mechanical systems, with a focus on "micro-optical systems that are inspired by nature."
"There is lots of research to get the material better, more responsive, more sensitive to light, stronger and more robust so that it can be used for 30 to 50 years," he said.
Go to tinyurl.com/nanosunflower to see a video on the research.
