New solar-thermal device harnesses heat and light
April 7, 2011
Researchers at Wake Forest University have developed a new type of polymer solar-thermal device that combines photovoltaics with a system that captures the Sun's infrared radiation to generate heating. By taking advantage of both heat and light, researchers say the device could deliver up to 40 percent savings on the cost of heating, as well as helping reduce power bills by producing electricity.
The hybrid cell is designed with an integrated array of clear tubes, five millimeters (approx 1/4 inch) in diameter. Lying flat, visible sunlight shines into the clear tube which is filled with an oil blended with a proprietary dye, heating the oil which then flows into a heat pump to transfer the warmth inside a home.
Electrical current is produced via a polymer photovoltaic sprayed onto the back of the tubes.
The result is a solar-thermal device with an impressive 30 percent conversion efficiency.
In comparison to flat solar cells, the tube design also has the advantage of being able to capture light at oblique angles, so it can accumulate power for a much longer stretch in the day and be more readily integrated into building materials – it could be produced to resemble a roofing tile for example.
The research team aims to produce a 3 foot square solar thermal cell over the coming months, a key step in bringing the technology closer to market.
"It's a systems approach to making your home ultra-efficient because the device collects both solar energy and heat," said David Carroll, Ph.D., director of the Center for Nanotechnology and Molecular Materials at Wake Forest University. "Our solar-thermal device takes better advantage of the broad range of power delivered from the sun each day."