A research team at the Center for Nanotechnology and Molecular Materials of Wake Forest University has designed a new polymer-derived solar-thermal device that is capable of capturing both heat and solar energy to generate electricity. This innovation could reduce the cost of heating a home by around 40%.
The solar-thermal device utilizes a fluid that moves via a module mounted on the roof. The fluid captures heat from the sun, while an inbuilt solar cell produces energy from the visible light of the sun.
David Carroll, Director of the Center for Nanotechnology and Molecular Materials at Wake Forest University, stated that the scientists have adopted a systems approach to make home energy-efficient as the device gathers both heat and visible sunlight. He added that the device leverages the wider range of energy obtained from the sun every day.
The research was published in the March issue journal, Solar Energy Materials and Solar Cells. Around 75% of solar energy will be left unabsorbed by a traditional roof-mounted solar cell since the longest light wavelengths like infrared heat cannot be absorbed by the solar cell. Daily a huge quantity of solar power will be missed by such solar cells since sunlight is effectively absorbed from 10 a.m. to 2 p.m. Carroll mentioned that on a rooftop, infrared radiation have both heat and visible sunlight and this heat aspect has been ignored so far.
The device features an integrated arrangement of clear tubes, each measuring 5 mm in diameter. The tubes are positioned in a flat fashion. Oil mixed with a specific dye flows through the tubes. The visible light of the sun falls on the clear tubes and the oil. A spray-on polymer photovoltaic is included on the backside of the clear tubes and converts the visible sunlight into electricity. The oil gets superheated and flows into the heat pump for transmitting the heat inside a house.
In contrast to currently used flat solar cells, the clear tubes found inside the device are curved, enabling the absorption of both hat and solar energy between sunrise and sunset and supplying power throughout the day. Due to its innovative design and the capability to collect sunlight at tilted angles, the device is recognized as the first solar-thermal equipment that can be installed in a building to appear almost similar to the roofing tiles.
Experiments made on the new device have revealed 30% efficiency in transforming solar energy into electricity, while a usual solar cell featuring a polymer-based absorber has only 8% of conversion efficiency.
This summer, the team will develop the first solar-thermal cell measuring 1 sqm. This initiative will serve as a significant step in commercializing the technology.