A new polymer-based solar-thermal device developed by the Center for Nanotechnology and Molecular Materials at Wake Forest University can generate power from both heat and visible sunlight. The concept could potentially slash the cost of home heating by as much as 40 percent.
The new device incorporates a heat-collecting fluid and an integrated solar cell to generate electricity. Standard rooftop solar panels can only capture a small part of the sun’s power and around 75 percent of solar energy is wasted by normal photovoltaic systems as the cells are unable to longest wavelengths of light – infrared heat.
The solar-thermal device developed at Wake Forest University consists of an array of 5 millimeter diameter tubes with a special fluid containing oil and proprietary dye flowing through. Visible sunlight shines into the tubing and is converted to electricity by a spray-on polymer photovoltaic substance applied to the back of the tubes. In the process, the oil is also heated to very high temperatures, flows into a heat pump and then can be used to transfer the heat inside the home or to heat water.
The curving of the tubes provides an additional benefit – the ability to collect infrared heat and visible light for a much greater part of the day than a standard solar cell.
The design of the cell also allows for flexibility in implementation and could be made into roofing tile form; offering a truly building-integrated solar power solution.
Testing of the solar-thermal device has demonstrated a 30 percent efficiency in converting solar power to usable energy; whereas a standard polymer absorber based solar cell performs at up to just 8 percent conversion efficiency.
The next step in the device’s development will be the research team constructing a square-meter-size solar-thermal cell around the middle of this year, an important step in preparing the technology for the commercial market.
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