By integrating solar harvesting concepts into the sides of a building, builders could considerably reduce the amount of energy that a structure would require from the grid.
In a study recently published in the Renewable Energy journal, a research team from Rensselaer Polytechnic Institute, headed by Diana-Andra Borca-Tasciuc, a professor of mechanical, aerospace, and nuclear engineering, showed the potential of wedge-shaped luminescent solar concentrators (LSCs). It is feasible to easily hang these efficient modular solar units at the side of a building.
The LSCs reviewed in this study are developed using transparent plastic coated with a film of photoluminescent particles at the back, analogous to those used in LEDs. The larger edge of the LSC is fitted with solar cells that convert energy harnessed from the sun into electric power.
The manner in which these devices harness and concentrate sunlight improves the power generated by each unit of surface area inside a solar cell.
To date, such exclusive shape and construction have exhibited only theoretical potential. As part of this study, the researchers took it a step ahead and investigated how these LSCs could work within the laboratory. They also used light data from the field to estimate the annual energy production by hanging the LSCs on walls.
As per data obtained from Albany, New York, and Phoenix, Arizona, the estimated annual energy production for these devices was about 40% higher compared to the annual energy generated by solar panels, while installing both vertically.
While this technology is not meant to replace solar panels, it expands our capacity to efficiently harvest solar energy in the built environment. It works well for vertical wall applications where a solar panel does not perform as well.
Diana-Andra Borca-Tasciuc, Professor of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute
According to Duncan Smith, a doctoral student in mechanical engineering at Rensselaer, “As the world transitions toward carbon neutrality, using vertical surfaces effectively for solar power harvesting will be a necessity for the solar industry.”
Particularly in urban settings, the roof area of taller buildings is usually dedicated to HVAC equipment and cannot be used for solar panel installations. In these same buildings, however, there is extra room on the walls.
Duncan Smith, Doctoral Student, Rensselaer Polytechnic Institute
Next, the researchers are making efforts to improve the shape of the LSC and seeking ways to engineer surface properties for more efficient harnessing and retention of the light that enters the device.
Michael Hughes, the director of Faculty Development for the Education for Working Professionals Program at Rensselaer, collaborated with Borca-Tasciuc and Smith in this study.
The researchers also collaborated with undergraduate students who were completing a capstone project under the Multidisciplinary Research Laboratory at Rensselaer, a platform that offers real-world experiences for students in preparation for their future careers.
Hughes, M. D., et al. (2020) Performance of wedge-shaped luminescent solar concentrators employing phosphor films and annual energy estimation case studies. Renewable Energy. doi.org/10.1016/j.renene.2020.07.005.