Performance of wedge-shaped luminescent solar concentrators employing phosphor films and annual energy estimation case studies

Abstract

Abstract Luminescent solar concentrators (LSCs) are solar devices that focus sunlight through red-shifted internal reflection and have been proposed as a potential alternative to traditional photovoltaic (PV) panels. Such systems also have potential applications as multi-functional building envelope materials. This paper investigates the performance of wedge-shaped LSCs employing inorganic luminescent phosphors that demonstrate enhanced performance at incidence angles that conventional solar panels do not use effectively. This behavior is investigated experimentally through the current-voltage (I–V) characteristics of solar cells attached to wedge-shaped LSCs illuminated at angles covering the entire range of possible insolation conditions. Similar experiments were also performed on solar cells to determine the power ratio, or the power produced by solar cells within an LSC normalized to the power produced by bare solar cells exposed to identical insolation conditions. Using laboratory measured power ratio and recorded direct normal irradiance data for two case studies in Phoenix AZ and Albany NY, the annual energy production for wedge-shaped LSCs mounted on vertical walls due to direct-beam irradiance was determined. The energy produced by solar cells within vertically installed LSCs is between 20 and 40% above annual energy produced by vertically installed solar panels, depending on location and orientation (facing east or south). Moreover, depending on orientation, wedge-LSC power production peaks at traditionally suboptimal times for a solar panel. In all, these results demonstrate the potential for wedge-shaped LSCs as a power harvesting building envelope, an architectural solution emerging in response to net-zero energy building legislation.