Photothermal Solar Cell

A community’s supply of fresh water can be assessed in terms of its per capita energy cost. If the energy cost is low, the supplies are likely good, but for areas lacking fresh water, the energy usage is high. Energy use has a direct monetary correlation, and typically, greenhouse gas related environmental consequences. The water-energy requirement is highest for locations where potable water must be obtained by desalination (purification) or delivery by land, sea, or air. The design and implementation of desalination systems utilizing sustainable renewable energy sources would be beneficial in many communities that currently pay a high energy cost for potable water. Aquaneers Inc. proposes this Phase I DOE SBIR/STTR project for the development of a Solar Desalination System (SDS) that operates by virtue of an innovative Photo-Thermal (PT) Solar Cell. The PT cell generates steam when illuminated in an aqueous environment and is used to facilitate a highly efficient solar distillation process in the SDS. Plasmonic nanostructures that convert light into heat are incorporated into a three dimensional plasmonic crystal type structure that comprises the PT solar cell. The PT cell uses solar energy to generate steam within the SDS, which is condensed and collected as pure water end product. In future work, the solar steam can also be energy harvested as electricity in the condensation process. In the Phase I program, Aquaneers will advance its SDS prototype efforts through continued design iterations using 3D printing. The initial product is a small scale (1-10 person, 10-100 liters) water desalination system designed for customers in the military or humanitarian relief spaces. Research will be performed in optimizing the PT cell performance and manufacturing process, the SDS solar optical and water collection subsystems, and the overall device design and performance metrics. The demonstration of a self-contained solar-powered water-desalination system that has efficient operation in an economical design that can be scaled into a commercial product during Phase II is the primary goal of the Phase I project. The commercialization of Aquaneers SDS would be of societal benefit in a world where nearly 1 billion people lack access to safe water and global warming brought on by fossil fuel based energy overuse is a looming disaster. Energy requirements typically make desalination a choice only when other water options are exhausted. Nonetheless, increased global demand for water concurrent with resource depletion leads many to look to the bountiful reserves of the oceans. Desalination is highly compatible with solar energy use, as purified water can be generated during sunny hours and readily stored for later use Climate change is a substantial cause of current water shortages, and thus, renewable energy-based desalination technologies are essential to fulfill water needs while not furthering the problem. Aquaneers current target market lies in the $1Billion/year portable (point of use) water desalination (purification) industry, a subset of the $27B/year global desalination market. Keywords: Desalination, Water Purification, Photothermal, Nanotechnology, Plasmonics, Solar Energy, Steam Generation, Heat