Hydrogen fuel is receiving increased attention in residential applications, public or private transportation, and other societal energy needs. Photocatalytic generation of hydrogen may provide a pathway for efficient solar energy utilization. We are collaborating with Hydrogen Solar of London and Henderson to assist in developing their Solar Tandem Cell™ technology. The concept is depicted in Figure 1.

Figure 1. Principle of operation of the Hydrogen Solar Tandem Cell™ is depicted.

In order to design and use the Tandem Cell™ effectively, models for the device are necessary so that the system may be optimized. The present task is attempted to better understand the phenomena occurring within the solar tandem cell. Parametric studies are performed based on appropriate mass balances, transport, solar, and electrochemical kinetics applied to the electrolysis cell. The performance of innovative designs, voltage losses and water management requirements, and the response of the solar tandem cell to parameter changes for simple designs will be predicted. The developed parametric models will allow engineers and designers to predict the performance of the cell given geometric parameters, material properties and operating conditions for the purpose of optimizing operation of the solar tandem cell.

Part of this work is computational, including computational fluid dynamics, heat transfer, charge transfer, and species transfer. An example of this is shown in Figure 2. Experimental evaluations are also taking place on-sun. See Figure 3.

Figure 2. Surface plot of mass fraction of water on anode side and contour plot of electric potential (V).

Figure 3. The test apparatus for on-sun evaluation of Tandem Cells™ is shown.