Direct Solar Thermochemical Hydrogen Production by Water Splitting

Solarflux Energy Technologies, Inc. was founded in 2019 with a strong focus on developing groundbreaking technologies to address growing energy demands worldwide. The Solarflux team is optimistic about the potential of parabolic dish concentrators to provide cost-effective and sustainable energy solutions to underserved market sectors, particularly in regions of the world with an abundance of direct sunlight. Fostered by PITA, the company has collaborated with Lehigh University’s Energy Research Center (ERC) over the last five years on solar energy-related projects.

Solarflux (Reading, PA) manufactures solar concentrators from low-cost, fully recyclable materials that are easy to install with low maintenance requirements. The company’s flagship product is the FOCUS parabolic reflector dish system, capable of dual-axis tracking and a 10 kWth peak power rating. Electrically powered by PV panels, the concentrator is autonomous and is integrated with a Dynalene SF heat transfer fluid loop for operation up to 310°C. FOCUS also includes a CCD camera for direct solar tracking, supported by GPS for passive tracking during periods of cloud coverage.

The Solarflux team recently donated one of its FOCUS solar concentrator units to Lehigh University, where the ERC team continues to contribute their technical expertise in energy systems. The FOCUS unit, along with an associated Thermal Energy Storage (TES) system, will be used to study the dynamics of solar energy-TES as part of the PITA project.

"Thermal energy studies are generally done with steady thermal sources, whereas the current project will enable the study of the temporal nature of solar thermal energy storage,” says John Fangman, CEO of Solarflux.

The integrated system will also be available for instructional projects for students and as a testbed for joint research projects.

This testbed addition by Solarflux provides another resource to continue developing these thermal energy storage technologies while linking them with the real dynamics of solar harvesting.

Carlos Romero, director, Energy Research Center at Lehigh University

“The ERC has been working for many years on thermal energy storage projects that include sensible, latent and thermochemical energy storage,” says Dr. Carlos Romero, ERC director. “This testbed addition by Solarflux provides another resource to continue developing these thermal energy storage technologies while linking them with the real dynamics of solar harvesting.”

The Solarflux and Lehigh University collaboration investigated research on membrane distillation (MD), a thermally-driven separation process in which only water vapor travels through a microporous hydrophobic membrane. This process has various applications, such as desalination and wastewater treatment. The MD project consisted of membrane selection, characterization, and process optimization for maximum clean permeate flux transport using process conditions typical of solar thermal collectors. A complete lab-scale rig was built for membrane testing. The project demonstrated the effectiveness of solar energy as a cost-effective option for impaired water treatment, resulting in a competitive cost of water cleaning using a renewable resource.

The partnership also explored the production of hydrogen gas through solar energy. Hydrogen has been proposed as a potentially viable contributor to the global decarbonization effort and for moving the global economy to a net-zero carbon future. Direct solar thermochemical hydrogen (STCH) production by water splitting is one approach which can utilize the full spectrum of solar radiation and has the potential of achieving high solar energy conversion efficiencies.

The hydrogen conversion project is currently ongoing. It consists of a two-step STCH cycle, using a metal oxide high temperature step provided by a solar concentrator for metal oxide reduction, followed by an oxidation step for water splitting at a lower temperature. This concept will demonstrate the effectiveness of locating a solar hydrogen producing reactor at the focal point of Solarflux’s solar concentrator for utilization of solar thermal energy for hydrogen production.