Producing hydrogen on the roof with KIT photoreactor panels

Towards a mass market optimized photoreactor

(sustainabilityenvironment.com) – What if a day not too far away it was possible to producing hydrogen on the roof safely and economically? An international group of scientists, creators of innovative photoreactor panels, is working on the objective.

The generation of green hydrogen on a small scale, exploiting sunlight is nothing new. In recent years, several projects have emerged that offer modular and scalable systems for the renewable generation of the carrier. In some cases so advanced that it is able to exploit atmospheric humidity instead of a source of pure water. One element remains, however, constant: the high technological cost. To reduce this, scientists from the Karlsruhe Institute of Technology (KIT) and colleagues from Canada have developed new high-efficiency and low-cost photoreactor modules for the synthesis of solar fuels.

Producing hydrogen on the roof

The system has some fundamental elements: the photocatalyst, that is the compound that facilitates the production reaction of H2 once activated by sunlight; a space for the starting materials of the reaction; an optical system that leads the incoming rays to the photoatlas, minimizing losses, regardless of their angle of incidence. At the structural level, scientists opted for a design consisting of hundreds of tiny parallel reaction channels. Each of these incorporates a V-shaped concentrator and a tubular cavity that collects the reaction volume. The design allows to obtain a high photocatalytic efficiency: a 5.8% which is more than 4 times higher than that obtained using a simple capillary photoreactor made of quartz glass.

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But the strong point, which could one day lead to hydrogen production on the roof, is the technological cost. “To reduce costs, we use economic geometries and materials that can be manufactured using established mass production processes,” says Paul Kant of the Institute for Micro Process Engineering at the KIT. According to initial calculations, the researchers estimate a price of about 22 dollars per square meter of photoreactor module. That is just over 20 euros per m2. The research was published in Joule.