EPFL engineers have built and tested a solar reactor capable of producing hydrogen gas from sunlight and water. The system is not only highly efficient in producing hydrogen, but also recovers and utilizes the “waste” products of oxygen and heat.
Hydrogen will play an important role in renewable energy, and one of the most effective ways to produce hydrogen is to split water into its constituent molecules. This process, powered by solar energy, is called artificial photosynthesis, and it’s the process this new reactor uses.
An EPFL reactor looks like a parabolic antenna and works on a similar principle. A large curved area collects as much light as possible and concentrates it into a small centrally suspended device. In this case, the dish collects heat from the sun and focuses it about 800 times into the photoelectrochemical reactor. Water is pumped into this reactor, where solar energy is used to split the molecules into hydrogen and oxygen.
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The reactor also captures two waste products of the process that are usually just released: oxygen and heat. Oxygen is useful for hospital and industrial applications, and heat can be passed through heat exchangers and used to heat water and the interior of buildings.
The reactor was tested at the EPFL campus over 13 days in August 2020 and February and March 2021 to understand how it performed in different weather conditions. Its solar-to-hydrogen conversion efficiency was found to average over 20%, producing about 500 g (1.1 pounds) of hydrogen per day. At this output, the team says, the system can power his 1.5 hydrogen fuel cell vehicles, which he drives on average over a year, providing about half the electricity needs of a four-person household.
“At more than 2 kilowatts of power, we have broken through the 1-kilowatt limit for pilot reactors while maintaining this large-scale, record-high efficiency,” said Sophia Hausener, corresponding author of the study. “The hydrogen production rate achieved in this study is a truly promising step towards the commercial realization of this technology.”
According to the researchers, the next step is to build a multi-hundred-kilowatt demonstration plant at a metal-making facility, where hydrogen will be used to anneal metal, heat will be used for hot water, and oxygen will be supplied to a nearby hospital. is collected to
A study was published in a journal natural energy.
Source: EPFL
