EPFL researchers have built a pilot-scale solar reactor that produces usable heat and oxygen in addition to producing hydrogen with unprecedented efficiency for its size.
Often overlooked, EPFL campus satellite dishes resemble satellite antennas and other communications infrastructure. But this dish is special because it works like artificial wood. After concentrating solar radiation nearly 1,000 times, a nuclear reactor on a plate uses that sunlight to convert water into valuable, renewable hydrogen, oxygen, and heat.
“This is the first system-level demonstration of solar hydrogen generation. Unlike typical lab-scale demonstrations, all ancillary devices and components are included, so the entire system, not just the device itself. It gives us a better understanding of the energy efficiencies we can expect when considering.” Renewable Energy Science and Engineering Laboratory (LRESE), Faculty of Engineering.
“At more than 2 kilowatts of power, we have surpassed the 1-kilowatt limit for pilot reactors while maintaining this large-scale, record-high efficiency. It represents a really promising step towards realization.”
This work builds on preliminary proof-of-concept work at the lab scale using LRESE’s high-flux solar simulator, published in Nature Energy in 2019. Product process under real conditions in the same journal.
I don’t waste it, I don’t want to
Harnessing solar energy to produce hydrogen from water is called artificial photosynthesis, but the LRESE system is unique in that it can produce heat and oxygen on a large scale.
After the dish focuses the sun’s rays, water is pumped into the focal spot, which houses an integrated photoelectrochemical reactor. Within this reactor, a photoelectrochemical cell uses solar energy for electrolysis, the splitting of water molecules into hydrogen and oxygen. Heat is also produced, but rather than being released as system losses, this heat can be passed through a heat exchanger and used for heating the surroundings, for example.
In addition to the main outputs of the system, hydrogen and heat, the oxygen molecules released by the photoelectrolysis reaction are also recovered and used.
“Oxygen is often seen as a waste product, but in this case it can also be used for medical applications,” says Haussener.
Industrial and Residential Energy
This system is suitable for industrial, commercial and residential applications. In fact, his SoHHytec SA spin-off from LRESE is already deployed and commercialized. The EPFL start-up is working with a Swiss-based metals production facility to build a multi-hundred-kilowatt-scale demonstration plant that will produce hydrogen for the metal annealing process, oxygen for nearby hospitals and heat for hot water in the factory. is building needs.
“The pilot demonstration at EPFL has reached a major milestone by demonstrating unprecedented efficiency at high output power densities,” said Saurabh Tembhurne, co-founder and CEO of SoHHytec. increase.
The system can be used for residential and commercial central heating and hot water supply, as well as powering hydrogen fuel cells. At a solar hydrogen output level of about 0.5 kilograms per day, the EPFL campus system will be able to power about 1.5 hydrogen fuel cell vehicles driving the average annual distance. Or meet up to half the electricity needs of his typical Swiss family of four and more than half of the annual heat needs.
Haussener is already exploring new technical avenues as the artificial photosynthesis system is successfully scaled up. In particular, the lab is working on a large-scale photovoltaic system that splits carbon dioxide instead of water to produce useful materials such as the liquid fuel syngas and the green plastic precursor ethylene.
Original: Solar hydrogen system that co-generates heat and oxygen
Than: Lausanne Federal Institute of Technology
