Researchers studying how sunlight damages DNA have developed a molecular energy storage system capable of storing large amounts of solar energy and releasing it later as heat, offering a possible future alternative for low-emission heating technologies.
The work centers on molecular solar thermal energy storage systems, known as Most systems, which use specially designed molecules that change shape when exposed to sunlight, storing energy in the process.
The energy can later be released when the molecules return to their original form.
Grace Han said the idea emerged after she moved from Boston to southern California and noticed stronger sunlight affecting her skin more quickly.
“I was just reading about DNA photochemistry — for leisure,” Han recalled.
Her research focused on how DNA molecules damaged by sunlight temporarily shift into strained shapes after exposure to ultraviolet radiation.
Scientists have spent decades attempting to replicate similar behavior artificially for energy storage purposes.
DNA Repair Process Inspired The System
Han realized certain biological systems already perform this process naturally.
Some organisms use an enzyme called photolyase to repair DNA molecules distorted by sunlight.
The molecules temporarily store energy after being altered by ultraviolet radiation before returning to their original structure.
Han and her colleagues identified these shape-changing molecules as promising candidates for thermal energy storage.
“They are very, very small,” Han said. “And can store a massive amount of energy per mass.”
In a paper published in February, Han’s research team described a new Most system with what researchers said is the highest energy density yet achieved for this type of technology.
The stored energy was sufficient to rapidly boil a small amount of water inside a laboratory vial.
“When I actually saw the video and saw how quickly the entire solution was boiling, that was really remarkable,” Han said.
She credited computer modeling performed by collaborator Kendall Houk and his research group at the University of California, Los Angeles as critical to the project.
Energy Density Exceeded Lithium-Ion Batteries
Kasper Moth-Poulsen, who studies Most systems but was not involved in the project, said the results exceeded previous benchmarks in the field.
“I think our best systems were one megajoule [of energy per kilogram]. They had, I think, 1.6, which is really amazing,” he said.
The system achieved an energy density of 1.65 megajoules per kilogram.
According to the researchers, that exceeds the energy density typically associated with lithium-ion batteries used in smartphones and electric vehicles.
Moth-Poulsen conducts research at the Polytechnic University of Barcelona and other institutions.
Researchers say Most systems could potentially store energy for months, years, or even decades.
Unlike fossil fuels, the systems would not require combustion to generate heat.
“The Most technology operates without burning anything,” Moth-Poulsen said.
He also noted that the technology could theoretically function globally rather than depending on geographically concentrated fuel supplies.
Researchers Acknowledge Technical Challenges
The current system still faces significant limitations.
The molecular transformation requires ultraviolet light at a wavelength of approximately 300 nanometres.
John Griffin said this type of ultraviolet radiation exists naturally in sunlight but only in limited quantities.
“That does come from the sun to us but only in very small quantities,” Griffin said.
The present system also requires hydrochloric acid to trigger the energy release process.
Han acknowledged that hydrochloric acid is highly corrosive and not an ideal long-term solution.
She said future work will focus on improving responsiveness to natural sunlight and replacing the chemical trigger with safer alternatives.
Researchers are also examining solid-state versions of the technology.
Han said future applications could include transparent window coatings capable of releasing stored heat to reduce condensation or warm indoor spaces.
Griffin said his research team is also investigating solid-state Most systems.
Experts Debate Future Applications
Harry Hoster said the technology still faces engineering obstacles related to light penetration and fluid movement.
According to Hoster, light-sensitive molecules in Most systems cannot be packed too densely because sunlight must still reach them.
“In a really optimistic scenario, you could probably make this 5mm thick,” he estimated.
Hoster also noted that liquid-based Most systems require pumps and moving components, adding cost and mechanical complexity.
“The moment you need to pump stuff around you have more things that can get broken,” he said.
Hoster questioned whether the technology could provide all heating needs for buildings but suggested it may prove useful for temperature-sensitive systems on satellites or aircraft.
“It’s great science,” he said. “It’s beautiful that they managed to get this functionality right.”
Despite growing interest, researchers said molecular solar thermal storage remains a relatively small scientific field.
Griffin recalled attending a conference on Most technology last year with roughly 70 participants.
“That was basically the whole community in the world on working this stuff,” he said.
Featured image credits: Public Domain Pictures
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