As it stands, we have already got a fair number of different techniques for trapping and utilising solar energy – from photovoltaic cells to solar fuels – although, given the pressing need for renewable energy, there can never be too many.
Recently, Swedish researchers had reported a new, compact and efficient method for storing solar energy in a chemical solution.
To prove its usefulness, they had built a prototype device, comprised of two parts: one stores solar energy in the chemical bonds of a molecule, while the other uses it to heat up water for immediate use.
By combining both short- and long-term storage, the device is capable of utilising up to 80 percent of incoming sunlight, which can then either be used immediately or delivered in small, precise amounts over a period of several months.
As the new method is further refined and developed, it’s potential uses could include off-grid power stations, extreme environments, and satellite thermal control systems.
There might, however, also be a more immediate application – as photovoltaic cells become less expensive and therefore more widespread, the need for storing excess energy is on the rise.
As regards efficiency, regular batteries work just fine, but a cheaper and less bulky alternative would certainly be a welcome development.
The problem with previous chemical storage methods was their inability to absorb photons with energies below a certain threshold, thereby leading to lower efficiencies.
To address this issue, the research team cobbled up a hybrid two-layer system made out of silica and quartz glass with tiny fluid channels carved into either one.
The top layer is filled with a solution of an organic hydrocarbon compounds that absorbs high-energy photons, leaving the lower energy ones for the water-filled bottom layer.
According to the team, the updated system is massive improvement over their previous effort, allowing the device to store and release energy more than 100 times without any significant loss in efficiency.
“As is the case with any new technology, initial applications will be in niches where [molecular storage] offers unique technical properties and where cost-per-joule is of lesser importance,” the researchers write.
Further up the road will be real-world performance and cost-efficiency tests, and potentially a solvent-free version of the hybrid to decrease toxicity.