Scientists Develop Gel That Turns Humidity Into Energy

Researchers in Singapore have produced a super moisture-absorbent gel that can dehumidify a room while “harvesting” the atmospheric water to generate its own energy supply. (Courtesy of the National Institute of Singapore)

(CN) – Researchers in Singapore have created a moisture-absorbent gel that generates its own energy while dehumidifying a room and could provide an efficient and sustainable alternative to conventional air conditioners, according to a study released Wednesday.

To develop the technology, researchers closely examined photosynthesis, the mechanism used by plants to generate energy from water and sunlight.

Lead researcher Swee Ching Tan of the National University of Singapore said in a statement that the humidity digester, as it’s been dubbed, was also inspired by people’s misperception of Singapore as a high-temperature environment.

“People feel hotter because of relative humidity, as it can affect how we perceive temperature,” Tan said in the statement. “That got me thinking, what if I can invent something that harvests water from our ambient air and, at the same time, reduces relative humidity and provides water or energy?”

The result was a moisture-grabbing hydrogel containing photoelectrochemical technology, which behaves similarly to photosynthesis.

When placed inside of a box by researchers, a moisture-absorbent gel worked in tandem with a solar cell and photoanode to oxidize water and generate a low energy current. (Courtesy of the National Institute of Singapore)

Researchers placed photoanode, a cathode and a solar cell in a box with the gel. Together, the elements activated oxidation and splitting of the atmospheric water.

Humidity inside the box dropped by as much as 35% compared to the air outside the box, according to the study published Wednesday in the journal Joule.

The water in the box is pulled by the gel and fed into the photoanode, providing a constant fuel supply for energy production.

The gel, composed mainly of zinc and cobalt, can harvest more than four times its weight in water and produce a low-energy current under ambient light, the study found.

“The second-generation cobalt hydrogel that we developed absorbs moisture faster than any commercially available drying agents in the market,” Tan said in the statement. “We put our hand in the dry box; it felt like a fridge. It’s so cold inside the box because it’s so dry.”

Researchers said the humidity digester could eventually replace conventional air conditioners when paired with a fan and can even be scaled up inexpensively to an industrial level of output.

“The world population is increasing, and people generally spend a lot of money on air conditioners to maintain adequate thermal comfort,” Tan said. “The increasing need for air conditioners to cool us down results in increased energy consumption as well. This device, when coupled with a fan, can help reduce relative humidity and thereby improve thermal comfort and reduce the reliance on air conditioners. This could lead to potential energy and monetary benefits.”

The study was supported by the Temasek Foundation Escoperity and the Ministry of Education Academic Research Fund.


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