Using a unique hydrogel, scientists in Saudi Arabia have created a solar-powered system that successfully grows spinach using water drawn from the air and producing electricity.
The proof-of-concept design, described in the journal Cell Reports Physical Science, offers a low-cost, sustainable strategy to improve food and water security for people living in dry climate regions.
“A fraction of the world population still does not have access to clean water or green energy, and many of them live in rural areas with an arid or semi-arid climate”recalls lead author Peng Wang, a professor of environmental science and engineering at the King Abdullah University of Science and Technology (KAUST).
“Our design makes water from air using clean energy that would have gone to waste and is suitable for small-scale, decentralized farms in remote locations such as deserts and ocean islands,” Add.
The system, called WEC2Pis made up of a photovoltaic solar panel placed on a layer of hydrogel, which is mounted on a large metal box to condense and collect the water. Wang and his team developed the hydrogel in their previous research, and the material can effectively absorb water vapor from ambient air and release the water content when heated.
The researchers used the waste heat from the solar panels when generating electricity to expel the absorbed water from the hydrogel. The metal box below collects the steam and condenses the gas into water. In addition, the hydrogel increases the efficiency of photovoltaic solar panels by up to 9% by absorbing heat and reducing the temperature of the panels.
The team conducted a plant-growing test using the WEC2P in Saudi Arabia for two weeks in June, when it was very hot. They used the water collected solely from the air to irrigate 60 water spinach seeds planted in a plastic grow box.
Throughout the experiment, the solar panel, about the size of the top of a student’s desk, generated a total of 1,519 watt-hours of electricity, and 57 of the 60 water spinach seeds sprouted and grew normally. up to 18 centimeters. In total, about 2 liters of water was condensed from the hydrogel during the two week period.
“Our goal is to create an integrated system of clean energy, water and food production, especially the water creation part of our design, which differentiates us from current agrophotovoltaics”it says Wang. To turn the proof-of-concept design into a real product, the team plans to create a better hydrogel that can absorb more water from the air.
“Ensuring that everyone on Earth has access to clean water and affordable clean energy is part of the Sustainable Development Goals set by the United Nations,” points out Wang. “I hope our design can be a decentralized power and water system to light homes and irrigate crops.”