Scientists in Saudi Arabia created a solar-driven system that successfully grows spinach by using water drawn from the air while producing electricity.
The system, called WEC2P, is composed of a solar photovoltaic panel placed atop a layer of hydrogel, which is mounted on top of a large metal box to condense and collect water. Wang and his team developed the hydrogel in their prior 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 solar panels when generating electricity to drive absorbed water out of the hydrogel. The metal box below collects the vapor and condenses the gas into water. Alternatively, the hydrogel increases the efficiency of solar photovoltaic panels by as much as 9% by absorbing the heat and lowering the panels’ temperature.
The team conducted a plant-growing test by using WEC2P in Saudi Arabia for two weeks in June, when the weather was very hot. They used the water solely collected from air to irrigate 60 water spinach seeds planted in a plastic plant-growing box. Over the course of the experiment, the solar panel, with a size similar to the top of a student desk, generated a total of 1,519 watt-hours of electricity, and 57 out of 60 of the water spinach seeds sprouted and grew normally to 18 centimeters. In total, about 2 liters of water were condensed from the hydrogel over the two-week period.
To turn the proof-of-concept design into an actual product, the team plans to create a better hydrogel that can absorb more water from the air.