Researchers in Saudi Arabia have developed a solar-driven system with the help of a special hydrogel. It has proven efficient in growing spinach by making use of water drawn from the air while generating electricity.
This is a schematic of WEC2P deployed in an arid region. Image Credit: Renyuan Li.
The proof-of-concept design explained in the study provides an affordable and sustainable strategy to enhance food and water security for people living in dry-climate regions. The study was published in the journal Cell Reports Physical Science on March 1st, 2022.
A fraction of the world’s population still doesn’t have access to clean water or green power, and many of them live in rural areas with arid or semi-arid climate. Our design makes water out of air using clean energy that would’ve been wasted and is suitable for decentralized, small-scale farms in remote places like deserts and oceanic islands.
Peng Wang, Study Senior Author and Professor, Environmental Science and Engineering, King Abdullah University of Science and Technology
The system, known as WEC2P, is made up of a solar photovoltaic panel positioned atop a layer of hydrogel, which has been fixed on top of a large metal box to condense and gather water. Wang and his research group designed the hydrogel in their early research, and the material can efficiently absorb water vapor from ambient air and discharge the water content when heated.
The scientists made use of the waste heat gathered from solar panels while generating electricity to drive absorbed water out of the hydrogel. The metal box kept below gathers the vapor and condenses the gas into water. The hydrogel increases the efficiency of solar photovoltaic panels by as much as 9% by absorbing the heat and reducing the temperature of the panel.
A plant-growing test was performed by the researchers by making use of WEC2P in Saudi Arabia for two weeks in June when the weather was very hot. They utilized the water solely gathered from air to irrigate 60 water spinach seeds planted in a plastic plant-growing box.
During the course of the experiment, the solar panel, having a size similar to the top of a student desk, produced a sum of 1,519 watt-hours of electricity, and 57 out of the 60 water spinach seeds sprouted and grew normally to 18 cm. As a whole, around 2 L of water was condensed from the hydrogel over a period of two weeks.
Our goal is to create an integrated system of clean energy, water, and food production, especially the water-creation part in our design, which sets us apart from current agrophotovoltaics.
Peng Wang, Study Senior Author and Professor, Environmental Science and Engineering, King Abdullah University of Science and Technology
The team plans to make a better hydrogel that has the ability to absorb more water from the air to convert the proof-of-concept design into an actual product.
Making sure everyone on Earth has access to clean water and affordable clean energy is part of the Sustainable Development Goals set by the United Nations. I hope our design can be a decentralized power and water system to light homes and water crops.
Peng Wang, Study Senior Author and Professor, Environmental Science and Engineering, King Abdullah University of Science and Technology
Journal Reference:
Li, R., et al. (2022) An integrated solar-driven system produces electricity with fresh water and crops in arid regions. Cell Reports Physical Science. doi.org/10.1016/j.xcrp.2022.100781.