Solar panels that grow spinach by drawing water vapor from the air may offer a low-cost strategy for desert crop production, a new study says.
A new system called WEC2P consists of hydrogel-coated solar panels, a type of loose water-loving polymer, researchers at Saudi Arabia report.
Hydrogel-coated solar panels are mounted on a large metal box that converts water vapor from the air into liquid water for growing crops.
In two weeks of hot weather last summer, researchers were able to grow spinach with a 95 percent crop survival rate.
According to experts, the technology offers a “sustainable and cheap strategy” to improve food and water security.
It is described as “low cost” because hydrogels use $ 1 per kilogram of material, although the combined cost of building and deploying such a system would be much higher.
In two weeks of hot weather last summer, researchers were able to grow spinach with a 95 percent survival rate
This photo shows solar photovoltaic panels that use a water-absorbing hydrogel underneath to stay cool and increase their efficiency.
This photo shows the solar panels connected to a box for growing plants that contains 60 water spinach seeds
REMOVAL OF WATER FOR GROWING RECELLS
The system, called WEC2P, uses humid weather – when there is a lot of water vapor in the ambient air.
It consists of a solar panel placed on a layer of hydrogel, which is mounted on a large metal box to condense and collect water.
Hydrogels are water-loving – they suck water vapor from the environment.
The waste heat from the solar panels removes the absorbed water from the hydrogel.
A metal box below, called a condensing chamber, collects the vapor and condenses the gas into water that feeds the crops.
In addition to fueling crop growth, collecting water vapor from the air can also provide clean drinking water.
“Part of the world’s population still does not have access to clean water or green energy, and many live in rural areas with dry or semi-dry climates,” said senior author Peng Wang, a professor of environmental science and engineering. at the King Abdullah University of Science and Technology (KAUST) in Tuvalu, Saudi Arabia.
“Our design makes water from the air using clean energy that would be wasted and suitable for decentralized, small farms in remote places such as deserts and ocean islands.”
Moreover, the technology tackles a little-known problem with solar panels – it uses energy from sunlight that solar panels cannot use.
Commercial solar panels can usually convert less than a quarter of the absorbed sunlight into electricity, while the rest of the radiation is either lost as heat or heats the panels, which in turn reduces their efficiency.
Because solar panels are less effective for any degree of temperature rise, the problem of heat dissipation becomes more acute in hot environments such as the Arabian Desert.
This is a WEC2P scheme located in a dry region. Researchers have not yet commented on the exact cost of implementing such a system
THE AMAZING NATURE OF HYDROGELS
Hydrogels are three-dimensional networks of cross-linked, “hydrophilic” (water-loving) polymers.
They do not dissolve in water and are instead highly absorbent, but are able to maintain well-defined structures.
While most hydrogels are synthetic in origin, some are naturally occurring.
They can be used for a variety of applications, from soft robotics and contact lenses to skeletal tissue repair and disposable diapers.
Unfortunately, efforts to cool solar panels with conventional techniques, including cooling or air conditioning, usually consume too much energy.
A few years ago, Wang’s team began considering the concept of using hydrogels, three-dimensional networks of cross-linked, “hydrophilic” (water-loving) polymers that do not dissolve in water, to deal with this problem.
An intriguing property of the hydrogel is its ability to adhere to many surfaces, including the underside of solar panels.
in 2020 they announced that their hydrogel can release enough water to reduce the panel temperatures by 18 ° F (10 ° C).
Since then, they have turned their attention to the use of this water, such as growing crops in the desert.
While the hydrogel sucks water vapor from the environment, the excess heat from the panels removes the absorbed water from the hydrogel.
During both the summer and winter seasons, the gel can absorb water from the stuffy air at night and then release the liquid as daytime temperatures rise.
Hydrogel-lined solar panels are mounted on a large metal box that converts water vapor from the air into liquid water for growing crops
An intriguing property of the hydrogel is its ability to adhere to many surfaces, including the underside of solar panels
The team conducted a test on growing plants using WEC2P in Saudi Arabia for two weeks last June, when the weather was very hot.
They used the water collected only from the air to irrigate 60 water spinach seeds planted in a plastic box for growing plants.
In the course of the experiment, the solar panel, similar in size to the top of the student desk, generated a total of 1,519 watts of electricity.
Fifty-seven of the 60 spinach seeds sprouted successfully and grew normally to seven inches (18 cm).
A total of about 2 liters of water was condensed from the hydrogel over the two-week period.
In 2020, researchers announced a new way to cool solar panels and increase their efficiency – through the use of hydrogels
To turn the concept-proof design into a real product, the team plans to create a better hydrogel that can absorb more water from the air.
“Our goal is to create an integrated system for producing clean energy, water and food, especially the water creation part of our design,” Wang said.
One potential problem with the system is that it relies on high levels of humidity – when there is a lot of water vapor in the ambient air – and may not be as effective in very dry climates.
“The efficiency and cost of the system will have to be further and significantly improved before it can become economically attractive,” Wang told MailOnline.
The study was published in the journal Cell Reports Physical Science.
“SUPER JELLY” MADE OF 80 PERCENT OF WATER CAN SURVIVE TO BE CAREFUL
In 2021, experts from the University of Cambridge said they had created “super jelly”, a material made up of 80 percent water that can survive being run over by a car, which could pave the way for efficient soft robotics.
The glass-like hydrogel may look and feel like greasy jelly, but when compressed, it acts like unbreakable glass, its developers said.
It is formed by a network of polymers held together by a series of reversible chemical interactions that can be adapted to control the mechanical properties of the gel.
This is the first time a soft material has been produced that is capable of such significant resistance to compressive forces.
The key to super jelly lies in barrel-shaped molecules called cucurbiturils, which are cross-linking molecules that can hold two guest molecules in their cavity in a way that researchers compare to handcuffs.
Read more: Super jelly, made from 80 percent water, can survive running over