China Develops Solar-Powered Technology That Could Make Drinking Water Cheaper Than Bottled Water
A team of Chinese scientists has unveiled a solar-powered desalination prototype that converts seawater into safe drinking water using only sunlight, with no external energy costs.
Researchers from the Institute of Process Engineering (Chinese Academy of Sciences) and Shenzhen University say the technology could eventually produce fresh water at a cost lower than commercially bottled water after around two years of operation.
How the Technology Works
Traditional desalination methods, such as reverse osmosis, require large amounts of electricity to force seawater through specialised membranes.
The new system instead relies on a specially designed three-dimensional photothermal material that captures sunlight and converts it into heat, dramatically improving the rate of solar evaporation.
Researchers created what they describe as a microscopic “nanoforest” by combining polymer chains with hollow multi-shelled nanospheres, allowing water to flow efficiently while absorbing sunlight more effectively.
Higher Efficiency
According to the research team, the new material achieved an evaporation rate of 38.14 kilograms per square metre per hour—around 8.5 times higher than many existing two-dimensional solar evaporation systems.
The structure absorbs more than 90% of sunlight while reducing the energy required to convert water into vapour by 45.7%.
Successful Outdoor Trials
The team tested the technology using a 0.75-square-metre outdoor prototype powered entirely by sunlight.
A small solar panel operated a fan that directed water vapour into a condensation chamber, producing more than 20 litres of drinking water per day—enough to meet the daily needs of around ten people.
Researchers said the purified water met World Health Organization (WHO) drinking water standards.
The desalinated water was also used to successfully grow crops including spinach, maize and Chinese cabbage during field trials.
Built for Long-Term Use
To test durability, researchers subjected the material to continuous seawater exposure while rotating it at 450 revolutions per minute for 30 days.
They reported no nanoparticle leakage or signs of material degradation after prolonged sunlight exposure.
According to the team, the prototype has now completed one year of stable outdoor operation.
The findings were published in the journal Advanced Materials on 21 June, with researchers saying the technology could eventually provide an affordable source of fresh water for remote islands, drought-prone regions and coastal communities facing water shortages.
