Renewables
Researchers unveil portable solar water purification device
A compact solar-powered system developed in China converts contaminated water into drinking water using an innovative interlayer electrothermal evaporator.
Key points
- Researchers at Soochow University built a portable water treatment prototype powered by foldable solar cells.
- The device uses an internal heating layer to reduce energy consumption and heat losses significantly.
- Outdoor tests demonstrated the production of 1.64 liters of clean water over eight hours.
What happened
A research team at Soochow University in China has designed a portable, solar-powered device capable of producing drinking water from highly saline, oily, acidic, and turbid sources. According to pv magazine, the prototype yielded 1.64 liters of clean water during an eight-hour test using an evaporation surface area of just 30.72 square centimetres.
The system relies on an electrothermal evaporation process driven by integrated foldable solar cells and a Fresnel lens that concentrates sunlight onto the active surface. Rather than heating the entire volume of wet material, the design features an interlayer electrothermal evaporator that places the heating element within the internal structure. This configuration cuts heat losses and energy consumption by nearly two-thirds compared to conventional volumetric heating setups.
Outdoor trials conducted in early 2025 tested the device on various challenging sources, including real seawater and sediment-laden wastewater. The unit operates entirely off-grid without external fuel supplies, making it suitable for locations lacking standard water treatment infrastructure.
What comes next
While the initial trials demonstrate the technical viability of the interlayer evaporation concept, further development remains necessary. The research team noted that larger systems and extended testing under diverse real-world conditions must be conducted before the technology can be considered for commercial deployment and large-scale emergency relief operations.
Why it matters
Access to reliable clean water and decentralized power remains a critical development challenge across many developing regions, particularly in remote areas or during emergency situations caused by extreme weather and conflicts. Although the reported innovations originate in China—where electricity access reached 100 percent and renewable sources formed 28.4 percent of electricity output by respective World Bank metrics for 2024 and 2021—off-grid technologies of this nature hold considerable relevance for energy and resource planners globally.
For energy professionals and policymakers operating in regions vulnerable to climate shocks and infrastructure deficits, decentralized solar applications offer pathways to improve community resilience. Integrating solar power directly with essential public health functions, such as water purification, minimizes reliance on centralized grids and fossil-fuel-powered generators, aligning with broader goals for sustainable resource management and universal basic service delivery.
Original reporting
This article draws on the following reports. Read them in full on the publishers’ sites.
Context from CEII
Renewables are the fastest-growing part of the world’s energy system. The COP28 goal is to triple capacity by 2030, and solar mini-grids are the fastest route to power for millions of people without electricity.
28.4% of electricity in China was renewable in 2021Countries in this story
Written by the CEII Desk, the Centre’s automated newsroom, from the reporting credited above and CEII’s own data. Facts are attributed to their sources; the publishers have not reviewed this article. Spotted an error? Tell our editors.
