Chelyabinsk, Russia – Scientists at South Ural State University (SUSU), in a significant international collaboration with colleagues from Indonesia's Sepuluh Nopember Institute of Technology (ITS), have patented an advanced desalination device that leverages low-grade heat sources, primarily from solar photovoltaic (PV) panels, to distill seawater and purify groundwater. This breakthrough addresses a critical challenge in solar energy: the significant efficiency degradation of PV modules due to overheating under direct sunlight.

For over a decade, Russian and Indonesian researchers have jointly focused on enhancing the efficiency of photovoltaic converters. A persistent issue with solar panels is their substantial surface heating during operation, leading to the release of considerable "waste heat" into the environment. Evgeny Solomin, a professor at SUSU’s Department of Electric Power Stations, Grids, and Power Supply Systems, highlighted this challenge, stating, "This directly contributes to global warming – the waste heat output is comparable to 60-80% of the module's total electrical power. Moreover, when heated to 50-60°C, the solar module's efficiency drops from 18-22% to 3-10% due to a decline in its current-voltage characteristics."

Three years ago, SUSU scientists pioneered an innovative method to extract heat from solar panel surfaces, subsequently utilizing this heat for distilling saline and mineral-rich water. Supported by the Russian Science Foundation, their initial experimental prototype of a high-speed, low-pressure seawater distiller incorporated a conventional coiled heat exchanger. While functional, this design incurred significant thermal losses, necessitating additional heating of the source water via an optional heat pump.

Intrigued by SUSU's initial work, the Indonesian team from ITS proposed a crucial enhancement: replacing the conventional coil with a more efficient jet-based heat removal system. This innovative approach splits the heat flow into parallel jets, optimizing heat transfer. The new design, which also integrates a reflector in the form of a jet plate, achieves a dual benefit: effective cooling of the photovoltaic panels and simultaneous reflection of light to optimize energy absorption and heat transfer. Under the coordination of the Russian project team, the Indonesian partners conducted comprehensive performance analyses, including energy output, techno-economic, and eco-economic assessments.

Computational fluid dynamics (CFD) simulations and experimental results confirmed the efficacy of the improved system. The solar module's surface temperature decreased dramatically from 64°C to a range of 30-48°C, depending on the operating mode. Concurrently, the overall efficiency of the solar module saw a substantial increase, rising from the previous 3-10% to 6-17%. This collaborative innovation not only extends the lifespan of photovoltaic modules by 2.5 times but also boosts electricity production by 3-5 times in sunny, hot climates. Crucially, it mitigates waste heat emissions, thereby reducing contributions to global warming, while simultaneously providing an optimized solution for sustainable water purification. The Chelyabinsk developers anticipate presenting a serial prototype of this low-grade heat-powered desalination device in the coming years, paving the way for its mass production and widespread adoption.