2024-10-01 07:00:00
Small adjustments to film design are key to improving an innovative technology developed at King Abdullah University of Science and Technology (KAUST). This technology takes advantage of the waste heat generated by solar panels, not only to produce electricity, but also to desalinate seawater, transforming the process into an efficient and sustainable energy solution, especially in arid and coastal regions.
Solar panels, especially in desert areas, tend to heat up a lot, reaching temperatures that are more than 40 degrees Celsius higher than the surrounding air temperature. This excessive heating is due to the fact that silicon photovoltaic cells, the main components of solar panels, only convert a quarter of the solar energy they receive into electricity. The rest of the absorbed energy is dissipated as heat, affecting the efficiency of the panels and their useful life. These extreme conditions have been a recurring challenge in implementing solar technologies in hot climates.
In 2019, Peng Wang and his team at KAUST found a creative way to reuse that waste heat. They found that excess heat, instead of being a disadvantage, could be used to desalinate salt water, a resource that is scarce and critical in many of those same regions. To do this, they developed an innovative device that is placed under the solar panels, and uses the heat of the photovoltaic cells to evaporate seawater, producing fresh water through a multi-stage system.
Image (a)
- Photovoltaic panel: Photovoltaic panel
- Water source: Water source
- Clean water: Clean water
- Clean water container: Clean water container
- Source water container: Well water container
- Wick: mech
Image (b)
- Photovoltaic panel: Photovoltaic panel
- Water source: Water source
- Clean water: Clean water
- Clean water container: Clean water container
- Source water container: Well water container
- Concentrated water container: Condensed water container
- Inlet: prohibited
- An outlet: Salida
- Source water flow: Source of water flow
Color legend:
- Evaporation layer: Evaporation layer
- Porous hydrophobic film: A hydrophobic porous film
- Recycling layer: Recycling layer
- Condensation layer: Condensation layer
- Thermal conductivity layer: Thermal conductive layer
- Thermal isolation: Thermal insulation
- Clean water flow: Clear water flow
- Source water flow: Source of water flow
The design of this device is ingenious: seawater is drawn in a series of layered channels. In the upper channel, the heat generated by the solar panels evaporates water, which passes through a porous membrane to a lower layer, where it is condensed and purified. After going through a series of purifications, the system is capable of producing up to 1.6 liters of fresh water per hour, which represents a significant advance in desalination efficiency.
However, despite this water-based cooling system, Wang’s team found that the operating temperature of the solar panels was still high, which continued to limit their efficiency. This is where the researchers Wenbin Wang and Sara Aleid came into play, who developed a theoretical model to analyze the relationship between certain membrane parameters, such as its thickness and porosity, and the effect on the temperature of solar cells.
The conclusion was clear: a thinner membrane with greater porosity not only improves desalination performance, but also allows to reduce the temperature of the solar panels, which increases the efficiency of the entire system. As Peng Wang explained, “the key is to regulate the heat transfer through the hydrophobic membrane. By adjusting the parameters, we achieve better desalination and lower temperature of the solar cell.”
After obtaining these results in the laboratory, the next step was to adapt the technology for real-world use. Here came another challenge: minimizing energy consumption and waste by-products generated by the desalination process. To achieve this, the team was inspired by the technologies used in intravenous infusions, developing a system that introduces seawater by gravity, eliminating the need for external mechanical pumps. This approach not only simplifies the system, but also makes it more energy efficient, critical for use in communities that do not have access to the electrical grid.
In addition, the researchers implemented an innovative solution to manage the solid waste generated by desalination, such as salts and minerals. By using a special fabric, they managed to absorb these salts and prevent the release of toxic liquid brine, a common problem in traditional desalination methods.
This combination of advances yielded surprising results. Tests conducted outdoors on KAUST’s sunny campus showed that the new design not only increased electricity production by 8%, but also doubled the amount of fresh water generated compared to previous systems. This dual advantage makes the technology extremely promising for communities without access to clean water or electricity, offering a sustainable and accessible solution.
This innovative system could revolutionize the lives of thousands of people in coastal and arid regions of the world, where access to drinking water is a daily challenge and solar energy is one of the best alternatives for generating electricity. With greater efficiency and lower environmental impact, this technology has the potential to revolutionize the way we manage two critical resources: water and energy.
#Clean #water #desalination #Solar #Energy #Device