SUMMARY:
UCLA researchers in the Department of Materials Science and Engineering have developed a passive method for water desalination that does not require direct solar irradiation.
BACKGROUND:
With increasing water scarcity there is now a significant push to find efficient and low-cost methods to generate fresh water from seawater or other non-potable water sources. Conventional methods, such as reverse osmosis and thermal desalination, consume large amounts of energy and are difficult to scale. Solar desalination, on the other hand, is a passive form of thermal desalination and uses solar energy to achieve water and salt separation through an evaporation-condensation cycle. While it is more energy efficient, weather conditions and solar insolation limit its usage. Furthermore, the use of evaporation, a high-temperature phase change, introduces additional operational costs due to scaling and corrosion. Novel methods are needed to enable reliable and scalable water desalination that are highly energy efficient.
INNOVATION:
The present invention introduces a two-stage water desalination method that does not require solar heat for desalination. Since the invention utilizes an inherently passive radiative cooling process, it does not require active energy input resulting in a very efficient desalinization system. The inventors experimentally demonstrate passive freezing desalination driven by radiative cooling of sea water using a custom-build thermally-efficient apparatus. The inventors have also developed models that can accurately predict the performance of the system in particular regions of the globe and probe the system’s theoretical limits. The system can also be utilized in cold environments which allows the system to utilize water desalination in areas where solar desalination is not typically as effective. Modeling predicts the system could produce as much as 20 L/m2/day of fresh water.
POTENTIAL APPLICATIONS:
- Fresh water production through desalination
- Saline wastewater remediation and recycle
ADVANTAGES:
- Passive process with no active energy input
- Thermally efficient apparatus
- Efficient water desalination without weather limitation
- Enhanced freshwater production
- Simple implementation
- Low operational cost
- Can be used in multiple locations
- Can be used for low as well as high-salinity desalination
DEVELOPMENT TO DATE:
Experimental implementation completed.
NEWS ARTICLES & PRESS RELEASES
UCLA News: Forward Thinker: Keeping It Cool to Create Power
Washington Post: Bringing the chill of the cosmos to a warming planet
TED Talk: How we can turn the cold of outer space into a renewable resource | Aaswath Raman