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Published on : Jun 20, 2019

Scientists enhanced the efficacy of solar desalination system 50% concentrating sunlight into hot spots, using low-cost plastic lenses. This is a work of a team of researchers at Laboratory for Nanophotonics (LANP), Rice University. Further, the outcome of this experiment is available online in the PNAS USA.

A graduate student in applied physics at Brown School of Engineering, Rice University, Pratiksha Dongare speaks about this. She says that the typical method to enhance performance of solar systems is adding solar concentrators to get more light. "The main difference here is the use of the same amount of light. With this, we have confirmed the possibility of inexpensive redistribution of the power. Further, this can increase the purified water production rate,” she adds. Pratiksha Dongare is the co-lead author of this paper.

Hitherto, the traditional membrane distillation method was quite popular. In this process, one side of the membrane has hot and salty water and cool and filtered water on the other side. The difference in the temperature creates a fluctuation in vapor pressure. As a result, this pushes the water vapor from the warmer side towards the cooler side through the membrane.

Scaling the Technology Up with Nanoparticles

Researchers have been facing difficulty in scaling up this technology. Thus, the increase in membrane size results into a decrease in the temperature difference across the membrane. Therefore, it eventually reduces the resultant output of clean water. Now, researchers at Rice University are addressing this issue with nanophotonics-enabled solar membrane distillation technology. As a result, it converts the membrane into a solar power heating element.

The team is using inexpensive nanoparticles to coat the upper layer of the membranes, which converts over 80% solar energy into heat. Thus, this heating method decreases production costs to a great extent. Rice researchers are working hard to scale up this technology for its wide application in remote areas with no access to electricity.