The efficiency of a solar-powered desalination system is boosted by more than 50 percent by simply adding inexpensive plastic lenses to concentrate sunlight into “hot pots”:
“The typical way to boost performance in solar-driven systems is to add solar concentrators and bring in more light,” says Pratiksha Dongare, a graduate student in applied physics at Rice University’s Brown School of Engineering and co-lead author of a new paper in PNAS.
“The big difference here is that we’re using the same amount of light. We’ve shown it’s possible to inexpensively redistribute that power and dramatically increase the rate of purified water production.”
Scaling up the conventional membrane distillation is difficult since the temperature difference across the membrane decreases as the size of the membrane increases.
The new “nanophotonics-enabled solar membrane distillation” (NESMD) technology addresses this by using light-absorbing nanoparticles to turn the membrane itself into a solar-driven heating element.
Dongare and colleagues, including study co-lead author Alessandro Alabastri, coat the top layer of their membranes with low-cost, commercially available nanoparticles designed to convert more than 80 percent of sunlight energy into heat.
Water scarcity is a reality to about half of the world’s people, and efficient solar distillation is a promising solution to that.
Image Credit: Pratiksha Dongare/Rice