Researchers at the Massachusetts Institute of Technology (MIT) have found a way to use a sponge to turn sunlight into steam and produce electricity.
The sponge is designed to generate steam for energy in an emission-free way, and has the potential to lead to more efficient, cheap and emission-free methods for creating steam for energy, desalination and sterilization, according to Discovery News.
Almost every utility plant around the world, including coal, nuclear and solar thermal plants, uses steam to generate electricity, using fuel to create the steam that turns a turbine, which then generates the power.
Hadi Ghasemi, mechanical engineer at MIT, led the research team in creating the material, which includes a thin double-layered disc, ExtremeTech reported. The topic layer (active layer) is made of flakes of graphite broken apart by a microwave. Gang Chen, one of the researchers, said the microwave causes the graphite to bubble up "just like popcorn." The bottom layer includes spongy carbon foam that works as a flotation device and a thermal insulator that keeps solar energy from wasting away into the fluid underneath.
When sunlight hits the surface of the sponge, hotspots are created in the graphite that pull water up through the material, resulting in the rising water being heated and turning into steam, Discovery News reported. The sponge has so far been able to convert sunlight into steam 85 percent of the time and wastes very little heat.
While today's solar-thermal plants that use sunlight need almost 1,000 times the amount of energy found on an average sunny day to heat fluids that create steam, the approach at MIT can produce steam with only 10 times the solar energy found on a sunny day.
"This is a huge advantage in cost-reduction," Ghasemi said. "That's exciting for us because we've come up with a new approach to solar steam generation."
The research team is now focusing on improving their new system so it can be used as a cheaper alternative for generating steam from the sun in the future, Discovery News reported.
Our system is not pressurized currently, and we plan to explore that direction," Chen said in an email.
