MIT engineers’ latest creation can use solar power to boil water and produce “superheated” steam with a temperature well over 100 degrees Celsius. Furthermore, it does not require any expensive optics to do so.
According to the MIT press release, the structure can steadily pump out steam on a sunny day that is hot enough to sterilize medical equipment, use for cooking and cleaning or for supplying heat to industrial processes. Additionally, the steam can also be collected and condensed to produce desalinated, distilled drinking water.
The device is being seen as a replacement to one of MIT’s previous creations; a sponge-like structure that floated in a container of water, turning the water it absorbed into steam. However, impurities in the water caused the sponge to degrade over time. To counter this problem, the new device is suspended over water rather than submerged in it, to avoid contamination.
“It’s a completely passive system — you just leave it outside to absorb sunlight,” says Thomas Cooper, assistant professor of mechanical engineering at York University, who led the work as a postdoc at MIT. “You could scale this up to something that could be used in remote climates to generate enough drinking water for a family, or sterilize equipment for one operating room.”
The device’s dimensions are similar to those of a small tablet device and it’s structure is somewhat sandwich-like. The top layer is made of a metal ceramic composite which absorbs the sun’s energy efficiently. The bottom layer is coated with a material which allows it to emit the absorbed energy to the water below. Once the water reaches its boiling point (100 degrees Celsius), steam rises into the device where it is funnelled through its middle layer. This layer is made of reticulated carbon foam, which heats the steam beyond water’s boiling point before it is pumped out through a tube. The entire setup is encased in a polymer enclosure to prevent heat from escaping and ensuring maximum efficiency.
“It’s this clever engineering of different materials and how they’re arranged that allows us to achieve reasonably high efficiencies with this noncontact arrangement,” Cooper says.