Graphite popcorn could boost solar steam generation
Published: Wednesday, 06 August 2014
A new system for creating solar steam developed by scientists at MIT could prove a cheaper and more efficient way of desalinating water and sterilising equipment, as well as providing a new end market for graphite.
graphite-based heat concentration system could drastically
improve energy generated from
solar steam, scientists at the Massachusetts Institute of
MIT) have discovered.
|Current solar steam generation systems rely on large
fields of mirrors
to concentrate sunlight, but a new graphite-based
method developed by
MIT could significantly cut costs and improve efficiency
(source: Activ Solar).
According to the research published in the journal Nature
Communications, the new method involves heating graphite
in a microwave to create a popcorn of exfoliated
This is placed over a layer of porous graphite
foam, which is floated on top of water that is then
heated by sunlight to create steam that evaporates through the
The steam can be used for a variety of applications
including desalination, hygiene systems and sterilisation.
The experiments to develop the new system were led by Hadi
Ghasemi, a postdoctoral researcher in MITs department of
mechanical engineering, along with the departments head,
professor Gang Chen.
Advantages of the graphite-based approach include the low
cost of the graphite material, and, more importantly, its
ability to convert 85% of incoming solar energy into steam
a marked improvement over existing solar steam
Current systems for generating solar steam rely on large
fields of mirrors or lenses to concentrate sunlight in order to
heat large volumes of liquid. Such systems are costly and can
be inefficient as significant amounts of heat may be lost
during the process.
The MIT teams findings show that by using graphite,
which is both hydrophilic and thermally insulating, heat is
concentrated into a hotspot to raise the temperature of the
water and yield steam at a solar intensity of around 10 times
that of an average sunny day.
This is a huge advantage in cost reduction,
Ghasemi told MIT News, adding that this approach is
likely to prove especially useful in remote areas where
the sun is the only source of energy.
While graphite has proved a successful candidate for
MITs initial published research in this area, Ghasemi
believes that the system can be designed to be even more
efficient by using different combinations of materials.
There can be different
combinations of materials that can be used in these two layers
that can lead to higher efficiencies at lower
concentrations, he said. There is still a lot of
research that can be done on implementing this in larger