MIT has created a new, cheap material that converts sunlight into steam at an amazing 85% efficiency. MIT mechanical engineer, Hadi Ghasemi developed the new material which consists of a thin double layered disc. The bottom layer is a spongy carbon foam that doubles as flotation for the disc and a thermal insulator that prevents solar energy from dissipating into the fluid below. The top layer is the active layer and consists of graphite flakes that are exfoliated in a microwave. The microwave makes the graphite bubble like “popcorn” according to Gang Chen who is also researching the new material.
Here is how it works.
Sunlight hits the graphite which creates hot spots. These hot spots draw water up through the foam via capillary action. The water turns into steam when it hits the graphite hot spots. The efficiency is determined by the amount of incoming light at a solar concentration of 10 times that of a typical Sunday which makes for 85% solar energy converted to steam. The efficiency may even be made higher by using Graphene.
So what can you use the sponge for? 10X solar intensity is relatively easy to produce with the use of a simple lens or reflector. Producing steam in the field is a good way to sterilize things. Another use is desalination; however, removal of the leftover salt crystals is a problem that would need addressing.
The most exiting possible use is power generation. Currently to produce energy the Sun’s intensity must be concentrated up to 1,000 times to produce sufficient steam. If this new material can produce steam at only the intensity of ten Suns then MIT may be onto something here.