Nanotechnology has long been an area of cutting edge research within fields such as medicine, materials science and computing. Recently, however, it is within the area of energy production that researchers from Rice University in Houston have made one of the most profound advances in modern times.
The sun has been worshipped for its life giving warmth for millennia and, more recently, has become one of the best candidates for the power source in a global vision of clean energy. Ninety percent of the world’s energy is currently created using steam; therefore large scale solar power stations have been constructed to harness sunlight to heat water and create it. These usually require vast footprints in order to capture enough solar energy to be commercially viable; so researchers at Rice University decided to stop looking at steam production on the macroscopic scale and wondered whether it would be possible to create steam on a microscopic level.
Head researcher, Professor Halas, one of the world’s leading nano-scientists, and her team hypothesised that by creating nanoparticles which heat up when exposed to solar radiation they would be able to create localised sites of steam creation. As the nanoparticles heat up quickly and have such small surface areas to transmit energy, they effectively vaporise water molecules in close proximity to themselves; this means that steam can be created without having to raise the overall temperature of the water to boiling point. This is, of course, a huge efficiency saver.
Halas’ team were already experienced in creating nanoparticles for medical research. In this field the particles are usually activated by shining light of a specified electromagnetic wavelength upon them, which they absorb and use as energy. Conventional photovoltaic panels also usually respond best to a specific wavelength of solar radiation, meaning that much of the sun’s energy is wasted as it can’t easily be absorbed.
The challenge for Halas and her team lay in developing nanoparticles which absorb a broad spectrum of electromagnetic radiation, the idea being that all solar light incident upon them would then be useful.
In fact, creating particles which absorb almost the entire solar spectrum has proved to be very successful and the university has reported that the overall energy efficiency is pretty constant at around the twenty-three percent mark, despite using a variety of different materials; for instance metallic and conductive carbon particles, in the research. This level of twenty-three percent efficiency already dwarfs the fifteen percent overall efficiency of conventional photovoltaic panels and researchers say that with future refinements they expect to be able to increase this even further.
Professor Halas and her team have been quick to point out that this new “Solar Steam” method can have far reaching effects in fields such as industry, medicine, sanitation and desalination as well as the obvious opportunities it creates in the quest for clean energy; indeed Halas expects that the first use of this technology will be in providing clean drinking water in third world countries. With this in mind it isn’t unreasonable to suggest that “Solar Steam” will be a technology we will be seeing a lot more of in the near future.