The best solar cells have an energy conversion efficiency of 30 pecent. This means that 70 percent of the collected energy is lost rather than stored. Improvements have been made under test conditions with solar powered heaters. Despite these incremental improvements many technologists believe that considerable improvements can be made. The answer to this lies with nanotechnology.
A new idea comes in the form of a so-called “nanofluid”, designed to be added to solar water heaters. The fluid is a type of liquid that contains specially-designed nanoparticles. These particles are t capable of absorbing sunlight and then transforming the light into thermal energy. The thermal energy then functions to heat water directly.
The pioneering technologist who has devised this is Dr. Satoshi Ishii, who works at the International Center for Materials Nanoarchitectonics (WPI-MANA). The project has been supported by the Japan Science and Technology Agency.
The basis of the nanofluid, according to Controlled Environments magazine, is titanium nitride nanoparticles which are added to the fluid. In trials, the prepared fluid has shown high efficiency in heating water and with generating water vapor. The measure was to see how effectively the nanoparticles heat pure water.
The success comes down to the optical absorption efficiency of a titanium nitride nanoparticle. The researchers discovered that the particles have a strong absorption peak. Comparative studies showed that the sunlight absorption efficiency of titanium nitride nanoparticles are superior to carbon nanoparticles and a gold nanoparticles.
The efficiency of the titanium nitride nanoparticles peaked at close to 90 percent. The particles have an additional advantage in that they are self-sustaining, offering a renewable solution to a renewable source of energy.
Once commercialized it is hoped the titanium nitride based nanofluids can be used in the domestic setting, such as powering the heat used in showers at home.
The research has been reported to The Journal of Physical Chemistry, in a research study called “Titanium nitride nanoparticles as plasmonic solar heat transducers.”
