Using minute graphite particles 1,000 times smaller than the width of human hair, mechanical engineers hope to boost the efficiency and profitability of solar power plants.

An alternative that can make use of all of the sunlight, including light photovoltaics can't use, is the solar thermal collector, reports the Journal of Renewable and Sustainable Energy.

The purpose of these collectors, is to collect heat that can then be used. To further increase the efficiency of solar collectors, nanoparticles, a billionth of a metre in size, were mixed into the heat-transfer oils normally used in solar thermal power plants, according to an Arizona State University (where the research took place) statement.

The researchers chose graphite nanoparticles, in part because they are black and therefore absorb light very well, making them efficient heat collectors.

In lab tests, lead researcher Robert Taylor and his colleagues found that nanoparticles increased heat-collection efficiency by up to 10 per cent.

Keywords: solar energy