Static electricity could run AC

Researchers at RMIT have created an invention from waste polystyrene that generates static electricity from motion and wind.

Created in collaboration with Riga Technical University in Latvia, the invention could lower power usage by recycling waste energy in air conditioners and other applications. With more than 25 million tonnes of single-use polystyrene packaging materials made each year (and most of it headed to landfill), this research provides an option for the materials to be recycled.

Lead researcher from the School of Science at RMIT, Dr Peter Sherrell, says the innovative thin patch is made from multiple layers of polystyrene that are each around one-tenth the thickness of a human hair, and can produce static electricity.

“We can produce this static electricity just from air blowing on the surface of our clever patches, then harvest that energy,” says Sherrell.

He explains the energy that could be collected from the turbulent exhaust of air conditioning units could reduce the energy demand by up to 5 per cent.

The maximum voltage that the devices were able to produce in experiments was approximately 230 volts – which is a comparable voltage to mains voltage in homes, though at much lower power.

In for a shock

Although static electricity has been studied for thousands of years, this is one of the first studies that have been done on a nanoscale level.

Sherrell says the team figured out how to make the insides of reformed polystyrene rub across each other in a controlled way, making all the charge pull in the same direction to produce electricity.

“The biggest [volt] numbers come from a compression and separation, where you’ve got faster speeds and bigger motion, while smaller motion generates less energy,” he says.

“This means that in addition to air conditioners, integrating our patches in high traffic areas such as underground walkways could supplement local energy supply without creating additional demand on the grid.”

A stable option

In addition to saving polystyrene from landfill, Sherrell also says using polystyrene makes the devices really stable. The more layers a device has, the more energy can be harvested.

“The great thing here is the same reason that it takes 500 years for polystyrene to break down in landfill makes these devices really stable – and able to keep making electricity for a long time,” says Sherrell.

“Plastics are like millions of little strands and when you put two plastic films together these strands get knotted together.

“When these knots break, there’s a little bit of charge on each part of that broken bond.”

Future planning

The team has been exploring the use of other single-use plastics to create energy-generating patches. They’ve also experimented with different structures; such as making rough and smooth surfaces, and changing the thickness in the materials.

“The culmination of all our learning has gone into developing these simple little patches that can create quite a large amount of energy,” says Sherrell.

“The impact of this research now relies on the development of devices for a range of commercial applications with industry partners.”

RMIT has filed a provisional patent application for the invention and is now seeking industry partners to invest in developing it for commercial technologies.

Images courtesy of Seamus Daniel, RMIT.