New record for concentrated Sun
Australian researchers have set a new record for solar power generation.
A team at The Australian National University (ANU) has built a new receiver for its solar concentrator dish, that halves its losses to achieve a 97 per cent conversion of sunlight into steam.
Concentrating solar thermal systems use reflectors to concentrate sunlight and generate steam, which drives power station turbines.
When combined with efficient heat storage systems such as salt, concentrating systems can supply power on demand at a much lower cost than solar energy from photovoltaic panels stored in traditional batteries.
“When our computer model told us the efficiency that our design was going to achieve, we thought it was alarmingly high,” said Dr John Pye, from the ANU Research School of Engineering.
“But when we built it and tested it, sure enough, the performance was amazing.”
The ANU engineers are part of a broader group of scientists working with funding from the Australian Renewable Energy Agency, Dr Pye said.
“Ultimately the work in this project is all about reducing the cost of concentrating solar thermal energy. Our aim is to get costs down to 12 cents per kilowatt-hour of electricity, so that this technology will be competitive,” he said.
“This new design could result in a 10 per cent reduction in the cost of solar thermal electricity.
“I’m optimistic that our technology can play a role in the grid, by helping to provide power at night without fossil fuel power stations running.”
At 500 square metres, the ANU solar concentrator is the largest of its kind in the world, focusing sunlight onto a receiver through which water is pumped and heated to 500 degrees Celsius.
The new receiver design is a cavity that resembles a top hat with narrow opening and a wide brim. Water pipes spiral around the underside of the brim and up into the hat.
The sunlight is focused onto the pipes, heating the water as it enters at the brim and spirals up into the cavity. The water reaches peak temperature in the deepest reaches of the cavity, which minimises heat loss. Heat which does leak out of the cavity can be absorbed by the cooler water around the hat’s brim.
The power of the concentrated radiation is so strong that the machinery can damage itself if not aligned properly, so the team actually had to calibrate the dish using light from a full moon.
Watch ANU researchers describe their achievement in the video below.