Australian researchers have set a world record for efficiency for a solar concentrator dish, achieving a 97 per cent conversion of sunlight into steam.
By designing and building a new receiver for a solar concentrator dish, Australian National University (ANU) researchers were able to halve the losses, and achieve an unprecedented conversion efficiency.
The breakthrough, which could be applicable to power stations, could lead to the generation of cheaper base-load electricity from renewable energy, helping lower carbon emissions that cause global warming.
According to Dr John Pye, one of the ANU engineers, the computer model predicted an “alarmingly high” efficiency for the design.
“But when we built it and tested it, sure enough, the performance was amazing,” he said.
Concentrating solar thermal systems use reflectors to concentrate sunlight in order to generate steam, which then drives conventional power station turbines. It can be combined with efficient heat storage systems and can supply power on demand at a significantly lower cost than solar energy from photovoltaic panels that have been stored in batteries.
The new receiver design is a cavity that resembles a top hat with a 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 leaking out can be absorbed by cooler water in the brim.