A new record for solar thermal efficiency has been set at 97% by a team at the Australian National University using a 500 square meter solar concentrator. The record was set as part of a project aimed at reducing the cost of concentrated solar thermal technology.
Solar thermal systems typically use mirrors to focus sunlight and generate heat.
The breakthrough with this new design comes in the “receiver” that the sunlight gets focused on. This new receiver design is a cavity with a narrow opening and a wide brim. Pipes filled with water spiral around the underside of receiver.
The sunlight is focused onto the pipes to heat the water. The magic of this design is that the water/steam achieves its peak temperature of 500 degrees Celsius while it is in the cavity. This means that any heat that escapes will get absorbed by the cooler water that is spiraling around the receiver.
A best case estimate by the team projects that the new design can reduce the cost of solar thermal electricity by 10%.