Parabolic dish concentrating systems use parabolic dish shaped mirrors to focus the incoming solar radiation onto a receiver that is positioned at the focal point of the dish, like it’s illustrated in the image below:
The fluid in the receiver is heated to very high temperatures of about 750oC. This fluid is then used to generate electricity in a small Stirling Engine, or Brayton cycle engine, which is attached to the receiver. Parabolic dish systems are the most efficient of all solar technologies, at approximately 25% efficient, compared to around 20% for other solar thermal technologies. The Australian National University and Wizard Information Systems have negotiated the terms of a licence to commercialise the Big Dish solar concentrator technology and is working towards construction of a demonstration plant in Whyalla, South Australia (see the picture below).
The Big Dish at the Australian National University