Dish Design

An individual solar parabolic dish - stirling engine unit consists of a two axis tracking, parabolic dish reflector that focuses incoming sunlight onto a stirling cycle engine/generator. The engine/generator uses the Stirling thermodynamic cycle to produce electricity without producing steam as an intermediate step. The parabolic dish reflector which moves to continuously face the sun, thus producing a high temperature (~1452oF) in the fluid receiving the focused solar energy. Individual solar parabolic dish - stirling engine units, typically produce 3 to 25 kW each. By using a great many units in an array for a solar plant, solar power can be produced at the MW level in a solar plant.

 

Advantages and Disadvantages of a Solar Parabolic Dish-Sterling Engine System

Advantages:

  • The high fluid temperature attainable by the two axis tracking solar parabolic dish leads to high conversion efficiency of solar power to electricity (for a heat engine). Conversion efficiency approaching 30% has been achieved. This is the highest conversion efficiency of the concentrating solar power technologies.
  • The solar parabolic dish - stirling engine system can be used as a relatively small distributed power source, because a single unit is self-contained. By combining a lot of the units, MW levels of electricity from solar power can be produced.
  • The solar parabolic dish - stirling engine system has only a very minimal water requirement. The engine is air cooled, so no cooling water is needed and the performance penalty associated with dry air condenser cooling for a steam power plant doesn't enter into the picture.

Disadvantage:

  • Due to the distributed nature of the solar parabolic dish - stirling engine system, with many individual units, this type of system doesn't lend itself well for thermal energy storage, to allow electricity generation when the sun isn't shining.

 

Status of Commercialization of Solar Parabolic Dish - Stirling Engine system

There are currently no commercial solar parabolic dish - stirling engine solar plants in operation till 31st Dec 2009. Several projects are in the planning stages, however in the southwestern United States and around the world.