Dish-Stirling plants serve local or centralized solar energy production.
Their electrical output lies between a few and 50 kW per unit.
A parabolically curved concentrator, constantly positioned towards the sun, reflects the parallel solar rays hitting its face and gathers them into one focal point. This is the precise location of the Stirling engine’s solar heat exchanger. The heat exchanger (receiver) absorbs the concentrated solar radiation, thus heating the thermal transfer medium (helium or hydrogen) of the Stirling engine. The Stirling engine transforms the amassed heat into rotational energy and then into electrical power through a generator attached directly to the crankshaft of the motor.

In recent years we have developed, built and extensively tested several prototypes of between 10 and 50 kW per unit. Upon completing development of the prototype, the first plants were installed in various countries (Spain, France, Germany, Italy, India). Thousands of operating hours have since been logged. The engineering has been technologically perfected.

The essential components of a Dish-Stirling system are the concentrator, the Stirling engine with a solar receiver and the solar tracking device.

The concentrator is one of the critical components of a Dish-Stirling plant.
In our 10 kW systems, the concentrator has a diameter of 8.5 m and is manufactured in a sandwich construction of easily transportable segments made of fibreglass-reinforced epoxy resin. Thin-glass mirrors with a long-term high reflectivity of 94% are fixed onto the high-precision surface.

The Stirling engine uses a highly efficient thermodynamic cycle to convert the heat into mechanical energy. It has several excellent qualities:
As opposed to Otto and diesel engines, which operate using internal combustion, the introduction of heat in a Stirling engine comes from outside the system. It is thus particularly well suited to the use of solar heat.
Heat input at a temperature of 650 °C allows for a motor efficiency of 30-35 %.
Furthermore, the help of an additional gas burner (e.g. for biogas) can ensure power supply around the clock.

The animated film shows the plant’s solar tracking over the course of a day.

Computer guidance is used to track the concentrator along the exact path of the sun. The plant can be remotely monitored using the internet, so that servicing and diagnosis can be carried out from any location.

schlaich bergermann und partner developed the entire system in cooperation with several partners.

As with all regenerative power generation processes, Dish-Stirling plants entail significant investment costs; however, in contrast to fossil fuel facilities, operational costs are low, as no combustible raw materials are required.

Of course, the costs of generating electricity, as well as interest rates and the amortization period, are largely dependent on the solar radiation parameters of the location at hand. In Southern Europe, power generation costs of as low as 0.20 €/kWh can be reached in large-scale plants, while very good solar locations can see costs reduced to 0.12 €/kWh or lower.

Dish-Stirling facilities offer the possibility of interconnecting several individual plants into one “farm”, which can meet demands ranging from just a few kilowatts to several megawatts. Thus, small-scale Dish-Stirling power plants are suitable for a wide range of uses and are an attractive alternative to today’s environmentally harmful and expensive local energy supplies derived from diesel generators.