Improvement Options in the Dish Stirling Technology
Abstract
The dish-Stirling technology for electricity generation has been in development during more than 25 years. This technology using a Stirling engine fed with solar energy means a promising development regarding power generation. The value of efficiency of this technology, around 30% of normal direct solar radiation, is the highest when compared with other solar energy generation systems. However, the dish-Stirling technology has not achieved enough advancement to be really competitive with other renewable energy technologies. The competitiveness must take into account technical, economic and environmental issues. A state-of-the art review has been carried out in order to identify the developments needed to guarantee the feasibility of using the dish-Stirling technology for energy production, further than demonstration facilities that have been operated so far. The economic feasibility of dish-Stirling depends highly on equipment amortization, so the continuous operation of the system is a key factor. It would also improve the environmental impact since it means to decrease the environmental load of facility construction, due to the fact that this facility would be used for more time than exclusively operating from sun energy. The developments enabling this use are, on one hand the system hybridization, in such a way that guarantees the operation of the system with other energy sources when solar is lower than nominal operation value or is not available. On the other hand the thermal storage, providing system operation with stored energy during some periods such as transients. The stored energy would be obtained from excess of sun radiation in relation to nominal operation value. In this paper, a review of literature concerning state-of-the-art and developments of dish-Stirling technology has been performed, presenting the most outstanding issues considered for future implementation.