Aalto-China collaboration resulted in a novel 2-stage dish solar concentrator

Peter Lund

Aalto University New Energy Technologies Group and Southeast University's Key Laboratory of Solar Energy Science and Technology have developed a novel solar concentrator for central solar power plants.

Figure. Solar irradiance distribution at focal point of the new concentrator.

Here we propose a novel 2-stage dish concentrator system for concentrating solar power plants based on the so-called overlap method, which improves both the radial flux concentration ratio (b) and the intercept factor (g) of the concentrator. The 2-stage dish is composed of paraboloid primary and hyperboloid secondary mirrors having a special hollow structure enabling the mirrors to overlap, but avoiding excess shading. Geometric and optical analyses with ray-tracing show maximum values ofconcentration ratio15,498 and  intercept factor 0.78. Also, the size of the focal spot could be reduced. The concept is applicable for solar tower concepts enabling more compact unit mirrors and reducing the receiver size. The results were recently presented in a journal article:  Jun Wang , Song Yang , Chuan Jiang , Qianwen Yan , Peter D. Lund: A novel 2-stage dish concentrator with improved optical performance for concentrating solar power plants. Renewable Energyy 108 (2017) 92-97. http://dx.doi.org/10.1016/j.renene.2017.02.059