A novel 2-stage dish concentrator with improved optical performance for concentrating solar power plants

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 (β) and the intercept factor (γ) 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 of β = 15,498 and γ = 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.