Design of heliostat at filed for a central receiver system and solar flux energy calculation

Abstract

Central receiver system for a collection of solar energy is studied and simulated. The main task of this research focus on two issues. Firstly, the reflected solar beams from the mirror of 0.3 m in width and 0.2 m in height are studied by using ray tracing. The flux density distribution is calculated by superposition technique. The result of a single heliostat is that a peak locates at the central area of the distribution and it falls to zero at the boundaries. The flux density distribution depends on distance from heliostat to receiver. As the mirror is moved further away from the receiver the distribution spread out and the shape changes from a rectangle to smooth curve. Secondly, the whole system is simulated by summation of flux density distribution from 5,844 mirrors placed into 36 circles around the tower. The tower height is 10 m and cylindrical receiver situated on top the tower. With a single aim-point strategy, the distributions spread over the cylindrical surface with maximum flux dimensionless less than the number of the heliostat rings. With multiple aiming point strategies, by changing aim point from the center of cylinder to surface of the cylinder, the solar flux density can be further increased up to 60 suns.