Analysis of Optical Efficiency in Heliostat Field Layout with Various Separation Distance

Abstract

The main aim of this paper is to design the heliostat field layout of solar thermal generation for a concentrated solar tower power
plant, based on the central power tower technology. In this design, the radial staggered pattern is proposed to reduce shadowing
and blocking losses. The radial stagger arrangement is the most efficient for a given land area as it cuts down the land usage and
atmospheric attenuation losses. By using this pattern, the heliostat can be placed with higher optical efficiency as well as a faster speed due to the fact that each heliostat could move freely and the heliostats standing between two heliostats of the first ring reduce the shadowing and blocking. The field layout consists of 650 heliostats around a 62m tall tower and each heliostat has a 121m2 reflecting area. The power plant is designed to produce an output of 30MWth thermal power with the molten salt storage
system. The optical efficiency is calculated by the product of the mirror reflectivity, the atmospheric attenuation efficiency, the
shadowing and blocking efficiency and the cosine efficiency. The available separation distance of attenuation efficiency is evaluated the optical efficiency. The separation distance of the attenuation efficiency is less; the optical efficiency of the field layout is more. The separation distance of the attenuation efficiency is increased; the heliostat field area of the layout is also increased. By varying the separation distance between the heliostats is achieved the optical efficiency and the heliostat field area for under different conditions. The input data are assigned in MATLAB for testing this proposed method.