Autonomous light-weight heliostat with rim drives

Abstract

To achieve the current challenging cost objectives, several approaches for cost reduction, which fit well to each other, are combined: The wind loads are reduced by appropriate manipulators which reduces weight and cost of the heliostat structure and the ground anchor foundation. Laminated mirror facets are of high reflectivity and shape accuracy and of low weight. The low weight is advantageous for the dimensioning of the bearings and regarding energy consumption. Energy consumption is further reduced by a highly efficient drive train. Thus small capacity of the wireless energy supply of the autonomous heliostat is sufficient which reduces significantly its cost. By the combination of horizontal primary axis with rims and winch wheels a cheap and precise solution for the drives was found. Ray tracing calculations show that the losses due to the reduced angle range are negligible. With the new heliostat concept the current cost goals seem to be achievable.