Autonomous light-weight heliostat with rim drives

• With a new autonomous heliostat current challenging cost objectives are achievable.
• Wind load reduction, sandwich facets and ground anchors reduce weight.
• Rim drives with winch wheels are efficient, cheap and precise.
• The low energy consumption reduces cost for PV cell and energy storage.
• With optimized axis orientation losses due to reduced angle range are negligible.

Several approaches for cost reduction of heliostats, which fit well to each other, are combined to a new heliostat concept to achieve the current challenging cost objectives: 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 compromised angle range are negligible. With the new heliostat concept the current cost goals seem to be achievable.

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