Heliostats 101

The heliostat is the basic building block of the Solar Collector System (SCS). In our system, a heliostat consists of three main components:

  • The drive – The drive houses two motors enabling our heliostat to move in two axes. The control software provides commands to the drive to use the motors to track the sun very accurately as it moves through the sky.
  • The reflector module -┬áThe reflector module consists of the mirrored glass and metal frame that can be easily attached to the drive so it can be accurately controlled.
  • The structure – The structure provides a rigid, sturdy anchor for the heliostat to the ground.


Small Size, High Volume Approach

All of the heliostat components are designed to take advantage of high volume manufacturing techniques proven in industries such as automotive manufacturing. This enables both a cost effective design as well as rapid production and deployment of hardware.

  • The drive is almost completely composed of aluminum die cast, sintered powdered metal, and injection molded plastic components. Final assembly is performed on a streamlined, dedicated line that includes an automated end of line test.
  • The reflector module utilizes roll formed steel components, robotic welding, and a fully automated, robotic final assembly which ensures high quality and repeatability. Automated end of line tests evaluate the shape of the reflector using proprietary software based image analysis.
  • The structure also takes advantage of roll formed steel components and robotic welding as well as progressive dies stamping. The optimized triangular truss structure offers a greater stiffness with less steel consumed.


History in the Making

From eSolar’s first heliostat in 2007, the design has come a long way! Quality and performance information from field testing and commercial plant installations has been leveraged to create a high value product. Additionally, advanced system modeling has led to optimization of heliostat size and packing density.

A comparison of eSolar’s last heliostat design to its current one shows improvements in manufacturability and cost, as well as some optimization to its size and shape.