Foundations and mounts for heliostats and large mirrors
Foundations and mounting systems secure heliostats to the ground and must handle static and dynamic loads from wind, seismic activity, and tracking movements. Cost-effective, durable foundations are essential for long-term field operation.
Common approaches:
- Concrete pad foundations: Individual concrete footings anchor each heliostat. They provide strong, permanent support but add material and labor costs.
- Driven piles: Steel or concrete piles driven into the ground work well on soft soils and reduce the need for heavy excavation.
- Screw piles: Helical piles screwed into the soil offer fast installation and are useful in remote or environmentally sensitive sites.
- Ballasted foundations: For temporary or low-impact installations, ballasted frames hold mirrors without deep foundations; however, they may be less stable in high winds.
Mount designs:
- Central column mounts: A single vertical column with bearings supports two-axis movement and provides a durable core structure.
- Truss or frame mounts: Larger mirrors or panels use trussed frames for stiffness and to support multiple mirror facets.
- Integrated modular mounts: Preassembled modules reduce on-site labor and simplify replacement.
Design trade-offs and site considerations:
- Soil conditions: Geotechnical surveys guide foundation choice to prevent settlement and ensure long-term stability.
- Installation speed and cost: Pile systems and modular mounts often reduce construction time compared with poured concrete pads.
- Environmental impact: Foundations that minimize soil disturbance and groundwater impact may be preferred for sensitive sites.
Choosing the right foundation and mount approach balances upfront cost, durability, site conditions, and long-term maintenance needs to support reliable heliostat operation.