Heliostat

Dual-axis solar trackers are a core component of solar power towers where they concentrate sunlight onto a receiver to harness energy for thermal power plants.   

Constituting 38% of the plant costs [1], heliostats must be made cheaper for this form of concentrated solar power to be more widely adopted as a source of renewable electricity and industrial heat.

 

An adaptation of the basic brick offered by Plithos Renewables can be used to simplify the construction and installation of fields of heliostats.

 

Attaching a joist hanger modification to the outside surface of a three brick pole will allow for horizontal beams to link heliostats together without concrete foundations or partial burial of the pole. The result is a hexagonally arranged field where the mirrored surface will be a triangular assembly rather than rectangular to maximise the reflective area.

 

As the number of layers of bricks used in the pole will determine the total height, the heliostats can be made incrementally taller the further they are from the central tower on a north-south orientation. This will increase reflector density and efficiency as shading is reduced, making this arrangement particularly suitable for a polar field.       

Tracking systems for the heliostat can be a hybrid between a more traditional azimuth-elevation drive and a more modern but limited slope drive. This would mean a pole mounted stepper motor that controls the azimuth position and a linear actuator that tips the mirror for elevation. 

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Above left; A joist hanger brick used in the foundation of the heliostat on the right. 

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Field assembly is simplified by having a repeating hexagonal pattern of heliostats that only needs a flat ground to build upon.

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[1] Kolb GJ, Ho CK, Mancini TR, Gary JA. Power Tower Technology Roadmap and Cost Reduction Plan, Sandia National Laboratories, 2011. Report number SAND2011-2419