An innovative solution to calibrate heliostats
To simplify adjustment tasks and optimise thermal solar power plant operations.
The development of a system that allows an entire heliostat field to be calibrated simultaneously, in only a few hours and without any production downtime.
To guarantee optimum operation, it is essential to adjust heliostat orientation whilst a plant is under construction and repeat this action periodically throughout their service life.
Until now, most of the existing solar fields are made up of a limited number (a few thousands) of devices of this kind whose calibration is performed sequentially, i.e., only one device at a time. The desire to reduce solar power generation costs, however, has given rise to the construction of larger plants which are sometimes equipped with smaller heliostats, a scenario in which sequential calibrations are no longer feasible.
It is in this context that the CENER and Tekniker technology centres have developed and patented a simultaneous calibration system for heliostats to simplify adjustments and optimise operations at solar thermal power plants. It provides a more rapid solution that allows calibrations to be performed frequently and diminishes stability requirements that heliostats must meet. This also reduces manufacturing costs.
The calibration procedure developed and patented by CENER and Tekniker allows an entire field of heliostats to be adjusted simultaneously in a matter of only a few hours. Calibration, moreover, can be carried out without interfering in plant operations as it is done either overnight or during shutdowns.
This innovative system is mainly based on low-cost cameras installed on each device with targets scattered throughout the field.
Heliostat movement depends on kinematics and their location in a field. In theory, this is given by design, although accuracy parameters related to manufacturing, assembly and installation or lack of stability over time introduce errors that influence heliostat accuracy and effectiveness. It is only possible to compensate these errors is by closely monitoring their real kinematics and progression over the years.
To address this problem, the solution developed by both organisations features a system that captures and processes images to identify the real kinematics of heliostats installed in the field.
The solution has been tested by the Almería Solar Platform (PSA) with satisfactory results and is protected by the “Heliostat calibration method" patent.