Mirrors and Collector Shape Qualification

.

.

Deflectometry Measurement System for analysis of reflector surface slope error.

This non-contact method allows for accurate and quick measurements of mirror shape accuracy and therefore the assessment of concentration quality
 
Mirror panel Deflectometry:

1. Projection of a known stripe pattern onto a plane
2. Photograph of the pattern distortion reflected by mirror
3. Calculation of the slope error of the mirror surface with 
   - High resolution of surface normal vectors (1000 x 1000 pixel)
   - High measurement precision (< 0.5 mrad)

Field-Version Deflectometry:
Reflection of the absorber tube is used instead of projected patterns and permits a robust and simple application of the method for measurements in existing trough fields (with lower accuracy).

Heliostat Field Deflectometry:
An automated system allows for the measurement of many or all heliostats within an existing field during one night (depending on circumstances of the field).

Deliverables:

• Space-resolved shape deviation of mirror, may lead to identification of optimization potential
• Evaluation of quality parameter (focal deviation of concentrated light)
• Evaluation of performance consequences for respective solar technology (intercept factor)

The Photogrammetry Measurement System

The Photogrammetry Measurement System is a flexible, portable and non-tactile tool for the accurate geometry evaluation of large structures and surfaces.

Method:

1. Application of retro-reflective targets on measurement points
2. Calibration with high precision length standards
3. Photographs of the object from many perspectives
4. Analysis of photo set with professional software

Torsion Measurement:

Additional methods characterize the torsion stiffness and similar parameters of a structure.

Deliverables:

• Analysis of 3D coordinates of reference points for quality control with very high precision of measurement: 1/50.000-1/100.000
• Assessment of geometry concerning CSP specific requirements