AUTOMATED HIGH RESOLUTION MEASUREMENT OF HELIOSTAT SLOPE ERRORS

A new optical measurement method that simplifies and optimizes the mounting and canting of heliostats and helps to assure their optical quality before commissioning of the solar field was developed. This method is based on the reflection of regular patterns in the mirror surface and their distortions due to mirror surface errors. The measurement has a resolution of about one million points per heliostat with a measurement uncertainty of less than 0.2 mrad and a measurement time of about one minute per heliostat. The system is completely automated and allows the automatic measurement of an entire heliostat field during one night. It was extensively tested at the CESA-1 heliostat field at the Plataforma Solar de Almería. Comparisons of flux simulations based on the measurement results with real flux density measurements were performed. They showed an excellent agreement and demonstrated in a striking manner the high measurement accuracy and high grade of detail in the simulation achieved by this technique

Das Aufkommen des französischen Notablen-Bürgertums im 18. Jahrhundert und die Krise der absoluten Monarchie

Mager W. Das Aufkommen des französischen Notablen-Bürgertums im 18. Jahrhundert und die Krise der absoluten Monarchie. In: Reinalter H, Mager W, eds. Staat und Bürgertum im 18. und frühen 19. Jahrhundert : Studien zu Frankreich, Deutschland und Österreich ; Ingrid Mittenzwei zum 65. Geburtstag. Schriftenreihe der Internationalen Forschungsstelle "Demokratische Bewegungen in Mitteleuropa 1770 - 1850", 17. Frankfurt a.M.: Lang; 1996: 11-61

Automated High Resolution Measurement of Heliostat Slope Errors

A new optical measurement method that simplifies and optimizes the mounting and canting of heliostats and helps to assure their optical quality before commissioning of the solar field was developed. This method is based on the reflection of regular patterns in the mirror surface and their distortions due to mirror surface errors. The measurement has a resolution of about one million points per heliostat with a measurement uncertainty of less than 0.2 mrad and a measurement time of about one minute per heliostat. The system is completely automated and allows the automatic measurement of an entire heliostat field during one night. It was extensively tested at the CESA-1 heliostat field at the Plataforma Solar de Almería. Comparisons of flux simulations based on the measurement results with real flux density measurements were performed. They showed an excellent agreement and demonstrated in a striking manner the high measurement accuracy and high grade of detail in the simulation achieved by this technique

Staat und Bürgertum im 18. und frühen 19. Jahrhundert: Studien zu Frankreich, Deutschland und Österreich ; Ingrid Mittenzwei zum 65. Geburtstag

Reinalter H, Mager W, eds. Staat und Bürgertum im 18. und frühen 19. Jahrhundert: Studien zu Frankreich, Deutschland und Österreich ; Ingrid Mittenzwei zum 65. Geburtstag. Schriftenreihe der Internationalen Forschungsstelle "Demokratische Bewegungen in Mitteleuropa 1770 - 1850" ; 17. Frankfurt a.M.: Lang; 1996

Slope Measurements of Parabolic Dish Concentrators Using Color Codified Targets

A new fast and highly accurate method for measuring the slope errors of parabolic dish concentrators has been developed. This method uses a flat target with colored stripes placed close to the focal plane of the concentrator and a digital camera located at an observation point on the optical axis at some distance from it. A specially developed image analysis algorithm detects the different colors of the images of the reflection of the target in the concentrator and assigns them their known position on the color target. This information, along with the geometry of the measurement setup and the theoretical parabolic shape of the concentrator, is used to calculate the normal vectors of the concentrator surface. From these normal vectors the radial and tangential slopes can be calculated and compared to the design values of the concentrator. The resulting slope errors not only give the total concentrator error for general characterization of the dish, but also indicate systematic errors from fabrication and installation with a high spatial resolution. In order to verify the quality of the results obtained, a ray-tracing code was developed that calculates the flux distribution on planes perpendicular to the optical axis. Measured slope errors of a 8.5m dish concentrator are presented and the calculated flux distributions are compared to measured flux distributions. The comparison shows excellent agreement in the flux distribution on the absorber plane. This verifies the promising potential of this fast and highly precise new method for measuring imperfections in dish concentrator shape