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Slope Error Measurements of Parabolic Troughs Using the Reflected Image of the Absorber Tube

Ulmer, Steffen and Heinz, Boris and Pottler, Klaus and Lüpfert, Eckhard (2009) Slope Error Measurements of Parabolic Troughs Using the Reflected Image of the Absorber Tube. Journal of Solar Energy Engineering, 131 (1).

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Abstract

A new and fast method for optically measuring the reflector slope of parabolic troughs with high accuracy has been developed. It uses the reflection of the absorber tube in the concentrator, as seen from some distance, and is therefore called �absorber reflection method.� A digital camera is placed at a distant observation point perpendicular to the trough axis with the concentrator orientated toward it. Then, a set of pictures from the absorber tube reflection is taken with slightly different tilt angles of the concentrator. A specially developed image analysis algorithm detects the edges of the absorber tube in the reflected images. This information, along with the geometric relationship between the components, the relative collector tilt angles, and the known approximately parabolic shape of the concentrator, is used to calculate the slopes perpendicular to the trough axis. Measurement results of a EuroTrough segment of four facets are presented and verified with results from a reference measurement using high-resolution close-range photogrammetry. The results show good agreement in statistical values as well as in local values of the reflector slope. Compared to the existing photogrammetric method, the new technique reduces drastically the time measurement.

Document Type:Article
Title:Slope Error Measurements of Parabolic Troughs Using the Reflected Image of the Absorber Tube
Authors:
AuthorsInstitution or Email of Authors
Ulmer, SteffenUNSPECIFIED
Heinz, BorisUNSPECIFIED
Pottler, KlausUNSPECIFIED
Lüpfert, EckhardUNSPECIFIED
Date:February 2009
Journal or Publication Title:Journal of Solar Energy Engineering
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:131
Status:Published
Keywords:parabolic trough, slope error, distant observer, photogrammetry, absorber reflection method, deflectometry
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:E SF - Solar research (old)
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Qualifizierung (old)
Location: other
Institutes and Institutions:Institute of Technical Thermodynamics > Solar Research
Deposited By: Dr.-Ing. Steffen Ulmer
Deposited On:26 Feb 2009
Last Modified:12 Dec 2013 20:36

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