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OPTICAL PERFORMANCE AND WEIGHT ESTIMATION OF A HELIOSTAT WITH GANGED FACETS

Amsbeck, Lars and Buck, Reiner and Pfahl, Andreas and Uhlig, Ralf (2006) OPTICAL PERFORMANCE AND WEIGHT ESTIMATION OF A HELIOSTAT WITH GANGED FACETS. In: Proc. 13th SolarPACES Int. Symposium. 13th SolarPACES Int. Symposium, 2006-06-19 - 2006-06-23, Sevilla, Spain.

Full text not available from this repository.

Abstract

In standard heliostat design the usual strategy of cost reduction is to increase the mirror area of the heliostats. This leads to a reduction of specific drive cost, but also to an increase of the torques caused by the wind loads, resulting in higher specific weight and higher specific drive power. The opposite strategy focuses on the reduction of the specific weight and driving power. Therefore the mirror area is decreased. In total the drive power is much lower then, but it has to be divided into more units which means a drawback for cost reduction. A combination of both strategies is to couple small heliostats so that they can be tracked by the same drive. At the Torque Tube Heliostat (TTH) the mirrors are mounted on torque tubes to simplify the coupling mechanism for the elevation angle. The optimal tracking speed of heliostats depends on the position in the field. In a heliostat with ganged facets all facets are tracked with the same speed. This leads to higher astigmatism losses compared to independently tracked mirrors. To reduce shading a certain space is foreseen between the facets of the TTH. To achieve a high mirror density and to avoid too long and therefore too flexible torque tubes this distance is limited. Thus the shading is higher than usually. Ray tracing calculations were done to obtain optimized heliostat configurations and to estimate the energy yield of a heliostat field built of 288 m² TTHs. The results are compared to a conventional heliostat field. To get an idea of the weight reduction potential of the TTH the dimensions of the torque tube, the secondary axis tube and the mirror support structure were weight optimized via FEM. The layout criterion was a mean mirror error of 5 mrad under a wind load and gravity, which was calculated from the deviations of the FE model.

Document Type:Conference or Workshop Item (Speech)
Title:OPTICAL PERFORMANCE AND WEIGHT ESTIMATION OF A HELIOSTAT WITH GANGED FACETS
Authors:
AuthorsInstitution or Email of Authors
Amsbeck, LarsUNSPECIFIED
Buck, ReinerUNSPECIFIED
Pfahl, AndreasUNSPECIFIED
Uhlig, RalfUNSPECIFIED
Date:19 June 2006
Journal or Publication Title:Proc. 13th SolarPACES Int. Symposium
Refereed publication:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:solar power, solar heat, solar tower, central receiver, heliostat
Event Title:13th SolarPACES Int. Symposium
Event Location:Sevilla, Spain
Event Type:international Conference
Event Dates:2006-06-19 - 2006-06-23
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 - Solare Hochtemperatursysteme (old)
Location: Stuttgart
Institutes and Institutions:Institute of Technical Thermodynamics > Solar Research
Deposited By: Lars Amsbeck
Deposited On:18 Dec 2007
Last Modified:27 Apr 2009 13:29

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