Quality Assurance Program for Solar Thermal Test Facility (STTF) heliostat production

A heliostat array is a field of heliostats that focuses sunlight continuously on a central receiver in a power tower solar concentration system. Each heliostat consists of a structurally mounted mirror surface capable of reflecting sunlight onto a given target throughout the day. Typically, most heliostats are actually a group of individual mirror facets on a single moving frame. To achieve highly concentrated solar flux on a central receiver, each heliostat mirror facet has to be properly aligned (both canted and focused) when attached to the heliostat frame. In order to accurately evaluate and correct heliostat facet alignment, Sandia National Laboratories (SNL) and New Mexico Tech (NMT) have developed the Heliostat Focusing and Canting Enhancement Technique (H-FACET), a new and unique heliostat alignment tool that allows technicians to make fast and effective adjustments to facet canting and focusing. H-FACET uses a high resolution digital camera mounted on top of a receiver tower to observe the image of a stationary target reflected by a heliostat. Custom image processing software compares specific measurement points on the actual target reflection image with the corresponding measurement points on an ideally reflecting heliostat. Deviations between the actual and ideal reflection points reveal facet misalignments. Additionally, a live image of the ideal and theoretical points provides real-time feedback during the alignment correction process. SNL has implemented H-FACET at the National Solar Thermal Test Facility (NSTTF). Technicians have used the canting portion of the software to successfully cant a large section of the SNL NSTTF heliostat field. Visual inspections of reflected heliostat beam patterns have demonstrated noticeable improvements in beam size and shape resulting from the use of H-FACET. Preliminary quantitative analyses of H-FACET have shown beam diameter reductions of up to fifty percent. The beam reductions resulting from the use of H-FACET will assist in minimizing beam spillage and increasing flux densities. As a result, H-FACET may be a valuable tool in increasing the annual performance of a heliostat field. This paper details the computational algorithms used in H-FACET. These algorithms include accurate models of heliostat field geometries, sun position, facet orientations and facet shapes. This paper also discusses the optical methods used to determine the orientations and surface shapes of ideally aligned facets. Lastly, it investigates probable sources of error and ways to improve H-FACET.

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10-MWe pilot-plant-receiver panel test requirements document solar thermal test facility

10.2172/5248849 ◽

1978 ◽

Author(s):

Keyword(s):

Pilot Plant ◽

Solar Thermal ◽

Test Facility ◽

Thermal Test ◽

Panel Test ◽

Test Requirements ◽

Requirements Document

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Climate Measurement Plan for the Central Receiver Pilot Plant and the Solar Thermal Test Facility

10.2172/12040532 ◽

1975 ◽

Author(s):

Keyword(s):

Pilot Plant ◽

Solar Thermal ◽

Test Facility ◽

Measurement Plan ◽

Thermal Test ◽

Central Receiver

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The development and impact of an outdoor solar thermal test facility

Journal of Energy in Southern Africa ◽

10.17159/2413-3051/2005/v16i4a3104 ◽

2005 ◽

Vol 16 (4) ◽

pp. 67-71

Author(s):

M J Brooks

Keyword(s):

Thermal Energy ◽

Solar Thermal ◽

Test Facility ◽

Solar Thermal Energy ◽

Energy Research ◽

Thermal Test ◽

Outdoor Test ◽

Productive Environment

A recently established programme of solar thermal energy research at the Mangosuthu Technikon has benefited from the development of an outdoor test facility. STARlab provides a secure and productive environment for conducting equipment tests. A brief description of the facility’s development is given together with its impact on various solar thermal projects, including the characterisation of a solar collector’s performance.

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