Parabolic Trough System and Component Testing
Here you'll find information about parabolic trough system and components testing, as well facilities and laboratories used for testing. Tests include those for:
- Concentrator thermal efficiency
- Receiver thermal performance
- Mirror contour and collector alignment
- Mirror reflectivity and durability
Some of the following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.
Concentrator Thermal Efficiency Testing
Researchers and industry use the following facilities for testing parabolic trough collectors.
AZTRAK Rotating Platform
At Sandia National Laboratories' National Solar Thermal Test Facility (NSTTF), the AZTRAK rotating platform has been used to test several parabolic trough modules and receivers. Initially, researchers tested a LS-2 collector. And they've recently conducted a number of additional collector/receiver tests.
For more information, read Sandia's poster on Testing Capabilities-NSTTF (AZTRAK) Rotating Platform (PDF 545 KB).
Plataforma Solar de Almería
CIEMAT and DLR (German Aerospace Center) have tested a number of parabolic trough collectors at the Plataforma Solar de Almeria (PSA) in Spain on its collector thermal test loop. In addition, it has installed a collector loop to test direct steam generation (DSG) in the solar field.
For more details, see Plataforma Solar de Almeria's information on its linear-focusing concentrator facilities.
ENEA Solar Collector Test Facility
The Italian National Agency for New Technologies, Energy and the Environment (ENEA) in Cesano, Italy, has installed a collector thermal test loop to test the operation of parabolic trough collectors using molten-salt heat transfer fluid. This solar collector test facility-called PCS-can operate at temperatures up to 550°C.
For more information, read ENEA's presentation on Trough Molten Salt HTF (Heat Transfer Fluid) Field Test Experience (PDF 4 MB).
SEGS Plant Test Loops
A number of instrumented test loops have been installed in operating parabolic trough plants to validate collector or component performance.
KJC Operating Company installed a number of test loops at the SEGS (solar electric generation system) plants to evaluate alignment improvements in the LS-3 collectors and to test the original UVAC receiver.
At SEGS VI, the EuroTrough consortium installed the SKAL-ET test loop to test the new EuroTrough collector design in an operating power plant environment. For more information, read EuroTrough Design Issues and Prototype Testing at PSA (PDF 690 KB).
Receiver Thermal Performance Testing
Researchers and industry use the following facilities to test parabolic trough receiver thermal performance.
For an overview, read NREL's presentation on Parabolic Trough Receiver Thermal Performance (PDF 2.2 MB).
NREL Receiver Thermal Test Bed
NREL has developed an electric resistance heating system to measure parabolic trough receiver thermal losses.
For more information, read NREL's poster on Parabolic Trough Receiver Heat Loss Testing (PDF 354 KB), the report on Heat-Loss Testing of Solel's UVAC3 Parabolic Trough Receiver (PDF 554 KB), and the report on Heat-Loss Testing of Schott's 2008 PTR70 Parabolic Trough Receiver (PDF 1.3 MB).
DLR Receiver Test Stand
DLR (German Aerospace Center) has developed a test stand using electric resistance heating to measure the thermal losses from parabolic trough receivers.
Sandia NSTTF AZTRAK Platform
At Sandia National Laboratories' National Solar Thermal Test Facility (NSTTF), the AZTRAK platform has been used to test receiver thermal losses. For more information, read Sandia's poster on Testing Capabilities—NSTTF (AZTRAK) Rotating Platform (PDF 545 KB).
Field Testing with IR Camera
NREL has developed an approach for evaluating receiver thermal performance by measuring the receiver glass temperature with a solar blind infrared (IR) camera.
Mirror Contour and Collector Alignment Testing
Researchers have developed the following techniques to evaluate the curvature of parabolic trough mirrors.
Video Scanning Hartman Optical Test
The Video Scanning Hartmann Optical Test (VSHOT) was initially developed to evaluate the contour of parabolic dish (or point focus) concentrators. NREL then modified VSHOT to work on parabolic trough (or linear focus) concentrators.
Researchers use VSHOT as an R&D tool to evaluate new parabolic trough mirrors and concentrators. It's also suited as a factory quality control tool for evaluating the shape of mirrors coming off the production line.
For more information, read NREL's poster on Optical Characterization of Concentrating Solar Power Technologies at NREL (PDF 147 KB).
DLR (German Aerospace Center) has developed a photogrammetric approach to evaluate mirror and collector optical accuracy. This system has been useful for evaluating the optical accuracy of new collector designs.
In addition, DLR has developed an automated system that could be used to conduct quality control during collector assembly. The approach also can be expanded to measure mirror slope errors.
For more information, read DLR's poster on Automatic Photogrammetric Qualification of Parabolic Trough Collectors (PDF 337 KB).
Theoretical Overlay Photographic Alignment
Sandia National Laboratories are developing a system based on a variation of the distant observer technique. The system allows relatively rapid field measurements to determine mirror and receiver alignment on collectors installed in a solar field.
This system should be well suited for quality control applications after initial construction of solar fields. It should also work well for periodic testing to check and correct collector alignment over time.
For more information, read Sandia's presentation on the Current Status of TOP (Theoretical Overlay Photographic) Alignment (PDF 641 KB).
Mirror Reflectivity and Durability Testing
Researchers use the following systems and techniques for evaluating parabolic trough mirrors.
Portable Specular Reflectometer
The D&S Portable Specular Reflectometer Model 15R is designed for field and laboratory measurements of flat or curved reflectors. The Model 15R has been extensively used at the SEGS (solar electric generation station) parabolic trough plants to measure mirror soiling for determining when mirror washing is required.
Advanced Optical Materials Laboratory
NREL's Advanced Optical Materials Laboratory provides substantial analytical and measurement capabilities for developing and testing optical materials used in concentrating solar power systems.
NREL offers three types of exposure testing capabilities for optical materials, including:
- An international network of instrumented, outdoor exposure test sites
- Accelerated laboratory-controlled exposure chambers
- An ultra-accelerated, natural sunlight exposure testing facility.
For more information, read NREL's poster on the Optical Durability of Candidate Solar Reflector Materials (PDF 810 KB).