Development and Analysis of the Heliostat Focusing and Canting Enhancement Technique for Full Heliostat Alignments

2012 ◽  
Author(s):  
Kyle Chavez ◽  
Evan Sproul ◽  
Julius Yellowhair
Keyword(s):  
Digital Camera ◽  
Test Facility ◽  
Total System ◽  
Test Results ◽  
Error Sources ◽  
Stationary Target ◽  
Enhancement Technique ◽  
Central Receiver ◽  
Solar Noon ◽  
Utility Scale

Central receiver power towers are regarded as a proven concentrating solar power (CSP) technology for generating utility-scale electricity. In central receiver systems, improper alignment (canting and focusing) of heliostat facets results in beam spillage at the receiver and leads to significant degradation in performance. As a result, proper alignment of heliostats is critical for increasing plant efficiency. Past tools used for analyzing and correcting heliostat alignment at the National Solar Thermal Test Facility (NSTTF) have proven to be laborious and inaccurate, sometimes taking up to six hours per heliostat. In light of these drawbacks, Sandia National Labs (SNL) and New Mexico Tech (NMT) have created the Heliostat Focusing and Canting Enhancement Technique (H-FACET). H-FACET uses a high-resolution digital camera to observe the image of a stationary target reflected by a heliostat facet. By comparing this image to a theoretical image generated via a custom software package, technicians can efficiently identify and correct undesirable deviations in facet orientation and shape. Previous tests have only proven the viability of H-FACET for canting heliostats. As a result, SNL and NMT have expanded H-FACET’s capabilities and analyzed the system’s ability to simultaneously cant and focus heliostats. Initial H-FACET focusing test results have shown improved beam sizes and shapes for single facets. Furthermore, simulations of these tests revealed an approximated system accuracy of better than 1.80 milliradians. This accuracy accounted for technician, position, and additional error sources, suggesting that H-FACET was capable of focusing facets to an even greater accuracy than those seen in the initial tests. When implemented for simultaneous canting and focusing of heliostats, H-FACET has demonstrated its capability to increase peak flux and decrease beam size. These full alignment test results demonstrated an average total system accuracy of 1.17 milliradians on five heliostats. As before, this accuracy included multiple error sources which cannot be corrected by H-FACET. Additionally, these tests revealed that H-FACET can align heliostats in about 1 hour and 30 minutes. Finally, two heliostats aligned with H-FACET maintained average accuracies 1.46 and 1.24 milliradians over a four hour window centered about solar noon. This implies that H-FACET is capable of aligning heliostats to a true off-axis alignment over NSTTF’s operating window. In light of these results, SNL has implemented both the focusing and canting portions of H-FACET at the NSTTF.

scholarly journals The Development of the Heliostat Focusing and Canting Enhancement Technique: An Optical Heliostat Alignment Tool for the National Solar Thermal Test Facility

2011 ◽  
Author(s):  
Evan Sproul ◽  
Kyle Chavez ◽  
Julius Yellowhair
Keyword(s):  
Solar Thermal ◽  
Optical Methods ◽  
Test Facility ◽  
Moving Frame ◽  
Beam Diameter ◽  
Stationary Target ◽  
Enhancement Technique ◽  
Thermal Test ◽  
Central Receiver ◽  
Alignment Tool

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.

Heliostat Operation at the Central Receiver Test Facility, 1978–1980

1982 ◽  
Vol 104 (3) ◽  
pp. 133-138 ◽  
Author(s):  
J. T. Holmes
Keyword(s):  
Test Facility ◽  
Total Power ◽  
Peak Intensity ◽  
Central Receiver ◽  
Operations And Maintenance ◽  
Solar Noon ◽  
Mirror Reflectance ◽  
Targeting Accuracy

The operations and maintenance data and conclusions presented in this report are for the 222 heliostats that have been in use at the Central Receiver Test Facility (CRTF) from 1978 through 1980. The CRTF beam produces a total power of 5.5 MWth and a peak intensity of 2250 kW/m2 near solar noon. Improvements in the targeting accuracy have been made. The mirror reflectance is maintained near 80 percent by cleaning with rain or snow. The CRTF heliostats logged almost 300,000 operating hrs by the end of 1980.

The Design and Testing of a Molten Salt Steam Generator for Solar Application

1988 ◽  
Vol 110 (1) ◽  
pp. 38-44 ◽  
Author(s):  
W. A. Allman ◽  
D. C. Smith ◽  
C. R. Kakarala
Keyword(s):  
Molten Salt ◽  
Steam Generator ◽  
Test Facility ◽  
Process Conditions ◽  
Test Results ◽  
Overall Design ◽  
Central Receiver ◽  
And Performance ◽  
Design And Testing ◽  
Solar Application

This paper describes the design and testing of the Steam Generator Subsystem (SGS) for the Molten Salt Electric Experiment at Sandia Laboratories in Albuquerque, New Mexico. The Molten Salt Electric Experiment (MSEE) has been established at the Department of Energy’s five megawatt thermal Solar Central Receiver Test Facility, to demonstrate the feasibility of the molten salt central receiver concept. The experiment is capable of generating 0.75 megawatts of electric power from solar energy, with the capability of storing seven megawatt-hours of thermal energy. The steam generator subsystem transfers sensible heat from the solar-heated molten nitrate salt to produce steam to drive a conventional turbine. This paper discusses the design requirements dictated by the steam generator application and also reviews the process conditions. Details of each of the SGS components are given, featuring the aspects of the design and performance unique to the solar application. The paper concludes with a summary of the test results confirming the overall design of the subsystem.

A Photographic Flux Mapping Method for Concentrating Solar Collectors and Receivers

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Clifford K. Ho ◽  
Siri S. Khalsa
Keyword(s):  
Digital Camera ◽  
Mapping Method ◽  
Test Facility ◽  
The Novel ◽  
Error Sources ◽  
Additional Information ◽  
Direct Normal Irradiance ◽  
Beam Characterization ◽  
Pixel Value ◽  
Relative Errors

A new method is described to determine irradiance distributions on receivers and targets from heliostats or other collectors for concentrating solar power applications. The method uses a digital camera, and, unlike previous beam characterization systems, it does not require additional sensors, calorimeters, or flux gauges on the receiver or target. In addition, spillage can exist and can also be measured (the beam does not need to be contained within the target). The only additional information required besides the images recorded from the digital camera is the direct normal irradiance and the reflectivity of the receiver. Methods are described to calculate either an average reflectivity or a reflectivity distribution for the receiver using the digital camera. The novel feature of this new photographic flux (PHLUX) mapping method is the use of recorded images of the sun to scale both the magnitude of each pixel value and the subtended angle of each pixel. A test was performed to evaluate the PHLUX method using a heliostat beam on the central receiver tower at the National Solar Thermal Test Facility in Albuquerque, NM. Results showed that the PHLUX method was capable of producing an accurate flux map of the heliostat beam on a Lambertian surface with a relative error in the peak flux of ∼2% when the filter attenuation factors and effective receiver reflectivity were well characterized. Total relative errors associated with the measured irradiance using the PHLUX method can be up to 20%–40%, depending on various error sources identified in the paper, namely, uncertainty in receiver reflectivity and filter attenuation.

Status Report—Advanced Heat Exchanger Technology for a CCGT Power Generation System

1983 ◽  
Vol 105 (2) ◽  
pp. 348-353 ◽  
Author(s):  
D. E. Wright ◽  
L. L. Tignac
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Ceramic Materials ◽  
Department Of Energy ◽  
Test Facility ◽  
Status Report ◽  
Test Results ◽  
Generation System ◽  
Power Generation System

Rocketdyne is under contract to the Department of Energy for the development of heat exchanger technology that will allow coal to be burned for power generation and cogeneration applications. This effort involves both atmospheric fluidized bed and pulverized coal combustion systems. In addition, the heat exchanger designs cover both metallic and ceramic materials for high-temperature operations. This paper reports on the laboratory and small AFB test results completed to date. It also covers the design and installation of a 6×6 ft atmospheric fluidized bed test facility being used to correlate and expand the knowledge gained from the initial tests. The paper concludes by showing the direction this technology is taking and outlining the steps to follow in subsequent programs.

An Improved Test Facility for Studying Deposit Fouling on Steam Turbine Blades

2016 ◽  
Author(s):  
Alan R. May Estebaranz ◽  
Richard J. Williams ◽  
Simon I. Hogg ◽  
Philip W. Dyer
Keyword(s):  
Turbine Blades ◽  
Steam Pressure ◽  
Reactor Vessel ◽  
Test Facility ◽  
Test Results ◽  
Steam Turbines ◽  
Steam Power ◽  
Scale Test ◽  
Steam Turbine Blades ◽  
Asme Paper

A laboratory scale test facility has been developed to investigate deposition in steam turbines under conditions that are representative of those in steam power generation cycles. The facility is an advanced two-reactor vessel test arrangement, which is a more flexible and more accurately controllable refinement to the single reactor vessel test arrangement described previously in ASME Paper No. GT2014-25517 [1]. The commissioning of the new test facility is described in this paper, together with the results from a series of tests over a range of steam conditions, which show the effect of steam conditions (particularly steam pressure) on the amount and type of deposits obtained. Comparisons are made between the test results and feedback/experience of copper fouling in real machines.

TEST RESULTS OF 60-cm BORE Nb3Sn TEST MODULE COIL (TMC-I) IN THE CLUSTER TEST FACILITY

1984 ◽  
Vol 45 (C1) ◽  
pp. C1-101-C1-104
Author(s):  
T. Ando ◽  
S. Shimamoto ◽  
T. Hiyama ◽  
H. Tsuji ◽  
Y. Takahashi ◽  
...  
Keyword(s):  
Time Constant ◽  
Decay Time ◽  
Superconducting State ◽  
Heat Input ◽  
Test Facility ◽  
Test Results ◽  
Normal Zone ◽  
Out Of Plane ◽  
Force Mode ◽  
Test Module

An extended test of a 60-cm-bore Nb3Sn coil (TMC-I), constructed as a development of superconducting toroidal coil in tokamak machine, has been carried out in the cluster test facility. A 192-cm-length (one turn) normal zone, nucleated by a heat-input in the innermost turn, is recovered to superconducting state at 6 kA and 10 T. For the manual dump with a decay time constant of 6.6 sec (B = 1.0 T/sec), no damage is found on the TMC-I. In addition, a out-of-plane force mode operation, using one of the cluster test coils, is done with no trouble. With these good results, the first stage in TMC-I test was completed. And as the next stage, up-grading the cluster test facility for further TMC-I test in 11 T is now going ahead.

scholarly journals Control of Fan Blade Vibrations Using Piezoelectrics and Bi-Directional Telemetry

2011 ◽  
Author(s):  
Andrew J. Provenza ◽  
Carlos R. Morrison
Keyword(s):  
Low Voltage ◽  
Radio Telemetry ◽  
Magnetic Bearing ◽  
Test Facility ◽  
Test Results ◽  
Novel Device ◽  
Ac Power ◽  
Dynamic Spin ◽  
Wireless Device ◽  
Fan Blade

A novel wireless device which transfers supply power through induction to rotating operational amplifiers and transmits low voltage AC signals to and from a rotating body by way of radio telemetry has been successfully demonstrated in the NASA Glenn Research Center (GRC) Dynamic Spin Test Facility. In the demonstration described herein, a rotating operational amplifier provides controllable AC power to a piezoelectric patch epoxied to the surface of a rotating Ti plate. The amplitude and phase of the sinusoidal voltage command signal, transmitted wirelessly to the amplifier, was tuned to completely suppress the 3rd bending resonant vibration of the plate. The plate’s 3rd bending resonance was excited using rotating magnetic bearing excitation while it spun at slow speed in a vacuum chamber. A second patch on the opposite side of the plate was used as a sensor. This paper discusses the characteristics of this novel device, the details of a spin test, results from a preliminary demonstration, and future plans.

Test results of the FER/ITER conductors in the FENIX test facility

1994 ◽  
Vol 30 (4) ◽  
pp. 2042-2045 ◽  
Author(s):  
M. Sugimoto ◽  
T. Isono ◽  
K. Koizuni ◽  
Y. Takahashi ◽  
M. Nishi ◽  
...  
Keyword(s):  
Test Facility ◽  
Test Results

scholarly journals Wind turbine icing characteristics and icing-induced power losses to utility-scale wind turbines

2021 ◽  
Vol 118 (42) ◽  
pp. e2111461118
Author(s):  
Linyue Gao ◽  
Hui Hu
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Turbine Blades ◽  
Digital Camera ◽  
Unmanned Aircraft ◽  
Ice Accretion ◽  
Power Losses ◽  
Field Campaign ◽  
Output Losses ◽  
Utility Scale

A field campaign was carried out to investigate ice accretion features on large turbine blades (50 m in length) and to assess power output losses of utility-scale wind turbines induced by ice accretion. After a 30-h icing incident, a high-resolution digital camera carried by an unmanned aircraft system was used to capture photographs of iced turbine blades. Based on the obtained pictures of the frozen blades, the ice layer thickness accreted along the blades’ leading edges was determined quantitatively. While ice was found to accumulate over whole blade spans, outboard blades had more ice structures, with ice layers reaching up to 0.3 m thick toward the blade tips. With the turbine operating data provided by the turbines’ supervisory control and data acquisition systems, icing-induced power output losses were investigated systematically. Despite the high wind, frozen turbines were discovered to rotate substantially slower and even shut down from time to time, resulting in up to 80% of icing-induced turbine power losses during the icing event. The research presented here is a comprehensive field campaign to characterize ice accretion features on full-scaled turbine blades and systematically analyze detrimental impacts of ice accumulation on the power generation of utility-scale wind turbines. The research findings are very useful in bridging the gaps between fundamental icing physics research carried out in highly idealized laboratory settings and the realistic icing phenomena observed on utility-scale wind turbines operating in harsh natural icing conditions.

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