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An Air Concentrator for Very Low Grade Colorado Plateau Uranium Ores

Description: Report discussing the use of an air concentrator on uraniferous sandstones for producing concentrates with over ten times the amount of uranium as original sandstone. A description of the concentrator, information regarding its operation, results of the concentration, information on the concentrator's applications, and a general summary are included.
Date: January 1953
Creator: Stieff, L. R. & Erickson, E. S., Jr.
Partner: UNT Libraries Government Documents Department

Optimal Heat Collection Element Shapes for Parabolic Trough Concentrators

Description: For nearly 150 years, the cross section of the heat collection tubes used at the focus of parabolic trough solar concentrators has been circular. This type of tube is obviously simple and easily fabricated, but it is not optimal. It is shown in this article that the optimal shape, assuming a perfect parabolic figure for the concentrating mirror, is instead oblong, and is approximately given by a pair of facing parabolic segments.
Date: November 15, 2007
Creator: Bennett, C
Partner: UNT Libraries Government Documents Department

Method and apparatus for aligning a solar concentrator using two lasers

Description: A method and apparatus are provided for aligning the facets of a solar concentrator. A first laser directs a first laser beam onto a selected facet of the concentrator such that a target board positioned adjacent to the first laser at approximately one focal length behind the focal point of the concentrator is illuminated by the beam after reflection thereof off of the selected facet. A second laser, located adjacent to the vertex of the optical axis of the concentrator, is used to direct a second laser beam onto the target board at a target point thereon. By adjusting the selected facet to cause the first beam to illuminate the target point on the target board produced by the second beam, the selected facet can be brought into alignment with the target point. These steps are repeated for other selected facets of the concentrator, as necessary, to provide overall alignment of the concentrator.
Date: October 5, 2000
Creator: Diver, Richard Boyer Jr.
Partner: UNT Libraries Government Documents Department

Concentrator and Space Applications of High-Efficiency Solar Cells-Recent Developments

Description: GaInP/GaAs cells invented and developed at NREL have achieved world-record efficiencies. We estimate that their production for space applications has grown to > $100 million/yr. Approximately 300 MW/yr of 1000X terrestrial concentrator cells could be fabricated with the existing manufacturing capacity at a cost of about 21{cents}/Wp. A resurgence of interest in terrestrial PV concentrators, together with the strength of the III-V space-solar-cell industry, indicate that III-V cells are also attractive for terrestrial applications.
Date: October 26, 1998
Creator: Kurtz, S. R. & Friedman, D. J.
Partner: UNT Libraries Government Documents Department

Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

Description: A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.
Date: July 1, 2013
Creator: Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I. & Sala, G.
Partner: UNT Libraries Government Documents Department

Development of a 2f optical performance measurement system

Description: Commercialization of faceted stretched-membrane concentrators has created the need for quality control measurements for facet optical performance. High-volume production scenarios require a test method that is quick, can be performed on the production floor, and does not require laboratory-grade equipment. At Sandia, we are developing an optical test method that can be done in a relatively short period of time, requires little space, uses ``off the shelf`` test equipment, and provides a quantitative measure adequate to address quality control requirements. The test method is based on common ray trace calculations for targets and images at the radius of curvature for spherical and parabolic (f/D > 3) concentrators. The initial development work was done using a monochrome television camera and the beam characterization system. Twenty-four 3-meter facets built for a faceted stretched-membrane dish were characterized using this system. Other smaller facets have also been tested with the system to help establish a correlation with this method and other optical characterization tests. Current work involves adapting a color camera to the system and developing custom software to reduce analysis time and make the system viable for the production floor. This paper discusses the development of the monochrome system, reviews the results of testing, and presents plans for the development of a color system.
Date: December 1, 1993
Creator: Grossman, J. W.
Partner: UNT Libraries Government Documents Department

Luminescent solar concentrator development: Final subcontract report, 1 June 1982-31 December 1984

Description: An investigation of luminescent solar concentrators (LSCs) was begun by the US Department of Energy (DOE) at Owens-Illinois, Inc., in 1978. Experimental and theoretical results of that investigation are summarized in this report. An assessment of the LSC technology was compiled to provide a concise description to guide future research in this field. Since 1978, tremendous progress was made in the development of this device as a practical nonimaging concentrator for achieving solar concentration ratios on the order of 10X. The two most important technical achievements appear to be first, the understanding that dye self-absorption of radiated energy is not as serious a problem as originally thought; and second, the demonstration that organic dyes in polymeric hosts are capable of surviving outdoors in bright sunlight for years without serious degradation. System efficiencies approaching 4% have been achieved for photovoltaic conversion and theoretical efficiencies on the order of 9% appear feasible for large-area devices.
Date: April 1, 1987
Creator: Friedman, P.S. & Parent, C.R.
Partner: UNT Libraries Government Documents Department

Software and codes for analysis of concentrating solar power technologies.

Description: This report presents a review and evaluation of software and codes that have been used to support Sandia National Laboratories concentrating solar power (CSP) program. Additional software packages developed by other institutions and companies that can potentially improve Sandia's analysis capabilities in the CSP program are also evaluated. The software and codes are grouped according to specific CSP technologies: power tower systems, linear concentrator systems, and dish/engine systems. A description of each code is presented with regard to each specific CSP technology, along with details regarding availability, maintenance, and references. A summary of all the codes is then presented with recommendations regarding the use and retention of the codes. A description of probabilistic methods for uncertainty and sensitivity analyses of concentrating solar power technologies is also provided.
Date: December 1, 2008
Creator: Ho, Clifford Kuofei
Partner: UNT Libraries Government Documents Department

Conceptual design of a 5x CPC for solar total energy systems

Description: The results of a conceptual design of a nontracking collector for a solar total energy system are described. Sandia Laboratories has responsibility for the evaluation of concentrating collectors in a total energy test bed. A Rankine cycle turbine, generator, controls, thermal storage, and air conditioning equipment have been installed and checked out. The thermal energy for the facility is to be provided by a large (approximately 800 m/sup 2/) concentrating collector field. At present a portion of the area is installed as E-W oriented linear parabolic troughs. Three additional concepts for the remaining area have been selected--a fixed mirror-moving receiver system, fixed receiver-moving reflector slats, and a two-axis tracking parabolic dish. All four systems use diurnal tracking and have the reflecting surfaces exposed to the elements. Argonne National Laboratory has been working on the development of non-tracking concentrators for high temperature operation. The recent experimental results indicate that a 5x CPC collector with only 12 adjustments per year could effectively compete with the systems presently being considered. These collectors would be enclosed under a protective cover glass, eliminating many of the problems with dirt, etc. A conceptual design of a CPC collector system is presented.
Date: January 1, 1977
Creator: Cole, R; Schertz, W W & Teagan, W P
Partner: UNT Libraries Government Documents Department

Performance and testing of a stationary concentrating collector. [Compound parabolic concentrators coupled to tubular evacuated receivers]

Description: The development of nonimaging solar collectors for heating and cooling applications is reported. A totally stationary concentrating collector has been designed, built, and tested. The collectors employ compound parabolic concentrators coupled to tubular evacuated receivers. Performance of the collector is substantially better than flat plate collectors, and the collectors are suitable for powering mechanically driven air conditioning systems as well as conventional absorption cycle machines. This collector concept was awarded an IR-100 award by Industrial Research Magazine as one of the 100 most significant new developments in 1977.
Date: January 1, 1977
Creator: Cole, R L; Allen, J W; Levitz, N M; McIntire, W R & Schertz, W W
Partner: UNT Libraries Government Documents Department

Application of glass technology to novel solar energy collectors

Description: Various compound parabolic concentrator (CPC) configurations are discussed, and the application of glass technology to CPC designs is discussed. CPC designs with flat absorbers, cylindrical absorbers, evacuated receivers, and evacuated tube receivers are considered. Also a floodlamp collector concept and a fluorescent tube collector concept are discussed. (WHK)
Date: January 1, 1979
Creator: Reed, K A
Partner: UNT Libraries Government Documents Department

Performance of evacuated solar collectors with Compound Parabolic Concentrators

Description: Compound Parabolic Concentrators (CPC) achieve the highest possible concentration for a given acceptance angle, permitting geometric concentration ratios up to about 2 in fixed solar collectors and up to about 10 in collectors with day-to-day tilt adjustments. Design, construction and test results are reported for several CPC collectors with evacuated receivers supplied by Corning Glass, by General Electric and by Owens-Illinois. Efficiencies of 45 percent at ..delta..T = 150/sup 0/K above ambient have been reached with a fixed collector. This collector accepts more than half of the diffuse radiation in addition to all of the direct beam, for at least seven hours per day.
Date: January 1, 1978
Creator: Rabl, A.
Partner: UNT Libraries Government Documents Department

A Preliminary Low-Frequency Electromagnetic Analysis of a Flux Concentrator

Description: The objective of this investigation was to conduct a quick, preliminary transient magnetostatic analysis of a Brechna-type[1] flux concentrator to determine its feasibility for collecting positrons in the International Linear Collider. The magnetostatic transient module of Maxwell 3D, Version 10, from the Ansoft Corporation was used to model the flux concentrator.
Date: June 7, 2006
Creator: Mayhall, D J
Partner: UNT Libraries Government Documents Department

Markets for concentrating solar power

Description: The report describes the markets for concentrating solar power. As concentrating solar power technologies advance into the early stages of commercialization, their economic potential becomes more sharply defined and increasingly tangible.
Date: April 1, 1998
Partner: UNT Libraries Government Documents Department

Side-by-Side Comparisons of Evacuated Compound Parabolic Concentrator and Flat Plate Solar Collector Systems

Description: Three liquid-based solar heating systems employing different types of solar collectors were tested side by side near Chicago, Illinois for one year. The three different types of collectors were: (1) a flat plate collector with a black-chrome coated absorber plate and one low-iron glass cover; (2) an evacuated-tube compound parabolic concentrator (CPC) with a concentration ratio of 1.1, oriented with tubes and troughs along a north-south axis; and (3) an evacuated-tube CPC collector with a concentration ratio of 1.3 and one low-iron glass cover, with tubes and troughs oriented along an east-west axis. Results indicate that the flat plate collector system was the most efficient during warm weather, but the CPC systems were more efficient during cold weather, but the CPC systems were more efficient during cold weather, and the CPC systems operated under conditions too adverse for the flat plate collector. The computer simulation model ANSIM was validated by means of the side-by-side tests. The model uses analytical solutions to the storage energy balance. ANSIM is compared with the general simulation TRNSYS.
Date: October 1983
Creator: McGarity, Arthur E.; Allen, John W. & Schertz, William W.
Partner: UNT Libraries Government Documents Department

Innovative point focus solar concentrator

Description: Acurex Corporation has a Cooperative Agreement with the United States Department of Energy (DOE) to design, build and test a 15-meter diameter Innovative Point Focus Solar Concentrator. This report presents the results of the Phase I prototype reflective panel optical test. The approach selected for this test was a quick, simple, and relatively inexpensive evaluation of the first outer reflective panel produced. This approach represented a tradeoff between extent of results and test costs. The test measured the focal quality of the panel, and this result was then related to the focal quality of the complete dish assembly.
Date: February 1, 1986
Partner: UNT Libraries Government Documents Department

Felt-metal-wick heat-pipe solar receiver

Description: Reflux heat-pipe receivers have been identified as a desirable interface to couple a Stirling-cycle engine with a parabolic dish solar concentrator. The reflux receiver provides power nearly isothermally to the engine heater heads while decoupling the heater head design from the solar absorber surface design. The independent design of the receiver and engine heater head leads to higher system efficiency. Heat pipe reflux receivers have been demonstrated at approximately 65 kW{sub t} power throughput. Several 25 to 30-kW{sub e} Stirling-cycle engines are under development, and will soon be incorporated in commercial dish-Stirling systems. These engines will require reflux receivers with power throughput limits reaching 90-kW{sub t}. The extension of heat pipe technology from 60 kW{sub t} to 100 kW{sub t} is not trivial. Current heat pipe wick technology is pushed to its limits. It is necessary to develop and test advanced wick structure technologies to perform this task. Sandia has developed and begun testing a Bekaert Corporation felt metal wick structure fabricated by Porous Metal Products Inc. This wick is about 95% porous, and has liquid permeability a factor of 2 to 8 times higher than conventional technologies for a given maximum pore radius. The wick has been successfully demonstrated in a bench-scale heat pipe, and a full-scale on-sun receiver has been fabricated. This report details the wick design, characterization and installation into a heat pipe receiver, and the results of the bench-scale tests are presented. The wick performance is modeled, and the model results are compared to test results.
Date: December 31, 1994
Creator: Andraka, C. E.; Adkins, D. R.; Moss, T. A.; Cole, H. M. & Andreas, N. H.
Partner: UNT Libraries Government Documents Department

Status of photovoltaic concentrator modules and systems

Description: Several leading line- and point-focus photovoltaic concentrator system development programs are reviewed, including those by ENTECH, SEA Corporation, AMONIX, and Alpha Solarco. Concentrating collectors and trackers are gaining maturity and reaching product status as designs are made more manufacturable and reliable. Utilities are starting to take notice of this emerging technology, and several privately-funded utility installations are underway. Several advantages are offered by concentrators, including low system and capital cost and rapid production ramp-up. These are discussed along with issues generally raised concerning concentrator technology.
Date: April 1, 1994
Creator: Maish, A. B.
Partner: UNT Libraries Government Documents Department

Photovoltaic solar concentrator module

Description: This invention consists of a planar photovoltaic concentrator module for producing an electrical signal from incident solar radiation which includes an electrically insulating housing having a front wall, an opposing back wall and a hollow interior. A solar cell having electrical terminals is positioned within the interior of the housing. A planar conductor is connected with a terminal of the solar cell of the same polarity. A lens forming the front wall of the housing is operable to direct solar radiation incident to the lens into the interior of the housing. A refractive optical element in contact with the solar cell and facing the lens receives the solar radiation directed into the interior of the housing by the lens and directs the solar radiation to the solar cell to cause the solar cell to generate an electrical signal. An electrically conductive planar member is positioned in the housing to rest on the housing back wall in supporting relation with the solar cell terminal of opposite polarity. The planar member is operable to dissipate heat radiated by the solar cell as the solar cell generates an electrical signal and further forms a solar cell conductor connected with the solar cell terminal to permit the electrical signal generated by the solar cell to be measured between the planar member and the conductor.
Date: May 16, 1991
Creator: Chiang, C. J.
Partner: UNT Libraries Government Documents Department

Design and test of non-evacuated solar collectors with compound parabolic concentrators

Description: The intermediate range of concentration ratios (1.5X-10X) which can be achieved with CPC's without diurnal tracking provides both economic and thermal advantages for solar collector design even when used with non-evacuated absorbers. The present paper summarizes more than 3 years of research on non-evacuated CPC's and reviews measured performance data and critical design considerations. Concentrations in the upper portions of the practical range (e.g. 6X) can provide good efficiency (40% to 50%) in the 100/sup 0/C to 160/sup 0/C temperature range with relatively frequent tilt adjustments (12 to 20 times per year). At lower concentrations (e.g. 3X) performance will still be substantially better than that for a double glazed flat plate collector above about 70/sup 0/C and competitive below, while requiring only semi-annual adjustments for year round operation. In both cases the cost savings associated with inexpensive reflectors, and the optimal coupling to smaller, simple inexpensive absorbers (e.g. tubes, fins, etc.) can be as important an advantage as the improved thermal performance.
Date: July 1, 1979
Creator: Rabl, A.; O'Gallagher, J. & Winston, R.
Partner: UNT Libraries Government Documents Department

Fundamentals and techniques of nonimaging optics for solar energy concentration. Final report

Description: Nonimaging optics is a new discipline with techniques, formalism and objectives quite distinct from the traditional methods of focusing optics. These new systems achieve or closely approach the maximum concentration permitted by the Second Law of Thermodynamics for a given angular acceptance and are often called ideal. Application of these new principles to solar energy over the past seven years has led to the invention of a new class of solar concentrators, the most well known version of which is the Compound Parabolic Concentrator or CPC. A new formalism for analyzing nonimaging systems in terms of a quantity called the geometrical vector flux has been developed. This has led not only to a better understanding of the properties of ideal concentrators but to the discovery of several new concentrator designs. One of these new designs referred to as the trumpet concentrator has several advantageous features when used as a secondary concentrator for a point focusing dish concentrator. A new concentrator solution for absorbers which must be separated from the reflector by a gap has been invented. The properties of a variety of new and previously known nonimaging optical configurations have been investigated: for example, Compound Elliptical Concentrators (CEC's) as secondary concentrators and asymmetric ideal concentrators. A thermodynamic model which explains quantitatively the enhancement of effective absorptance of gray body receivers through cavity effects has been developed. The classic method of Liu and Jordan, which allows one to predict the diffuse sunlight levels through correlation with the total and direct fraction was revised and updated and applied to predict the performance of nonimaging solar collectors. The conceptual design for an optimized solar collector which integrates the techniques of nonimaging concentration with evacuated tube collector technology was carried out.
Date: May 20, 1980
Creator: Winston, R.
Partner: UNT Libraries Government Documents Department

Development and demonstration of compound parabolic concentrators for solar thermal power generation and heating and cooling applications. Progress report, July--December 1975

Description: Work on the development of Compound Parabolic Concentrators (CPC) is described. A tenfold concentrator with a cavity receiver was constructed and tested. The optical efficiency was very good (65 percent), but the thermal performance was degraded by heat losses of the cavity receiver. A 20 ft/sup 2/ (1.86 m/sup 2/) concentrating collector (5.3x) has been tested for thermal and optical performance, and the optical efficiency was excellent (68 percent). In this collector, aluminum extrusions were used to define the CPC shape and provide the fluid-flow path. A 30 ft (9.14 m) long collector (10x) has been designed and is being built for daily-cycle testing. The expected performance of this collector has been evaluated. The conceptual design of a lightweight collector using evacuated glass tubes around the absorber is presented. Various construction techniques for use with low-cost materials, such as plastics, are being evaluated for this collector. Optical design studies of Compound Parabolic Concentrators for tubular absorbers and for use as secondary concentrators are discussed. Comparison of the CPC with tube and the CPC with one-sided flat absorber shows that the tubular configuration is preferable not only because of lower heat losses but also because of lower collector cost. For tracking concentrators with line focus, the use of second-stage concentrators is found to be cost effective; the CPC is found to be significantly better for this application than a V-trough. A summary of the results of subcontracts described in the previous progress report are presented, and the influence of these results on ANL programs is noted.
Date: January 1, 1977
Creator: Allen, J.W.; Levitz, N.M.; Rabl, A.; Reed, K.A.; Schertz, W.W.; Thodos, G. et al.
Partner: UNT Libraries Government Documents Department

CPC thermal collector test plan

Description: A comprehensive set of test procedures has evolved at Argonne National Laboratory for establishing the performance of compound parabolic and related concentrating thermal collectors with large angular fields of view. The procedures range from separate thermal and optical tests, to overall performance tests. A calorimetric ratio technique has been developed to determine the heat output of a collector without knowledge of the heat transfer fluid's mass flow rate and heat capacity. Sepcial attention is paid to the problem of defining and measuring the incident solar flux with respect to which the collector efficiency is to be calculated.
Date: January 1, 1977
Creator: Reed, K A
Partner: UNT Libraries Government Documents Department