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1

Solar Cookers.  

ERIC Educational Resources Information Center

Describes the use of solar cookers in the science classroom. Includes instructions for construction of a solar cooker, an explanation of how solar cookers work, and a number of suggested activities. (DS)

King, Richard C.

1981-01-01

2

Solar Cooker  

NSDL National Science Digital Library

Learners build a simple solar oven from a shoebox, black construction paper, and aluminum foil. Over the course of a few hours, the oven heats up water enough to brew tea. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. As a larger assessment, learners can complete the Smart Attack game after they've completed several activities.

2012-06-26

3

Solar Cookers International  

NSDL National Science Digital Library

With diminishing supplies of firewood in many impoverished nations, how can rural people cook food for their families? In 1987, 17 solar cooking Californians started Solar Cookers International (SCI), and produced manuals on how to produce and use a simple solar box cooker. Since then, 30,000 families in eastern and southern Africa have learned to use solar cooking with the assistance of SCI. Visitors should definitely check out the ten-minute video on the homepage that explains the spread of the use of the solar cooker in Africa, which began in refugee camps where food had to be cooked for tens of thousands of people. Eventually, its use spread to rural villages, but the video explains it has been a slow process. Visitors interested in the Solar Review Cooker e-newsletter that is published thrice-yearly can sign up to receive it free, under the "Newsletter" tab. It is also available in dozens of languages, including French, Arabic, and Chinese.

4

Flat Plate Collector Solar Cooker  

Microsoft Academic Search

This paper reports on the design, construction, and testing of a solar cooker. Efforts were made to tap and utilize direct solar energy for cooking. The solar cooker was made of a casing and an absorber (which doubled as a pot). The absorber was a square base pot, blackened with smoke, and it was made of stainless steel. The casing

O. A. Ogunwole

5

Reflective Solar Cooker  

NSDL National Science Digital Library

In this activity, learners use the Sun's energy to cook marshmallows. Learners construct the solar oven out of simple everyday materials. They experiment to see how the color of the marshmallow (vanilla or chocolate) and height of the straws affect cooking time. Use this activity to introduce learners to solar energy and reflection. Note: this activity requires adult supervision.

McDonald Observatory

2011-01-01

6

Promotion of solar box cooker technology  

SciTech Connect

Over 1.5 billion people are affected by fuel wood shortage, according to the UN Food and Agricultural Organization. Meanwhile solar cookers are under-exploited. The author presents one version of this technology and discusses how it may be promoted world-wide. The increased use of non fossil fuel energy is essential world-wide in combating global warming trends, preserving the environment, conserving resources and achieving sustainable development. The Solar Box Cooker (SBC) - a box within a box - uses an easily available source of such energy that is also renewable (in contrast to energy that, once used, is not, such as oil, coal, gas, wood). It is also readily available for the developing world, and for much of the developed world too.

Stibravy, R.

1992-09-01

7

Through the wall solar cooker  

SciTech Connect

This patent describes a solar appliance for extending from the interior of a kitchen through an exterior wall of the building and beyond a predetermined distance in a cantilever manner to receive and concentrate in the appliance outside of the building, solar radiation rays for cooking purposes comprising: a housing, the housing being mounted to extend from a kitchen through an external wall of a building and beyond in a cantilever manner and forming a closed oven, the oven comprising a bottom, glass top, a pair of sides and a first end positioned with access from within the kitchen and comprising an oven door, a first reflective panel member mounted above, juxtapositioned to one edge of the glass top for positioning against the outer surface of the external wall and extending laterally therefrom for receiving and directing solar rays impinging thereon through the glass top and into the oven, and a second double-sided reflective panel mounted above and juxtapositioned to the glass top and extending substantially perpendicular to the first reflective panel for receiving solar rays impinging on either side thereof, and directing the solar rays into the oven.

Kerr, B.P.

1987-04-07

8

A solar box cooker for mass production in East Africa  

SciTech Connect

A solar box cooker produced in Tanzania, East Africa with indigenous materials is described. When compared to a commercially produced glass and cardboard one, it was found to perform as well. Heat transfer through each major component of the cooker is presented. The smallest losses were through the walls of the box. The greatest losses were observed in the cover system.

Funk, P.A.; Wilcke, W.F. [Univ. of Minnesota, St. Paul, MN (United States). Dept. of Agricultural Engineering

1992-12-31

9

Solar thermal collector system modeling and testing for novel solar cooker  

E-print Network

Solar cookers are aimed at reducing pollution and desertification in the developing world. However, they are often disregarded as they do not give users the ability to cook after daylight hours. The Wilson solar cooker is ...

Foley, Brian, S.B. (Brian M.). Massachusetts Institute of Technology

2014-01-01

10

Development of an asynchronous solar-powered cooker  

E-print Network

One reason that solar cookers have not gained widespread acceptance is because their use has proved inconvenient and impractical. Users are restricted to cooking when, and where, the sun is shining. Furthermore, the cooking ...

Akinwale, P. Femi (Pamela Femi)

2006-01-01

11

Transient-heat-transfer and stress analysis of a thermal-storage solar cooker module  

E-print Network

This paper details the analysis carried out in Solidworks to determine the best material and configuration of a thermal-storage solar cooker module.The thermal-storage solar cooker utilizes the high-latent-heat lithium ...

Zengeni, Hazel C

2014-01-01

12

SOLAR COOKER UTILIZING SATELLITE DISH TECHNOLOGY Mechanical Engineering Department , Philadelphia University, Amman Jordan, e-mail  

E-print Network

SOLAR COOKER UTILIZING SATELLITE DISH TECHNOLOGY A. Saleh1 A. Badran2 1 Mechanical Engineering dish­type solar cooker was built and tested utilizing satellite dish technology. A common satellite-TV dish was utilized as a solar cooker after covering it with a highly­reflective aluminum foil, which

13

Cookin' with Sun: Design and Build Solar Cookers  

ERIC Educational Resources Information Center

Having students design and construct solar cookers is a great way to teach them about designing to meet human needs and about many basic global issues related to health and the environment. Because the activity includes solid content from the fields of math, science and technology, it is an excellent vehicle for technology educators who want to

Brand, Lance; Warren, Ande; Fitzgerald, Mike

2006-01-01

14

Parabolic solar systems  

NASA Astrophysics Data System (ADS)

The further development of parabolic solar collectors to increase their efficiency and simplify their operation was the prime objective of this research project. Three primary objectives were pursued. The first of these was to investigate the simplest and most efficient techniques to build and mass-produce parabolic solar collectors. The second objective was to further develop and simplify absorber tubes used to collect and transfer the solar energy. Absorber tubes represented a significant area of this research project. The third objective was to develop accurate, low cost, and durable tracking systems for solar collectors. Solar tracking systems are covered including several schematic representations of various systems and designs. The testing systems and associated mechanisms for the designs discussed in this report are described.

Parsons, W. L., IV; Goetchius, W.

15

Thermal performance parameters estimation of hot box type solar cooker by using artificial neural network  

Microsoft Academic Search

Work to date has shown that Artificial Neural Network (ANN) has not been used for predicting thermal performance parameters of a solar cooker. The objective of this study is to predict thermal performance parameters such as absorber plate, enclosure air and pot water temperatures of the experimentally investigated box type solar cooker by using the ANN. Data set is obtained

Hseyin Kurt; Kemal Atik; Mehmet zkaymak; Ziyaddin Recebli

2008-01-01

16

The ``Sol Kitchen'' solar coffee can cooker kit and curriculum package  

SciTech Connect

The Sol Kitchen Solar Coffee Can Cooker Kit is being developed, by Solar utilities, as a product, with several contexts in mind, including (1) the need to sustain the long term market development of solar energy through education, (2) the need for an improved set of performance criteria for the technology, as it is presented in the classroom and (3) an awareness of newly evolving bench marks in environmental education ({hor_ellipsis}which is about learning how to save the earth.). The category of technology discussed in this paper is the solar cooker, also known as, the solar oven, furnace, or box cooker, with or without reflective panels. The use of full scale solar cookers, modified to act as curriculum aids, can augment educational programs; but only if they work well, are appropriate to the educational objectives, and engage the attention and active involvement of the learners.

Donald, R.M.

1999-07-01

17

Estimation of design parameters for thermal performance evaluation of box-type solar cooker  

Microsoft Academic Search

The paper presents a simple test procedure for determination of design parameters to predict the thermal performance of a box-type solar cooker. A series of out-door experiments were performed on the double-glazed solar cooker of aperture area 0.245m2 with a fibre body to obtain two figures of merit, F1 and F2. The necessary design parametersoptical efficiency, F??o and heat capacity,

Subodh Kumar

2005-01-01

18

Solar parabolic trough forming process  

Microsoft Academic Search

A new forming process is presented which exceeds an 8\\/1 concentration. Expanding on work previously done, many variables were investigated. Using one foot long trough samples, a high degree of slope accuracy was obtained. The forming process eliminated the need for ribs, boxes or other devices now used to maintain the parabolic shape of a solar parabolic shell. The process,

O. G. Williams; R. L. Skaggs

1978-01-01

19

Design and thermal performance evaluation of a box-type solar cooker with non-tracking planar reflectors  

Microsoft Academic Search

A model of a box-type solar cooker employing non-tracking planar reflectors has been designed and fabricated, and its thermal performance investigated experimentally. The concentrator, consisting of two planar reflectors suitably positioned in an east-west (E-W) configuration on an inclined framework, is mounted on the box of the cooker to reflect incident solar radiation on the base absorber of the cooker.

I. Purohit

2007-01-01

20

Twelve years experience with solar cookers: Necessary tools for a clean environment  

SciTech Connect

In this review the author shares his personal experience of 12 years on cooking and working with hot box type Solar Ovens (SO), Electric cum Solar Oven (ECSO) and simple Heat Storage Oven (HESO). In addition to informing, advantages and limitations of conventional hot box Solar Oven, economic, social, ecological, and dissemination aspects will be mentioned. Finally some other applications of the solar cooker alone, as well as combined with other solar thermal devices like water heaters, driers and stills, are discussed.

Nandwani, S.S. [Univ. Nacional Herida (Costa Rica). Dept. de Fisica

1992-12-31

21

Shenandoah parabolic dish solar collector  

SciTech Connect

The objectives of the Shenandoah, Georgia, Solar Total Energy System are to design, construct, test, and operate a solar energy system to obtain experience with large-scale hardware systems for future applications. This report describes the initial design and testing activities conducted to select and develop a collector that would serve the need of such a solar total energy system. The parabolic dish was selected as the collector most likely to maximize energy collection as required by this specific site. The fabrication, testing, and installation of the parabolic dish collector incorporating improvements identified during the development testing phase are described.

Kinoshita, G.S.

1985-01-01

22

Shenandoah parabolic dish solar collector  

NASA Astrophysics Data System (ADS)

The objectives of the Shenandoah, Georgia, Solar Total Energy System are to design, construct, test, and operate a solar energy system to obtain experience with large scale hardware systems for future applications. The initial design and testing activities conducted to select and develop a collector that would serve the need of such a solar total energy system are described. The parabolic dish was selected as the collector most likely to maximize energy collection as required by this specific site. The fabrication, testing, and installation of the parabolic dish collector incorporating improvements identified during the development testing phase are described.

Kinoshita, G. S.

1985-01-01

23

Plane and parabolic solar panels  

E-print Network

We present a plane and parabolic collector that absorbs radiant energy and transforms it in heat. Therefore we have a panel to heat water. We study how to increment this capture of solar beams onto the panel in order to increase its efficiency in heating water.

Sales, J H O

2009-01-01

24

Plane and parabolic solar panels  

E-print Network

We present a plane and parabolic collector that absorbs radiant energy and transforms it in heat. Therefore we have a panel to heat water. We study how to increment this capture of solar beams onto the panel in order to increase its efficiency in heating water.

J. H. O. Sales; A. T. Suzuki

2009-05-14

25

First and Second Law Efficiencies in the Cooking Process of Eggplant using a Solar Cooker Box-Type  

NASA Astrophysics Data System (ADS)

In this work an experimental procedure and the determination of first and second law efficiencies for the cooking process of eggplant using a solar cooker box-type are shown. The eggplant was modelled as cylinder. In the experimental process a NI Compact Field Point was used as acquisition data system which allows measure temperatures in simultaneous form. The temperatures evolution was defined using thermocouples located at water, surface and central point of the eggplant. After to measure the evolution temperatures in a solar cooker thermodynamics principles were applied to determine the first and second laws. The results obtained indicates what is the numerical difference between the first and second laws in the cooking process of eggplant. The results allow to understand how the inlet energy that impacts on solar cooker is converted in energy useful in the cooking process of eggplant. This work be used in future designs of solar cookers.

Terres, H.; Chvez, S.; Lizardi, A.; Lpez, R.; Vaca, M.; Flores, J.; Salazar, A.

2015-01-01

26

Parabolic Trough Solar Thermal Electric Power Plants  

SciTech Connect

Although many solar technologies have been demonstrated, parabolic trough solar thermal electric power plant technology represents one of the major renewable energy success stories of the last two decades.

Not Available

2003-06-01

27

Heat Transfer Convection in The Cooking of Apple Using a Solar Cooker Box-Type  

NASA Astrophysics Data System (ADS)

In this work, experimental results to determine the convection heat transfer coefficient in the cooking process of apple using a solar cooker box-type are presented. Experimental data of temperatures for water, surface and central point of the apple were used. To determine the convection coefficient, the apple was modelled as a sphere. The temperatures evolution was defined using thermocouples located at water, surface and central point in the vegetables. Using heat transfer convection equations in transitory state and the temperatures measured, the Biot number and the convection coefficient were determined.

Terres, H.; Chvez, S.; Lizardi, A.; Lpez, R.; Vaca, M.; Flores, J.; Salazar, A.

2015-01-01

28

Solar parabolic dish technology evaluation report  

NASA Technical Reports Server (NTRS)

The activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1983 are summarized. Included are discussions on designs of module development including concentrator, receiver, and power conversion subsystems together with a separate discussion of field tests, Small Community Experiment system development, and tests at the Parabolic Dish Test Site.

Lucas, J. W.

1984-01-01

29

Solar Parabolic Dish Annual Technology Evaluation Report  

NASA Technical Reports Server (NTRS)

The activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1982 are summarized. Included are discussions on designs of module development including their concentrator, receiver, and power conversion subsystems. Analyses and test results, along with progress on field tests, Small Community Experiment System development, and tests at the Parabolic Dish Test Site are also included.

1983-01-01

30

Design, fabrication, and testing of a mechanical timer in application of a stored-heat solar cooker  

E-print Network

There is a large need in third-world tropical areas for a method of cooking in which users need minimal resources and traversing to heat food at night. A solution to this problem is to create a stored-heat solar cooker ...

Hsu, Julia C

2014-01-01

31

Elastic approximation for a solar parabolic February 29, 2012  

E-print Network

Elastic approximation for a solar parabolic trough February 29, 2012 Gang Xiao (University of Nice, France) Abstract For the production of the reective surface of a solar parabolic trough concentrator energy solutions. Introduction A parabolic trough [8] is a concentrating solar thermal energy collector

Paris-Sud XI, Universit de

32

Solar Thermal Power Systems parabolic dish project  

NASA Technical Reports Server (NTRS)

The status of the Solar Thermal Power Systems Project for FY 1980 is summarized. Included is: a discussion of the project's goals, program structure, and progress in parabolic dish technology. Analyses and test results of concentrators, receivers, and power converters are discussed. Progress toward the objectives of technology feasibility, technology readiness, system feasibility, and system readiness are covered.

Truscello, V. C.

1981-01-01

33

Building a parabolic solar concentrator prototype  

NASA Astrophysics Data System (ADS)

In order to not further degrade the environment, people have been seeking to replace non-renewable natural resources such as fossil fuels by developing technologies that are based on renewable resources. An example of these technologies is solar energy. In this paper, we show the building and test of a solar parabolic concentrator as a prototype for the production of steam that can be coupled to a turbine to generate electricity or a steam engine in any particular industrial process.

Escobar-Romero, J. F. M.; Montiel, S. Vzquez y.; Granados-Agustn, F.; Cruz-Martnez, V. M.; Rodrguez-Rivera, E.; Martnez-Yez, L.

2011-01-01

34

Performance contracting for parabolic trough solar thermal systems  

Microsoft Academic Search

Several applications of solar energy have proven viable in the energy marketplace, due to competitive technology and economic performance. One example is the parabolic trough solar collectors, which use focused solar energy to maximize efficiency and reduce material use in construction. Technical improvements are complemented by new business practices to make parabolic trough solar thermal systems technically and economically viable

H. Brown; R. Hewett; A. Walker; R. Gee; K. May

1997-01-01

35

Parabolic dish collectors - A solar option  

NASA Technical Reports Server (NTRS)

A description is given of several parabolic-dish high temperature solar thermal systems currently undergoing performance trials. A single parabolic dish has the potential for generating 20 to 30 kW of electricity with fluid temperatures from 300 to 1650 C. Each dish is a complete power-producing unit, and may function either independently or as part of a group of linked modules. The two dish designs under consideration are of 11 and 12 meter diameters, yielding receiver operating temperatures of 925 and 815 C, respectively. The receiver designs described include (1) an organic working fluid (toluene) Rankine cycle engine; (2) a Brayton open cycle unit incorporating a hybrid combustion chamber and nozzle and a shaft-coupled permanent magnet alternator; and (3) a modified Stirling cycle device originally designed for automotive use. Also considered are thermal buffer energy storage and thermochemical transport and storage.

Truscello, V. C.

1981-01-01

36

Simplified Methodology for Designing Parabolic Trough Solar Power Plants  

Microsoft Academic Search

The performance of parabolic trough based solar power plants over the last 25 years has proven that this technology is an excellent alternative for the commercial power industry. Compared to conventional power plants, parabolic trough solar power plants produce significantly lower levels of carbon dioxide, although additional research is required to bring the cost of concentrator solar plants to a

Ricardo Vasquez Padilla

2011-01-01

37

Alignment method for parabolic trough solar concentrators  

DOEpatents

A Theoretical Overlay Photographic (TOP) alignment method uses the overlay of a theoretical projected image of a perfectly aligned concentrator on a photographic image of the concentrator to align the mirror facets of a parabolic trough solar concentrator. The alignment method is practical and straightforward, and inherently aligns the mirror facets to the receiver. When integrated with clinometer measurements for which gravity and mechanical drag effects have been accounted for and which are made in a manner and location consistent with the alignment method, all of the mirrors on a common drive can be aligned and optimized for any concentrator orientation.

Diver, Richard B. (Albuquerque, NM)

2010-02-23

38

Test results, Industrial Solar Technology parabolic trough solar collector  

Microsoft Academic Search

Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated

V. E. Dudley; L. R. Evans; C. W. Matthews

1995-01-01

39

Midtemperature Solar Thermal Systems Design Handbook Parabolic troughs  

Microsoft Academic Search

This paper outlines ongoing efforts at Sandia Laboratories (SLA) to develop a Solar Thermal System's Design Handbook. The handbook deals, at this time, only with parabolic trough collector systems operating up to 315 C (600 F). While useful to anyone doing solar thermal design involving parabolic troughs, the handbook application is primarily aimed at commercial Architectural and Engineering firms. Publication

R. W. Harrigan

1979-01-01

40

Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

Microsoft Academic Search

As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the

J. K. Stynes; B. Ihas

2012-01-01

41

Parabolic Trough Solar Power for Competitive U.S. Markets  

Microsoft Academic Search

Nine parabolic trough power plants located in the California Mojave Desert represent the only commercial development of large-scale solar power plants to date. Although all nine plants continue to operate today, no new solar power plants have been completed since 1990. Over the last several years, the parabolic trough industry has focused much of its efforts on international market opportunities.

Henry W. Price

1998-01-01

42

Steam engine research for solar parabolic dish  

NASA Technical Reports Server (NTRS)

The parabolic dish solar concentrator provides an opportunity to generate high grade energy in a modular system. Most of the capital is projected to be in the dish and its installation. Assurance of a high production demand of a standard dish could lead to dramatic cost reductions. High production volume in turn depends upon maximum application flexibility by providing energy output options, e.g., heat, electricity, chemicals and combinations thereof. Subsets of these options include energy storage and combustion assist. A steam engine design and experimental program is described which investigate the efficiency potential of a small 25 kW compound reheat cycle piston engine. An engine efficiency of 35 percent is estimated for a 700 C steam temperature from the solar receiver.

Demler, R. L.

1981-01-01

43

Solar Thermal Power Plants with Parabolic-Trough Collectors  

Microsoft Academic Search

Parabolic-trough collectors (PTC) are solar concentrating devices suitable to work in the 150C- 400C temperature range. Power plants based on this type of solar collectors are a very efficient way to produce electricity with solar energy. At present, there are eight commercial solar plants (called SEGS-II, III,.. IX) producing electricity with parabolic-trough collectors and their total output power is 340

E. Zarza; L. Valenzuela; J. Len

2004-01-01

44

Proceedings of the Fifth Parabolic Dish Solar Thermal Power Program  

NASA Technical Reports Server (NTRS)

The proceedings of the Fifth Parabolic Dish Solar Thermal Power Program Annual Review are presented. The results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program were emphasized. Among the topics discussed were: overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development along with associated hardware and test results; distributed systems operating experience; international parabolic dish development activities; and non-DOE-sponsored domestic dish activities. Solar electric generation was also addressed.

Lucas, J. W. (editor)

1984-01-01

45

A Study of Solar Reflector Efficiency of Parabolic Dual Trough  

Microsoft Academic Search

Problem statement: The receiver of parabolic dual trough had been designed and built in order to increase efficiency of solar radiation acc umulation by using iron-aluminum sheet as an intermediate in receiving heat and it is the study into how to benefit from solar radiation energy. Th is research proposed the principle of changing solar r adiation to be heating

Sopa Cansee; Adisak Pattiya; Singthong Pattanasethanon

2010-01-01

46

Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers  

Microsoft Academic Search

Solar parabolic trough systems for electricity production are receiving renewed attention, and new solar plants are under construction to help meet the growing demands of the power market in the Western United States. The growing solar trough industry will rely on operating experience it has gained over the last two decades. Recently, researchers found that trough plants that use organic

L. Moens; D. M. Blake

2008-01-01

47

Test results, Industrial Solar Technology parabolic trough solar collector  

SciTech Connect

Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated Pyrex{reg_sign} glass receiver envelopes. The development effort has been successful, producing an advanced collector with 77% optical efficiency, using silver-film reflectors, a black nickel receiver coating, and a solgel anti-reflective glass receiver envelope. For each receiver configuration, performance equations were empirically derived relating collector efficiency and thermal losses to the operating temperature. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature.

Dudley, V.E. [EG and G MSI, Albuquerque, NM (United States); Evans, L.R.; Matthews, C.W. [Sandia National Labs., Albuquerque, NM (United States)

1995-11-01

48

Testing the figure of parabolic reflectors for solar concentrators.  

PubMed

A novel method for testing the optical quality of large parabolic solar concentrators is presented, based on autocollimation. An optical system continuously scans the reflector along a fixed reference axis. At each position along the axis, the spread function is obtained. Analysis of the location, width, and intensity changes of this function gives quantitative information about the reflector's defects. A figure of merit describing the performance of parabolic trough reflectors is proposed. PMID:20401092

Bodenheimer, J S; Eisenberg, N P; Gur, J

1982-12-15

49

Solar parabolic dish technology annual evaluation report. Fiscal year 1983  

SciTech Connect

This report summarizes the activities of the JPL Solar Thermal Power Systems Parabolic Dish Project for FY 1983. Included are discussions on designs of module development including their concentrator, receiver, and power conversion subsystem together with a separate discussion of concentrator development. Analyses and test results, along with progress on field tests, Small Community Experiment system development, and tests at the Parabolic Dish Test Site are also included.

Not Available

1984-04-15

50

Solar steam generating systems using parabolic trough concentrators  

Microsoft Academic Search

Solar steam generating systems using parabolic trough concentrators have been in use for the past decade in several countries in the world. During the past years, various R & D efforts have been put into use to improve the performance. This paper reviews various aspects of solar steam generating systems and the operational problems that were encountered by various users

A. Thomas

1996-01-01

51

Solar Thermal Power Plants with Parabolic-Trough Collectors  

NASA Astrophysics Data System (ADS)

Parabolic-trough collectors (PTC) are solar concentrating devices suitable to work in the 150C- 400C temperature range. Power plants based on this type of solar collectors are a very efficient way to produce electricity with solar energy. At present, there are eight commercial solar plants (called SEGS-II, III,.. IX) producing electricity with parabolic-trough collectors and their total output power is 340 MW. Though all SEGS plants currently in operation use thermal oil as a heat transfer fluid between the solar field and the power block, direct steam generation (DSG) in the receiver tubes is a promising option to reduce the cost of electricity produced with parabolic- trough power plants. Most of technical uncertainties associated to the DSG technology were studied and solved in the DISS project and it is expected that this new technology will be commercially available in a short term. In Spain, the Royal Decree No. 436/204 (March 12th , 2004) has defined a premium of 0,18/kWh for the electricity produced by solar thermal power plants, thus promoting the installation of solar thermal power plants up to a limit of 200 MW. Due to the current legal and financial framework defined in Spain, several projects to install commercial solar power plants with parabolic-trough collectors are currently underway.

Zarza, E.; Valenzuela, L.; Len, J.

2004-12-01

52

Coupling flexible solar cell with parabolic trough solar-concentrator-prototype design and performance  

Microsoft Academic Search

Solar cells are still too expensive (5-20\\/watt) to compete with traditional fossil fuel power generating methods (1\\/watt). Parabolic trough solar concentrator has the advantage of modest concentration ratio (10-100) which is well suited for coupling with solar cell. Thus using small area solar cell placed in the focal line of parabolic trough may be economically viable alternative to flat solar

Alexander Panin; Jonathon Bergquist

2007-01-01

53

Federal technology alert. Parabolic-trough solar water heating  

SciTech Connect

Parabolic-trough solar water heating is a well-proven renewable energy technology with considerable potential for application at Federal facilities. For the US, parabolic-trough water-heating systems are most cost effective in the Southwest where direct solar radiation is high. Jails, hospitals, barracks, and other facilities that consistently use large volumes of hot water are particularly good candidates, as are facilities with central plants for district heating. As with any renewable energy or energy efficiency technology requiring significant initial capital investment, the primary condition that will make a parabolic-trough system economically viable is if it is replacing expensive conventional water heating. In combination with absorption cooling systems, parabolic-trough collectors can also be used for air-conditioning. Industrial Solar Technology (IST) of Golden, Colorado, is the sole current manufacturer of parabolic-trough solar water heating systems. IST has an Indefinite Delivery/Indefinite Quantity (IDIQ) contract with the Federal Energy Management Program (FEMP) of the US Department of Energy (DOE) to finance and install parabolic-trough solar water heating on an Energy Savings Performance Contract (ESPC) basis for any Federal facility that requests it and for which it proves viable. For an ESPC project, the facility does not pay for design, capital equipment, or installation. Instead, it pays only for guaranteed energy savings. Preparing and implementing delivery or task orders against the IDIQ is much simpler than the standard procurement process. This Federal Technology Alert (FTA) of the New Technology Demonstration Program is one of a series of guides to renewable energy and new energy-efficient technologies.

NONE

1998-04-01

54

hal-00177601,version2-30Oct2007 A closed parabolic trough solar collector  

E-print Network

hal-00177601,version2-30Oct2007 A closed parabolic trough solar collector Gang Xiao 30th October 2007 Parabolic trough[1] is the most mature technology for large scale exploitation of solar energy of closed-box parabolic trough concentrated solar collector. By accepting an optical loss of a few

Paris-Sud XI, Universit de

55

Fast thermal cycling of acetanilide and magnesium chloride hexahydrate for indoor solar cooking  

Microsoft Academic Search

Solar cookers are broadly divided into a direct or focusing type, indirect or box-type and advanced solar cookers. The focusing and box-type solar cookers are for outdoor applications. The advanced solar cookers have the advantage of being usable indoors and thus solve one of the problems, which impede the social acceptance of solar cookers. The advanced type solar cookers are

A. A. El-Sebaii; S. Al-Amir; F. M. Al-Marzouki; Adel S. Faidah; A. A. Al-Ghamdi; S. Al-Heniti

2009-01-01

56

Parabolic Dish Solar Thermal Power Annual Program Review Proceedings  

NASA Technical Reports Server (NTRS)

The results of activities of the parabolic dish technology and applications development element of DOE's Solar Thermal Energy System Program are presented. Topics include the development and testing of concentrators, receivers, and power conversion units; system design and development for engineering experiments; economic analysis and marketing assessment; and advanced development activities. A panel discussion concerning industrial support sector requirements is also documented.

Lucas, J. W.

1982-01-01

57

A new parabolic trough solar collector P. Kohlenbach1  

E-print Network

, Canberra ACT 0200 3 Wizard Power, 15 Barry Drive, Turner, ACT, 2612 ABSTRACT This paper presents a new) power generation system. The parabolic trough collectors have been installed in the National Solar Energy Centre at CSIRO Energy Technology in Newcastle, NSW. They consist of four rows of 18 mirrors each

58

Gas Turbine\\/Solar Parabolic Trough Hybrid Designs: Preprint  

Microsoft Academic Search

A strength of parabolic trough concentrating solar power (CSP) plants is the ability to provide reliable power by incorporating either thermal energy storage or backup heat from fossil fuels. Yet these benefits have not been fully realized because thermal energy storage remains expensive at trough operating temperatures and gas usage in CSP plants is less efficient than in dedicated combined

C. S. Turchi; Z. Ma; M. Erbes

2011-01-01

59

Novel second-stage solar concentrator for parabolic troughs  

Microsoft Academic Search

Conventional parabolic troughs can be combined with second stage concentrators (SSC), to increase temperature and pressure inside the absorber, making possible the direct production of steam, improving substantially the overall system efficiency and leading to a new generation of distributed solar power plants. To attain this objective, research is needed at the optical, thermodynamic, system control, and engineering levels. In

Manuel Collares-Pereira; Joao F. Mendes

1995-01-01

60

Thermoeconomic analysis of a solar parabolic trough collector distillation plant  

Microsoft Academic Search

Thermoeconomy, which is based on the Systems Theory and the Second Law of Thermodynamic, gives strategies for diagnoses and control of energetic systems (these are systems which consume great amounts of energy). In this paper a thermoeconomic analysis of a multi-stage flash and a multi-effect distillation plant coupled to a solar parabolic trough collector field have been made. The analysis

L. Garca-Rodrguez; C. Gmez-Camacho

1999-01-01

61

Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

Microsoft Academic Search

The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of

J. K. Stynes; B. Ihas

2012-01-01

62

Gas Turbine/Solar Parabolic Trough Hybrid Designs: Preprint  

SciTech Connect

A strength of parabolic trough concentrating solar power (CSP) plants is the ability to provide reliable power by incorporating either thermal energy storage or backup heat from fossil fuels. Yet these benefits have not been fully realized because thermal energy storage remains expensive at trough operating temperatures and gas usage in CSP plants is less efficient than in dedicated combined cycle plants. For example, while a modern combined cycle plant can achieve an overall efficiency in excess of 55%; auxiliary heaters in a parabolic trough plant convert gas to electricity at below 40%. Thus, one can argue the more effective use of natural gas is in a combined cycle plant, not as backup to a CSP plant. Integrated solar combined cycle (ISCC) systems avoid this pitfall by injecting solar steam into the fossil power cycle; however, these designs are limited to about 10% total solar enhancement. Without reliable, cost-effective energy storage or backup power, renewable sources will struggle to achieve a high penetration in the electric grid. This paper describes a novel gas turbine / parabolic trough hybrid design that combines solar contribution of 57% and higher with gas heat rates that rival that for combined cycle natural gas plants. The design integrates proven solar and fossil technologies, thereby offering high reliability and low financial risk while promoting deployment of solar thermal power.

Turchi, C. S.; Ma, Z.; Erbes, M.

2011-03-01

63

Thermal analysis of solar parabolic trough with porous disc receiver  

Microsoft Academic Search

In this paper, 3-D numerical analysis of the porous disc line receiver for solar parabolic trough collector is presented. The influence of thermic fluid properties, receiver design and solar radiation concentration on overall heat collection is investigated. The analysis is carried out based on renormalization-group (RNG) k? turbulent model by using Therminol-VP1 as working fluid. The thermal analysis of the

K. Ravi Kumar; K. S. Reddy

2009-01-01

64

Coupling flexible solar cell with parabolic trough solar-concentrator-prototype design and performance  

NASA Astrophysics Data System (ADS)

Solar cells are still too expensive (5-20/watt) to compete with traditional fossil fuel power generating methods (1/watt). Parabolic trough solar concentrator has the advantage of modest concentration ratio (10-100) which is well suited for coupling with solar cell. Thus using small area solar cell placed in the focal line of parabolic trough may be economically viable alternative to flat solar panels. We experiment with flexible solar cell (backed by water cooling pipe) placed in the focus of parabolic trough reflector. Another advantage of parabolic trough concentrator is very relaxed tracking requirement. For example, east-west oriented concentrator (aligned with the ecliptic plane) does not even need any tracking during core 4-6 hours around noon (when maximum illumination is available). The design and the performance of the prototype, as well as possible economical benefits of full scale projects are discussed in the presentation.

Panin, Alexander; Bergquist, Jonathon

2007-10-01

65

Second-generation parabolic trough solar energy systems optimization analysis  

NASA Astrophysics Data System (ADS)

In the near future high-efficiency, low-cost, parabolic trough collectors will probably become available. The economic feasibility of these parabolic trough solar-energy systems is affected by many parameters which include component cost, load shape, fraction of the load supplied by solar energy, average temperature of the collector field and its axis of rotation, and for solar Rankine cogeneration systems, the electrical-to-thermal energy output ratio. The sensitivity of economic feasibility and system design to changes in these and other relevant parameters is discussed. System design and economics generally were found to be sensitive to component cost. They were also found to be quite sensitive to some of the other parameters in restricted ranges.

Peters, R. R.

1982-04-01

66

Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

SciTech Connect

As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

Stynes, J. K.; Ihas, B.

2012-04-01

67

Irrigation market for solar thermal parabolic dish systems  

NASA Technical Reports Server (NTRS)

The potential size of the onfarm-pumped irrigation market for solar thermal parabolic dish systems in seven high-insolation states is estimated. The study is restricted to the displacement of three specific fuels: gasoline, diesel and natural gas. The model was developed to estimate the optimal number of parabolic dish modules per farm based on the minimum cost mix of conventional and solar thermal energy required to meet irrigation needs. The study concludes that the potential market size for onfarm-pumped irrigation applications ranges from 101,000 modules when a 14 percent real discount rate is assumed to 220,000 modules when the real discount rate drops to 8 percent. Arizona, Kansas, Nebraska, New Mexico and Texas account for 98 percent of the total demand for this application, with the natural gas replacement market accounting for the largest segment (71 percent) of the total market.

Habib-Agahi, H.; Jones, S. C.

1981-01-01

68

Proceedings: Fourth Parabolic Dish Solar Thermal Power Program Review  

NASA Technical Reports Server (NTRS)

The results of activities within the parabolic dish technology and applications development program are presented. Stirling, organic Rankine and Brayton module technologies, associated hardware and test results to date; concentrator development and progress; economic analyses; and international dish development activities are covered. Two panel discussions, concerning industry issues affecting solar thermal dish development and dish technology from a utility/user perspective, are also included.

1983-01-01

69

Solar Parabolic Trough Simulation and Application for a Hybrid Power Plant in Thailand  

Microsoft Academic Search

The purpose of this research project was to develop a software simulation of a solar parabolic trough for use in the design of a solar thermal power plant. In order to determine the optimum size of a parabolic trough to power a solar thermal power plant system in Thailand, a simulation is necessary to determine both long-term operating performance and

Eron Jacobson; Nipon Ketjoy; Sukruedee Nathakaranakule; Wattanapong Rakwichian

2006-01-01

70

Thermal storage requirements for parabolic dish solar power plants  

NASA Technical Reports Server (NTRS)

The cost effectiveness of a high temperature thermal storage system is investigated for a representative parabolic dish solar power plant. The plant supplies electrical power in accordance with a specific, seasonally varying demand profile. The solar power received by the plant is supplemented by power from fuel combustion. The cost of electricity generated by the solar power plant is calculated, using the cost of mass-producible subsystems (specifically, parabolic dishes, receivers, and power conversion units) now being designed for this type of solar plant. The trade-off between fuel and thermal storage is derived in terms of storage effectiveness, the cost of storage devices, and the cost of fuel. Thermal storage requirements, such as storage capacity, storage effectiveness, and storage cost are established based on the cost of fuel and the overall objective of minimizing the cost of the electricity produced by the system. As the cost of fuel increases at a rate faster than general inflation, thermal storage systems in the $40 to $70/kWthr range could become cost effective in the near future.

Wen, L.; Steele, H.

1980-01-01

71

Techno-Economic Study of Solar Parabolic Trough-Biomass Hybrid Power Plant  

Microsoft Academic Search

This paper presents a study of techno-economic feasibility of solar parabolic-biomass technology for power generation in Thailand. The study uses mathematical model technique with Microsoft Excel and Fortran program. The simulation structure divided into two main parts; first technical model as included sub- model solar radiation, parabolic trough, biomass system, power conversion unit and technical performance of overall system. The

Nipon Ketjoy; Wattanapong Rakwichian

72

Numerical Investigation of Energy-Efficient Receiver for Solar Parabolic Trough Concentrator  

Microsoft Academic Search

In this paper, a thermal analysis of an energy-efficient receiver for solar parabolic trough concentrator is presented. Various porous receiver geometries are considered for the performance evaluation of a solar parabolic trough concentrator. Numerical models are proposed for a porous energy-efficient receiver for internal heat gain characteristics and heat loss due to natural convection. The internal flow and heat transfer

K. S. Reddy; K. Ravi Kumar; G. V. Satyanarayana

2008-01-01

73

Fifth parabolic dish solar thermal power program annual review: proceedings  

SciTech Connect

The primary objective of the Review was to present the results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program. The Review consisted of nine technical sessions covering overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development, and associated hardware and test results to date; distributed systems operating experience; international dish development activities; and non-DOE-sponsored domestic dish activities. A panel discussion concerning business views of solar electric generation was held. These Proceedings contain the texts of presentations made at the Review, as submitted by their authors at the beginning of the Review; therefore, they may vary slightly from the actual presentations in the technical sessions.

None

1984-03-01

74

Validation of the FLAGSOL parabolic trough solar power plant performance model  

NASA Astrophysics Data System (ADS)

This paper describes the results of a validation of the FLAGSOL parabolic trough solar power plant performance model. The validation was accomplished by simulating an operating solar electric generating system (SEGS) parabolic trough solar thermal power plant and comparing the model output results with actual plant operating data. This comparison includes instantaneous, daily, and annual total solar thermal electric output, gross solar electric generation, and solar mode parasitic electric consumption. The results indicate that the FLAGSOL model adequately predicts the gross solar electric output of an operating plant, both on a daily and an annual basis.

Price, H. W.; Svoboda, P.; Kearney, D.

1994-10-01

75

Fluid temperature control for parabolic trough solar collectors  

NASA Astrophysics Data System (ADS)

Computer simulation studies of temperature control techniques for the heat transfer fluid in parabolic trough solar collector fields are discussed. In particular, the temperature control requirements associated with thermal electric power generation or cogeneration systems are addressed. Computer models representing the fluid temperature dynamics of the collectors and interconnecting piping were developed and integrated with dynamic models of control elements to obtain a simulation of a closed loop control system. A specific control configuration was chosen consisting of a flow control valve and one or more temperature sensors to control the flow in each row of collectors. Various control algorithms were evaluated for stability and static errors, and time responses to startup transients and to partial and full collector cloud shadowing transients were obtained. The results indicate that the temperature control requirements can be satisfied using readily available components.

Schindwolf, R.

1980-06-01

76

Novel second-stage solar concentrator for parabolic troughs  

NASA Astrophysics Data System (ADS)

Conventional parabolic troughs can be combined with second stage concentrators (SSC), to increase temperature and pressure inside the absorber, making possible the direct production of steam, improving substantially the overall system efficiency and leading to a new generation of distributed solar power plants. To attain this objective, research is needed at the optical, thermodynamic, system control, and engineering levels. In what concerns the receiver of such a system, different practical solutions have been proposed recently and in the past for the geometry of the second stage concentrator: CPC type and others. In this work we discuss these solutions and we propose a new one, 100% efficient in energy collection while reaching a total concentration ratio which is almost 65% of the thermodynamic limit. This SSC has an asymmetric elliptical geometry, rendering possible a smooth solution for the reflectors while maintaining a reasonable size for the receiver.

Collares-Pereira, Manuel; Mendes, Joao F.

1995-08-01

77

Fluid temperature control for parabolic trough solar collectors  

NASA Astrophysics Data System (ADS)

Techniques for controlling the temperature of the heat transfer fluid in parabolic trough solar collectors fields were studied by computer simulation. In particular, the rather stringent temperature control requirements associated with thermal electric power generation or cogeneration systems are addressed. Computer models representing the fluid temperature dynamics of the collectors and interconnecting piping were developed and integrated with dynamic models of control elements to obtain a closed loop control system simulation. A specific control configuration was chosen consisting of a flow control valve and one or more temperature sensors to control the flow in each row of collectors. Various control algorithms were evaluated for stability and static errors, and time responses to startup transients and to partial and full collector cloud shadowing transients were obtained. The results indicated that the temperature control requirements can be satisfied using readily available components.

Schindwoff, R.

1980-05-01

78

A parabolic dish\\/AMTEC solar thermal power system and its performance evaluation  

Microsoft Academic Search

This paper proposes a parabolic dish\\/AMTEC solar thermal power system and evaluates its overall thermalelectric conversion performance. The system is a combined system in which a parabolic dish solar collector is cascaded with an alkali metal thermal to electric converter (AMTEC) through a coupling heat exchanger. A separate type heat-pipe receiver is selected to isothermally transfer the solar energy from

Shuang-Ying Wu; Lan Xiao; Yiding Cao; You-Rong Li

2010-01-01

79

Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers  

SciTech Connect

Solar parabolic trough systems for electricity production are receiving renewed attention, and new solar plants are under construction to help meet the growing demands of the power market in the Western United States. The growing solar trough industry will rely on operating experience it has gained over the last two decades. Recently, researchers found that trough plants that use organic heat transfer fluids (HTF) such as Therminol VP-1 are experiencing significant heat losses in the receiver tubes. The cause has been traced back to the accumulation of excess hydrogen gas in the vacuum annulus that surrounds the steel receiver tube, thus compromising the thermal insulation of the receiver. The hydrogen gas is formed during the thermal decomposition of the organic HTF that circulates inside the receiver loop, and the installation of hydrogen getters inside the annulus has proven to be insufficient for controlling the hydrogen build-up over the lifetime of the receivers. This paper will provide an overview of the chemical literature dealing with the thermal decomposition of diphenyl oxide and biphenyl, the two constituents of Therminol VP-1.

Moens, L.; Blake, D. M.

2008-03-01

80

Gas Turbine\\/Solar Parabolic Trough Hybrid Design Using Molten Salt Heat Transfer Fluid: Preprint  

Microsoft Academic Search

Parabolic trough power plants can provide reliable power by incorporating either thermal energy storage (TES) or backup heat from fossil fuels. This paper describes a gas turbine \\/ parabolic trough hybrid design that combines a solar contribution greater than 50% with gas heat rates that rival those of natural gas combined-cycle plants. Previous work illustrated benefits of integrating gas turbines

C. S. Turchi; Z. Ma

2011-01-01

81

Application of direct steam generation into a solar parabolic trough collector to multieffect distillation  

Microsoft Academic Search

In this paper, the application of the direct steam generation into a solar parabolic trough collector to multieffect distillation is proposed and economically evaluated. The thermal fluid of the solar field is pure water, which boils as circulating along the solar collectors. The steam generated drives a multieffect distillation unit. This solar distillation system is compared with multieffect plants connected

Lourdes Garca-Rodrguez; Ana I. Palmero-Marrero; Carlos Gmez-Camacho

1999-01-01

82

Mechanical development of the actuation system of a parabolic solar trough  

E-print Network

This thesis documents my personal contribution to the engineering and design of an actuation system with the purpose of rotating a parabolic solar trough to track the sun throughout the day. The primary focus of the design ...

O'Rourke, Conor R. (Conor Rakis)

2011-01-01

83

Wind Tunnel Tests of Parabolic Trough Solar Collectors: March 2001--August 2003  

SciTech Connect

Conducted extensive wind-tunnel tests on parabolic trough solar collectors to determine practical wind loads applicable to structural design for stress and deformation, and local component design for concentrator reflectors.

Hosoya, N.; Peterka, J. A.; Gee, R. C.; Kearney, D.

2008-05-01

84

The parabolic trough power plants Andasol 1 to 3 The largest solar power plants in the world  

E-print Network

The parabolic trough power plants Andasol 1 to 3 The largest solar power plants in the world and solar-thermal power plants The first parabolic trough power plants in Europe the world's largest solar power plants: Andasol 1 to 3 Regulatory framework in Spain Project partners 4 8 20 22 #12;4 Solar energy

Laughlin, Robert B.

85

Development of a solar-flux tracker for parabolic-trough collectors  

Microsoft Academic Search

The development of a solar flux tracker for application to a parabolic trough solar thermal collector is described. Tests were conducted at the Collector Module Test Facility and Performance Prototype Trough Test Facility on a resistance wire type solar flux sensor. The device consists of two fine wires installed along each side of the absorber tube parallel to the axis.

K. D. Boultinghouse

1982-01-01

86

Reducing the Cost of Energy from Parabolic Trough Solar Power Plants: Preprint  

Microsoft Academic Search

Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. However, no new plants have been built during the past ten years because the cost of power from these plants is more expensive than power

H. Price; D. Kearney

2003-01-01

87

Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

SciTech Connect

The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of the reflection of the absorber finds the reflector slope errors from the reflection of the absorber and an independent measurement of the absorber location. The accuracy of the reflector slope error measurement is thus dependent on the accuracy of the absorber location measurement. By measuring the combined reflector-absorber errors, the uncertainty in the absorber location measurement is eliminated. The related performance merit, the intercept factor, depends on the combined effects of the absorber alignment and reflector slope errors. Measuring the combined effect provides a simpler measurement and a more accurate input to the intercept factor estimate. The minimal equipment and setup required for this measurement technique make it ideal for field measurements.

Stynes, J. K.; Ihas, B.

2012-04-01

88

Comparison of flat plate and cylindrical parabolic focusing solar energy collectors for Oak Ridge (Part 2)  

Microsoft Academic Search

The performance of three solar energy collectors (flat plate-..cap alpha.. = epsilon = 0.98, parabolic focusing--..cap alpha.. = epsilon = 0.98, and flat plate with a selective surface--..cap alpha..\\/epsilon = 10.9) was investigated under Oak Ridge sky conditions at working fluid temperatures above 200F. The optimum orientation of the noncircular receiver on the parabolic focusing collector was found to be

H. A. Klemm; H. F. Quarls; A. P. Cohen

1974-01-01

89

EUROTROUGH - Parabolic Trough Collector Developed for Cost Efficient Solar Power Generation  

Microsoft Academic Search

e CIEMAT Plataforma Solar, Apartado 22, E-04200 Tabernas (Almera), Spain f DLR Plataforma Solar, Apartado 39, E-04200 Tabernas (Almera), Spain Abstract - The high-performance EuroTrough parabolic trough collector models ET100 and ET150 have been developed for the utility scale generation of solar steam for process heat applications and solar power generation. With corresponding receiver tubes they can be used in

Michael Geyer; Rafael Osuna; Antonio Esteban; Wolfgang Schiel; Axel Schweitzer; Eduardo Zarza; Paul Nava; Josef Langenkamp; Eli Mandelberg

90

Design parameter selection for a distillation system coupled to a solar parabolic trough collector  

Microsoft Academic Search

In this paper a seawater multi-stage flash and a multi-effect distillation system, coupled to a solar parabolic trough collector (PTC) field, are considered. The influence on distilled water production of the main operation and design parameters was studied by thermodynamic analysis. The parameters analyzed define the solar field, the thermal storage and the desalination plant. Firstly, the orientation of the

L. Garca-Rodrguez; C. Gmez-Camacho

1999-01-01

91

Survey Cycle of Linear Parabolic Solar Power Plant; Design & Control of Collectors Efficiency  

Microsoft Academic Search

With taking into special consideration the importance of the competition which exists in the world to utilize new energies; and also in agreement with our country from the viewpoint of superficies and duration of solar radiation, it is necessary to use such energy as much as possible. Therefore, in this article, Shiraz linear parabolic solar power plant has been used

H. Moaveni

2006-01-01

92

Survey Cycle of Linear Parabolic Solar Power Plant; Design & Control of Collectors Efficiency  

Microsoft Academic Search

With taking into special consideration the importance of the competition which exists in the world to utilize new energies; and also in agreement with our country from the viewpoint of superficies and duration of solar radiation, it is necessary to use such energy as much as possible. Therefore, in this article, Shiraz Linear Parabolic Solar Power Plant has been used

Houtan Moaveni

2007-01-01

93

Experimental studies on non-parabolic asymmetrical solar concentrators with evacuated receivers  

Microsoft Academic Search

Asymmetrical solar concentrators may offer significant advantages over symmetrical ones by the higher yearly average energy input per unit aperture area and the wider range of flexibilities in the design and operation. This paper describes the design, construction and performance evaluation of a non-parabolic asymmetrical solar concentrator with an evacuated receiver. The concentrator has a concentration ratio of 3.25 and

S. K. Chan; C. T. Leung; Y. B. Ng

1983-01-01

94

Numerical simulation of parabolic trough solar collector: Improvement using counter flow concentric circular heat exchangers  

Microsoft Academic Search

Detailed numerical simulations of thermal and fluid-dynamic behavior of a single-pass and double-pass solar parabolic trough collector are carried out. The governing equations inside the receiver tube, together with the energy equation in the tube walls and cover wall and the thermal analysis in the solar concentrator were solved iteratively in a segregated manner. The single-pass solar device numerical model

O. Garca-Valladares; N. Velzquez

2009-01-01

95

Experimental investigation on a parabolic trough solar collector for thermal power generation  

Microsoft Academic Search

Developing solar thermal power technology in an effective manner is a great challenge in China. In this paper an experiment\\u000a platform of a parabolic trough solar collector system (PTCS) was developed for thermal power generation, and the performance\\u000a of the PTCS was experimentally investigated with synthetic oil as the circulate heat transfer fluid (HTF). The solar collectors\\u000a efficiency with the

QiBin Liu; YaLong Wang; ZhiChao Gao; Jun Sui; HongGuang Jin; HePing Li

2010-01-01

96

The 3X Compound Parabolic Concentrating (CPC) solar energy collector  

Microsoft Academic Search

A 3X compounds parabolic concentrating (CPC) collector was designed. The collector is a completely housed, 105.75 x 44.75 x 10.23 inch, 240 pound unit with six each evacuated receiver assemblies, a center manifold and a one piece glass cover. A truncated version of a CPC trough reflector system and the General Electric Company tubular evacuated receiver were integrated with a

R. W. Ballheim

1980-01-01

97

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2013 CFR

...accessible for cleaning. Each cooker shall be equipped with an indicating thermometer, and shall be equipped with a temperature recording device. The recording thermometer stem may be placed in the cooker if satisfactory time charts are...

2013-01-01

98

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2010 CFR

...accessible for cleaning. Each cooker shall be equipped with an indicating thermometer, and shall be equipped with a temperature recording device. The recording thermometer stem may be placed in the cooker if satisfactory time charts are...

2010-01-01

99

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2014 CFR

...accessible for cleaning. Each cooker shall be equipped with an indicating thermometer, and shall be equipped with a temperature recording device. The recording thermometer stem may be placed in the cooker if satisfactory time charts are...

2014-01-01

100

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2012 CFR

...accessible for cleaning. Each cooker shall be equipped with an indicating thermometer, and shall be equipped with a temperature recording device. The recording thermometer stem may be placed in the cooker if satisfactory time charts are...

2012-01-01

101

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2011 CFR

...accessible for cleaning. Each cooker shall be equipped with an indicating thermometer, and shall be equipped with a temperature recording device. The recording thermometer stem may be placed in the cooker if satisfactory time charts are...

2011-01-01

102

A technical note on application of internally finned tubes in solar parabolic trough absorber pipes  

Microsoft Academic Search

The heterogeneous incoming heat flux in solar parabolic trough absorber tubes generates huge temperature difference in each pipe section. Helical internal fins can reduce this effect, homogenising the temperature profile and reducing thermal stress with the drawback of increasing pressure drop. Another effect is the decreasing of the outer surface temperature and thermal losses, improving the thermal efficiency of the

Javier Muoz; Alberto Abnades

2011-01-01

103

Thermal performance and biological evaluation of solar water disinfection systems using parabolic trough collectors  

Microsoft Academic Search

Thermal and optical performance of solar water disinfecting systems using parabolic trough collector, PTC, have been investigated experimentally and numerically. Four PTCs systems were designed, manufactured and field tested under the same weather conditions of Cairo 30N. The four systems were installed to be compared thermally and biologically. Each system consists of a 2-m PTC and line-focus pipe to carry

A. M. Abdel Dayem; H. H. El-Ghetany; G. E. El-Taweel; M. M. Kamel

2011-01-01

104

Study of a new solar adsorption refrigerator powered by a parabolic trough collector  

Microsoft Academic Search

This paper presents the study of solar adsorption cooling machine, where the reactor is heated by a parabolic trough collector (PTC) and is coupled with a heat pipe (HP). This reactor contains a porous medium constituted of activated carbon, reacting by adsorption with ammonia.We have developed a model, based on the equilibrium equations of the refrigerant, adsorption isotherms, heat and

A. El Fadar; A. Mimet; A. Azzabakh; M. Prez-Garca; J. Castaing

2009-01-01

105

Thermal performance analysis of a novel compound parabolic concentrator solar collector  

Microsoft Academic Search

The heat transfer mechanism of compound parabolic concentrator (CPC) evacuated tubular solar collector is analyzed. And its performance prediction model is developed. Through the comparison We conclude that the collector without glass cover gets a better thermal efficiency than that of the collector with glass cover under the same radiation intensity, when the operating temperature is low. And the collector

Hong-yu Gao; Hui-tao Wang; Hua Wang

2011-01-01

106

Using air flow to alleviate temperature elevation in solar cells within asymmetric compound parabolic concentrators  

Microsoft Academic Search

Air filled asymmetric compound parabolic photovoltaic concentrators (ACPPVC) have been studied using a comprehensive validated unified model for optics and heat transfer in line-axis solar energy systems. The heat transfer that occurs within the cavity of a single concentrator, multiple concentrators, the space between adjacent concentrators and in an air duct behind the photovoltaics was simulated and is presented. For

Tapas K. Mallick; Philip C. Eames; Brian Norton

2007-01-01

107

Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver  

Microsoft Academic Search

This report describes the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver. The model determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element. All heat transfer and thermodynamic equations, optical properties, and parameters used in the model are discussed. The modeling assumptions and limitations are also

R. Forristall

2003-01-01

108

TECHNICAL CONCEPT AND SOME POSSIBLE APPLICATIONS FOR HIGH-TEMPERATURE PARABOLIC BLIND-REFLECTING SOLAR CONCENTRATORS  

Microsoft Academic Search

There is a steady prejudice that the mirrors reflecting the light flux towards the source are necessary when the maximum possible one-stage concentration of solar radiation is required. The well-known parabolic dish collector is a most effective optical system among such mirrors. An alternative approach for creating the better-concentrating solar collectors is proposed and discussed in this paper. The optical

VIKTOR VASYLYEV

109

Side-by-side comparisons of evacuated compound parabolic concentrator and flat plate solar collector systems  

Microsoft Academic Search

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: a flat plate collector with a black-chrome coated absorber plate and one low-iron glass cover; an evacuated-tube compound parabolic concentrator (CPC) with a concentration ratio of 1.1, oriented with tubes and

A. E. McGarity; J. W. Allen; W. W. Schertz

1983-01-01

110

Study of Solar Radiation Factor for the Parabolic Trough Solar Thermal Power Plant in Typical Chinese Sites  

Microsoft Academic Search

This paper studied the effect radiation of the parabolic trough concentrator thoroughly, and it was revealed that Incident Direct Insolation (IDR) should be used to evaluate the solar resource for locating a PTSTP plant, instead of Direct Normal Insolation (DNI), for it takes latitude into consideration. Lhasa, with latitude of 29.43, and Naiman, with latitude of 43.47, were studied respectively,

Hang Qu; Xiao Yu; Qinglai Fan; Jun Zhao

2011-01-01

111

Modeling of a Parabolic Trough Solar Field for Acceptance Testing: A Case Study  

SciTech Connect

As deployment of parabolic trough concentrating solar power (CSP) systems ramps up, the need for reliable and robust performance acceptance test guidelines for the solar field is also amplified. Project owners and/or EPC contractors often require extensive solar field performance testing as part of the plant commissioning process in order to ensure that actual solar field performance satisfies both technical specifications and performance guaranties between the involved parties. Performance test code work is currently underway at the National Renewable Energy Laboratory (NREL) in collaboration with the SolarPACES Task-I activity, and within the ASME PTC-52 committee. One important aspect of acceptance testing is the selection of a robust technology performance model. NREL1 has developed a detailed parabolic trough performance model within the SAM software tool. This model is capable of predicting solar field, sub-system, and component performance. It has further been modified for this work to support calculation at subhourly time steps. This paper presents the methodology and results of a case study comparing actual performance data for a parabolic trough solar field to the predicted results using the modified SAM trough model. Due to data limitations, the methodology is applied to a single collector loop, though it applies to larger subfields and entire solar fields. Special consideration is provided for the model formulation, improvements to the model formulation based on comparison with the collected data, and uncertainty associated with the measured data. Additionally, this paper identifies modeling considerations that are of particular importance in the solar field acceptance testing process and uses the model to provide preliminary recommendations regarding acceptable steady-state testing conditions at the single-loop level.

Wagner, M. J.; Mehos, M. S.; Kearney, D. W.; McMahan, A. C.

2011-01-01

112

A Linear Parabolic Trough Solar Collector Performance Model  

E-print Network

Collector (PTSC). This steady state, single dimensional model comprises the fundamental radiative and convective heat transfer and mass and energy balance relations programmed in the Engineering Equation Solver, EES. It considers the effects of solar...

Qu, M.; Archer, D.; Masson, S.

2006-01-01

113

Gas Turbine/Solar Parabolic Trough Hybrid Design Using Molten Salt Heat Transfer Fluid: Preprint  

SciTech Connect

Parabolic trough power plants can provide reliable power by incorporating either thermal energy storage (TES) or backup heat from fossil fuels. This paper describes a gas turbine / parabolic trough hybrid design that combines a solar contribution greater than 50% with gas heat rates that rival those of natural gas combined-cycle plants. Previous work illustrated benefits of integrating gas turbines with conventional oil heat-transfer-fluid (HTF) troughs running at 390?C. This work extends that analysis to examine the integration of gas turbines with salt-HTF troughs running at 450 degrees C and including TES. Using gas turbine waste heat to supplement the TES system provides greater operating flexibility while enhancing the efficiency of gas utilization. The analysis indicates that the hybrid plant design produces solar-derived electricity and gas-derived electricity at lower cost than either system operating alone.

Turchi, C. S.; Ma, Z.

2011-08-01

114

The 3X Compound Parabolic Concentrating (CPC) solar energy collector  

NASA Astrophysics Data System (ADS)

A 3X compounds parabolic concentrating (CPC) collector was designed. The collector is a completely housed, 105.75 x 44.75 x 10.23 inch, 240 pound unit with six each evacuated receiver assemblies, a center manifold and a one piece glass cover. A truncated version of a CPC trough reflector system and the General Electric Company tubular evacuated receiver were integrated with a mass producible collector design suitable for operation at 250 to 450 F. The key criterion for optimization of the design was minimization of the cost per Btu collected annually at an operating temperature of 400 F. The reflector is a 4.1X design truncated to a total height of 8.0 inches with a resulting actual concentration ratio of 2.6 to 1. The manifold is an insulated area housing the fluid lines which connect the six receivers in series with inlet and outlet tubes extending from one side of the collector at the center.

Ballheim, R. W.

1980-04-01

115

Life cycle cost analysis of new FRP based solar parabolic trough collector hot water generation system  

Microsoft Academic Search

Parabolic trough collectors (PTCs) are employed for a variety of applications including steam generation and hot water generation.\\u000a This paper deals with the experimental results and an economic analysis of a new fibre reinforced plastic (FRP) based solar\\u000a PTC with an embedded electronic controlled tracking system designed and developed for hot water generation in a restaurant\\u000a in Madurai, India. The

A. Valan Arasu; T. Sornakumar

2008-01-01

116

Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver  

SciTech Connect

This report describes the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver. The model determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element. All heat transfer and thermodynamic equations, optical properties, and parameters used in the model are discussed. The modeling assumptions and limitations are also discussed, along with recommendations for model improvement.

Forristall, R.

2003-10-01

117

Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish  

SciTech Connect

The concept of solar driven chemical reactions in a commercial-scale volumetric receiver/reactor on a parabolic concentrator was successfully demonstrated in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) test. Solar reforming of methane (CH{sub 4}) with carbon dioxide (CO{sub 2}) was achieved in a 64-cm diameter direct absorption reactor on a parabolic dish capable of 150 kW solar power. The reactor was a catalytic volumetric absorber consisting of a multi-layered, porous alumina foam disk coated with rhodium (Rh) catalyst. The system was operated during both steady-state and solar transient (cloud passage) conditions. The total solar power absorbed reached values up to 97 kW and the maximum methane conversion was 70%. Receiver thermal efficiencies ranged up to 85% and chemical efficiencies peaked at 54%. The absorber performed satisfactorily in promoting the reforming reaction during the tests without carbon formation. However, problems of cracking and degradation of the porous matrix, nonuniform dispersion of the Rh through the absorber, and catalyst deactivation due to sintering and possible encapsulation, must be resolved to achieve long-term operation and eventual commercialization. 17 refs., 11 figs., 1 tab.

Muir, J.F.; Hogan, R.E. Jr.; Skocypec, R.D. (Sandia National Labs., Albuquerque, NM (USA)); Buck, R. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Stuttgart (Germany, F.R.). Inst. fuer Technische Thermodynamik)

1990-01-01

118

Concentrating Solar Power, Seawater Desalination, Parabolic Troughs, Fresnel Systems  

Microsoft Academic Search

Today's conflicts on oil are tomorrow's conflicts on water has become a popular issue to describe the enduring water and energy crisis, although solution for both energy and water shortage seems to be on hand: Making power and water from sun and sea. Concentrating solar power (CSP) offers a sustainable alternative to fossil fuels for large scale seawater desalination. CSP

V. K. SethiE; Mukesh Pandey; Priti Shukla; R. G. P. V. Bhopal

2012-01-01

119

Performance test of a non-parabolic asymmetrical solar concentrator  

Microsoft Academic Search

This paper reviews the geometrical optics for constructing the reflector of a nonparabolic asymmetrical solar concentrator. A prototype concentrator of this kind has been constructed with a concentration ratio of 4.07 and a theoretical optical efficiency of 0.67. Standard performance tests on such a concentrator indicate a heat loss coefficient relative to the collector aperture area of 4.35 and a

C. T. Leung; Y. B. Ng

1980-01-01

120

Thermal buffering of receivers for parabolic dish solar thermal power plants  

NASA Technical Reports Server (NTRS)

A parabolic dish solar thermal power plant comprises a field of parabolic dish power modules where each module is composed of a two-axis tracking parabolic dish concentrator which reflects sunlight (insolation) into the aperture of a cavity receiver at the focal point of the dish. The heat generated by the solar flux entering the receiver is removed by a heat transfer fluid. In the dish power module, this heat is used to drive a small heat engine/generator assembly which is directly connected to the cavity receiver at the focal point. A computer analysis is performed to assess the thermal buffering characteristics of receivers containing sensible and latent heat thermal energy storage. Parametric variations of the thermal inertia of the integrated receiver-buffer storage systems coupled with different fluid flow rate control strategies are carried out to delineate the effect of buffer storage, the transient response of the receiver-storage systems and corresponding fluid outlet temperature. It is concluded that addition of phase change buffer storage will substantially improve system operational characteristics during periods of rapidly fluctuating insolation due to cloud passage.

Manvi, R.; Fujita, T.; Gajanana, B. C.; Marcus, C. J.

1980-01-01

121

Optimization of spherical facets for parabolic solar concentrators  

NASA Technical Reports Server (NTRS)

Solar concentrator designs which employ deployable hexagonal panels are being developed for space power systems. An offset optical configuration has been developed which offers significant system level advantages over previously proposed collector designs for space applications. Optical analyses have been performed which show offset reflector intercept factors to be only slightly lower than those for symmetric reflectors with the same slope error. Fluxes on the receiver walls are asymmetric but manageable by varying the tilt angle of the receiver. Greater producibility is achieved by subdividing the hexagonal panels into triangular mirror facets of spherical contour. Optical analysis has been performed upon these to yield near-optimum sizes and radii.

White, J. E.; Erikson, R. J.; Sturgis, J. D.; Elfe, T. B.

1986-01-01

122

Use of parabolic trough solar collectors for building air conditioning and domestic hot water production - case study  

Microsoft Academic Search

The aim of this study is the evaluation of the economic and technical viability for the installation of a solar air conditioning system based on parabolic solar concentrators and adsorption technology, in an existent building. As case study was selected a university canteen located in the centre region of Portugal. Besides air conditioning, this system is also used for domestic

E. S. Quintal; H. S. Bernardo; P. G. Amaral; L. P. Neves

2011-01-01

123

Sensitivity analysis on the effect of key parameters on the performance of parabolic trough solar collectors  

NASA Astrophysics Data System (ADS)

Solar troughs are amongst the most commonly used technologies for collecting solar thermal energy and any attempt to increase the performance of these systems is welcomed. In the present study a parabolic solar trough is simulated using a one dimensional finite element model in which the energy balances for the fluid, the absorber and the envelope in each element are performed. The developed model is then validated using the available experimental data . A sensitivity analysis is performed in the next step in order to study the effect of changing the type of the working fluid and the corresponding Reynolds number on the overall performance of the system. The potential improvement due to the addition of a shield on the upper half of the annulus and enhancing the convection coefficient of the heat transfer fluid is also studied.

Muhlen, Luis S. W.; Najafi, Behzad; Rinaldi, Fabio; Marchesi, Renzo

2014-04-01

124

Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems  

NASA Technical Reports Server (NTRS)

This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

Ramakumar, R.; Bahrami, K.

1981-01-01

125

An optimized model and test of the China's first high temperature parabolic trough solar receiver  

SciTech Connect

The vacuum solar receiver is the key component of a parabolic trough solar plant, which plays a prominent role in the gross system efficiency. Recently, China's first high temperature vacuum receiver, Sanle-3 HCE, has been developed and produced by Southeast University and Sanle Electronic Group. Before being utilized in China's first parabolic trough solar plant, accurately estimating the thermal properties of this new receiver is important. This paper first establishes and optimizes a 1-D theoretical model at Matlab program to compute the receiver's major heat loss through glass envelope, and then systematically analyzes the major influence factors of heat loss. With the laboratorial steady state test stand, the heat losses of both good vacuum and non-vacuum Sanle-3 receivers were surveyed. Comparison shows the original 1-D model agrees with the ends covered test while remarkably deviating from end exposed test. For the purpose of identifying the influence of receiver's end to total heat loss, an additional 3-D model is built by CFD software to further investigate the different heat transfer processes of receiver's end components. The 3-D end model is verified by heating power and IR temperature distribution images in the test. Combining the optimized 1-D model with the new 3-D end model, the comparison with test data shows a good accordance. At the same time the heat loss curve and emittance curve of this new receiver are given and compared with those of several other existing receivers as references. (author)

Gong, Guangjie; Huang, Xinyan; Wang, Jun; Hao, Menglong [Southeast University, Nanjing (China)

2010-12-15

126

Freeform lens design to achieve 1000X solar concentration with a parabolic trough reflector  

NASA Astrophysics Data System (ADS)

Line-focus parabolic trough mirrors for solar thermal generation cannot produce the high concentration required for concentrating photovoltaic (CPV) systems. We describe a freeform lens array with toroidal symmetry which intercepts the low-concentration line focus to produce a series of elongated, high-concentration foci. The design employs 2D K?hler illumination to improve the acceptance angle in one direction. The two-stage concentrator has 1000X average geometric concentration with an acceptance angle of +/-1.49 in the azimuthal direction and +/-0.29 in the elevation direction. Preliminary results of a prototype roll-forming process are shown in thermoplastics and B270 glass.

Wheelwright, Brian M.; Angel, Roger; Coughenour, Blake

2014-12-01

127

Test results on parabolic dish concentrators for solar thermal power systems  

NASA Technical Reports Server (NTRS)

This paper presents results of development testing of various solar thermal parabolic dish concentrators. The concentrators were mostly designed for the production of electric power using dish-mounted Rankine, Brayton or Stirling cycle engines, intended to be produced at low cost. Measured performance for various dishes included optical efficiencies ranging from 0.32 to 0.86 at a geometric concentration ratio of 500, and from about 0.09 to 0.85 at a geometric concentration ratio of 3000. Some malfunctions were observed. The tests should provide operating information of value in developing concentrators with improved performance and reduced maintenance.

Jaffe, Leonard D.

1989-01-01

128

Experimental results of pitching moment tests on parabolic-trough solar-collector array configurations  

NASA Astrophysics Data System (ADS)

Two wind-tunnel tests were conducted to investigate specifically the pitching moment characteristics of parabolic-trough solar-collector modules deployed within a collector array. The collector modules were located within various rows of a simulated array configuration to investigate shielding effects from upstream collector rows and/or wind-screen fences. Selected fence configurations and fence spacing upstream from the initial array row were studied. The test results demonstrate that pitching moment is significantly reduced by sheilding provided by upstream fencing or collector rows.

Randall, D. E.; Tate, R. E.; Powers, D. A.

1982-12-01

129

Development, solar test, and evaluation of a high-temperature air receiver for point-focusing parabolic dish applications  

Microsoft Academic Search

A high temperature solar receiver was fabricated and tested in excess of 1370 C on an 11-meter-diameter test bed concentrator at the Jet Propulsion Laboratory Parabolic Dish Test Site, Edwards, California. The 60-kilowatt thermal receiver design utilizes state-of-the-art silicon carbide honeycomb matrix panels to receive and transfer the solar energy and mullite elements for thermal buffer storage. Solar tests were

E. J. Hanseth

1981-01-01

130

Cleaning strategies for parabolic-trough solar-collector fields; guidelines for decisions  

SciTech Connect

This report is intended to assist the owner or operator of a parabolic trough solar collector system to decide on a cleaning strategy (equipment, materials, procedures, and schedules). The guidelines are based on information obtained in past research studies, as well as interviews with vendors and users of cleaning and water treatment equipment. The basic procedure recommended utilizes high pressure portable washing equipment. However, since the cleaning problem is so site-specific, no single, detailed approach can be specified. A systematic procedure for evaluating the particular requirements of a site is therefore given. This will allow the solar energy system operator to develop a cleaning strategy which is cost-effective because it is suited to local conditions.

Bergeron, K.D.; Freese, J.M.

1981-06-01

131

Prediction and optimization of the performance of parabolic solar dish concentrator with sphere receiver using analytical function  

E-print Network

Parabolic solar dish concentrator with sphere receiver is less studied. We present an analytic function to calculate the intercept factor of the system with real sun bright distribution and Gaussian distribution, the results indicate that the intercept factor is related to the rim angle of reflector and the ratio of open angle of receiver at the top of reflector to optical error when the optical error is larger than or equal to 5 mrad, but is related to the rim angle, open angle and optical error in less than 5 mrad optical error. Furthermore we propose a quick process to optimize the system to provide the maximum solar energy to net heat efficiency for different optical error under typical condition. The results indicate that the parabolic solar dish concentrator with sphere receiver has rather high solar energy to net heat efficiency which is 20% more than solar trough and tower system including higher cosine factor and lower heat loss of the receiver.

Huang, Weidong; Hu, Peng; Chen, Zeshao

2011-01-01

132

Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors  

Microsoft Academic Search

Usual size of parabolic trough solar thermal plants being built at present is approximately 50 MW{sub e}. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice.

M. J. Montes; A. Abanades; J. M. Martinez-Val; M. Valdes

2009-01-01

133

Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors  

Microsoft Academic Search

Usual size of parabolic trough solar thermal plants being built at present is approximately 50MWe. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice. A too

M. J. Montes; A. Abnades; J. M. Martnez-Val; M. Valds

2009-01-01

134

Performance model for parabolic trough solar thermal power plants with thermal storage: Comparison to operating plant data  

Microsoft Academic Search

This paper describes a simulation model that reproduces the performance of parabolic trough solar thermal power plants with a thermal storage system. The aim of this model is to facilitate the prediction of the electricity output of these plants during the various stages of their planning, design, construction and operation. Model results for a 50MWe power plant are presented and

Isabel Llorente Garca; Jos Luis lvarez; Daniel Blanco

2011-01-01

135

Life Cycle Assessment of a Parabolic Trough Concentrating Solar Power Plant and Impacts of Key Design Alternatives: Preprint  

Microsoft Academic Search

Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, California, along four sustainability metrics: life cycle greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback

G. A. Heath; J. J. Burkhardt; C. S. Turchi

2011-01-01

136

Summary assessment of solar thermal parabolic dish technology for electrical power generation  

NASA Technical Reports Server (NTRS)

An assessment is provided of solar thermal parabolic dish technology for electrical power generation. The assessment is based on the development program undertaken by the Jet Propulsion Laboratory for the U.S. Department of Energy and covers the period from the initiation of the program in 1976 through mid-1984. The program was founded on developing components and subsystems that are integrated into parabolic dish power modules for test and evaluation. The status of the project is summarized in terms of results obtained through testing of modules, and the implications of these findings are assessed in terms of techno-economic projections and market potential. The techno-economic projections are based on continuation of an evolutionary technological development program and are related to the accomplishments of the program as of mid-1984. The accomplishments of the development effort are summarized for each major subsystem including concentrators, receivers, and engines. The ramifications of these accomplishments are assessed in the context of developmental objectives and strategies.

Penda, P. L.; Fujita, T.; Lucas, J. W.

1985-01-01

137

Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator  

NASA Astrophysics Data System (ADS)

In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.

Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.

2013-07-01

138

Utility-Scale Parabolic Trough Solar Systems: Performance Acceptance Test Guidelines, April 2009 - December 2010  

SciTech Connect

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The Guidelines contained here are specifically written for parabolic trough collector systems with a heat-transport system using a high-temperature synthetic oil, but the basic principles are relevant to other CSP systems.

Kearney, D.

2011-05-01

139

An overview of the value of parabolic dish solar thermal systems in industrial cogeneration applications  

NASA Technical Reports Server (NTRS)

The essential elements of the cogeneration system configuration to be captured were the displacement of thermal energy by collection and use of the Brayton exhaust stream, and the sale back to the utility of any electricity production in excess of on-site requirements. In contrast to simply dumping these energy flows, their use or sale obviously serves, by itself, to increase gross value of the solar thermal energy system. Net allowable cost of the parabolic dish modules may or may not be increased, however. A consideration is that the waste heat capture and delivery subsystems are not free. This study does not address the incremental cost of adding waste heat capture, transport, and conversion (to steam, if necessary). It does compute a value for the thermal energy thereby displaced. This value can serve as a first-round input to any detailed economic evaluation of waste heat recovery.

1982-01-01

140

Comparison of electrochemical and thermal storage for hybrid parabolic dish solar power plants  

NASA Technical Reports Server (NTRS)

The economic and operating performance of a parabolic point focus array of solar electricity generators combined with either battery or thermal energy storage are examined. Noting that low-cost, mass-producible power generating units are under development for the point focus of distributed dishes, that Zn-Cl battery tests will begin in 1981 and a 100 kWh Na-S battery in 1983, the state of thermal storage requires acceleration to reach the prototype status of the batteries. Under the assumptions of 10,000 units/yr with an expected 30 yr lifetime, cost comparisons are developed for 10 types of advanced batteries. A 5 MWe plant with full thermal or 80% battery storage discharge when demand occurs in conditions of no insolation is considered, specifically for Fe-Cr redox batteries. A necessity for the doubling of fuel prices from 1980 levels by 1990 is found in order to make the systems with batteries economically competitive.

Steele, H. L.; Wen, L.

1981-01-01

141

Development of Performance Acceptance Test Guidelines for Large Commercial Parabolic Trough Solar Fields: Preprint  

SciTech Connect

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the EPC contractor or owners. In lieu of the present absence of engineering code developed for this purpose, NREL has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. The fundamental differences between acceptance of a solar power plant and a conventional fossil-fired plant are the transient nature of the energy source and the necessity to utilize an analytical performance model in the acceptance process. These factors bring into play the need to establish methods to measure steady state performance, potential impacts of transient processes, comparison to performance model results, and the possible requirement to test, or model, multi-day performance within the scope of the acceptance test procedure. The power block and BOP are not within the boundaries of this guideline. The current guideline is restricted to the solar thermal performance of parabolic trough systems and has been critiqued by a broad range of stakeholders in CSP development and technology.

Kearney, D.; Mehos, M.

2010-12-01

142

Vanguard I solar parabolic dish-Stirling engine module. Final report, May 28, 1982-September 30, 1984  

SciTech Connect

Advanco Corporation and the US Department of Energy entered into a cooperative agreement in May 1982 for the design, manufacture, and test of a 25-kWe solar parabolic dish module utilizing a Stirling engine power conversion unit. The product of the cooperative agreement is the Vanguard solar parabolic dish-Stirling engine module. It was designed, fabricated, and shop assembled in Los Angeles, California, and Malmoe, Sweden, and was then installed and tested at Rancho Mirage, California, in accordance with the agreement's specifications. The design features simple fabrication and assembly techniques, low cost, and high operating efficiency. The cover displays the Vanguard module operating on-sun. The concept combines the United Stirling AB (USAB) 4-95 Solar II Stirling engine, the Jet Propulsion Laboratory (JPL) developed mirror facets, the Rockwell/Advanco exocentric gimbal mechanism (EGM), the advanced USAB receiver, and a dry, integrated heat rejection system.

Washom, B.J.

1984-09-30

143

Solar multiple optimization for a solar-only thermal power plant, using oil as heat transfer fluid in the parabolic trough collectors  

SciTech Connect

Usual size of parabolic trough solar thermal plants being built at present is approximately 50 MW{sub e}. Most of these plants do not have a thermal storage system for maintaining the power block performance at nominal conditions during long non-insolation periods. Because of that, a proper solar field size, with respect to the electric nominal power, is a fundamental choice. A too large field will be partially useless under high solar irradiance values whereas a small field will mainly make the power block to work at part-load conditions. This paper presents an economic optimization of the solar multiple for a solar-only parabolic trough plant, using neither hybridization nor thermal storage. Five parabolic trough plants have been considered, with the same parameters in the power block but different solar field sizes. Thermal performance for each solar power plant has been featured, both at nominal and part-load conditions. This characterization has been applied to perform a simulation in order to calculate the annual electricity produced by each of these plants. Once annual electric energy generation is known, levelized cost of energy (LCOE) for each plant is calculated, yielding a minimum LCOE value for a certain solar multiple value within the range considered. (author)

Montes, M.J. [E.T.S.I.Industriales - U.N.E.D., C/Juan del Rosal, 12, 28040 Madrid (Spain); Abanades, A.; Martinez-Val, J.M.; Valdes, M. [E.T.S.I.Industriales - U.P.M., C/Jose Gutierrez Abascal, 2, 28006 Madrid (Spain)

2009-12-15

144

An Optical Characterization Technique for Parabolic Trough Solar Collectors Using Images of the Absorber Reflection  

NASA Astrophysics Data System (ADS)

As the concentrating solar power industry competes to develop a less-expensive parabolic trough collector, assurance is needed that new parabolic trough collectors maintain accurate optical alignment. Previous optical characterization techniques are either too slow, ill-suited for field testing, or do not allow the collector to be tested in realistic orientations. The Observer method presented here enables the rapid optical characterization of parabolic trough collectors in any orientation in the field. The Observer method directly measures the combined optical angular errors in the reflector surface shape and the absorber position, which can be separated into its two components: reflector surface slope and absorber misalignment. The data acquisition requires the placement of photogrammetry targets on and around the collector. Multiple photographs of the absorber and its reflection are taken with a digital camera from different angles with respect to the collector. The images are processed to determine the camera location of each image using photogrammetry bundle analysis. The absorber and its reflection are found in the photographs using image-processing techniques. A Monte Carlo uncertainty model was developed to determine the uncertainty in the Observer measurements. The uncertainty was estimated for a wide array of measurement test scenarios to demonstrate the user's control over the measurement uncertainty. To validate the Observer method, the absorber alignment technique was compared to traditional photogrammetry; the absorber position measured with the two methods compared with a root-mean-square difference of 1.5 mm in the transverse direction and 0.86 mm along the optical axis. The reflector surface slope error measurement was compared to both VSHOT and SOFAST, two well-established optical characterization tools, by measuring a single reflector panel in the laboratory. The VSHOT and SOFAST measurements agreed with the Observer with a root-mean-square difference of 1.6 mrad and 2.1 mrad, respectively. In the field, the Observer method's capability to test collectors in any orientation was demonstrated by mounting the camera on a radio-controlled helicopter and measuring a collector oriented at 90 above the horizon. The absorber measurement capability was demonstrated in the field for a collector facing both horizontally and vertically.

Owkes, Jeanmarie Kathleen

145

The small community solar thermal power experiment. Parabolic dish technology for industrial process heat application  

NASA Technical Reports Server (NTRS)

Aspects of incorporating a thermal energy transport system (ETS) into a field of parabolic dish collectors for industrial process heat (IPH) applications were investigated. Specific objectives are to: (1) verify the mathematical optimization of pipe diameters and insulation thicknesses calculated by a computer code; (2) verify the cost model for pipe network costs using conventional pipe network construction; (3) develop a design and the associated production costs for incorporating risers and downcomers on a low cost concentrator (LCC); (4) investigate the cost reduction of using unconventional pipe construction technology. The pipe network design and costs for a particular IPH application, specifically solar thermally enhanced oil recovery (STEOR) are analyzed. The application involves the hybrid operation of a solar powered steam generator in conjunction with a steam generator using fossil fuels to generate STEOR steam for wells. It is concluded that the STEOR application provides a baseline pipe network geometry used for optimization studies of pipe diameter and insulation thickness, and for development of comparative cost data, and operating parameters for the design of riser/downcomer modifications to the low cost concentrator.

Polzien, R. E.; Rodriguez, D.

1981-01-01

146

Numerical Modeling of Year-Round Performance of a Solar Parabolic Dish Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

This paper presents the year-round performance of a solar parabolic dish thermoelectric generator under different values of operating parameters such as ambient temperature, wind velocity, direct normal irradiation, and water inlet temperature to the heat sink. The solar thermoelectric generator (TEG) is examined for an Indian location of Tiruchirappalli. The electrical power output and TEG efficiency are maximum during the months of April and August, while they are minimum during the month of December. It is found that the monthly average hot-side temperature of the TEG varies from 556.53 K to 592.68 K and the cold-side temperature of the TEG varies from 413.21 K to 438.91 K. When the hot-side temperature reaches the optimum value, the conversion efficiency is reduced, although the power increases. A TEG model is useful to find the temperature of the junctions for different operating parameter values and predict the performance of the TEG at any time. A small standalone power-generating system using this technology is a promising option.

Muthu, G.; Shanmugam, S.; Veerappan, AR.

2015-03-01

147

Charcoal-methanol adsorption refrigerator powered by a compound parabolic concentrating solar collector  

SciTech Connect

A compound parabolic concentrating solar collector (CPC) of concentration ratio 3.9 and aperture area 2.0 m[sup 2] was used to power an intermittent solid adsorption refrigerator and ice maker using activated charcoal (carbon) as the adsorbing medium and methanol as the working fluid. The copper tube receiver of the CPC was packed with 2.5 kg of imported adsorbent 207E3, which was only utilized when the performance of activated charcoal (ACJ1, produced from local coconut shells) was found to be inferior to the imported adsorbent. Up to 1 kg of ice at an evaporator temperature of [minus]6[degrees]C was produced, with the net solar coefficient of performance (COP) being of the order of 0.02. Maximum receiver/adsorbent temperature recorded was 154[degrees]C on a day when the insolation was 26.8 MJ/m[sup [minus]2]. Temperatures in excess of 150[degrees]C are undesirable since they favour the conversion of methanol to dimethyl ether, a noncondensable gas which inhibits both condensation and adsorption. The major advantage of this system is its ability to produce ice even on overcast days (insolation [approximately] 10 MJ/m[sup [minus]2]).

Headley, O.StC.; Kothdiwala, A.F.; McDoom, I.A. (Univ. of the West Indies, St. Augustine (Trinidad and Tobago))

1994-08-01

148

A 40 W cw Nd:YAG solar laser pumped through a heliostat: a parabolic mirror system  

NASA Astrophysics Data System (ADS)

Solar-pumped solid-state lasers are promising for renewable extreme-temperature material processing. Here, we report a significant improvement in solar laser collection efficiency by pumping the most widely used Nd:YAG single-crystal rod through a heliostatparabolic mirror system. A conical-shaped fused silica light guide with 3D-CPC output end is used to both transmit and compress the concentrated solar radiation from the focal zone of a 2 m diameter parabolic mirror to a 5 mm diameter Nd:YAG rod within a conical pump cavity, which enables multi-pass pumping through the laser rod. 40 W cw laser power is measured, corresponding to 13.9 W m?2 record-high collection efficiency for the solar laser pumped through a heliostatparabolic mirror system. 2.9% slope efficiency is fitted, corresponding to 132% enhancement over that of our previous pumping scheme. A 209% reduction in threshold pump power is also registered.

Almeida, J.; Liang, D.; Guillot, E.; Abdel-Hadi, Y.

2013-06-01

149

Numerical simulation and design of a parabolic trough solar collector used as a direct generator in a solar-GAX cooling cycle?  

Microsoft Academic Search

In this work, a solar parabolic trough collector (PTC) has been dimensioned and its technical feasibility has been evaluated\\u000a in order to be used as ammonia direct vapor generator in an advanced absorption air-cooled Solar-GAX cycle of 10.6 kW cooling\\u000a capacity. A detailed numerical simulation model that takes into account the geometry and the optical, thermal and fluid dynamic\\u000a behavior

Daniel Sauceda; Nicols Velzquez; Octavio Garca-Valladares; Ricardo Beltrn

2011-01-01

150

Solar Cooking. What We Make. Science and Technology Education in Philippine Society.  

ERIC Educational Resources Information Center

This module is designed to help students: (1) describe a way of tapping solar energy; (2) identify the main parts of a box type solar cooker; (3) describe how each part contributes to the trapping of heat energy in the cooker; (4) cook some food in a solar cooker; and (5) recognize that food cooked in a solar cooker is safe to eat. It includes: an

Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

151

Estimating intercept factor of a parabolic solar trough collector with new supporting structure using off-the-shelf photogrammetric equipment  

Microsoft Academic Search

► We study the optical efficiency of a parabolic solar collector. ► A method based on close-range photogrammetry with off-the-shelf equipment is proposed. ► The collector interception coefficient of the absorber tube is estimated. ► We estimate that almost 10% of the reflected rays do not reach the absorber. ► According to our analysis there are errors on the mounting

2012-01-01

152

Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish: I-test and analysis  

SciTech Connect

The concept of solar driven chemical reaction in a commercial-scale volumetric receiver/reactor on a parabolic concentrator was successfully demonstrated in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) test. Solar reforming of methane (CH[sub 4]) with carbon dioxide (CO[sub 2]) was achieved in a 64 cm diameter direct absorption reactor on a parabolic dish capable of 150 kW solar power. The reactor was a catalytic volumetric absorber consisting of a multilayered, porous alumina foam disk coated with rhodium (Rh) catalyst. The system was operated during both steady-state and solar transient (cloud passage) conditions. The total solar power absorbed reached values up to 97 kW and the maximum methane conversion was 70%. Receiver thermal efficiencies ranged up to 85% and chemical efficiencies peaked at 54%. The absorber performed satisfactorily in promoting the reforming reaction during the tests without carbon formation. However, problems of cracking and degradation of the porous matrix, nonuniform dispersion of the Rh through the absorber, the catalyst deactivation due to sintering and possible encapsulation, must be resolved to achieve long-term operation and eventual commercialization.

Muir, J.F.; Hogan, R.E. Jr.; Skocypec, R.D. (Sandia National Lab., Albuquerque, NM (United States)); Buck, R. (DLR-ITT, Stuttgart (Germany))

1994-06-01

153

Secondary and compound concentrators for parabolic-dish solar-thermal power systems  

SciTech Connect

A secondary optical element may be added to a parabolic dish solar concentrator to increase the geometric concentration ratio attainable at a given intercept factor. This secondary may be a Fresnel lens or a mirror, such as a compound elliptic concentrator or a hyperbolic trumpet. At a fixed intercept factor, higher overall geometric concentration may be obtainable with a long focal length primary and a suitable secondary matched to it. Use of a secondary to increase the geometric concentration ratio is more likely to be worthwhile if the receiver temperature is high and if errors in the primary are large. Folding the optical path with a secondary may reduce cost by locating the receiver and power conversion equipment closer to the ground and by eliminating the heavy structure needed to support this equipment at the primary focus. Promising folded-path configurations include the Ritchey-Chretien and perhaps some three-element geometries. Folding the optical path may be most useful in systems that provide process heat.

Jaffe, L.D.; Poon, P.T.

1981-04-15

154

Secondary and compound concentrators for parabolic dish solar thermal power systems  

NASA Technical Reports Server (NTRS)

A secondary optical element may be added to a parabolic dish solar concentrator to increase the geometric concentration ratio attainable at a given intercept factor. This secondary may be a Fresnel lens or a mirror, such as a compound elliptic concentrator or a hyperbolic trumpet. At a fixed intercept factor, higher overall geometric concentration may be obtainable with a long focal length primary and a suitable secondary matched to it. Use of a secondary to increase the geometric concentration ratio is more likely to e worthwhile if the receiver temperature is high and if errors in the primary are large. Folding the optical path with a secondary may reduce cost by locating the receiver and power conversion equipment closer to the ground and by eliminating the heavy structure needed to support this equipment at the primary focus. Promising folded-path configurations include the Ritchey-Chretien and perhaps some three element geometries. Folding the optical path may be most useful in systems that provide process heat.

Jaffe, L. D.; Poon, P. T.

1981-01-01

155

Design of a single flat null-screen for testing a parabolic trough solar collector  

NASA Astrophysics Data System (ADS)

We present a null-screen design for testing the shape quality of the reflecting surface of a parabolic trough solar collector (PTSC). This technique is inexpensive, the whole surface is tested at once, and it is easy to implement. For this, we propose the design of a flat null-screen perpendicular to the optical axis of the PTSC in such a way that it allows testing of the full aperture; we compute the caustic associated with the reflected light rays on the desired surface and analyze the parameters that determine the null-screen dimensions. Additionally, we perform a numerical simulation to analyze the accuracy of the method by introducing random displacement errors into the measured data. Accuracies >0.35 mrad were found to evaluate the quality of surfaces with this method. The errors in the determination of the coordinates of the centroids of the reflected images must be measured with an accuracy >0.5 pixels, and the errors in the coordinates of the spots of the null-screen must be <0.5 mm.

Moreno-Oliva, Vctor Ivn; Campos-Garca, Manuel; Romn-Hernndez, Edwin; Santiago-Alvarado, Agustn

2014-11-01

156

Numerical study on coupled fluid flow and heat transfer process in parabolic trough solar collector tube  

SciTech Connect

A unified two-dimensional numerical model was developed for the coupled heat transfer process in parabolic solar collector tube, which includes nature convection, forced convection, heat conduction and fluid-solid conjugate problem. The effects of Rayleigh number (Ra), tube diameter ratio and thermal conductivity of the tube wall on the heat transfer and fluid flow performance were numerically analyzed. The distributions of flow field, temperature field, local Nu and local temperature gradient were examined. The results show that when Ra is larger than 10{sup 5}, the effects of nature convection must be taken into account. With the increase of tube diameter ratio, the Nusselt number in inner tube (Nu{sub 1}) increases and the Nusselt number in annuli space (Nu{sub 2}) decreases. With the increase of tube wall thermal conductivity, Nu{sub 1} decreases and Nu{sub 2} increases. When thermal conductivity is larger than 200 W/(m K), it would have little effects on Nu and average temperatures. Due to the effect of the nature convection, along the circumferential direction (from top to down), the temperature in the cross-section decreases and the temperature gradient on inner tube surface increases at first. Then, the temperature and temperature gradients would present a converse variation at {theta} near {pi}. The local Nu on inner tube outer surface increases along circumferential direction until it reaches a maximum value then it decreases again. (author)

Tao, Y.B.; He, Y.L. [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2010-10-15

157

Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems  

NASA Technical Reports Server (NTRS)

Parabolic dish solar concentrator cluster concepts are explored, with attention given to thermal storage systems coupled to Stirling and Brayton cycle power conversion devices. Sensible heat storage involving molten salt (NaOH), liquid sodium, and solid cordierite bricks are considered for 1500 F thermal storage systems. Latent heat storage with NaF-MgF2 phase change materials are explored in terms of passive, active, and direct contact designs. Comparisons are made of the effectiveness of thermal storage relative to redox, Na-S, Zn-Cl, and Zn-Br battery storage systems. Molten lead trickling down through a phase change eutectic, the NaF-MgF2, formed the direct contact system. Heat transport in all systems is effected through Inconel pipes. Using a cost goal of 120-150 mills/kWh as the controlling parameter, sensible heat systems with molten salts transport with either Stirling or Brayton engines, or latent heat systems with Stirling engines, and latent heat-Brayton engine with direct contact were favored in the analyses. Battery storage systems, however, offered the most flexibility of applications.

Fujita, T.; Birur, G. C.; Schredder, J. M.; Bowyer, J. M.; Awaya, H. I.

1982-01-01

158

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

NASA Astrophysics Data System (ADS)

The design, construction and testing of two prototype nonevacuated compound parabolic concentrator (CPC) solar collectors with concentration ratios of 6.5 and 3.0 are discussed. Considerations of heat losses, heat transfer into the reflector structure and the placement of the absorber relative to the reflector lead to the selection of a panel of seven CPC troughs with tube absorbers of diameter 0.64 and 0.79 cm, resulting in concentration ratios of 6.5 and 5.2, respectively, and a two-trough vertical fin CPC module for the 3X concentrator intended for heating applications. Results of measurements of collector performance as indicated by operating efficiency and the angular acceptance properties are presented which are in good agreement with calculations and predictions derived from preliminary measurements of optical properties, heat loss and stagnation temperature. The CPC collectors are also found to outperform typical double and single glazed flat plate collectors above temperatures 10 C above ambient for the 5.2X collector and 35 C above ambient for the 3X. The low cost potential of the CPC prototypes is also pointed out.

Rabl, A.; Ogallagher, J.; Winston, R.

1980-01-01

159

Software used with the flux mapper at the solar parabolic dish test site  

NASA Technical Reports Server (NTRS)

Software for data archiving and data display was developed for use on a Digital Equipment Corporation (DEC) PDP-11/34A minicomputer for use with the JPL-designed flux mapper. The flux mapper is a two-dimensional, high radiant energy scanning device designed to measure radiant flux energies expected at the focal point of solar parabolic dish concentrators. Interfacing to the DEC equipment was accomplished by standard RS-232C serial lines. The design of the software was dicated by design constraints of the flux-mapper controller. Early attemps at data acquisition from the flux-mapper controller were not without difficulty. Time and personnel limitations result in an alternative method of data recording at the test site with subsequent analysis accomplished at a data evaluation location at some later time. Software for plotting was also written to better visualize the flux patterns. Recommendations for future alternative development are discussed. A listing of the programs used in the anaysis is included in an appendix.

Miyazono, C.

1984-01-01

160

Effect of porous disc receiver configurations on performance of solar parabolic trough concentrator  

NASA Astrophysics Data System (ADS)

In this article, heat transfer enhancement of line focus solar collector with porous disc receiver is studied with water and therminol oil. A three dimensional (3-D) numerical simulation of porous disc enhanced receiver is carried out using commercial CFD software Fluent 6.3 to evolve the optimum configuration. The 3-D numerical model is solved by renormalization-group based k-? turbulent model associated with standard wall function. The effect of porous disc receiver configurations (solid disc at bottom; porous disc at bottom; porous disc at top; and alternative porous disc) on performance of the trough concentrator is investigated. The effect of porous disc geometric parameters (?, ?, W, H and t) and fluid parameters (Pr and m) on heat transfer enhancement of the receiver is also studied. The numerical simulation results show that the flow pattern around the solid and porous discs are entirely different and it significantly influences the local heat transfer coefficient. The porous disc receiver experiences low pressure drop as compared to that of solid disc receiver due to less obstruction. The optimum configuration of porous disc receiver enhances the heat transfer rate of 221 W m-1 and 13.5% with pumping penalty of 0.014 W m-1 for water and for therminol oil-55, heat transfer rate enhances of 575 W m-1 and 31.4% with pumping penalty of 0.074 W m-1 as compared to that of tubular receiver at the mass flow rate of 0.5 kg s-1. The Nusselt number and friction factor correlations are proposed for porous disc receiver to calculate heat transfer characteristics. The porous disc receiver can be used to increase the performance of solar parabolic trough concentrator.

Ravi Kumar, K.; Reddy, K. S.

2012-03-01

161

Development of Molten-Salt Heat Transfer Fluid Technology for Parabolic Trough Solar Power Plants - Public Final Technical Report  

SciTech Connect

Executive Summary This Final Report for the "Development of Molten-Salt Heat Transfer Fluid (HTF) Technology for Parabolic Trough Solar Power Plants describes the overall project accomplishments, results and conclusions. Phase 1 analyzed the feasibility, cost and performance of a parabolic trough solar power plant with a molten salt heat transfer fluid (HTF); researched and/or developed feasible component options, detailed cost estimates and workable operating procedures; and developed hourly performance models. As a result, a molten salt plant with 6 hours of storage was shown to reduce Thermal Energy Storage (TES) cost by 43.2%, solar field cost by 14.8%, and levelized cost of energy (LCOE) by 9.8% - 14.5% relative to a similar state-of-the-art baseline plant. The LCOE savings range met the projects Go/No Go criteria of 10% LCOE reduction. Another primary focus of Phase 1 and 2 was risk mitigation. The large risk areas associated with a molten salt parabolic trough plant were addressed in both Phases, such as; HTF freeze prevention and recovery, collector components and piping connections, and complex component interactions. Phase 2 analyzed in more detail the technical and economic feasibility of a 140 MWe,gross molten-salt CSP plant with 6 hours of TES. Phase 2 accomplishments included developing technical solutions to the above mentioned risk areas, such as freeze protection/recovery, corrosion effects of applicable molten salts, collector design improvements for molten salt, and developing plant operating strategies for maximized plant performance and freeze risk mitigation. Phase 2 accomplishments also included developing and thoroughly analyzing a molten salt, Parabolic Trough power plant performance model, in order to achieve the project cost and performance targets. The plant performance model and an extensive basic Engineering, Procurement, and Construction (EPC) quote were used to calculate a real levelized cost of energy (LCOE) of 11.50/kWhe , which achieved the Phase 2 Go/No Go target of less than 0.12/kWhe. Abengoa Solar has high confidence that the primary risk areas have been addressed in the project and a commercial plant utilizing molten salt is economically and technically feasible. The strong results from the Phase 1 and 2 research, testing, and analyses, summarized in this report, led Abengoa Solar to recommend that the project proceed to Phase 3. However, a commercially viable collector interconnection was not fully validated by the end of Phase 2, combined with the uncertainty in the federal budget, forced the DOE and Abengoa Solar to close the project. Thus the resources required to construct and operate a molten salt pilot plant will be solely supplied by Abengoa Solar.

Grogan, Dylan C. P.

2013-08-15

162

3X compound parabolic concentrating (CPC) solar energy collector. Final technical report  

SciTech Connect

Chamberlain engineers designed a 3X compound parabolic concentrating (CPC) collector for the subject contract. The collector is a completely housed, 105.75 x 44.75 x 10.23-inch, 240-pound unit with six each evacuated receiver assemblies, a center manifold and a one-piece glass cover. A truncated version of a CPC trough reflector system and the General Electric Company tubular evacuated receiver have been integrated with a mass producible collector design suitable for operation at 250 to 450/sup 0/F. The key criterion for optimization of the design was minimization of the cost per Btu collected annually at an operating temperature of 400/sup 0/F. The reflector is a 4.1X design truncated to a total height of 8.0 inches with a resulting actual concentration ratio of 2.6 to 1. The manifold is an insulated area housing the fluid lines which connect the six receivers in series with inlet and outlet tubes extending from one side of the collector at the center. The reflectors are polished, anodized aluminum which are shaped by the roll form process. The housing is painted, galvanized steel, and the cover glass is 3/16-inch thick tempered, low iron glass. The collector requires four slope adjustments per year for optimum effectiveness. Chamberlain produced ten 3X CPC collectors for the subject contract. Two collectors were used to evaluate assembly procedures, six were sent to the project officer in Albuquerque, New Mexico, one was sent to Argonne National Laboratory for performance testing and one remained with the Company. A manufacturing cost study was conducted to estimate limited mass production costs, explore cost reduction ideas and define tooling requirements. The final effort discussed shows the preliminary design for application of a 3X CPC solar collector system for use in the Iowa State Capitol complex.

Ballheim, R.W.

1980-04-25

163

Economic analysis of power generation from parabolic trough solar thermal plants for the Mediterranean regionA case study for the island of Cyprus  

Microsoft Academic Search

In this work a feasibility study is carried out in order to investigate whether the installation of a parabolic trough solar thermal technology for power generation in the Mediterranean region is economically feasible. The case study takes into account the available solar potential for Cyprus, as well as all available data concerning current renewable energy sources policy of the Cyprus

Andreas Poullikkas

2009-01-01

164

Thermal and electrical assessment of an integrated solar photovoltaic thermal (PV\\/T) water collector equipped with compound parabolic concentrator (CPC)  

Microsoft Academic Search

In this paper, an attempt is made to develop a thermal and electrical model for an integrated solar photovoltaic thermal (PV\\/T) water collector equipped with compound parabolic concentrator (CPC). For this purpose, initially a detailed energy balance is carried out to get a thermal model for the system and as the result analytical expressions are provided for finding solar cell

Mahdi Hedayatizadeh; Yahya Ajabshirchi; Faramarz Sarhaddi; Ali Safavinejad; Said Farahat; Hossein Chaji

2012-01-01

165

Solar Cookers and Other Cooking Alternatives  

Microsoft Academic Search

Nearly 50% of the world's population relies on coal, and biomass fuels such as wood, dung, and crop residue for domestic heating. (23) When these materials are burned inside the fumes are toxic. Health Risks include pulmonary disease, pneumonia, and respiratory infections. (10) Indoor air pollution is also associated with 1.6 million deaths per year. (23) The most commonly used

Sarah McGuire; Steven E. Jones

166

Development, solar test, and evaluation of a high-temperature air receiver for point-focusing parabolic dish applications  

SciTech Connect

A high temperature solar receiver was fabricated and tested in excess of 1370 C on an 11-meter-diameter test bed concentrator at the Jet Propulsion Laboratory Parabolic Dish Test Site, Edwards, California. The 60-kilowatt thermal receiver design utilizes state-of-the-art silicon carbide honeycomb matrix panels to receive and transfer the solar energy and mullite elements for thermal buffer storage. Solar tests were conducted with indicated air exit temperatures ranging from 885 C (1625 F) to 1427 C (2600 F), mass flow rates of 75 to 105 g/sec (0.16 to 0.23 lbm/sec), and pressures up to 265 kPa absolute (38.4 psia). Estimates of efficiency are 59.7% at 1120 C (2048 F) to 80.6% at 885 C (1625 F) when aperture spillage losses are considered separately. Results are presented which demonstrate the feasibility of this innovative receiver concept for point-focusing parabolic dish applications over a wide temperature range.

Hanseth, E.J.

1981-01-01

167

Development, solar test, and evaluation of a high-temperature air receiver for point-focusing parabolic dish applications  

NASA Astrophysics Data System (ADS)

A high temperature solar receiver was fabricated and tested in excess of 1370 C on an 11-meter-diameter test bed concentrator at the Jet Propulsion Laboratory Parabolic Dish Test Site, Edwards, California. The 60-kilowatt thermal receiver design utilizes state-of-the-art silicon carbide honeycomb matrix panels to receive and transfer the solar energy and mullite elements for thermal buffer storage. Solar tests were conducted with indicated air exit temperatures ranging from 885 C (1625 F) to 1427 C (2600 F), mass flow rates of 75 to 105 g/sec (0.16 to 0.23 lbm/sec), and pressures up to 265 kPa absolute (38.4 psia). Estimates of efficiency are 59.7% at 1120 C (2048 F) to 80.6% at 885 C (1625 F) when aperture spillage losses are considered separately. Results are presented which demonstrate the feasibility of this innovative receiver concept for point-focusing parabolic dish applications over a wide temperature range.

Hanseth, E. J.

1981-12-01

168

Experimental Performance of a Solar Thermoelectric Cogenerator Comprising Thermoelectric Modules and Parabolic Trough Concentrator without Evacuated Tube  

NASA Astrophysics Data System (ADS)

A prototype practical solar-thermoelectric cogenerator composed of (1) a primary component of a pile of solar-selective absorber (SSA) slab, thermoelectric (TE) modules, and a depressed water flow tube (multichannel cooling heat sink, MCS), and (2) a parabolic trough concentrator with aperture area of 2& m × 2 m and east"west focal axis was constructed. Its cogeneration performance under the best climatic and solar insolation conditions in Guangzhou, China was tested. For simplicity, the evacuated glass tube to cover the primary component was eliminated from the system. Six Bi2Te3 TE modules were arranged in series, directly bonded to the rear surface of the solar absorber slab. The hot-side temperature of the TE module reached up to 152°C. The experimentally obtained instantaneous results for the solar to electrical conversion efficiency, heat exchange coefficient of the MCS, and overall system efficiency under the best environmental and solar insolation conditions were about 1.14%, 56.1%, and 49.5%, respectively. To justify these values, an equivalent thermal network diagram based on a single-temperature-node heat transfer model representing the respective system components was used to analyze the thermal transfer and losses of the system. Finally, electrical power of 18 W was generated, with 2 L/min of hot water at 37C being produced and stored in the insulated container.

Miao, L.; Kang, Y. P.; Li, C.; Tanemura, S.; Wan, C. L.; Iwamoto, Y.; Shen, Y.; Lin, H.

2015-02-01

169

Design and thermal performance of an ICS solar water heater based on three parabolic sections  

Microsoft Academic Search

An integrated collector storage (ICS) consisting of a single cylindrical horizontal tank placed in a reflector composed of three parabolic branches is designed and geometric characteristics are determined. The suggested design aims to cover the need of hot water of a family composed of four persons. Based on this target, its geometric characteristics: reflector geometry, aperture, reflector length, are derived.The

O. Helal; B. Chaouachi; S. Gabsi

2011-01-01

170

Micro-structured reflector surfaces for a stationary asymmetric parabolic solar concentrator  

Microsoft Academic Search

One of the main problems in using parabolic concentrators with standard photovoltaics (PV) cells is the highly non-uniform illumination of the cells. The non-uniform irradiation causes high resistive losses in the standard cells due to their relatively high series resistance. This results in a considerably lowered efficiency. To solve the problem, we introduce three different structured reflectors that will create

Johan Nilsson; Ralf Leutz; Bjrn Karlsson

2007-01-01

171

Heating performance improvement and field study of the induction cooker  

Microsoft Academic Search

Magnetic induction heating is a common technique exploiting high frequency eddy current losses on metallic objects. In the past one to two decades, induction heating has been extended to the catering industry as induction cooker. Currently, the induction cooker draws more and more attentions as one of the popular kitchen appliances. This paper mainly investigates the magnetic field of induction

L. C. Meng; K. W. E. Cheng; K. W. Chan

2009-01-01

172

Performance evaluation and simulation of a Compound Parabolic Concentrator (CPC) trough Solar Thermal Power Plant in Puerto Rico under solar transient conditions  

NASA Astrophysics Data System (ADS)

The increasing fossil fuel costs as well as the need to move in a somewhat sustainable future has led the world in a quest for exploiting the free and naturally available energy from the Sun to produce electric power, and Puerto Rico is no exception. This thesis proposes the design of a simulation model for the analysis and performance evaluation of a Solar Thermal Power Plant in Puerto Rico and suggests the use of the Compound Parabolic Concentrator as the solar collector of choice. Optical and thermal analysis of such collectors will be made using local solar radiation data for determining the viability of this proposed project in terms of the electric power produced and its cost.

Feliciano-Cruz, Luisa I.

173

Design and fabrication of a low-specific-weight parabolic dish solar concentrator  

NASA Technical Reports Server (NTRS)

A segmented design and fabrication and assembly techniques were developed for a 1.8 m (6 ft) diameter parabolic concentrator for space application. This design and these techniques were adaptable to a low cost, mass-produced concentrator. Minimal machining was required. Concentrator segments of formed magnesium were used. The concentrator weighed only 1.6 kg sq m (0.32 lbm/sq ft).

Richter, C. W.; Birchenough, A. G.; Marquis, G. A.; Mroz, T. S.

1978-01-01

174

3X compound parabolic concentrating (CPC) solar energy collector. Final technical report  

Microsoft Academic Search

Chamberlain engineers designed a 3X compound parabolic concentrating (CPC) collector for the subject contract. The collector is a completely housed, 105.75 x 44.75 x 10.23-inch, 240-pound unit with six each evacuated receiver assemblies, a center manifold and a one-piece glass cover. A truncated version of a CPC trough reflector system and the General Electric Company tubular evacuated receiver have been

Ballheim

1980-01-01

175

Simulation of a photo-solar generator for an optimal output by a parabolic photovoltaic concentrator of Stirling engine type  

NASA Astrophysics Data System (ADS)

Solar energy is the source of the most promising energy and the powerful one among renewable energies. Photovoltaic electricity (statement) is obtained by direct transformation of the sunlight into electricity, by means of cells statement. Then, we study the operation of cells statement by the digital simulation with an aim of optimizing the output of the parabolic concentrator of Stirling engine type. The Greenius software makes it possible to carry out the digital simulation in 2D and 3D and to study the influence of the various parameters on the characteristic voltage under illumination of the cell. The results obtained enabled us to determine the extrinsic factors which depend on the environment and the intrinsic factors which result from the properties of materials used.

Kaddour, A.; Benyoucef, B.

176

Error analysis of motion transmission mechanisms : design of a parabolic solar trough  

E-print Network

This thesis presents the error analysis pertaining to the design of an innovative solar trough for use in solar thermal energy generation fields. The research was a collaborative effort between Stacy Figueredo from Prof. ...

Koniski, Cyril (Cyril A.)

2009-01-01

177

International Experience in Standards and Labeling Programs for Rice Cookers  

SciTech Connect

China has had an active program on energy efficiency standards for household appliances since the mid-1990s. Rice cooker is among the first to be subject to such mandatory regulation, since it is one of the most prevalent electric appliances in Chinese households. Since first introduced in 1989, the minimum energy efficiency standard for rice cookers has not been revised. Therefore, the potential for energy saving is considerable. Initial analysis from CNIS indicates that potential carbon savings is likely to reach 7.6 million tons of CO2 by the 10th year of the standard implementation. Since September 2007, CNIS has been working with various groups to develop the new standard for rice cookers. With The Energy Foundation's support, LBNL has assisted CNIS in the revision of the minimum energy efficiency standard for rice cookers that is expected to be effective in 2009. Specifically, work has been in the following areas: assistance in developing consumer survey on usage pattern of rice cookers, review of international standards, review of international test procedures, comparison of the international standards and test procedures, and assessment of technical options of reducing energy use. This report particularly summarizes the findings of reviewing international standards and technical options of reducing energy consumption. The report consists of an overview of rice cooker standards and labeling programs and testing procedures in Hong Kong, South Korea, Japan and Thailand, and Japan's case study in developing energy efficiency rice cooker technologies and rice cooker efficiency programs. The results from the analysis can be summarized as the follows: Hong Kong has a Voluntary Energy Efficiency Labeling scheme for electric rice cookers initiated in 2001, with revision implemented in 2007; South Korea has both MEPS and Mandatory Energy Efficiency Label targeting the same category of rice cookers as Hong Kong; Thailand's voluntary endorsement labeling program is similar to Hong Kong in program design but has 5 efficiency grades; Japan's program is distinct in its adoption of the 'Top Runner' approach, in which, the future efficiency standards is set based on the efficiency levels of the most efficient product in the current domestic market. Although the standards are voluntary, penalties can still be evoked if the average efficiency target is not met. Both Hong Kong and South Korea's tests involve pouring water into the inner pot equal to 80% of its rated volume; however, white rice is used as a load for its tests in Hong Kong whereas no rice is used for tests in South Korea. In Japan's case, water level specified by the manufactures is used and milled rice is used as a load only partially in the tests. Moreover, Japan does not conduct heat efficiency test but its energy consumption measurements tests are much more complex, with 4 different tests are conducted to determine the annual average energy consumption. Hong Kong and Thailand both set Minimum Allowable Heat Efficiency for different rated wattages. The energy efficiency requirements are identical except that the minimum heat efficiency in Thailand is 1 percentage point higher for all rated power categories. In South Korea, MEPS and label's energy efficiency grades are determined by the rice cooker's Rated Energy Efficiency for induction, non-induction, pressure, nonpressure rice cookers. Japan's target standard values are set for electromagnetic induction heating products and non-electromagnetic induction heating products by different size of rice cookers. Specific formulas are used by type and size depending on the mass of water evaporation of the rice cookers. Japan has been the leading country in technology development of various types of rice cookers, and developed concrete energy efficiency standards for rice cookers. However, as consumers in Japan emphasize the deliciousness of cooked rice over other factors, many types of models were developed to improve the taste of cooked rice. Nonetheless, the efficiency of electromagnetic induction heating (IH) rice cook

Zhou, Nan; Zheng, Nina

2008-05-01

178

Conceptual design of a self-deployable, high performance parabolic concentrator for advanced solar-dynamic power systems  

NASA Technical Reports Server (NTRS)

NASA has initiated technology development programs to develop advanced solar dynamic power systems and components for space applications beyond 2000. Conceptual design work that was performed is described. The main efforts were the: (1) conceptual design of self-deploying, high-performance parabolic concentrator; and (2) materials selection for a lightweight, shape-stable concentrator. The deployment concept utilizes rigid gore-shaped reflective panels. The assembled concentrator takes an annular shape with a void in the center. This deployable concentrator concept is applicable to a range of solar dynamic power systems of 25 kW sub e to in excess of 75 kW sub e. The concept allows for a family of power system sizes all using the same packaging and deployment technique. The primary structural material selected for the concentrator is a polyethyl ethylketone/carbon fiber composite also referred to as APC-2 or Vitrex. This composite has a nearly neutral coefficient of thermal expansion which leads to shape stable characteristics under thermal gradient conditions. Substantial efforts were undertaken to produce a highly specular surface on the composite. The overall coefficient of thermal expansion of the composite laminate is near zero, but thermally induced stresses due to micro-movement of the fibers and matrix in relation to each other cause the surface to become nonspecular.

Dehne, Hans J.

1991-01-01

179

Performance analysis of an Integrated Solar Combined Cycle using Direct Steam Generation in parabolic trough collectors  

Microsoft Academic Search

The contribution of solar thermal power to improve the performance of gas-fired combined cycles in very hot and dry environmental conditions is analyzed in this work, in order to assess the potential of this technique, and to feature Direct Steam Generation (DSG) as a well suited candidate for achieving very good results in this quest. The particular Integrated Solar Combined

M. J. Montes; A. Rovira; M. Muoz; J. M. Martnez-Val

2011-01-01

180

Two-tank molten salt storage for parabolic trough solar power plants  

Microsoft Academic Search

The most advanced thermal energy storage for solar thermal power plants is a two-tank storage system where the heat transfer fluid (HTF) also serves as storage medium. This concept was successfully demonstrated in a commercial trough plant (13.8 MWe SEGS I plant; 120 MWht storage capacity) and a demonstration tower plant (10 MWe Solar Two; 105 MWht storage capacity). However,

Ulf Herrmann; Bruce Kelly; Henry Price

2004-01-01

181

Design and analysis of hydraulically driven actuation system For a parabolic solar trough  

E-print Network

This thesis documents Katarina Popovic's contribution to the design of hydraulic cylinder actuation system for day to day solar trough sun tracking, a semester long project within 2.752 Development of Mechanical Products ...

Popovi?, Katarina, S.B. Massachusetts Institute of Technology

2013-01-01

182

Mechanical development of an actuation system for a parabolic solar trough collector  

E-print Network

This thesis documents my personal contribution to the development of a hydraulic-based actuation system for a solar trough collector. The goal of this project was to design the actuation system using hydraulic actuators ...

Carrillo, Juan Felipe (Carrillo Salazar)

2013-01-01

183

Preliminary study on optimization of pH, oxidant and catalyst dose for high COD content: solar parabolic trough collector  

PubMed Central

In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated. The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH?=?6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%. PMID:23369352

2013-01-01

184

Preliminary study on optimization of pH, oxidant and catalyst dose for high COD content: solar parabolic trough collector.  

PubMed

In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated.The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH?=?6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%. PMID:23369352

Singh, Chandan; Chaudhary, Rubina; Gandhi, Kavita

2013-01-01

185

Commercialization of parabolic dish systems  

NASA Technical Reports Server (NTRS)

The impact of recent federal tax and regulatory legislation on the commercialization of parabolic solar reflector technology is assessed. Specific areas in need of technical or economic improvement are noted.

Washom, B.

1982-01-01

186

A compound parabolic concentrator  

SciTech Connect

A compound parabolic concentrator (CPC) for solar energy applications is presented in this work. A prototype was built and its thermal performance was determined. Operating temperatures of the order of 150 /sup 0/C with a reasonable efficiency can be attained by means of a fixed CPC.

Manrique, J.A.

1984-05-01

187

Nexant Parabolic Trough Solar Power Plant Systems Analysis; Task 1: Preferred Plant Size, 20 January 2005 - 31 December 2005  

SciTech Connect

The Rankine cycles for commercial parabolic trough solar projects range in capacity from 13.5 MWe at the Solar Electric Generating Station I (SEGS I) plant, to a maximum of 89 MWe at the SEGS VIII/IX plants. The series of SEGS projects showed a consistent reduction in the levelized energy cost due to a combination of improvements in collector field technology and economies of scale in both the Rankine cycle and the operation and maintenance costs. Nonetheless, the question of the optimum Rankine cycle capacity remains an open issue. The capacities of the SEGS VIII/IX plants were limited by Federal Energy Regulatory Commission and Public Utility Regulatory Policy Act requirements to a maximum net output of 80 MWe. Further improvements in the Rankine cycle efficiency, and economies of scale in both the capital and the operating cost, should be available at larger plant sizes. An analysis was conducted to determine the effect of Rankine cycle capacities greater than 80 MWe on the levelized energy cost. The study was conducted through the following steps: (1) Three gross cycle capacities of 88 MWe, 165 MWe, and 220 MWe were selected. (2) Three Rankine cycle models were developed using the GateCycle program. The models were based on single reheat turbine cycles, with main steam conditions of 1,450 lb{sub f}/in{sup 2} and 703 F, and reheat steam conditions of 239 lb{sub f}/in{sup 2} and 703 F. The feedwater heater system consisted of 5 closed heaters and 1 open deaerating heater. The design condenser pressure was 2.5 in. HgA. (3) The optimization function within Excelergy was used to determine the preferred solar multiple for each plant. Two cases were considered for each plant: (a) a solar-only project without thermal storage, and (b) a solar-fossil hybrid project, with 3 hours of thermal storage and a heat transport fluid heater fired by natural gas. (4) For each of the 6 cases, collector field geometries, heat transport fluid pressure losses, and heat transport pump power requirements were calculated with a field piping optimization model. (5) Annual electric energy outputs, capital costs, and annual operating costs were calculated for each case using the default methods within Excelergy, from which estimates of the levelized energy costs were developed. The plant with the lowest energy cost was considered the optimum.

Kelly, B.

2006-07-01

188

Acceptance Performance Test Guideline for Utility Scale Parabolic Trough and Other CSP Solar Thermal Systems: Preprint  

SciTech Connect

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the engineering, procurement, and construction (EPC) contractor or owners. In lieu of the present absence of ASME or other international test codes developed for this purpose, the National Renewable Energy Laboratory has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level of accuracy consistent with good engineering knowledge and practice. Progress on interim guidelines was presented at SolarPACES 2010. Significant additions and modifications were made to the guidelines since that time, resulting in a final report published by NREL in April 2011. This paper summarizes those changes, which emphasize criteria for assuring thermal equilibrium and steady state conditions within the solar field.

Mehos, M. S.; Wagner, M. J.; Kearney, D. W.

2011-08-01

189

Light Scattering Measurements To Infer Solar System Dust Physical Properties:from Parabolic Flights To The Iss Laboratories  

NASA Astrophysics Data System (ADS)

Information about the physical properties of dust clouds and regoliths in the solar sys- tem is mainly provided by remote light scattering observations. Laboratory measure- ments, which avoid multiple scattering on gravity packed layers by elaborate levitation techniques, are required to accurately interpret such observations. The feasibility of light scattering measurements under microgravity conditions, both on dust clouds and on aggregating particles has been demonstrated by the PROGRA2 experiment during parabolic flight campaigns and by the CODAG-LSU experiment during a rocket flight. The European ICAPS (Interactions in Cosmic and Atmospheric Particle Systems) project has been selected for the International Space Station, and is now at the end of its phase A at ESA. ICAPS Research Topic 5 is devoted to the optical and morphological properties of aggregates. Key results of the PROGRA2 and CODAG-LSU experiments will be presented. Fu- ture steps in the development of light scattering measurements with ICAPS will be presented, with emphasis on new topics, such as the formation and evolution of ices on submicron- or micron-sized dust particles and on highly porous regoliths.

Levasseur-Regourd, A. C.

190

Life cycle assessment of a parabolic trough concentrating solar power plant and the impacts of key design alternatives.  

PubMed

Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, CA, along four sustainability metrics: life cycle (LC) greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback time (EPBT). This wet-cooled, 103 MW plant utilizes mined nitrates salts in its two-tank, thermal energy storage (TES) system. Design alternatives of dry-cooling, a thermocline TES, and synthetically derived nitrate salt are evaluated. During its LC, the reference CSP plant is estimated to emit 26 g of CO(2eq) per kWh, consume 4.7 L/kWh of water, and demand 0.40 MJ(eq)/kWh of energy, resulting in an EPBT of approximately 1 year. The dry-cooled alternative is estimated to reduce LC water consumption by 77% but increase LC GHG emissions and CED by 8%. Synthetic nitrate salts may increase LC GHG emissions by 52% compared to mined. Switching from two-tank to thermocline TES configuration reduces LC GHG emissions, most significantly for plants using synthetically derived nitrate salts. CSP can significantly reduce GHG emissions compared to fossil-fueled generation; however, dry-cooling may be required in many locations to minimize water consumption. PMID:21391722

Burkhardt, John J; Heath, Garvin A; Turchi, Craig S

2011-03-15

191

Life Cycle Assessment of a Parabolic Trough Concentrating Solar Power Plant and Impacts of Key Design Alternatives: Preprint  

SciTech Connect

Climate change and water scarcity are important issues for today's power sector. To inform capacity expansion decisions, hybrid life cycle assessment is used to evaluate a reference design of a parabolic trough concentrating solar power (CSP) facility located in Daggett, California, along four sustainability metrics: life cycle greenhouse gas (GHG) emissions, water consumption, cumulative energy demand (CED), and energy payback time (EPBT). This wet-cooled, 103 MW plant utilizes mined nitrate salts in its two-tank, thermal energy storage (TES) system. Design alternatives of dry-cooling, a thermocline TES, and synthetically-derived nitrate salt are evaluated. During its life cycle, the reference CSP plant is estimated to emit 26 g CO2eq per kWh, consume 4.7 L/kWh of water, and demand 0.40 MJeq/kWh of energy, resulting in an EPBT of approximately 1 year. The dry-cooled alternative is estimated to reduce life cycle water consumption by 77% but increase life cycle GHG emissions and CED by 8%. Synthetic nitrate salts may increase life cycle GHG emissions by 52% compared to mined. Switching from two-tank to thermocline TES configuration reduces life cycle GHG emissions, most significantly for plants using synthetically-derived nitrate salts. CSP can significantly reduce GHG emissions compared to fossil-fueled generation; however, dry-cooling may be required in many locations to minimize water consumption.

Heath, G. A.; Burkhardt, J. J.; Turchi, C. S.

2011-09-01

192

Method and apparatus for forming a segmented mirror parabolic solar collector trough  

Microsoft Academic Search

This invention relates in general to the manufacture of segmented mirror solar collector troughs and specifically to the method and apparatus employed to initially subject the faceted segments to a lateral compression by the application of a vacuum prior to impregnating the segments in a fiberglass substrate which maintains the compressive force when the vacuum is removed.

Chenault

1981-01-01

193

Development of Performance Acceptance Test Guidelines for Large Commercial Parabolic Trough Solar Fields: Preprint  

Microsoft Academic Search

Prior to commercial operation, large solar systems in utility-size power plants need to pass a performance acceptance test conducted by the EPC contractor or owners. In lieu of the present absence of engineering code developed for this purpose, NREL has undertaken the development of interim guidelines to provide recommendations for test procedures that can yield results of a high level

D. Kearney; M. Mehos

2010-01-01

194

Effect of porous disc receiver configurations on performance of solar parabolic trough concentrator  

Microsoft Academic Search

In this article, heat transfer enhancement of line focus solar collector with porous disc receiver is studied with water and therminol oil. A three dimensional (3-D) numerical simulation of porous disc enhanced receiver is carried out using commercial CFD software Fluent 6.3 to evolve the optimum configuration. The 3-D numerical model is solved by renormalization-group based k-? turbulent model associated

K. Ravi Kumar; K. S. Reddy

2011-01-01

195

SIMULATION OF A SOLAR ABSORPTION COOLING SYSTEM WITH PARABOLIC TROUGH COLLECTOR FOR SUNSHINE HOURS  

Microsoft Academic Search

The aim of this paper is to simulate a solar single effect lithium bromide-water absorption cooling system for Ahwaz, Iran. The system has been designed to supply cooling loads of the typical residential place for sunshine hours in all hot climate conditions of Ahwaz where maximum cooling load is about 17.5kw. Thermodynamic model have been used to simulate absorption cycle.

Mehrdad Mazloumi; Mohammad Naghashzadegan; Kourosh Javaherdeh

196

Wind effects on convective heat loss from a cavity receiver for a parabolic concentrating solar collector  

SciTech Connect

Tests were performed to determine the convective heat loss characteristics of a cavity receiver for a parabolid dish concentrating solar collector for various tilt angles and wind speeds of 0-24 mph. Natural (no wind) convective heat loss from the receiver is the highest for a horizontal receiver orientation and negligible with the reveler facing straight down. Convection from the receiver is substantially increased by the presence of side-on wind for all receiver tilt angles. For head-on wind, convective heat loss with the receiver facing straight down is approximately the same as that for side-on wind. Overall it was found that for wind speeds of 20--24 mph, convective heat loss from the receiver can be as much as three times that occurring without wind.

Ma, R.Y. [California State Polytechnic Univ., Pomoma, CA (United States). Dept. of Mechanical Engineering

1993-09-01

197

Solar Oven  

NSDL National Science Digital Library

In many rural parts of the world, people still cook with wood. They often must collect and carry the wood many miles on their backs. They also cut down trees and shrubs instead of letting them grow tall for shade. There is lots of sunshine in these areas, especially if the climate is dry, so a solar cooker would be very useful! Most solar cookers are ovens that convert sunlight into heat energy that is used for cooking. You will design a simple solar oven and improve the design by adding reflectors and insulation while testing heating power with a temperature sensor.

The Concord Consortium

2012-05-21

198

The CAESAR project: Experimental and modeling investigations of methane reforming in a CAtalytically Enhanced Solar Absorption Receiver on a parabolic dish  

SciTech Connect

A joint US/Federal Republic of Germany (FRG) project has successfully tested a unique solar-driven chemical reactor in the CAtalytically Enhanced Solar Absorption Receiver (CAESAR) experiment. The CAESAR test was a {open_quotes}proof-of-concept{close_quotes} demonstration of carbon-dioxide reforming of methane in a commercial-scale, solar, volumetric receiver/reactor on a parabolic dish concentrator. The CAESAR design; test facility and instrumentation; thermal and chemical tests; and analysis of test results are presented in detail. Numerical models for the absorber and the receiver are developed and predicted performance is compared with test data. Post test analyses to assess the structural condition of the absorber and the effectiveness of the rhodium catalyst are presented. Unresolved technical issues are identified and future development efforts are recommended.

Muir, J.F.; Hogan, R.E. Jr.; Skocypec, R.D. [Sandia National Labs., Albuquerque, NM (US); Buck, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt, Stuttgart (DE). Inst. of Technical Thermodynamics

1993-07-01

199

Manufacturing cost analysis of a parabolic dish concentrator (General Electric design) for solar thermal electric power systems in selected production volumes  

NASA Technical Reports Server (NTRS)

The manufacturing cost of a General Electric 12 meter diameter concentrator was estimated. This parabolic dish concentrator for solar thermal system was costed in annual production volumes of 100 - 1,000 - 5,000 - 10,000 - 50,000 100,000 - 400,000 and 1,000,000 units. Presented for each volume are the costs of direct labor, material, burden, tooling, capital equipment and buildings. Also presented is the direct labor personnel and factory space requirements. All costs are based on early 1981 economics.

1981-01-01

200

A Nomographic Methodology for Use in Performance Trade-Off Studies of Parabolic Dish Solar Power Modules  

NASA Technical Reports Server (NTRS)

A simple graphical method was developed to undertake technical design trade-off studies for individual parabolic dish models comprising a two-axis tracking parabolic dish with a cavity receiver and power conversion assembly at the focal point. The results of these technical studies are then used in performing the techno-economic analyses required for determining appropriate subsystem sizing. Selected graphs that characterize the performance of subsystems within the module were arranged in the form of a nomogram that would enable an investigator to carry out several design trade-off studies. Key performance parameters encompassed in the nomogram include receiver losses, intercept factor, engine rating, and engine efficiency. Design and operation parameters such as concentrator size, receiver type (open or windowed aperture), receiver aperture size, operating temperature of the receiver and engine, engine partial load characteristics, concentrator slope error, and the type of reflector surface, are also included in the graphical solution. Cost considerations are not included.

Selcuk, M. K.; Fujita, T.

1984-01-01

201

Slow cooker vs. oven preparation of meat loaves and chicken.  

PubMed

Meat loaves and chickens prepared by recommended methods for a slow electric cooker were not in the hazardous temperature zone long enough to allow appreciable growth of bacteria that might cause food-borne illness. Total plate counts were reduced to a greater extent than they were when meat loaves and chickens were prepared by conventional methods in a gas oven. Presumptive coliforms, C. perfringens, and coagulase positive staphylococci were not detected after either method of cooking. Other parameters of quality indicated that conventional methods of baking meat loaves and roasting chickens were superior to preparation in a slow electric cooker. Drip losses were significantly greater, as were total cooking losses (except for total losses for chickens in Experiment 2), when a slow electric cooker was used. All mean palatability scores except for interior color in meat loaves and tenderness in chickens were significantly higher after preparation in an oven. Significantly more thiamin was retained in oven-cooked meat loaves and chickens. PMID:6619457

Peters, C R; Sinwell, D D; Van Duyne, F O

1983-10-01

202

Parabolic trough collectors for industrial and commercial applications  

SciTech Connect

Industrial Solar Technology Corporation (IST) manufactures and installs parabolic trough solar energy systems for large-scale commercial and industrial applications. Parabolic trough collectors have advanced significantly over the last fifteen years and are the most developed and widely deployed type of solar concentrator. Collector efficiency has increased, installed costs have decreased, and system reliability has improved. These positive trends have moved parabolic trough technology to commercial viability in niche markets where energy costs are high and sunlight is abundant.

Gee, R.C.

1997-06-01

203

A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam  

NASA Astrophysics Data System (ADS)

This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Jaffe, Leonard D.

1988-11-01

204

A review of test results on parabolic dish solar thermal power modules with dish-mounted Rankine engines and for production of process steam  

NASA Technical Reports Server (NTRS)

This paper presents results of development testing of various solar thermal parabolic dish modules and assemblies. Most of the tests were at modules and assemblies that used a dish-mounted, organic Rankine cycle turbine for production of electric power. Some tests were also run on equipment for production of process steam or for production of electricity using dish-mounted reciprocating steam engines. These tests indicate that early modules achieve efficiencies of about 18 percent in converting sunlight to electricity (excluding the inverter but including parasitics). A number of malfunctions occurred. The performance measurements, as well as the malfunctions and other operating experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

Jaffe, Leonard D.

1988-01-01

205

Estimating intercept factor of a parabolic solar trough collector with new supporting structure using off-the-shelf photogrammetric equipment  

Microsoft Academic Search

When a new design for a solar collector is developed it is necessary to guarantee that its intercept factor is good enough to produce the expected thermal jump. This factor is directly related with the fidelity of the trough geometry with respect to its theoretical design shape. This paper shows the work carried out to determine the real shape and

Silverio Garca-Corts; Antonio Bello-Garca; Celestino Ordez

206

Design, construction, operation, and monitoring of a parabolic trough solar collection system for the Georgia Power Company Corporate Headquarters Building  

Microsoft Academic Search

The Corporate Headquarters Office Building of Georgia Power Company (GPC) has one of the largest commercial applications of solar energy for building heating, cooling, and domestic hot water in the U.S. A performance type specification was issued with a guaranteed performance in Btu\\/yr. A one year operation, maintenance, and monitoring effort is now underway. Conclusions reached during this project includes:

D. H. Jones; G. L. Bellamy; E. Ney

1983-01-01

207

Degradation of pharmaceutical beta-blockers by electrochemical advanced oxidation processes using a flow plant with a solar compound parabolic collector.  

PubMed

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L? of total organic carbon of each drug in 0.1 M Na?SO? with 0.5 mM Fe? of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single Pt/carbon felt (CF) and boron-doped diamond (BDD)/air-diffusion electrode (ADE) cells and combined Pt/ADE-Pt/CF and BDD/ADE-Pt/CF cells were used. SPEF treatments were more potent with the latter cell, yielding 95-97% mineralization with 100% of maximum current efficiency and energy consumptions of about 0.250 kWh g TOC?. However, the Pt/ADE-Pt/CF cell gave much lower energy consumptions of about 0.080 kWh g TOC? with slightly lower mineralization of 88-93%, then being more useful for its possible application at industrial level. The EF method led to a poorer mineralization and was more potent using the combined cells by the additional production of hydroxyl radicals (OH) from Fenton's reaction from the fast Fe? regeneration at the CF cathode. Organics were also more rapidly destroyed at BDD than at Pt anode. The decay kinetics of beta-blockers always followed a pseudo first-order reaction, although in SPEF, it was accelerated by the additional production of OH from the action of UV light of solar irradiation. Aromatic intermediates were also destroyed by hydroxyl radicals. Ultimate carboxylic acids like oxalic and oxamic remained in the treated solutions by EF, but their Fe(III) complexes were photolyzed by solar irradiation in SPEF, thus explaining its higher oxidation power. NO?? was the predominant inorganic ion lost in EF, whereas the SPEF process favored the production of NH?? ion and volatile N-derivatives. PMID:21693380

Isarain-Chvez, Eloy; Rodrguez, Rosa Mara; Cabot, Pere Llus; Centellas, Francesc; Arias, Conchita; Garrido, Jos Antonio; Brillas, Enric

2011-08-01

208

Solar Week Thursday: Shoebox Solar Water Heater  

NSDL National Science Digital Library

This is an activity during Solar Week, a twice-yearly event in March and October during which classrooms are able to interact with scientists studying the Sun. Outside of Solar Week, information, activities, and resources are archived and available online at any time. This is an activity about reflection. In this hands-on activity, learners will build a solar water heater by lining a box with reflective material, adding a translucent cover, and adding water-filled cans that are painted black. The temperature of the water is taken and recorded every fifteen minutes. This activity can use the same solar cooker built for the Solar Week Thursday: Solar Pizza Box Cooker activity. This activity is scheduled to occur during Thursday of Solar Week, and it requires use of a sunny outdoor location for an extended period of time.

2013-02-18

209

Cooking Amount Estimation of Rice Cooker by Signed Mahalanobis Distance  

NASA Astrophysics Data System (ADS)

This paper proposes a cooking amount estimation method for rice cookers based on Mahalanobis-Taguchi system. This estimation is important in that it can improve the cooking quality significantly. The proposed method enables us to estimate the amount in the early stage of cooking, thereby to give optimal heat in the whole process. To this end, an existing method adopts the minimal cooking quantity as a standard quantity and conduct estimation via outliers in terms of Mahalanobis distance, but this is easily affected by consumers' usage and nonlinearity peculiar to heat systems. Estimation precision is expected to be higher if the estimation is used by correlation of each characteristic data. The proposed method achieves this by adding sign to the estimation method for treating negative values in Mahalanobis distance, and verifies its effectiveness by experiments.

Suzuki, Arata; Sugimoto, Kenji

210

The parabolic Harnack inequality  

E-print Network

The parabolic Harnack inequality on metric graphs Sebastian Haeseler 1. Basic definitions 2. Volume-doubling properties 3. Poincar´e inequalities 4. The parabolic Harnack inequality 5. Examples The parabolic Harnack inequality on metric graphs Sebastian Haeseler Friedrich-Schiller Universit¨at Jena 28.09.2009 #12;The

Novak, Erich

211

Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish: II-modeling and analysis  

SciTech Connect

The CAtalytically Enhanced Solar Absorption Receiver (CAESAR) test was conducted to determine the thermal, chemical, and mechanical performance of a commercial-scale, dish-mounted, direct catalytic absorption receiver (DCAR) reactor over a range of steady state and transient (cloud) operating conditions. The focus of the test was to demonstrate [open quotes]proof-of-concept[close quotes] and determine global performance such as reactor efficiencies and overall methane conversion. A numerical model was previously developed to provide guidance in the design of the absorber. The one-dimensional, planar, and steady-state model incorporates the following energy transfer mechanisms: solar and infrared radiation, heterogeneous chemical reaction, conduction in the solid phase, and convection between the fluid and solid phases. Improvements to the model and improved property values are presented here. In particular, the solar radiative transfer model is improved by using a three-flux technique to more accurately represent the typically conical incident flux. A spatially varying catalyst loading is incorporated, convective and radiative properties for each layer in the multilayer absorber are determined, and more realistic boundary conditions are applied. Considering that this test was not intended to provide data for code validation, model predictions are shown to generally bound the test axial thermocouple data when test uncertainties are included. Global predictions are made using a technique in which the incident solar flux distribution is subdivided into flux contour bands. Reactor predictions for anticipated operating conditions suggest that a further decrease in optical density (i.e., extinction coefficient) at the front of the absorber inner disk may improve absorber conditions. Code-validation experiments are needed to improve the confidence in the simulation of large-scale reactor operation.

Skocypec, R.D.; Hogan, R.E. Jr.; Muir, J.F. (Sandia National Labs., Albuquerque, NM (United States))

1994-06-01

212

Optical, Energetic and Exergetic Analyses of Parabolic Trough Collectors  

NASA Astrophysics Data System (ADS)

Parabolic trough collectors generate thermal energy from solar energy. Especially, they are very convenient for applications in high temperature solar power systems. To determine the design parameters, parabolic trough collectors must be analysed with optical analysis. In addition, thermodynamics (energy and exergy) analysis in the development of an energy efficient system must be achieved. Solar radiation passes through Earth's atmosphere until it reaches on Earth's surface and is focused from the parabolic trough collector to the tube receiver with a transparent insulated envelope. All of them constitute a complex mechanism. We investigate the geometry of parabolic trough reflector and characteristics of solar radiation to the reflecting surface through Earth's atmosphere, and calculate the collecting total energy in the receiver. The parabolic trough collector, of which design parameters are given, is analysed in regard to the energy and exergy analysis considering the meteorological specification in May, June, July and August in Isparta/Turkey, and the results are presented.

Murat, ztrk; Nalan iek, Bezir; Nuri, zek

2007-07-01

213

Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish: 2, Modeling and analysis  

SciTech Connect

The CAtalytically Enhanced Solar Absorption Receiver (CAESAR) experiment was conducted to determine the thermal, chemical, and mechanical performance of a commercial-scale, dish-mounted, direct catalytic absorption receiver (DCAR) reactor over a range of steady state and transient (cloud) operating conditions. The focus of the experiment is on global performance such as receiver efficiencies and overall methane conversion; it was not intended to provide data for code validation. A numerical model was previously developed to provide guidance in the design of the absorber. The one-dimensional, planar and steady-state model incorporates, the following energy transfer mechanisms: solar and infrared radiation, heterogeneous chemical reaction, conduction in the solid phase, and convection between the fluid and solid phases. A number of upgrades to the model and improved property values are presented here. Model predictions are shown to bound the experimental axial thermocouple data when experimental uncertainties are included. Global predictions are made using a technique in which the incident solar flux distribution is subdivided into flux contour bands. Model predictions for each band are then spatially integrated to provide global predictions such as reactor efficiencies and methane conversions. Global predictions are shown to compare well with experimental data. Reactor predictions for anticipated operating conditions suggest a further decrease in optical density at the front of the absorber inner disk may be beneficial. The need to conduct code-validation experiments is identified as essential to improve the confidence in the capability to predict large-scale reactor operation.

Skocypec, R.D.; Hogan, R.E. Jr.; Muir, J.F.

1991-01-01

214

Solar reforming of methane in a direct absorption catalytic reactor on a parabolic dish. 2: Modeling and analysis  

NASA Astrophysics Data System (ADS)

The catalytically enhanced solar absorption receiver (CAESAR) experiment was conducted to determine the thermal, chemical, and mechanical performance of a commercial-scale, dish-mounted, direct catalytic absorption receiver (DCAR) reactor over a range of steady state and transient (cloud) operating conditions. The focus of the experiment is on global performance such as receiver efficiencies and overall methane conversion; it was not intended to provide data for code validation. A numerical model was previously developed to provide guidance in the design of the absorber. The one-dimensional, planar and steady-state model incorporates, the following energy transfer mechanisms: solar and infrared radiation, heterogeneous chemical reaction, conduction in the solid phase, and convection between the fluid and solid phases. A number of upgrades to the model and improved property values are presented here. Model predictions are shown to bound the experimental axial thermocouple data when experimental uncertainties are included. Global predictions are made using a technique in which the incident solar flux distribution is subdivided into flux contour bands. Model predictions for each band are then spatially integrated to provide global predictions such as reactor efficiencies and methane conversions. Global predictions are shown to compare well with experimental data. Reactor predictions for anticipated operating conditions suggest a further decrease in optical density at the front of the absorber inner disk may be beneficial. The need to conduct code-validation experiments is identified as being essential in improving the confidence in the capability to predict large-scale reactor operation.

Skocypec, Russell D.; Hogan, Roy E., Jr.; Muir, James F.

1991-01-01

215

Solar-parabolic dish-Stirling-engine-system module. Task 1: Topical report, market assessment/conceptual design  

SciTech Connect

The major activities reported are: a market study to identify an early market for a dish-Stirling module and assess its commercial potential; preparation of a conceptual system and subsystem design to address this market; and preparation of an early sales implementation plan. A study of the reliability of protection from the effects of walk-off, wherein the sun's image leaves the receiver if the dish is not tracking, is appended, along with an optical analysis and structural analysis. Also appended are the relationship between PURPA and solar thermal energy development and electric utility pricing rationale. (LEW)

Not Available

1982-11-30

216

Multi-scale and angular analysis of ray-optical light trapping schemes in thin-film solar cells: micro lens array, V-shaped configuration, and double parabolic trapper.  

PubMed

An efficient light trapping scheme is a key to enhancing the power conversion efficiency (PCE) of thin-film photovoltaic (PV) cells by compensating for the insufficient light absorption. To handle optical components from nano-scale to micro-scale seamlessly, a multi-scale optical simulation is carefully designed in this study and is used to qualitatively analyze the light trapping performances of a micro lens array (MLA), a V-shaped configuration, and the newly proposed scheme, which is termed a double parabolic trapper (DPT) according to both daily and annual movement of the sun. DPT has the potential to enhance the PCE significantly, from 5.9% to 8.9%, for PCDTBT:PC(70)BM-based polymer solar cells by perfectly trapping the incident light between two parabolic PV cells. PMID:23482290

Cho, Changsoon; Lee, Jung-Yong

2013-03-11

217

Optimal Heat Collection Element Shapes for Parabolic Trough Concentrators  

SciTech Connect

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.

Bennett, C

2007-11-15

218

Wind loads on heliostats and parabolic dish collectors  

Microsoft Academic Search

A major intent of this study was to define wind load reduction factors for parabolic dish solar collectors within a field protected by upwind collectors, wind protective fences, or other blockages. This information will help researchers improve the economy of parabolic collector support structures and drive mechanisms. The method used in the study was to generalize wind load data obtained

J. A. Peterka; Z. Tan; B. Bienkiewicz; J. E. Cermak

1988-01-01

219

The French thermo-helio-electricity-KW parabolic dish program  

NASA Astrophysics Data System (ADS)

The testing and development of parabolic dish solar thermal power plants to produce, thermal mechanical, or electrical energy are discussed. The design, construction, and experiments of prototype collectors to prove the feasibility of such collectors is described.

Audibert, M.; Peri, G.

1982-07-01

220

The French thermo-helio-electricity-KW parabolic dish program  

NASA Technical Reports Server (NTRS)

The testing and development of parabolic dish solar thermal power plants to produce, thermal mechanical, or electrical energy are discussed. The design, construction, and experiments of prototype collectors to prove the feasibility of such collectors is described.

Audibert, M.; Peri, G.

1982-01-01

221

Parabolic dish test site: History and operating experience  

NASA Technical Reports Server (NTRS)

The parabolic dish test site (PDTS) was established for testing point-focusing solar concentrator systems operating at temperatures approaching 1650 C. Among tests run were evaluation and performance characterization of parabolic dish concentrators, receivers, power conversion units, and solar/fossil-fuel hybrid systems. The PDTS was fully operational until its closure in June, 1984. The evolution of the test program, a chronological listing of the experiments run, and data summaries for most of the tests conducted are presented.

Selcuk, M. K. (compiler)

1985-01-01

222

Experimental analysis of effect of variation of convection heat losses on performance of parabolic dish collector with nickel chrome coated receiver  

Microsoft Academic Search

This paper reveals effect of variation of natural and forced convection heat losses on performance of prototype parabolic dish collector with black nickel chrome coated receiver. In general, concentrated solar collectors have high efficiency as compared to flat plate and parabolic trough type solar collectors. Therefore for water heating application high efficiency can be achieved. Design of solar parabolic dish

Atul A. Sagade; N. N. Shinde

2011-01-01

223

Parabolic Dish Concentrator (PDC-1)  

NASA Technical Reports Server (NTRS)

The design, construction, and installation of the Parabolic Dish Concentrator, Type 1 (PDC-1) has been one of the most significant JPL concentrator projects because of the knowledge gained about this type of concentrator and the development of design, testing, and analysis procedures which are applicable to all solar concentrator projects. The need for these procedures was more clearly understood during the testing period which started with the prototype panel evaluation and ended with the performance characterization of the completed concentrator. For each phase of the test program, practical test procedures were required and these procedures defined the mathematical analysis which was essential for successful concentrator development. The concentrator performance appears to be limited only by the distortions resulting from thermal gradients through the reflecting panels. Simple optical testing can be extremely effective, but comprehensive mechanical and optical analysis is essential for cost effective solar concentrator development.

Dennison, E. W.; Argoud, M. J.

1984-01-01

224

The Pressure Cooker: A Module on the Properties of Matter. Tech Physics Series.  

ERIC Educational Resources Information Center

Experiments to provide an understanding of the principles related to the pressure cooker are presented. Objectives included are designed to provide the learner with the ability to calibrate a thermistor for measuring temperature; explain the meaning of latent and specific heat; calculate latent and specific heat; use a Bourdon tube pressure gauge

Technical Education Research Center, Cambridge, MA.

225

Understanding the Clausius-Clapeyron Equation by Employing an Easily Adaptable Pressure Cooker  

ERIC Educational Resources Information Center

This article describes a simple and inexpensive laboratory exercise developed to understand the effect of pressure on phase equilibrium as described by the Clausius-Clapeyron equation. The only piece of equipment required is a pressure cooker adapted with a pressure gauge and a thermometer in the lid, allowing the measurement of the pressure and

Galleano, Monica; Boveris, Alberto; Puntarulo, Susana

2008-01-01

226

Parabolic Trough Organic Rankine Cycle Power Plant  

SciTech Connect

Arizona Public Service (APS) is required to generate a portion of its electricity from solar resources in order to satisfy its obligation under the Arizona Environmental Portfolio Standard (EPS). In recent years, APS has installed and operates over 4.5 MWe of fixed, tracking, and concentrating photovoltaic systems to help meet the solar portion of this obligation and to develop an understanding of which solar technologies provide the best cost and performance to meet utility needs. During FY04, APS began construction of a 1-MWe parabolic trough concentrating solar power plant. This plant represents the first parabolic trough plant to begin construction since 1991. The plant will also be the first commercial deployment of the Solargenix parabolic trough collector technology developed under contract to the National Renewable Energy Laboratory (NREL). The plant will use an organic Rankine cycle (ORC) power plant, provided by Ormat. The ORC power plant is much simpler than a conventional steam Rankine cycle power plant and allows unattended operation of the facility.

Canada, S.; Cohen, G.; Cable, R.; Brosseau, D.; Price, H.

2005-01-01

227

Solar Energy Education. Home economics: student activities. Field test edition  

SciTech Connect

A view of solar energy from the standpoint of home economics is taken in this book of activities. Students are provided information on solar energy resources while performing these classroom activities. Instructions for the construction of a solar food dryer and a solar cooker are provided. Topics for study include window treatments, clothing, the history of solar energy, vitamins from the sun, and how to choose the correct solar home. (BCS)

Not Available

1981-03-01

228

Optical and thermal properties of Compound Parabolic Concentrators  

Microsoft Academic Search

Compound Parabolic Concentrators (CPC) are relevant for solar energy collection because they achieve the highest possible concentration for any acceptance angle (tracking requirement). The convective and radiative heat transfers through a CPC are calculated, and formulas for evaluating the performance of solar collectors based on the CPC principle are presented. A simple analytic technique for calculating the average number of

A. Rabl

1976-01-01

229

Comparative effects of ohmic, induction cooker, and electric stove heating on soymilk trypsin inhibitor inactivation.  

PubMed

During thermal treatment of soymilk, a rapid incorporation of Kunitz trypsin inhibitor (KTI) into protein aggregates by covalent (disulfide bond, SS) and/or noncovalent interactions with other proteins is responsible for its fast inactivation of trypsin inhibitor activity (TIA). In contrast, the slow cleavage of a single Bowman-Birk inhibitor (BBI) peptide bond is responsible for its slow inactivation of TIA and chymotrypsin inhibitor activity (CIA). In this study, the effects of Ohmic heating (220 V, 50 Hz) on soymilk TIA and CIA inactivation were examined and compared to induction cooker and electric stove heating with similar thermal histories. It was found that: (1) TIA and CIA inactivation was slower from 0 to 3 min, and faster after 3 min as compared to induction cooker and electric stove. (2) The thiol (SH) loss rate was slower from 0 to 3 min, and similar to induction cooker and electric stove after 3 min. (3) Ohmic heating slightly increased protein aggregate formation. (4) In addition to the cleavage of one BBI peptide bond, an additional reaction might occur to enhance BBI inactivation. (5) Ohmic heating was more energy-efficient for TIA and CIA inactivation. (6) TIA and CIA inactivation was accelerated with increasing electric voltage (110, 165, and 220 V) of Ohmic heating. It is likely that the enhanced inactivation of TIA by Ohmic heating is due to its combined electrochemical and thermal effects. PMID:25678063

Lu, Lu; Zhao, Luping; Zhang, Caimeng; Kong, Xiangzhen; Hua, Yufei; Chen, Yeming

2015-03-01

230

Changes in the contents and profiles of selected phenolics, soyasapogenols, tocopherols, and amino acids during soybean-rice mixture cooking: Electric rice cooker vs electric pressure rice cooker.  

PubMed

This study investigated the changes in the contents and profiles of 35 phenolics (including 12 isoflavones), four tocopherols, two soyasapogenols and 20 amino acids when soybean and rice were cooked together (soybean-rice mixture) using either an electric rice cooker (ERC) or an electric pressure rice cooker (EPRC). The contents of the 35 selected phenolics in soybean decreased by 12% and 8% upon cooking by ERC and EPRC, respectively, and their profiles were different from that prior to cooking (P<0.05). Total tocopherol content of soybeans decreased by 7% after cooking in an ERC, but increased by 3% in soybeans cooked by EPRC. Total soyasapogenol content in soybeans cooked by ERC and EPRC decreased by 15% and 6%, respectively. Lastly, the total amino acid content of soybeans increased by 41% and 10% after cooking by ERC and EPRC, respectively. This study extends our knowledge about the effects of heat and pressure on the contents and profiles of bioactive compounds during soybean-rice mixture cooking. These results may be useful for improving the quality of bioactive compounds in soybean and rice depending on cooking conditions. PMID:25624205

Kim, Seung-Hyun; Yu, Bo-Ra; Chung, Ill-Min

2015-06-01

231

Session: Parabolic Troughs (Presentation)  

SciTech Connect

The project description is R and D activities at NREL and Sandia aimed at lowering the delivered energy cost of parabolic trough collector systems and FOA awards to support industry in trought development. The primary objectives are: (1) support development of near-term parabolic trought technology for central station power generation; (2) support development of next-generation trought fields; and (3) support expansion of US trough industry. The major FY08 activities were: (1) improving reflector optics; (2) reducing receiver heat loss (including improved receiver coating and mitigating hydrogen accumulation); (3) measuring collector optical efficiency; (4) optimizing plant performance and reducing cost; (5) reducing plant water consumption; and (6) directly supporting industry needs, including FOA support.

Kutscher, C.

2008-04-01

232

Fractional-Parabolic Systems  

Microsoft Academic Search

We develop a theory of the Cauchy problem for linear evolution systems of partial differential equations with the Caputo-Dzhrbashyan\\u000a fractional derivative in the time variable t. The class of systems considered in the paper is a fractional extension of the class of systems of the first order in t satisfying the uniform strong parabolicity condition. We construct and investigate the

Anatoly N. Kochubei

233

Wind loads on heliostats and parabolic dish collectors: Final subcontractor report  

Microsoft Academic Search

A major intent of this study was to define wind load reduction factors for parabolic dish solar collectors within a field protected by upwind collectors, wind protective fences, or other blockages. This information will help researchers improve the economy of parabolic collector support structures and drive mechanisms. The method used in the study was to generalize wind load data obtained

J. A. Peterka; Z. Tan; B. Bienkiewicz; J. E. Cermak

2009-01-01

234

Water Cooled TJ Dense Array Modules for Parabolic Dishes  

SciTech Connect

AZUR SPACE Solar Power GmbH has developed a novel type of dense array module for use in parabolic dishes. Such dishes never produce a perfectly homogeneous, rectangular light spot but an inhomogeneous light distribution. A regular module would use this light distribution very inefficiently. Therefore AZUR SPACE developed a dense array module concept which can be adapted to inhomogeneous light spots. It is populated with state of the art triple junction solar cells.The modules are designed for light intensities in the range of 50-100 W/cm{sup 2} and are actively water cooled. Prototypes are installed in 11 m{sup 2} parabolic dishes produced by Zenith Solar. A peak output of 2.3 kW electrical and 5.5 kW thermal power could be demonstrated. The thermal power may be used for solar heating, solar cooling or warm water.

Loeckenhoff, Ruediger; Kubera, Tim; Rasch, Klaus Dieter [AZUR SPACE Solar Power GmbH, Theresienstr. 2, 74072 Heilbronn (Germany)

2010-10-14

235

Status of APS 1-Mwe Parabolic Trough Project  

SciTech Connect

Arizona Public Service (APS) is currently installing new power facilities to generate a portion of its electricity from solar resources that will satisfy its obligation under the Arizona Environmental Portfolio Standard (EPS). During FY04, APS began construction on a 1-MWe parabolic trough concentrating solar power plant. This plant represents the first parabolic trough plant to begin construction since 1991. Site preparation and construction activities continued throughout much of FY05, and startup activities are planned for Fall 2005 (with completion early in FY06). The plant will be the first commercial deployment of the Solargenix parabolic trough collector technology developed under contract to the National Renewable Energy Laboratory. The plant will use an organic Rankine cycle (ORC) power plant, provided by Ormat. The ORC power plant is much simpler than the conventional steam Rankine cycle plant and allows unattended operation of the facility.

Canada, S.; Brosseau, D.; Kolb, G.; Moore, L.; Cable, R.; Price, H.

2005-11-01

236

A Better Steam Engine: Designing a Distributed Concentrating Solar Combined Heat and Power System  

E-print Network

Advances in parabolic trough solar power technology. Journalthe concentrating solar power (CSP) troughs in the centraltrough coefficients are comparable to those for a dish collector). Direct normal solar

Norwood, Zachary Mills

2011-01-01

237

A COMPARISON OF VOLATILE COMPOUNDS AND PHYSICAL CHARACTERISTICS OF KOSHIHIKARI AND BASMATI RICE PREPARED IN DIFFERENT COOKERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Koshihikari and Basmati rices, two premium rices from Japan and Pakistan respectively, were evaluated for volatile compounds and textural characteristics using three different cooking methods. Three hundred grams of each rice were prepared in National and Hitachi rice cookers and a covered saucepan...

238

Solar Cooking in the Sahel1 Beth Newton1  

E-print Network

Agrometeorological Applications Associates/TchadSolaire, B.P. 102, F-01210 Ferney5 Voltaire, France.6 3 Imperial-risk activity.27 For eight years Agrometeorological Applications Associates and TchadSolaire (AAA/TS)28 have direct-beam solar energy. Figure 1 shows a simple44 cooker consisting of aluminium foil glued onto

Marsham, John

239

Solar thermal technology evaluation, fiscal year 1982. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

Three primary solar concepts the central receiver, parabolic dish, and parabolic trough are investigated. To a lesser extent, the hemispherical bowl and salt-gradient solar pond are also being studied. Each technology is described.

1983-01-01

240

Analysis and conceptual design of a lunar radiator parabolic shade  

NASA Technical Reports Server (NTRS)

On the moon, the available heat sink temperature for a vertical unshaded radiator at the equator is 322 K. A method of reducing this heat sink temperature using a parabolic trough shading device was investigated. A steady state heat balance was performed to predict the available heat sink temperature. The effect of optical surface properties on system performance was investigated. Various geometric configurations were also evaluated. A flexible shade conceptual design is presented which greatly reduces the weight and stowed volume of the system. The concept makes use of the natural catenary shape assumed by a flexible material when supported at two points. The catenary shape is very near parabolic. The lunar radiator parabolic shade design presented integrates the energy collection and rejection of a solar dynamic power cycle with the moderate temperature waste heat rejection of a lunar habitat.

Ewert, Michael K.; Clark, Craig S.

1991-01-01

241

Analysis and conceptual design of a lunar radiator parabolic shade  

NASA Astrophysics Data System (ADS)

On the moon, the available heat sink temperature for a vertical unshaded radiator at the equator is 322 K. A method of reducing this heat sink temperature using a parabolic trough shading device was investigated. A steady state heat balance was performed to predict the available heat sink temperature. The effect of optical surface properties on system performance was investigated. Various geometric configurations were also evaluated. A flexible shade conceptual design is presented which greatly reduces the weight and stowed volume of the system. The concept makes use of the natural catenary shape assumed by a flexible material when supported at two points. The catenary shape is very near parabolic. The lunar radiator parabolic shade design presented integrates the energy collection and rejection of a solar dynamic power cycle with the moderate temperature waste heat rejection of a lunar habitat.

Ewert, Michael K.; Clark, Craig S.

242

Parabolic aircraft solidification experiments  

NASA Technical Reports Server (NTRS)

A number of solidification experiments have been utilized throughout the Materials Processing in Space Program to provide an experimental environment which minimizes variables in solidification experiments. Two techniques of interest are directional solidification and isothermal casting. Because of the wide-spread use of these experimental techniques in space-based research, several MSAD experiments have been manifested for space flight. In addition to the microstructural analysis for interpretation of the experimental results from previous work with parabolic flights, it has become apparent that a better understanding of the phenomena occurring during solidification can be better understood if direct visualization of the solidification interface were possible. Our university has performed in several experimental studies such as this in recent years. The most recent was in visualizing the effect of convective flow phenomena on the KC-135 and prior to that were several successive contracts to perform directional solidification and isothermal casting experiments on the KC-135. Included in this work was the modification and utilization of the Convective Flow Analyzer (CFA), the Aircraft Isothermal Casting Furnace (ICF), and the Three-Zone Directional Solidification Furnace. These studies have contributed heavily to the mission of the Microgravity Science and Applications' Materials Science Program.

Workman, Gary L. (Principal Investigator); Smith, Guy A.; OBrien, Susan

1996-01-01

243

Using Solar Cookers and Gardens to Improve Health in Urban and Rural Areas  

Microsoft Academic Search

Although health benefits of vegetables have been scientifically documented and well publicized, food habits and cost frequently limit vegetable consumption. Our work in Latin America in varied climates, in urban and rural areas, with different populations--especialy those with limited resources--has global applications. In Peru, Bolivia, Venezuela, and in Central America we found that often fresh vegetables are readily available but

R. M. Dow; C. R. Dow

1999-01-01

244

Concentrating Solar Power Commercial Application Study  

E-print Network

Concentrating Solar Power Commercial Application Study: Reducing Water Consumption of Concentrating Solar Power Electricity Generation Report to Congress U.S. Department of Energy This report is being Concentrating Solar Power Technologies............................................... 7 Parabolic Troughs

Laughlin, Robert B.

245

Parabolized stability equations  

NASA Technical Reports Server (NTRS)

The parabolized stability equations (PSE) are a new approach to analyze the streamwise evolution of single or interacting Fourier modes in weakly nonparallel flows such as boundary layers. The concept rests on the decomposition of every mode into a slowly varying amplitude function and a wave function with slowly varying wave number. The neglect of the small second derivatives of the slowly varying functions with respect to the streamwise variable leads to an initial boundary-value problem that can be solved by numerical marching procedures. The PSE approach is valid in convectively unstable flows. The equations for a single mode are closely related to those of the traditional eigenvalue problems for linear stability analysis. However, the PSE approach does not exploit the homogeneity of the problem and, therefore, can be utilized to analyze forced modes and the nonlinear growth and interaction of an initial disturbance field. In contrast to the traditional patching of local solutions, the PSE provide the spatial evolution of modes with proper account for their history. The PSE approach allows studies of secondary instabilities without the constraints of the Floquet analysis and reproduces the established experimental, theoretical, and computational benchmark results on transition up to the breakdown stage. The method matches or exceeds the demonstrated capabilities of current spatial Navier-Stokes solvers at a small fraction of their computational cost. Recent applications include studies on localized or distributed receptivity and prediction of transition in model environments for realistic engineering problems. This report describes the basis, intricacies, and some applications of the PSE methodology.

Herbert, Thorwald

1994-01-01

246

Energy 101: Concentrating Solar Power  

NSDL National Science Digital Library

This video describes how concentrating solar power (CSP) technologies reflect and collect solar energy to generate electricity. This video explains what CSP is, how it works, and focuses on parabolic troughs.

National Renewable Energy Laboratory (NREL)

247

Nonimaging secondary concentrators for large rim angle parabolic troughs with tubular absorbers.  

PubMed

For parabolic trough solar collectors with tubular absorbers, we design new tailored secondary concentrators. The design is applicable for any rim angle of a parabolic reflector. With the secondary, the concentration can be increased by a factor of more than 2 with a compact secondary reflector consisting of a single piece, even for the important case of a rim angle of 90 deg. The parabolic reflector can be used without changes; the reduced absorber is still tubular but smaller than the original absorber and slightly displaced toward the primary. PMID:21085359

Ries, H; Spirkl, W

1996-05-01

248

Solar thermal system engineering guidebook  

NASA Astrophysics Data System (ADS)

This report presents a graphical methodology for the preliminary evaluation of solar thermal energy plants by Air Force base civil engineers. The report is organized as a Guidebook with worksheets and nomograms provided for rapid estimation of solar collector area, land area, energy output, and thermal power output of a solar thermal plant. Flat plate, evacuated tube, parabolic trough, and parabolic dish solar thermal technologies are considered.

Selcuk, M. K.; Bluhm, S. A.

1983-05-01

249

Solar thermal parabolic dish energy applications  

NASA Technical Reports Server (NTRS)

Vu-graphs are presented that show that applications are a viable distributed renewable power generation option. Quality energy can be produced in the form of electricity and high temperature heat. Modular systems are described that can be distributed to new or existing plants and that are mass producible with the associated economies of production.

Pijawka, W.

1981-01-01

250

Criteria for evaluation of reflective surface for parabolic dish concentrators  

NASA Technical Reports Server (NTRS)

Commercial, second surface glass mirror are emphasized, but aluminum and metallized polymeric films are also included. Criteria for sealing solar mirrors in order to prevent environmental degradation and criteria for bonding sagged or bent mirrors to substrate materials are described. An overview of the technical areas involved in evaluating small mirror samples, sections, and entire large gores is presented. A basis for mirror criteria was established that eventually may become part of inspection and evaluation techniques for three dimensional parabolic reflective surfaces.

Bouquet, F.

1980-01-01

251

Markov processes and parabolic partial differential equations  

E-print Network

Markov processes and parabolic partial differential equations Mireille Bossy , Nicolas Champagnat stochastic differential equations (SDEs) and backward SDEs (BSDEs). The second part of this article is devoted to the links between Markov processes and parabolic partial differential equations (PDEs

Paris-Sud XI, Université de

252

Material and process screening as applied to a reinforced plastic parabolic trough concentrator module  

Microsoft Academic Search

Existing parabolic trough solar collectors are basically sheet metal designs utilizing aluminum or steel as the major structural materials. The relatively high labor content associated with these sheet metal designs has generated an interest in investigating the cost effectiveness of using reinforced plastics as a major structural material for trough solar collectors. This interest is bolstered by a growing desire

1980-01-01

253

Complex Ruelle Operator in a Parabolic Basin  

E-print Network

Complex Ruelle Operator in a Parabolic Basin Dynamical Systems _ where it is and where it is going". 1. Parabolic basin and holomorphic quadratic- __ __ ciated to a parabolic basin of a complex dynamical system. Let R : |C! |C be a rational mapping

Ushiki, Shigehiro

254

Parabolic tapers for overmoded waveguides  

DOEpatents

A waveguide taper with a parabolic profile, in which the distance along the taper axis varies as the square of the tapered dimension, provides less mode conversion than equal length linear tapers and is easier to fabricate than other non-linear tapers.

Doane, J.L.

1983-11-25

255

Effects of the Sun on our Planet  

NSDL National Science Digital Library

Students experiment with plants, light, heat, and water evaporation. They experiment with solar cells to design a simple solar cooker, create a "solar-powered" method to perform a routine task, or build a parabolic solar collector. They explore radio signals during daytime and nighttime. Older students construct an ionosphere monitor to track solar storms and other changes in the ionosphere.

256

Solar collectors  

Microsoft Academic Search

Current research and development activity on solar collectors for heating and cooling of buildings is reviewed. Topics covered include reduction to practice, fundamentals of flat plate collectors, collector testing, selective surfaces, heat reflecting glass, honeycomb collectors, evacuated collectors, and concentrating collectors of the V-trough, compound parabolic, and linear Fresnel lens types.

K. G. T. Hollands

1976-01-01

257

Renewable energy technologies for federal facilities: Solar water heating  

SciTech Connect

This sheet presents information on solar water heaters (passive and active), solar collectors (flat plate, evacuated tube, parabolic trough), lists opportunities for use of solar water heating, and describes what is required and the costs. Important terms are defined.

NONE

1996-05-01

258

Design requirements for interfaces in solar energy conversion technologies  

Microsoft Academic Search

Candidate materials for improving the durability and economics of solar energy conversion systems (SECS) are reviewed. A 30-yr lifetime is regarded as necessary for solar collector and concentrator materials in order to offset the high initial costs of SECS in parabolic dish, heliostat, parabolic trough, flat plate collector, OTEC, solar cell, and wind turbine configurations. The materials are required to

B. L. Butler

1982-01-01

259

Solar-thermal-program strategy  

NASA Astrophysics Data System (ADS)

The status of the solar thermal industry, including companies developing parabolic dish, parabolic trough, and central receiver systems was reviewed and the industry's strategy is assessed. Strategic targets are in the utility and industrial sectors. The approaches of the Carter and Reagan Administrations are compared. A case is made against cutting off funding at the present time.

1983-01-01

260

COVARIANCE STRUCTURE OF PARABOLIC STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS  

E-print Network

COVARIANCE STRUCTURE OF PARABOLIC STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS ANNIKA LANG, STIG LARSSON, AND CHRISTOPH SCHWAB Abstract. In this paper parabolic random partial differential equations and parabolic sto- chastic partial differential equations driven by a Wiener process are considered. A deter

Larsson, Stig

261

Simulation of point light concentration with parabolic trough collector  

NASA Astrophysics Data System (ADS)

As the amount of solar generated energy usage increases worldwide, researches are turning to more advanced methods to increase collection efficiencies and drive down system costs. In this paper, four different optical system designs for solar concentrator applications are discussed. Each of the designs studied utilizes a parabolic trough optical element. The use of the parabolic trough in conjunction with a secondary optical component eliminates the need for expensive complicated 2-axis tracking, whilst still allowing the precise point focus normally only possible with more complex paraboloid systems. The result is an optical system, which offers all the advantages of a linear focus geometry combined with the possibility to utilize point focus concentration. The results were obtained using photometric geometrical ray tracing methods. Ideal surface simulations were initially used to separate surface from geometrical loss contributions. Later, more realistic simulations, including surface and reflectivity data of typical manufacturing methods and materials, were used to compare optical output power densities and system losses. For the systems studied, the minimum and maximum optical efficiencies obtained were 76.73% and 81% respectively. The AM 1.5 solar spectrum power densities in the absorption plane ranged from 50 to 195.8Wm-2.

Danylyuk, Andriy; Zettl, Marcus; Lynass, Mark

2010-08-01

262

Overview of software development at the parabolic dish test site  

NASA Technical Reports Server (NTRS)

The development history of the data acquisition and data analysis software is discussed. The software development occurred between 1978 and 1984 in support of solar energy module testing at the Jet Propulsion Laboratory's Parabolic Dish Test Site, located within Edwards Test Station. The development went through incremental stages, starting with a simple single-user BASIC set of programs, and progressing to the relative complex multi-user FORTRAN system that was used until the termination of the project. Additional software in support of testing is discussed including software in support of a meteorological subsystem and the Test Bed Concentrator Control Console interface. Conclusions and recommendations for further development are discussed.

Miyazono, C. K.

1985-01-01

263

Adhesive Bonding Of Thin Glass Mirrors To Parabolic Steel Troughs  

NASA Astrophysics Data System (ADS)

Epoxy, urethane, anerobic, and acrylic adhesives are being investigated for laminating thin glass mirrors to aluminized steel sheet. The adhesive must withstand bending shear loads as well as stresses resulting from differential thermal expansion over the 20-year life of the solar collector. Following screening tests with one foot square laminates, panels two feet square were laminated and subjected to accelerated environmental testing while flexed into a parabolic shape. This paper discusses the effects of the processing variables and the results obtained with the various adhesives.

Hornberger, L. E.; Hull, J. L.

1982-04-01

264

QUASILINEAR PARABOLIC FUNCTIONAL EVOLUTION HERBERT AMANN  

E-print Network

(u) is for each suitable u a nonautonomous evolution equation on some Banach space. The new feature of our resultQUASILINEAR PARABOLIC FUNCTIONAL EVOLUTION EQUATIONS HERBERT AMANN Institut f¨ur Mathematik.amann@math.unizh.ch Based on our recent work on quasilinear parabolic evolution equations and maximal regularity we prove

Amann, Herbert

265

QUASILINEAR PARABOLIC FUNCTIONAL EVOLUTION HERBERT AMANN  

E-print Network

) is for each suitable u a nonautonomous evolution equation on some Banach space. The new feature of our resultQUASILINEAR PARABOLIC FUNCTIONAL EVOLUTION EQUATIONS HERBERT AMANN Institut f?ur Mathematik.amann@math.unizh.ch Based on our recent work on quasilinear parabolic evolution equations and maximal regularity we prove

Amann, Herbert

266

Solargenix Energy Advanced Parabolic Trough Development  

SciTech Connect

The Solargenix Advanced Trough Development Project was initiated in the Year 2000 with the support of the DOE CSP Program and, more recently, with the added support of the Nevada Southwest Energy Partnership. Parabolic trough plants are the most mature solar power technology, but no large-scale plants have been built in over a decade. Given this lengthy lull in deployment, our first Project objective was development of improved trough technology for near-term deployment, closely patterned after the best of the prior-generation troughs. The second objective is to develop further improvements in next-generation trough technology that will lead to even larger reductions in the cost of the delivered energy. To date, this Project has successfully developed an advanced trough, which is being deployed on a 1-MW plant in Arizona and will soon be deployed in a 64-MW plant in Nevada. This advanced trough offers a 10% increase in performance and over an 20% decrease in cost, relative to prior-generation troughs.

Gee, R. C.; Hale, M. J.

2005-11-01

267

Solar thermal technology  

NASA Astrophysics Data System (ADS)

This annual evaluation report provides the accomplishments and progress of government-funded activities initiated, renewed, or completed during Fiscal Year 1985 (October 1, 1984 through September 30, 1985). It highlights the program tasks conducted by participating national laboratories and by contracting industrial academic, or other research institutions. The focus of the STT Program is research and development leading to the commercial readiness of four primary solar thermal concepts: (1) central receiver; (2) parabolic dish; (3) parabolic trough; and (4) hemispherical bowl.

1986-08-01

268

Parabolic curves in Lie groups  

SciTech Connect

To interpolate a sequence of points in Euclidean space, parabolic splines can be used. These are curves which are piecewise quadratic. To interpolate between points in a (semi-)Riemannian manifold, we could look for curves such that the second covariant derivative of the velocity is zero. We call such curves Jupp and Kent quadratics or JK-quadratics because they are a special case of the cubic curves advocated by Jupp and Kent. When the manifold is a Lie group with bi-invariant metric, we can relate JK-quadratics to null Lie quadratics which arise from another interpolation problem. We solve JK-quadratics in the Lie groups SO(3) and SO(1,2) and in the sphere and hyperbolic plane, by relating them to the differential equation for a quantum harmonic oscillator00.

Pauley, Michael [School of Mathematics and Statistics, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

2010-05-15

269

Solar  

NSDL National Science Digital Library

What part does solar energy play in satisfying energy demands? This informational piece, part of a series about the future of energy, introduces students to solar energy. Here students read about the uses, benefits, and active and passive methods of solar energy. Information is also presented about limitations, geographical considerations of solar power in the United States, and current uses of solar energy around the world. Thought-provoking questions afford students chances to reflect on what they've read about the uses of solar energy. Articles and information about a solar power plant in the Mohave Desert, the use of solar energy in Iowa, and statistics about solar energy are provided in a sidebar.

Iowa Public Television. Explore More Project

2004-01-01

270

Solar thermal system engineering guidebook  

Microsoft Academic Search

This report presents a graphical methodology for the preliminary evaluation of solar thermal energy plants by Air Force base civil engineers. The report is organized as a Guidebook with worksheets and nomograms provided for rapid estimation of solar collector area, land area, energy output, and thermal power output of a solar thermal plant. Flat plate, evacuated tube, parabolic trough, and

M. K. Selcuk; S. A. Bluhm

1983-01-01

271

Application of solar thermal energy to buildings and industry  

Microsoft Academic Search

Flat plate collectors and evacuated tube collectors are described, as are parabolic troughs, Fesnel lenses, and compound parabolic concentrators. Use of solar energy for domestic hot water and for space heating and cooling are discussed. Some useful references and methods of system design and sizing are given. This includes mention of the importance of economic analysis. The suitability of solar

C. F. Kutscher

1981-01-01

272

1 MW SOLAR POWER PLANT Using ORMAT ENERGY CONVERTER  

Microsoft Academic Search

Ormat has supplied a 1 MW Power Plant to Arizona Public Service (APS) to its new power facility. APS decided on a 1 MWe parabolic trough concentrating solar power plant and selected the team of Solargenix Energy, Inc. and Ormat International to develop the plant. Solargenix is the system integrator and vendor of the parabolic trough solar field and Ormat

Joseph Sinai

2007-01-01

273

Reflective Properties of a Parabolic Mirror.  

ERIC Educational Resources Information Center

An incident light ray parallel to the optical axis of a parabolic mirror will be reflected at the focal point and vice versa. Presents a mathematical proof that uses calculus, algebra, and geometry to prove this reflective property. (MDH)

Ramsey, Gordon P.

1991-01-01

274

Parabolic equations without a minimum principle  

E-print Network

In this thesis, we consider several parabolic equations for which the minimum principle fails. We first consider a two-point boundary value problem for a one dimensional diffusion equation. We show the uniqueness and ...

Pang, Huadong

2007-01-01

275

High order difference methods for parabolic equations  

E-print Network

HIGH ORDER DIFFERENCE METHODS FOR PARABOLIC E(PATIONS A Thesis by Daniel Alan Matuska Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE May 1971 Ma...)or Sub]ect: Mathematics HIGH ORDER DIFFERENCE METHODS FOR PARABOLIC EQUATIONS A Thesis by Daniel Alan Matuska Approved as to style and content by: Pc~ &~ (Chairman of Committee) (Head of Department) (Member) C . (Member) (Member) (Member...

Matuska, Daniel Alan

1971-01-01

276

Calculations of parabolic reaction rate constants  

Microsoft Academic Search

The oxidation kinetics of only a very limited number of pure metals or binary alloys can be described by the simplest parabolic law, ?m2=kpt, Thus for a transient period of faster kinetics, the steady state parabolic law is given by (?m-?mi)2 = kp(t-ti) when the initial weight gain ?mi does not contribute to steady state rate control. In such a

B. Pieraggi

1987-01-01

277

A Process Heat Application Using Parabolic Trough Collector  

NASA Astrophysics Data System (ADS)

A pilot study has been performed based on a heat process application that is designed, installed and tested at Gaziantep University to establish the technical and economic feasibility of high temperature solar-assisted cooking process. The system has been designed to be satisfying the process conditions integrated with parabolic trough solar collector (PTSC). It is primarily consists of the PTSC array, auxiliary heater, plate type heat exchanger, cooking system and water heating tanks. In the operation of the process heat application, the energy required to cook wheat (used as cooking material) has been supplied from solar energy which is transferred to heat transfer fluid (HTF) by heat exchanging units and finally discharged to water in order to produce bulgur. The performance parameters of the sub-systems and the process compatibility have been accomplished depending on the system operation. In addition that the system performance of the high temperature solar heat process has been presented and the recommendations on its improvement have been evaluated by performing an experimental study. As a result that the use of solar energy in process heat application has been projected and its contribution to economics view with respect to conventional cooking systems has been conducted.

Y?lmaz, ?brahim Halil; Sylemez, Mehmet Sait; Hayta, Hakan; Yumruta?, Recep

278

Low-cost and gram-scale synthesis of water-soluble Cu-In-S/ZnS core/shell quantum dots in an electric pressure cooker.  

PubMed

We report an electric pressure cooker for large-scale synthesis of water-soluble Cu-In-S/ZnS core/shell quantum dots. Low-cost thioglycolic acid and sodium citrate were used as the dual stabilizers. ?3 grams of quantum dots with a tunable emission from 545 to 610 nm and quantum yield up to 40% were obtained in a batch. PMID:24337019

Chen, Yanyan; Li, Shenjie; Huang, Lijian; Pan, Daocheng

2014-01-01

279

Engineering Area Investigation of Reliability Attributes and Accelerated Stress Factors on Terrestrial Solar Cells  

NASA Technical Reports Server (NTRS)

Results obtained include the definition of a simplified stress test schedule for terrestrial solar cells based on the work performed during the first program year, and the design and fabrication of improved jigs and fixtures for electrical measurement and stress testing. Implementation of these advanced techniques for accelerated stress testing is underway on three solar cell types. In addition, review of the literature on second quadrant phenomena was begun and some preliminary second-quadrant electrical measurements were performed. Results obtained at the first down time for 75 C B-T testing and biased and unbiased T-H pressure cooker testing of type F cells showed little or no degradation in electrical parameters. Significant physical effects (large solder bubbles) were noted for type F cells subjected to the pressure cooker stress test.

Lathrop, J. W.; Prince, J. L.

1979-01-01

280

Wind loads on heliostats and parabolic dish collectors  

NASA Astrophysics Data System (ADS)

A major intent of this study was to define wind load reduction factors for parabolic dish solar collectors within a field protected by upwind collectors, wind protective fences, or other blockages. This information will help researchers improve the economy of parabolic collector support structures and drive mechanisms. The method used in the study was to generalize wind load data obtained during tests on model collectors placed in a modeled atmospheric wind in a boundary-layer wind tunnel. A second objective of the study was to confirm and document a sensitivity in load to level of turbulence, or gustiness, in the approaching wind. A key finding was that wind-load reduction factors for forces (horizontal and vertical) were roughly similar to those for flat heliostats, with some forces significantly less than those for flat shapes. However, load reductions for moments showed a smaller load reduction, particularly for the azimuth moment. The lack of load reduction could be attributed to collector shape, but specific flow features responsible for and methods to induce a load reduction were not explored.

Peterka, J. A.; Tan, Z.; Bienkiewicz, B.; Cermak, J. E.

1988-11-01

281

Sensitivity of Concentrating Solar Power Trough Performance, Cost and Financing with Solar Advisor Model  

Microsoft Academic Search

A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM) was developed to support the federal R&D community and the solar industry. This model, developed by staff at NREL and Sandia National Laboratory, is able to model the costs, finances, and performance of concentrating solar power and photovoltaics (PV). Currently, parabolic troughs and concentrating PV are the two

N. Blair; M. Mehos; C. Christensen

2008-01-01

282

OPTIMIZATION STUDIES FOR INTEGRATED SOLAR COMBINED CYCLE SYSTEMS  

Microsoft Academic Search

The integrated solar plant concept was initially proposed by Luz Solar International (1) as a means of integrating a parabolic trough solar plant with modern combined cycle power plants. An integrated plant consists of a conventional combined cycle plant, a solar collector field, and a solar steam generator. During sunny periods, feedwater is withdrawn from the combined cycle plant heat

Bruce Kelly; Ulf Herrmann; Mary Jane Hale

283

75 FR 20377 - Notice of Availability of the Draft Environmental Impact Statement for the Proposed Sonoran Solar...  

Federal Register 2010, 2011, 2012, 2013, 2014

...MW) concentrated solar thermal (CST) power plant and ancillary...use parabolic trough solar thermal technology to produce electrical power using steam turbine...infrastructure, including power blocks and solar trough arrays...

2010-04-19

284

Piecewise-Planar Parabolic Reflectarray Antenna  

NASA Technical Reports Server (NTRS)

The figure shows a dual-beam, dualpolarization Ku-band antenna, the reflector of which comprises an assembly of small reflectarrays arranged in a piecewise- planar approximation of a parabolic reflector surface. The specific antenna design is intended to satisfy requirements for a wide-swath spaceborne radar altimeter, but the general principle of piecewise-planar reflectarray approximation of a parabolic reflector also offers advantages for other applications in which there are requirements for wideswath antennas that can be stowed compactly and that perform equally in both horizontal and vertical polarizations. The main advantages of using flat (e.g., reflectarray) antenna surfaces instead of paraboloidal or parabolic surfaces is that the flat ones can be fabricated at lower cost and can be stowed and deployed more easily. Heretofore, reflectarray antennas have typically been designed to reside on single planar surfaces and to emulate the focusing properties of, variously, paraboloidal (dish) or parabolic antennas. In the present case, one approximates the nominal parabolic shape by concatenating several flat pieces, while still exploiting the principles of the planar reflectarray for each piece. Prior to the conception of the present design, the use of a single large reflectarray was considered, but then abandoned when it was found that the directional and gain properties of the antenna would be noticeably different for the horizontal and vertical polarizations.

Hodges, Richard; Zawadzki, Mark

2009-01-01

285

Performance of a solar-thermal collector  

NASA Technical Reports Server (NTRS)

Possible means of achieving the technology required for field application of solar thermal power systems are discussed. Simplifications in construction techniques as well as in measurement techniques for parabolic trough collectors are described. Actual measurement data is also given.

Higa, W. H.

1975-01-01

286

Current and Future Economics of Parabolic Trough Technology  

SciTech Connect

Solar energy is the largest energy resource on the planet. Unfortunately, it is largely untapped at present, in part because sunlight is a very diffuse energy source. Concentrating solar power (CSP) systems use low cost reflectors to concentrate the sun's energy to allow it to be used more effectively. Concentrating solar power systems are also well suited for large solar power plants that can be connected into the existing utility infrastructure. These two facts mean that CSP systems can be used to make a meaningful difference in energy supply in a relatively short period. CSP plants are best suited for the arid climates in the Southwestern United States, Northern Mexico, and many desert regions around the globe. A recent Western Governors' Association siting study [1] found that the solar potential in the U.S. Southwest is at least 4 times the total U.S. electric demand even after eliminating urban areas, environmentally sensitive areas, and all regions with a ground slope greater than 1%.While it is currently not practical to power the whole county from the desert southwest, only a small portion of this area is needed to make a substantial contribution to future U.S. electric needs. Many of the best sites are near existing high-voltage transmission lines and close to major power load centers in the Southwest (Los Angeles, Las Vegas, and Phoenix). In addition, the power provided by CSP technologies has strong coincidence with peak electric demand, especially in the Southwest where peak demand corresponds in large part to air conditioning loads. Parabolic troughs currently represent the most cost-effective CSP technology for developing large utility-scale solar electric power systems. These systems are also one of the most mature solar technologies, with commercial utility-scale plants that have been operating for over 20 years. In addition, substantial improvements have been made to the technology in recent years including improved efficiency and the addition of thermal energy storage. The main issue for parabolic trough technology is that the cost of electricity is still higher than the cost of electricity from conventional natural gas-fired power plants. Although higher natural gas prices are helping to substantially reduce the difference between the cost of electricity from solar and natural gas plants, in the near-term increased incentives such as the 30% Investment Tax Credit (ITC) are needed to make CSP technology approach competitiveness with natural gas power on a financial basis. In the longer term, additional reductions in the cost of the technology will be necessary. This paper looks at the near-term potential for parabolic trough technology to compete with conventional fossil power resources in the firm, intermediate load power market and at the longer term potential to compete in the baseload power market. The paper will consider the potential impact of a reduced carbon emissions future.

Price, H.; Mehos, M.; Kutscher, C.; Blair, N.

2007-01-01

287

Solar2010, the 48th AuSES Annual Conference 1-3 December 2010, Canberra, ACT, Australia  

E-print Network

by concentrating solar plants with storage. CURRENT COMMERCIAL STORAGE TECHNOLOGY Parabolic Trough plants and potassium nitrate. Andasol-1 uses parabolic trough mirrors to heat oil up to 393o C with concentrated solarSolar2010, the 48th AuSES Annual Conference 1-3 December 2010, Canberra, ACT, Australia A Global

288

Parabolic Ejecta Features on Titan? Probably Not  

NASA Astrophysics Data System (ADS)

Radar mapping of Venus by Magellan indicated a number of dark parabolic features, associated with impact craters. A suggested mechanism for generating such features is that ejecta from the impact event is 'winnowed' by the zonal wind field, with smaller ejecta particles falling out of the atmosphere more slowly, and hence drifting further. What discriminates such features from simple wind streaks is the 'stingray' or parabolic shape. This is due to the ejecta's spatial distribution prior to being winnowed during fallout, and this distribution is generated by the explosion plume of the impact piercing the atmosphere, allowing the ejecta to disperse pseudoballistically before re-entering the atmosphere, decelerating to terminal velocity and then being winnowed. Here we apply this model to Titan, which has a zonal wind field similar to that of Venus. We find that Cassini will probably not find parabolic features, as the winds stretch the deposition so far that ejecta will form streaks or bands instead.

Lorenz, R. D.; Melosh, H. J.

1996-03-01

289

Parabolic trough reflector manufactured with aluminum first surface mirrors thermally sagged  

Microsoft Academic Search

This project was conceived with the aim of developing a parabolic trough concentrator with first surface solar mirrors made over floated soda-lime glasses with concave geometry. In order to cover all the surface of the concentrator, whose measurements were 2.37m of aperture and 1.14m long, 16 mirrors were built with sizes of 0.30.6m and they were put together like a

Ivn Mart??nez; Rafael Almanza; Marcos Mazari; Genaro Correa

2000-01-01

290

Non-concentrating and asymmetric compound parabolic concentrating building faade integrated photovoltaics: An experimental comparison  

Microsoft Academic Search

Concentration of solar energy increases the illuminated flux on the photovoltaic (PV) surface thus less PV material is required. A novel asymmetric compound parabolic photovoltaic concentrator has been characterised experimentally with a similar non-concentrating system. Different numbers of PV strings connected within the system have been analysed and a power ratio of 1.62 measured compared to a similar non-concentrating PV

Tapas K. Mallick; Philip C. Eames; Brian Norton

2006-01-01

291

Development status of the PDC-1 Parabolic Dish Concentrator  

NASA Technical Reports Server (NTRS)

The status of development of the 12 m diameter parabolic dish concentrator which is planned for use with the Small Community Solar Thermal Power System. The PDC-1 unit features the use of plastic reflector film bonded to structural plastic gores supported by front-bracing steel ribs. An elevation-over-azimuth mount arrangement is employed, with a conventional wheel-and-track arrangement; outboard trunnions permit the dish to be stored in the face down position, with the added advantage of easy access to the power conversion assembly. The control system is comprised of a central computer (LSI 1123), a manual control panel, a concentrator control unit, two motor controllers, a Sun sensor, and two angular position resolvers. The system is designed for the simultaneous control of several concentrators. The optical testing of reflective panels is described.

Thostesen, T.; Soczak, I. F.; Pons, R. L.

1982-01-01

292

Parabolic refractive X-ray lenses.  

PubMed

Parabolic refractive X-ray lenses are optical components, especially suitable for third-generation synchrotron radiation sources. This article describes the status of the development of our lenses and illustrates the possibilities for micrometre and submicrometre focusing and for X-ray imaging in absorption and phase contrast. The parabolic lens profile ensures distortion-free imaging of high quality. First characteristics of Be lenses are given. A microscope based on Be lenses is expected to have a lateral resolution below 80 nm. PMID:11972363

Lengeler, Bruno; Schroer, Christian G; Benner, Boris; Gerhardus, Achim; Gnzler, Til Florian; Kuhlmann, Marion; Meyer, Jannik; Zimprich, Christiane

2002-05-01

293

Controllable parabolic-cylinder optical rogue wave.  

PubMed

We demonstrate controllable parabolic-cylinder optical rogue waves in certain inhomogeneous media. An analytical rogue wave solution of the generalized nonlinear Schrdinger equation with spatially modulated coefficients and an external potential in the form of modulated quadratic potential is obtained by the similarity transformation. Numerical simulations are performed for comparison with the analytical solutions and to confirm the stability of the rogue wave solution obtained. These optical rogue waves are built by the products of parabolic-cylinder functions and the basic rogue wave solution of the standard nonlinear Schrdinger equation. Such rogue waves may appear in different forms, as the hump and paw profiles. PMID:25375612

Zhong, Wei-Ping; Chen, Lang; Beli?, Milivoj; Petrovi?, Nikola

2014-10-01

294

Financing Solar Thermal Power Plants  

Microsoft Academic Search

The commercialization of concentrating solar power technology took a major step forward in the mid 1980s and early 1990s with the development of the SEGS plants in California. Over the years they have proven that parabolic trough power technologies are the most cost-effective approach for commercial scale solar power generation in the sunbelt countries of the world. However, the question

H. W. Price; R. Kistner

1999-01-01

295

Middle School Solar Energy Education  

Microsoft Academic Search

Designed as an educational tool to teach middle school students about what solar energy is, why we should use it, and how it works, the poster will focus on using parabolic troughs to power a solar thermal power plant and the basics of how that process works. Additionally, it highlights the research being done by UL Lafayette in this particular

Daniel Newman

2012-01-01

296

Analyticity of solutions to nonlinear parabolic equations on manifolds and  

E-print Network

of (finite dimensional) ordinary differential equations. Of course, an additional issue for parabolicAnalyticity of solutions to nonlinear parabolic equations on manifolds and an application to Stokes by surface tension. Key words: nonlinear parabolic equation, maximal regularity, Stokes flow, surface tension

Eindhoven, Technische Universiteit

297

Cogenerating Photovoltaic and Thermal Solar Collector  

E-print Network

Cogenerating Photovoltaic and Thermal Solar Collector Jinny Rhee and Jim Mokri COE Faculty · Solar Energy and Alternative Energy can contribute to the energy supply ­ Renewable, doesn't emit peak load and irradiance hours of the day #12;Design · Parabolic solar collector · GaAs PV cells

Su, Xiao

298

The linear regulator problem for parabolic systems  

NASA Technical Reports Server (NTRS)

The paper presents an approximation framework for computation (in finite dimensional spaces) of Riccati operators that can be guaranteed to converge to the Ricccati operator in feedback controls for abstract evolution systems in a Hilbert space. It is shown how these results may be used in the linear optimal regulator problem for a large class of parabolic systems.

Banks, H. T.; Kunisch, K.

1984-01-01

299

The linear regulator problem for parabolic systems  

NASA Technical Reports Server (NTRS)

An approximation framework is presented for computation (in finite imensional spaces) of Riccati operators that can be guaranteed to converge to the Riccati operator in feedback controls for abstract evolution systems in a Hilbert space. It is shown how these results may be used in the linear optimal regulator problem for a large class of parabolic systems.

Banks, H. T.; Kunisch, K.

1983-01-01

300

Nitsche finite element method for parabolic problems  

E-print Network

element method, existing software tools for the standard finite element method can be slightly modifiedNitsche finite element method for parabolic problems Bernd Heinrich and Beate Jung1 Abstract in two-dimensional polygonal domains which are allowed to be non-convex. The Nitsche finite element

301

Parabolic-Antenna Design for Microwaves  

Microsoft Academic Search

This paper is intended to give fundamental relations and design criteria for parabolic radiators at microwave frequencies (i.e., wavelengths between 1 and 10 centimeters). The frst part of the paper discusses the properties of the parabola which make it useful as a directional antenna, and the relation of phase polarization and amplitude of primary illumination to the over-all radiation characteristics.

C. C. Cutler

1947-01-01

302

Parabolic SPDEs driven by Poisson white noise  

Microsoft Academic Search

Stochastic partial differential equations (SPDEs) of parabolic type driven by (pure) Poisson white noise are investigated in this paper. These equations are interpreted as stochastic integral equations of the jump type involving evolution kernels. Existence and uniqueness of the solution is established.

Sergio Albeverio; Jiang-Lun Wu; Tu-Sheng Zhang

1998-01-01

303

Parabolic Dish Concentrator (PDC-2) Development  

NASA Technical Reports Server (NTRS)

The design of the Parabolic Dish Concentrator (PDC-2) is described. The following five subsystems of the concentrator are discussed: (1) reflective surface subsystem, (2) support structure subsystem, (3) foundation, (4) drive subsystem, and (5) electrical and control subsystem. The status of the PDC-2 development project is assessed.

Rafinejad, D.

1984-01-01

304

Parabolic Dish Concentrator (PDC-2) development  

SciTech Connect

The design of the Parabolic Dish Concentrator (PDC-2) is described. The following five subsystems of the concentrator are discussed: (1) reflective surface subsystem, (2) support structure subsystem, (3) foundation, (4) drive subsystem, and (5) electrical and control subsystem. The status of the PDC-2 development project is assessed.

Rafinejad, D.

1984-03-01

305

Discontinuous Mixed Covolume Methods for Parabolic Problems  

PubMed Central

We present the semidiscrete and the backward Euler fully discrete discontinuous mixed covolume schemes for parabolic problems on triangular meshes. We give the error analysis of the discontinuous mixed covolume schemes and obtain optimal order error estimates in discontinuous H(div) and first-order error estimate in L2. PMID:24983008

Zhu, Ailing

2014-01-01

306

Solar energy technology  

SciTech Connect

This book contains over 20 selections. Some of the titles are: Experimental analysis of a rotary silica gel dehumidifier: Adiabatic air dehumidification in laminar flow desiccant materices; A simplified design tool for composite Trombe-Michel wall solar collectors; and Wind tunnel tests on scale models of parabolic trough concentrators.

Murphy, L.M.; Guven, H.M.; Lowrey, P.

1987-01-01

307

Engineering aspects of a molten salt heat transfer fluid in a trough solar field  

Microsoft Academic Search

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating large-scale solar parabolic trough plants in the USA currently use a high temperature synthetic oil in the

D. Kearney; B. Kelly; U. Herrmann; R. Cable; J. Pacheco; R. Mahoney; H. Price; D. Blake; P. Nava; N. Potrovitza

2004-01-01

308

Performance Analysis of Thermocline Energy Storage Proposed for the 1 MW Saguaro Solar Trough Plant  

Microsoft Academic Search

The 1 MW Saguaro solar parabolic trough power plant began operation in December 2005. The plant will initially operate without an energy storage system. However, recent studies predict a thermocline-type storage should be the most cost-effective storage concept for solar parabolic troughs power plants. If such a system can be successfully demonstrated at Saguaro, future trough plants will likely adopt

Gregory J Kolb; Vahab Hassani

2006-01-01

309

Solar thermal technology  

NASA Astrophysics Data System (ADS)

The accomplishments and progress of the US Department of energy solar thermal technology (STT) program during FY 1983 are documented. The focus of the STT program is research and development leading to the commercial readiness of three primary solar thermal concepts: the central receiver, parabolic dish, and parabolic trough. The hemispherical bowl and salt-gradient solar pond are also being studied. This development effort is complemented by numerous research and planning activities. A brief description of each technology and highlights of the fiscal year's technical activities is given. FY 1983 accomplishments are enumerated and a bibliography, list of contacts, acronyms, and definitions of terms relevant to solar thermal technology and the STT program are included.

1984-08-01

310

SOLERAS - Solar Energy Water Desalination Project. Solar Energy Study, Yanbu, Saudi Arabia  

SciTech Connect

Measurements of global and normal incident radiation at the Yanbu, Saudi Arabia solar powered desalination plant site are documented. The use of parabolic, two axis tracking, point focusing solar collectors necessitates the measurement and analysis of the normal incident data. The accuracy of the measuring instruments and the results of analysis of one year solar radiation are briefly discussed. (BCS)

Not Available

1985-01-01

311

Near-term improvements in parabolic troughs: an economic and performance assessment  

SciTech Connect

Improved parabolic-trough concentrating collectors will result from better design, improved fabrication techniques, and the development and utilization of improved materials. This analysis qualifies the performance potential of various parabolic-trough component improvements from a systems viewpoint and uses these performance data to determine the worth of each improvement on an economic basis. The improvements considered are evacuated receivers, silvered-glass reflectors, improved receiver, selective coatings, higher optical accuracy concentrations, and higher transmittance receiver glazings. Upper-bound costs for each improvement are provided as well as estimates of the increased solar system rates of return that are made possible by these improvements. The performance and economic potential of some of these improvements are shown to be substantial, especially at higher collector operating temperatures.

Gee, R.; Murphy, L.M.

1981-08-01

312

Solar Generator  

NASA Technical Reports Server (NTRS)

The Vanguard I dish-Stirling module program, initiated in 1982, produced the Vanguard I module, a commercial prototype erected by the Advanco Corporation. The module, which automatically tracks the sun, combines JPL mirrored concentrator technology, an advanced Stirling Solar II engine/generator, a low cost microprocessor-controlled parabolic dish. Vanguard I has a 28% sunlight to electricity conversion efficiency. If tests continue to prove the system effective, Advanco will construct a generating plant to sell electricity to local utilities. An agreement has also been signed with McDonnell Douglas to manufacture a similar module.

1985-01-01

313

The parabolic concentrating collector: A tutorial  

NASA Technical Reports Server (NTRS)

A tutorial overview of point-focusing parabolic collectors is presented. Optical and thermal characteristics are discussed. Data representing typical achievable collector efficiencies are presented and the importance of balancing collector cost with concentrator quality is argued through the development of a figure of merit. Various types of two-axis tracking collectors are described. The Department of Energy program to develop these devices is briefly discussed, as are present and projected costs for these collectors.

Truscello, V. C.

1979-01-01

314

Finite Difference Method for Delay Parabolic Equations  

NASA Astrophysics Data System (ADS)

A finite difference method for the approximate solution of the initial-boundary value problem for the delay parabolic partial differential equation is considered. Stable difference schemes of first and second orders of accuracy for this problem are studied. The stability estimates for the solution of these difference schemes in Hlder norms are obtained. The theoretical statements for the solution of these difference schemes are supported by numerical examples.

Ashyralyev, Allaberen; A?irseven, Deniz

2011-09-01

315

Parabolic Trough VSHOT Optical Characterization in 2005-2006 (Presentation)  

SciTech Connect

This presentation regarding parabolic trough VSHOT optical characterization describes trough deployment and operation phases including: development, manufacture/installation, and maintenance/operation.

Wendelin, T.

2006-02-01

316

Solar energy modulator  

NASA Technical Reports Server (NTRS)

A module is described with a receiver having a solar energy acceptance opening and supported by a mounting ring along the optic axis of a parabolic mirror in coaxial alignment for receiving solar energy from the mirror, and a solar flux modulator plate for varying the quantity of solar energy flux received by the acceptance opening of the module. The modulator plate is characterized by an annular, plate-like body, the internal diameter of which is equal to or slightly greater than the diameter of the solar energy acceptance opening of the receiver. Slave cylinders are connected to the modulator plate for supporting the plate for axial displacement along the axis of the mirror, therby shading the opening with respect to solar energy flux reflected from the surface of the mirror to the solar energy acceptance opening.

Hale, R. R. (inventor); Mcdougal, A. R.

1984-01-01

317

Parabolic Dish Solar Thermal Power Annual Program Review Proceedings  

NASA Technical Reports Server (NTRS)

The development and testing of concentrators, receivers, and power conversion units are reported. System design and development for engineering experiments are described. Economic analysis and market assessments for advanced development activities are discussed. Technology development issues and application/user needs are highlighted.

Holbeck, H. J.

1981-01-01

318

Midtemperature solar systems test faclity predictions for thermal performance based on test data: Solar Kinetics T-700 solar collector with glass reflector surface  

SciTech Connect

Sandia National Laboratories, Albuquerque (SNLA), is currently conducting a program to predict the performance and measure the characteristics of commercially available solar collectors that have the potential for use in industrial process heat and enhanced oil recovery applications. The thermal performance predictions for the Solar Kinetics solar line-focusing parabolic trough collector for five cities in the US are presented. (WHK)

Harrison, T.D.

1981-03-01

319

Energy 101: Concentrating Solar Power  

ScienceCinema

From towers to dishes to linear mirrors to troughs, concentrating solar power (CSP) technologies reflect and collect solar heat to generate electricity. A single CSP plant can generate enough power for about 90,000 homes. This video explains what CSP is, how it works, and how systems like parabolic troughs produce renewable power. For more information on the Office of Energy Efficiency and Renewable Energy's CSP research, see the Solar Energy Technology Program's Concentrating Solar Power Web page at http://www1.eere.energy.gov/solar/csp_program.html.

None

2013-05-29

320

Energy 101: Concentrating Solar Power  

SciTech Connect

From towers to dishes to linear mirrors to troughs, concentrating solar power (CSP) technologies reflect and collect solar heat to generate electricity. A single CSP plant can generate enough power for about 90,000 homes. This video explains what CSP is, how it works, and how systems like parabolic troughs produce renewable power. For more information on the Office of Energy Efficiency and Renewable Energy's CSP research, see the Solar Energy Technology Program's Concentrating Solar Power Web page at http://www1.eere.energy.gov/solar/csp_program.html.

None

2010-01-01

321

Numerical Schemes for Rough Parabolic Equations  

SciTech Connect

This paper is devoted to the study of numerical approximation schemes for a class of parabolic equations on (0,1) perturbed by a non-linear rough signal. It is the continuation of Deya (Electron. J. Probab. 16:1489-1518, 2011) and Deya et al. (Probab. Theory Relat. Fields, to appear), where the existence and uniqueness of a solution has been established. The approach combines rough paths methods with standard considerations on discretizing stochastic PDEs. The results apply to a geometric 2-rough path, which covers the case of the multidimensional fractional Brownian motion with Hurst index H>1/3.

Deya, Aurelien, E-mail: deya@iecn.u-nancy.fr [Universite de Nancy 1, Institut Elie Cartan Nancy (France)

2012-04-15

322

Parabolic dunes in north-eastern Brazil  

E-print Network

In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The empirical vegetation distribution is finally used to validate the results of a recent continuous model of dune motion coupling sand erosion and vegetation growth.

Duran, O; Bezerra, L J C; Herrmann, H J; Maia, L P

2007-01-01

323

On the parallel solution of parabolic equations  

NASA Technical Reports Server (NTRS)

Parallel algorithms for the solution of linear parabolic problems are proposed. The first of these methods is based on using polynomial approximation to the exponential. It does not require solving any linear systems and is highly parallelizable. The two other methods proposed are based on Pade and Chebyshev approximations to the matrix exponential. The parallelization of these methods is achieved by using partial fraction decomposition techniques to solve the resulting systems and thus offers the potential for increased time parallelism in time dependent problems. Experimental results from the Alliant FX/8 and the Cray Y-MP/832 vector multiprocessors are also presented.

Gallopoulos, E.; Saad, Youcef

1989-01-01

324

Spectral methods in time for parabolic problems  

NASA Technical Reports Server (NTRS)

A pseudospectral explicit scheme for solving linear, periodic, parabolic problems is described which has infinite accuracy both in time and in space. The high accuracy is achieved while the time resolution parameter M ( = ) (1/delta t) for time marching algorithm) and the space resolution parameter N B = O(1/detla x) have to satisfy M = O(N sup/+epsilon) epsilon O, compared to the common stability condition M = O(N sup 2) which has to be satisfied in any explicit finite order time algorithm.

Tal-Ezer, H.

1985-01-01

325

OUT Success Stories: Solar Trough Power Plants  

Microsoft Academic Search

The Solar Electric Generating System (SEGS) plants use parabolic-trough solar collectors to capture the sun's energy and convert it to heat. The SEGS plants range in capacity from 13.8 to 80 MW, and they were constructed to meet Southern California Edison Company's periods of peak power demand.

2000-01-01

326

Mount Pinatubo and solar power plants  

Microsoft Academic Search

During the winter and spring of 1992, the operators of the Solar Electric Generating System (SEGS) parabolic concentrator power plants in southern California, noted that production was about 30 percent below normal. This drop was a result of a reduction in direct solar radiation and led to a significant reduction in revenues. The results of a study to quantify the

J. J. Michalsky; R. Perez; R. Seals; P. Ineichen

2009-01-01

327

Optimized solar powered freeze desalination technology  

SciTech Connect

This paper discusses the logic of integrating desalination technology with solar technology. Further analysis leads to the most desirable combination of different variations of these technologies. An integrated power system is proposed consisting of modular parabolic dish point focus solar energy collection, molten salt thermal energy storage, and a conventional steam turbine. 8 refs.

Mukherjee, S.P.; Nowak, T.J.; Husain, M.; Demler, R.; Engdahl, G.E.

1981-01-01

328

The potential economic benefit of using parabolic trough collectors to supplement power cycle boilers  

NASA Astrophysics Data System (ADS)

An economic analysis is presented for a combined parabolic trough solar/fossil fuel hybrid power plant. Applications are considered for investor-owned utilities and industries with stockholders and bond purchasers. Annual levelized revenues are calculated, based on the capital cost of equipment, annual operations and maintenance, and a rising cost of fossil fuel. The units of heat are considered as equal in value from each source, and project return on equity for an American Southwest user of the hybrid systems are calculated to show an annual project return on equity of 21% for a utility and 25% for an industry in 1985. Analysis of the total fuel replaced by a solar reheat system for a gas-fueled boiler system shows that a 20% reduction in fuel costs can be obtained by a 10% increase in the plant costs to include the solar reheat system furnishing low-temperature heat in 1985.

Schimmel, W. P., Jr.; Lukens, L. L.

1981-11-01

329

Solid-dielectric compound parabolic concentrators: on their use with photovoltaic devices.  

PubMed

Prototype solid dielectric compound parabolic concentrators have been made and tested. By means of the geometry and refractive properties of a transparent solid they provide a technique for increasing the power output of silicon solar cells exposed to the sun by an amount nearly equal to the increase in effective collecting area. The response is uniform over a large angle which eliminates the necessity of diurnal tracking of the sun. The technique can be applied to the construction of thin panels and has the potential for significantly reducing, their cost per unit area. PMID:20165416

Goodman, N B; Ignatius, R; Wharton, L; Winston, R

1976-10-01

330

Cell string model with mirror gap shading for a parabolic-trough photovoltaic collector  

NASA Astrophysics Data System (ADS)

A model is described of a photovoltaic cell string which is illuminated by a parabolic trough reflector. The model shows what effect reflector gaps have on cell illumination and how this effect influence shunting of dioded strings for various angles of solar incidence. The model was formulated to study diode string length and determine how best to maximize power under variant incidence angles. Qualitative results suggest that a nonuniform dioding arrangement would minimize power losses due to shunting; that small strings should be used where shading is most probable; and, for north-south axis collectors, that the receiver should be moved northward to avoid end losses and end shading of the receiver.

Burns, J. R.; Edenburn, M. W.

1981-04-01

331

Heat and electricity from the sun using parabolic dish collector systems  

NASA Technical Reports Server (NTRS)

The paper investigates point focus distributed receiver (PFDR) solar thermal technology for the production of electric power and of industrial process heat. Attention is given to a thermal systems project conducted by JPL under DOE sponsorship. It is reported that project emphasis is on the development of cost-effective systems which will accelerate the commercialization and industrialization of plants up to 10 MWe, using parabolic dish collectors. Also discussed are the characteristics of PFDR systems, the cost targets for major systems hardware, and markets for this technology. Finally, the present system status of the technology development effort is discussed.

Truscello, V. C.; Williams, A. N.

1979-01-01

332

Carbon nanotube conductance model in parabolic band structure  

Microsoft Academic Search

Fermi dirac integral is applied to study the parabolic band structure of Carbon Nanotube (CNT) which is in the range of minimum band energy. In this letter electronic transport property of one dimensional carbon nanotube with parabolic band structures near the charge neutrality point is investigated. The temperature dependent conductance model which shows minimum conductance near the charge neutrality point

M. T. Ahmadi; Z. Johari; N. A. Amin; S. M. Mousavi; R. Ismail

2010-01-01

333

Manipulation of dielectric particles with nondiffracting parabolic beams.  

PubMed

The trapping and manipulation of microscopic particles embedded in the structure of nondiffracting parabolic beams is reported. The particles acquire orbital angular momentum and exhibit an open trajectory following the parabolic fringes of the beam. We observe an asymmetry in the terminal velocity of the particles caused by the counteracting gradient and scattering forces. PMID:25606766

Ortiz-Ambriz, Antonio; Gutirrez-Vega, Julio C; Petrov, Dmitri

2014-12-01

334

Optimal Design of Parabolic Canal Section Bhagu R. Chahar1  

E-print Network

Optimal Design of Parabolic Canal Section Bhagu R. Chahar1 Abstract: Optimal design equations for a parabolic canal section are presented in this paper. The design equations for a minimum earthwork cost section and a minimum cost lined section are in explicit form and result in optimal dimensions of a canal

Chahar, B. R.

335

Numerical investigations into the parabolized Navier-Stokes equations  

Microsoft Academic Search

Several finite differences schemes for the parabolized Navier-Stokes (PNS) equations are introduced. These schemes are investigated for accuracy and robustness by solving the PNS equations over a 10% thick parabolic arc airfoil in a Mach 2 flowfield. Each scheme varies in the manner in which the finite difference equations are modeled in the subsonic sublayer region. Departure solutions associated with

D. W. Barnette

1984-01-01

336

Solution method of parabolized Navier-Stokes equations  

Microsoft Academic Search

Laminar and turbulent incompressible flow through curved channels is studied via artificially parabolized Navier-Stokes equations. It is shown how the laminar secondary flow develops if at the inlet of a streamwise curved channel a rigid body vortex moving in the cross section is prescribed. For low Reynolds numbers where no separation is expected, the fully parabolic Navier-Stokes equations can be

R. Grundmann

1986-01-01

337

The Parabolic Jet Structure in M87 as a Magnetohydrodynamic Nozzle  

NASA Astrophysics Data System (ADS)

The structure and dynamics of the M87 jet from sub-milliarcsec to arcsecond scales are continuously examined. We analyzed the Very Long Baseline Array archival data taken at 43 and 86 GHz to measure the size of very long baseline interferometry (VLBI) cores. Millimeter/sub-millimeter VLBI cores are considered as innermost jet emissions, which has been originally suggested by Blandford & Knigl. Those components fairly follow an extrapolated parabolic streamline in our previous study so that the jet has a single power-law structure with nearly 5 orders of magnitude in the distance starting from the vicinity of the supermassive black hole (SMBH), less than 10 Schwarzschild radius (r s). We further inspect the jet parabolic structure as a counterpart of the magnetohydrodynamic (MHD) nozzle in order to identify the property of a bulk acceleration. We interpret that the parabolic jet consists of Poynting-flux dominated flows, powered by large-amplitude, nonlinear torsional Alfvn waves. We examine the non-relativistic MHD nozzle equation in a parabolic shape. The nature of trans-fast magnetosonic flow is similar to the one of transonic solution of Parker's hydrodynamic solar wind; the jet becomes super-escape as well as super-fast magnetosonic at around ~103 r s, while the upstream trans-Alfvnic flow speed increases linearly as a function of the distance at ~102-103 r s. We here point out that this is the first evidence to identify these features in astrophysical jets. We propose that the M87 jet is magnetically accelerated, but thermally confined by the stratified interstellar medium inside the sphere of gravitational influence of the SMBH potential, which may be a norm in active galactic nucleus jets.

Nakamura, Masanori; Asada, Keiichi

2013-10-01

338

THE PARABOLIC JET STRUCTURE IN M87 AS A MAGNETOHYDRODYNAMIC NOZZLE  

SciTech Connect

The structure and dynamics of the M87 jet from sub-milliarcsec to arcsecond scales are continuously examined. We analyzed the Very Long Baseline Array archival data taken at 43 and 86 GHz to measure the size of very long baseline interferometry (VLBI) cores. Millimeter/sub-millimeter VLBI cores are considered as innermost jet emissions, which has been originally suggested by Blandford and Knigl. Those components fairly follow an extrapolated parabolic streamline in our previous study so that the jet has a single power-law structure with nearly 5 orders of magnitude in the distance starting from the vicinity of the supermassive black hole (SMBH), less than 10 Schwarzschild radius (r{sub s}). We further inspect the jet parabolic structure as a counterpart of the magnetohydrodynamic (MHD) nozzle in order to identify the property of a bulk acceleration. We interpret that the parabolic jet consists of Poynting-flux dominated flows, powered by large-amplitude, nonlinear torsional Alfvn waves. We examine the non-relativistic MHD nozzle equation in a parabolic shape. The nature of trans-fast magnetosonic flow is similar to the one of transonic solution of Parker's hydrodynamic solar wind; the jet becomes super-escape as well as super-fast magnetosonic at around ?10{sup 3} r{sub s}, while the upstream trans-Alfvnic flow speed increases linearly as a function of the distance at ?10{sup 2}-10{sup 3} r{sub s}. We here point out that this is the first evidence to identify these features in astrophysical jets. We propose that the M87 jet is magnetically accelerated, but thermally confined by the stratified interstellar medium inside the sphere of gravitational influence of the SMBH potential, which may be a norm in active galactic nucleus jets.

Nakamura, Masanori; Asada, Keiichi, E-mail: nakamura@asiaa.sinica.edu.tw, E-mail: asada@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2013-10-01

339

Thermal effects testing at the National Solar Thermal Test Facility  

Microsoft Academic Search

The National Solar Thermal Test Facility is operated by Sandia National Laboratories and located on Kirkland Air Force Base in Albuquerque, New Mexico. The permanent features of the facility include a heliostat field and associated receiver tower, two solar furnaces, two point-focus parabolic concentrators, and Engine Test Facility. The heliostat field contains 220 computer-controlled mirrors, which reflect concentrated solar energy

M. E. Ralph; C. P. Cameron; C. M. Ghanbari

1992-01-01

340

GREENHOUSE GAS ANALYSIS OF SOLAR-THERMAL ELECTRICITY GENERATION  

Microsoft Academic Search

Solar-thermal electricity generation contributes to climate change because it incurs the emission of greenhouse gases during the provision of services and the production of materials needed for the construction and operation of solar power plants. These greenhouse gas costs (GGC) can be determined using either material inventories in physical units or monetary cost breakdowns. Solar-only plants employing parabolic troughs, central

M. LENZEN

1999-01-01

341

Gain-scheduled control of a solar power plant  

Microsoft Academic Search

The application of gain-scheduled control to a pilot-scale solar power plant is described. A field of parabolic collectors focus the solar radiation onto a tube where oil is pumped through in order to collect the solar power. The control problem is to keep the temperature of the oil leaving the field at its desired value by manipulating the oil pump

Tor A. Johansen; Kenneth J. Hunt; Idar Petersen

2000-01-01

342

The Pressure Group Cooker.  

ERIC Educational Resources Information Center

Administrators across the nation have encountered vigorous challenges against textbooks, practices, and procedures that critics find laden with occult and New Age values. Attacks are becoming more aggressive, better organized, and well financed. This article and accompanying sidebars discuss pressure group tactics and ways to counter them. The

Graves, Bill

1992-01-01

343

Solar thermal aircraft  

DOEpatents

A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Bennett, Charles L. (Livermore, CA)

2007-09-18

344

Sensitivity of Concentrating Solar Power Trough Performance, Cost and Financing with Solar Advisor Model  

SciTech Connect

A comprehensive solar technology systems analysis model, the Solar Advisor Model (SAM) was developed to support the federal R&D community and the solar industry. This model, developed by staff at NREL and Sandia National Laboratory, is able to model the costs, finances, and performance of concentrating solar power and photovoltaics (PV). Currently, parabolic troughs and concentrating PV are the two concentrating technologies modeled within the SAM environment.

Blair, N.; Mehos, M.; Christensen, C.

2008-03-01

345

General theme report: Working session 2, solar thermal systems  

NASA Astrophysics Data System (ADS)

Currently, over 90 percent of the world's large-scale solar electric energy is generated with concentrating solar thermal power plants. Such plants have the potential to meet many of the world's future energy needs. Research efforts are generally focused on generating electricity, though a variety of other applications are being pursued. Today, the technology for using solar thermal energy is well developed, cost competitive, and in many cases, ready for widespread application. The current state of each of the solar thermal technologies and their applications is reviewed, and recommendations for increasing their use are presented. The technologies reviewed in detail are: parabolic trough systems, central tower systems, and parabolic dish systems.

Alpert, D. J.; Kolb, G. J.

1991-01-01

346

Experimental and theoretical study of a solar desalination system located in Cairo, Egypt  

Microsoft Academic Search

The experimental and theoretical study of a solar desalination system located in Cairo, Egypt, is presented in this research. A modification unit is provided to enhance the performance of the solar desalination. The modification unit includes a solar parabolic trough (solar energy concentrator) with focal pipe and simple heat exchanger (serpentine) Oil is selected as working fluid. Oil is flowing

Zeinab S. Abdel-Rehim; Ashraf Lasheen

2007-01-01

347

Utility scale hybrid windsolar thermal electrical generation: A case study for Minnesota  

Microsoft Academic Search

The performance of a hybrid windsolar power plant in southwestern Minnesota is modeled for a 2-yr period using hourly wind and solar insolation data. The wind portion of the plant consists of four interconnected wind farms within a radius of 90km. The solar component of the plant is a parabolic trough solar thermal electric generating system using a heat transfer

J. P. Reichling; F. A. Kulacki

2008-01-01

348

innovati nComponents Makeover Gives Concentrating Solar Power a Boost  

E-print Network

innovati nComponents Makeover Gives Concentrating Solar Power a Boost Parabolic trough technology is the most mature of the various concentrating solar power (CSP) options. But scientists at the National on various components in industrial partnerships with Acciona Solar Power, SkyFuel, Schott Solar, and others

349

Gain Scheduled Control of a Solar Power Plant Tor A. Johansen1  

E-print Network

Gain Scheduled Control of a Solar Power Plant Tor A. Johansen1 , Kenneth J. Hunt2 and Idar Petersen to a pilot-scale solar power plant is described. A eld of parabolic collectors focus the solar radiation onto a tube where oil is pumped through in order to collect the solar power. The control problem is to keep

Johansen, Tor Arne

350

Parabolic flight - Loss of sense of orientation  

NASA Technical Reports Server (NTRS)

On the earth, or in level flight, a blindfolded subject being rotated at constant velocity about his recumbent long body axis experiences illusory orbital motion of his body in the opposite direction. By contrast, during comparable rotation in the free-fall phase of parabolic flight, no body motion is perceived and all sense of external orientation may be lost; when touch and pressure stimulation is applied to the body surface, a sense of orientation is reestablished immediately. The increased gravitoinertial force period of a parabola produces an exaggeration of the orbital motion experienced in level flight. These observations reveal an important influence of touch, pressure, and kinesthetic information on spatial orientation and provide a basis for understanding many of the postural illusions reported by astronauts in space flight.

Lackner, J. R.; Graybiel, A.

1979-01-01

351

Homogenization of a parabolic model of ferromagnetism  

NASA Astrophysics Data System (ADS)

This work deals with the homogenization of hysteresis-free processes in ferromagnetic composites. A degenerate, quasilinear, parabolic equation is derived by coupling the Maxwell-Ohm system without displacement current with a nonlinear constitutive law: {?B?}/{?t}+curl{A(x?)/?curlH?}=curlE, B????(H?,?). Here A is a periodic positive-definite matrix, ??(?,y) is maximal monotone and periodic in y, E is an applied field, and ?>0. An associated initial- and boundary-value problem is represented by a minimization principle via an idea of Fitzpatrick. As ??0 a two-scale problem is obtained via two-scale convergence, and an equivalent coarse-scale formulation is derived. This homogenization result is then retrieved via ?-convergence, and the continuity of the solution with respect to the operator ?? and the matrix A is also proved. This is then extended to some relaxation dynamics.

Visintin, Augusto

352

Parabolic features and the erosion rate on Venus  

NASA Technical Reports Server (NTRS)

The impact cratering record on Venus consists of 919 craters covering 98 percent of the surface. These craters are remarkably well preserved, and most show pristine structures including fresh ejecta blankets. Only 35 craters (3.8 percent) have had their ejecta blankets embayed by lava and most of these occur in the Atla-Beta Regio region; an area thought to be recently active. parabolic features are associated with 66 of the 919 craters. These craters range in size from 6 to 105 km diameter. The parabolic features are thought to be the result of the deposition of fine-grained ejecta by winds in the dense venusian atmosphere. The deposits cover about 9 percent of the surface and none appear to be embayed by younger volcanic materials. However, there appears to be a paucity of these deposits in the Atla-Beta Regio region, and this may be due to the more recent volcanism in this area of Venus. Since parabolic features are probably fine-grain, wind-deposited ejecta, then all impact craters on Venus probably had these deposits at some time in the past. The older deposits have probably been either eroded or buried by eolian processes. Therefore, the present population of these features is probably associated with the most recent impact craters on the planet. Furthermore, the size/frequency distribution of craters with parabolic features is virtually identical to that of the total crater population. This suggests that there has been little loss of small parabolic features compared to large ones, otherwise there should be a significant and systematic paucity of craters with parabolic features with decreasing size compared to the total crater population. Whatever is erasing the parabolic features apparently does so uniformly regardless of the areal extent of the deposit. The lifetime of parabolic features and the eolian erosion rate on Venus can be estimated from the average age of the surface and the present population of parabolic features.

Strom, Robert G.

1993-01-01

353

Lightweight, low-cost solar energy collector  

NASA Technical Reports Server (NTRS)

A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of identical tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two identical spaced anchorplates, each containing a plurality of holes which lie on the desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers which control the shape and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.

Hochberg, Eric B. (Inventor); Costen, Michael K. (Inventor)

2006-01-01

354

Water Use in Parabolic Trough Power Plants: Summary Results from WorleyParsons' Analyses  

SciTech Connect

The National Renewable Energy Laboratory (NREL) contracted with WorleyParsons Group, Inc. to examine the effect of switching from evaporative cooling to alternative cooling systems on a nominal 100-MW parabolic trough concentrating solar power (CSP) plant. WorleyParsons analyzed 13 different cases spanning three different geographic locations (Daggett, California; Las Vegas, Nevada; and Alamosa, Colorado) to assess the performance, cost, and water use impacts of switching from wet to dry or hybrid cooling systems. NREL developed matching cases in its Solar Advisor Model (SAM) for each scenario to allow for hourly modeling and provide a comparison to the WorleyParsons results.Our findings indicate that switching from 100% wet to 100% dry cooling will result in levelized cost of electricity (LCOE) increases of approximately 3% to 8% for parabolic trough plants throughout most of the southwestern United States. In cooler, high-altitude areas like Colorado's San Luis Valley, WorleyParsons estimated the increase at only 2.5%, while SAM predicted a 4.4% difference. In all cases, the transition to dry cooling will reduce water consumption by over 90%. Utility time-of-delivery (TOD) schedules had similar impacts for wet- and dry-cooled plants, suggesting that TOD schedules have a relatively minor effect on the dry-cooling penalty.

Turchi, C. S.; Wagner, M. J.; Kutscher, C. F.

2010-12-01

355

Potential for using parabolic trough collectors to supplement power cycle boilers  

NASA Astrophysics Data System (ADS)

The advantage of such a system is that solar energy is used to heat the water in a steam Rankine cycle device up to the superheat regime, thus displacing the fossil fuel usually required. The temperature associated with this portion of the power cycle is typically on the order of 320 C or less, which makes it compatible with current parabolic trough collector systems. A system model which lends itself to optimization studies was constructed and exercised over a range of the multiparameter space involved. The collector field, storage, supplementary fossil boiler and superheater, and turbine/generator traded off to obtain a series of economically optimal systems for various years and solar fractions.

Schimmel, W. P., Jr.; Lukens, L. L.

1981-11-01

356

Modular solar food dryers for farm use  

SciTech Connect

Several solar food dryer modules have been constructed. Their design has been based on a low-cost, small-scale solar dryer using a unique parabolic reflector construction to increase radiation on the drying surface. Each module has a drying surface of 1.1 M/sup 2/ and a parabolic reflector area of 3.3 M/sup 2/. Some modules are being used to dry mango slices (a potential new food product) for market testing, while others are used for experiments to improve drying efficiency. A description is given of the operating conditions of the modules drying mango slices and the most effective modifications.

Wagner, C.J. Jr.; Coleman, R.L.; Berry, R.E.

1981-01-01

357

Evaluation and optimization of the optical performance of low-concentrating dielectric compound parabolic concentrator using ray-tracing methods.  

PubMed

We present a detailed design concept and optical performance evaluation of stationary dielectric asymmetric compound parabolic concentrators (DiACPCs) using ray-tracing methods. Three DiACPC designs, DiACPC-55, DiACPC-66, and DiACPC-77, of acceptance half-angles (0 and 55), (0 and 66), and (0 and 77), respectively, are designed in order to optimize the concentrator for building faade photovoltaic applications in northern latitudes (>55 N). The dielectric concentrator profiles have been realized via truncation of the complete compound parabolic concentrator profiles to achieve a geometric concentration ratio of 2.82. Ray-tracing simulation results show that all rays entering the designed concentrators within the acceptance half-angle range can be collected without escaping from the parabolic sides and aperture. The maximum optical efficiency of the designed concentrators is found to be 83%, which tends to decrease with the increase in incidence angle. The intensity is found to be distributed at the receiver (solar cell) area in an inhomogeneous pattern for a wide range of incident angles of direct solar irradiance with high-intensity peaks at certain points of the receiver. However, peaks become more intense for the irradiation incident close to the extreme acceptance angles, shifting the peaks to the edge of the receiver. Energy flux distribution at the receiver for diffuse radiation is found to be homogeneous within 12% with an average intensity of 520 W/m. PMID:21743533

Sarmah, Nabin; Richards, Bryce S; Mallick, Tapas K

2011-07-01

358

Offset semi-parabolic nanoantenna made of a photonic crystal parabolic mirror and a plasmonic bow-tie antenna.  

PubMed

In a parabolic mirror, light coming parallel to the antenna passes through its focal point. In this work, a waveguide feeds a semi-parabolic photonic crystal mirror and the emerging beam feeds a bow-tie antenna placed at the mirror's focal point-it is shown that the antenna system can not only feed a bow-tie antenna (producing a localized moderately high electric field) but also produces a directional radiation beam. The semi-parabolic mirror is also modified to reduce reflection back to the feeding waveguide. PMID:25322381

Hattori, Haroldo T

2014-10-10

359

The impact of geometrical parameters on the thermal performance of a solar receiver of dish-type concentrated solar energy system  

Microsoft Academic Search

A three-dimensional model of parabolic dish-receiver system with argon gas as the working fluid is designed to simulate the thermal performance of a dish-type concentrated solar energy system. The temperature distributions of the receiver wall and the working gas are presented. The impact of the aperture size, inlet\\/outlet configuration of the solar receiver and the rim angle of the parabolic

Mo Wang; Kamran Siddiqui

2010-01-01

360

Antenna cab interior showing waveguide from external parabolic antenna (later ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Antenna cab interior showing waveguide from external parabolic antenna (later addition), looking north. - Western Union Telegraph Company, Jennerstown Relay, Laurel Summit Road off U.S. 30, Laughlintown, Westmoreland County, PA

361

Detail, external parabolic antenna (later addition). Note how waveguide was ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail, external parabolic antenna (later addition). Note how waveguide was cut to remove active portion of antenna. - Western Union Telegraph Company, Jennerstown Relay, Laurel Summit Road off U.S. 30, Laughlintown, Westmoreland County, PA

362

Effect of Surface Radiation on Natural Convection in Parabolic Enclosures  

Microsoft Academic Search

The interaction of natural convection and surface radiation in two-dimensional parabolic cavities heated from below with insulated walls and flat top and bottom walls is studied numerically. The shape of the cavities arises from the design of non-imaging optics-based compound parabolic concentrators (CPC). A numerical model based on finite differences is developed to solve the mass, momentum, and energy equations.

Gerardo Diaz; Roland Winston

2008-01-01

363

Parabolic Trough Receiver Heat Loss Testing (Poster)  

SciTech Connect

Parabolic trough receivers, or heat collection elements (HCEs), absorb sunlight focused by the mirrors and transfer that thermal energy to a fluid flowing within them. Thje absorbing tube of these receivers typically operates around 400 C (752 F). HCE manufacturers prevent thermal loss from the absorbing tube to the environment by using sputtered selective Cermet coatings on the absorber and by surrounding the absorber with a glass-enclosed evacuated annulus. This work quantifies the heat loss of the Solel UVAC2 and Schott PTR70 HCEs. At 400 C, the HCEs perform similarly, losing about 400 W/m of HCE length. To put this in perspective, the incident beam radiation on a 5 m mirror aperture is about 4500 W/m, with about 75% of that energy ({approx} 3400 W/m) reaching the absorber surface. Of the 3400 W/m on the absorber, about 3000 W/m is absorbed into the working fluid while 400 W/m is lost to the environment.

Price, H.; Netter, J.; Bingham, C.; Kutscher, C.; Burkholder, F.; Brandemuehl, M.

2007-03-01

364

Design and thermal analysis of a two stage solar concentrator for combined heat and thermoelectric power generation  

Microsoft Academic Search

A design procedure and thermal performance analysis of a two stage solar energy concentrator suited to combined heat and thermoelectric power generation are presented. The concentrator is comprised of a primary one axis parabolic trough concentrator and a second stage compound parabolic concentrator mounted at the focus of the primary. The thermoelectric device is attached to the absorber plate at

Siddig A. Omer; David G. Infield

2000-01-01

365

A solar thermal cooling and heating system for a building: Experimental and model based performance analysis and design  

Microsoft Academic Search

A solar thermal cooling and heating system at Carnegie Mellon University was studied through its design, installation, modeling, and evaluation to deal with the question of how solar energy might most effectively be used in supplying energy for the operation of a building. This solar cooling and heating system incorporates 52 m of linear parabolic trough solar collectors; a 16

Ming Qu; Hongxi Yin; David H. Archer

2010-01-01

366

SARA - Concentration solar array with reflector-radiations  

Microsoft Academic Search

The feasibility of a new design for space solar generators is investigated, which uses cylinder-parabolic reflector-radiators to concentrate solar radiation on to solar cells and to radiate the thermal energy off the solar cells. The reflector-radiators are thermally optimized and their mechanical stability is investigated. A carbon fiber reinforced plastic (CFRP) frame which holds the CFRP reflectors is designed. The

W. D. Ebeling; D. Rex; J. Guelpen; E. Hornung

1978-01-01

367

Solar-thermal electric - Focal point for the desert sun  

Microsoft Academic Search

The applications of solar thermal systems are explored, including flat plate and line-focus collectors, and parabolic and heliostat point focus electrical generators. The first U.S. 10MWe solar tower power plant, Solar One, is due to begin operational testing in 1982, while five other projects are under way in Europe and Japan. Mention is made of the use of solar thermal

D. van Atta; J. Bigger

1981-01-01

368

Operational Experience from Solar Thermal Energy Projects  

NASA Technical Reports Server (NTRS)

Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

Cameron, C. P.

1984-01-01

369

Operational experience from solar thermal energy projects  

NASA Astrophysics Data System (ADS)

Over the past few years, Sandia National Laboratories were involved in the design, construction, and operation of a number of DOE-sponsored solar thermal energy systems. Among the systems currently in operation are several industrial process heat projects and the Modular Industrial Solar Retrofit qualification test systems, all of which use parabolic troughs, and the Shenandoah Total Energy Project, which uses parabolic dishes. Operational experience has provided insight to both desirable and undesirable features of the designs of these systems. Features of these systems which are also relevant to the design of parabolic concentrator thermal electric systems are discussed. Other design features discussed are system control functions which were found to be especially convenient or effective, such as local concentrator controls, rainwash controls, and system response to changing isolation. Drive systems are also discussed with particular emphasis of the need for reliability and the usefulness of a manual drive capability.

Cameron, C. P.

1984-03-01

370

Performance Study of the Solar Box type Stove using Two Phase Change Materials  

NASA Astrophysics Data System (ADS)

Solar cooker has not gained the popularity it deserves both in rural and urban India despite its obvious benefits and availability of plenty of sunny days. Some of the major limitations being: longer cooking time and non availability of the cooking facility during early morning and night hours. These drawbacks have been addressed in the present solar cooker by using a combination of two phase change materials (PCM) having melting temperatures in the range of 80-100C and 120-140C for efficient and sufficient storage of heat energy for extended cooking during night or early morning. The choice of PCM is decided by considering several factors which include melting temperature, latent heat capacity, and risk exposure to humans, water hazard and cost of the material. The right selection of PCM hence is very crucial in determining the performance and safety of operation. The optimization of increased solar flux with multiple reflectors, heat retention ability and utilization of heat conducting fins further reduces the cooking time considerably. An attempt has also been made to design tailor made cooking containers for good heat absorption from sun as well as good conduction of heat from PCM to containers during night cooking.

Bahal, Beni Madhaw

371

Control of a large scale solar thermal energy storage system  

Microsoft Academic Search

Dynamic simulation results for a thermal energy storage (TES) unit used in a parabolic trough concentrated solar power (CSP) system are presented. A two-tank-direct method is used for the thermal energy storage. The heat transfer fluid flow rate through the solar collector maintains a constant outlet temperature and the flow rate through the boiler regulates power output. The use of

Kody M. Powell; Thomas F. Edgar

2011-01-01

372

Fluidized bed- solar concentrator thermal storage system performance  

Microsoft Academic Search

The fluidized bed performance is predicted when it is coupled to a solar parabolic concentrator. The prediction method uses the one dimensional fluidized bed model in connection to a solar concentrator-receiver model. An analytical study of the different design parameters such as the concentration ratio, concentrator aperture area and the size of the fluidized bed is presented. The results are

I. E. Megahed; M. M. Elsayed; M. M. El-Refaee

1988-01-01

373

Line focus solar thermal central receiver research study  

Microsoft Academic Search

The results of a study to examine the line focus central receiver alternative for solar thermal generation of electric power on a commercial scale are presented. The baseline concept consists of the following elements: (1) A solar collector (heliostat) whose geometry is the equivalent of a focused parabolic cylinder. The heliostat reflecting surface is composed of an array of flexible

D. G. Dicanio; W. J. Treytl; F. A. Jur; C. D. Watson

1979-01-01

374

Exergetic analysis of a solar thermal power system  

Microsoft Academic Search

This communication presents a second law analysis based on an exergy concept for a solar thermal power system. Basic energy and exergy analysis for the system components (viz. parabolic trough collector\\/receiver and Rankine heat engine, etc.) are carried out for evaluating the respective losses as well as exergetic efficiency for typical solar thermal power systems under given operating conditions. It

Narendra Singh; S. C. Kaushik; R. D. Misra

2000-01-01

375

Siting Utility-Scale Concentrating Solar Power Projects  

Microsoft Academic Search

In 2002, Congress asked the U.S. Department of Energy to develop and scope out an initiative to fulfill the goal of having 1,000 megawatts (MW) of new parabolic trough, power tower, and dish engine solar capacity supplying the southwestern United States. In this paper, we present a review of the solar resource for Arizona, California, Nevada, and New Mexico. These

M. Mehos; B. Owens

2005-01-01

376

Surface Error Estimation of Pseudo-ParabolicSurface Made by Using Gore Membranes  

NASA Astrophysics Data System (ADS)

In this paper, we describe the surface error of pseudo-parabolic surface, to construct an inflatable parabolic reflector. The gore sheet is generated by cutting the three-dimensional parabolic surface. A scheme of generating the gore sheet is described, and the rms surface error between the parabolic surface and the three-dimensional shape composed of the gore sheets is proposed and formulated. The rms surface error between the parabolic surface and the shape produced by pressurizing the circular membrane is also formulated. Finally, the possibility that the parabolic reflector composed of the gore sheets has high surface accuracy is shown.

Nagata, Tomoko; Ishida, Ryohei

377

Performance of a direct steam generation solar thermal power plant for electricity production as a function of the solar multiple  

Microsoft Academic Search

This paper describes the influence of the solar multiple on the annual performance of parabolic trough solar thermal power plants with direct steam generation (DSG). The reference system selected is a 50MWe DSG power plant, with thermal storage and auxiliary natural gas-fired boiler. It is considered that both systems are necessary for an optimum coupling to the electricity grid. Although

M. J. Montes; A. Abnades; J. M. Martnez-Val

2009-01-01

378

Wind loads on heliostats and parabolic dish collectors: Final subcontractor report  

SciTech Connect

A major intent of this study was to define wind load reduction factors for parabolic dish solar collectors within a field protected by upwind collectors, wind protective fences, or other blockages. This information will help researchers improve the economy of parabolic collector support structures and drive mechanisms. The method used in the study was to generalize wind load data obtained during tests on model collectors placed in a modeled atmospheric wind in a boundary-layer wind tunnel. A second objective of the study was to confirm and document a sensitivity in load to level of turbulence, or gustiness, in the approaching wind. A key finding was that wind-load reduction factors for forces (horizontal and vertical) were roughly similar to those for flat heliostats, with some forces significantly less than those for flat shapes. However, load reductions for moments showed a smaller load reduction, particularly for the azimuth moment. The lack of load reduction could be attributed to collector shape, but specific flow features responsible for and methods to induce a load reduction were not explored. 62 figs., 13 tabs.

Peterka, J.A.; Tan, Z.; Bienkiewicz, B.; Cermak, J.E.

1988-11-01

379

One-axis tracking optimization of Concentrating Solar Power plant for electricity production  

Microsoft Academic Search

Among available technologies for energy production from solar source, Concentrating Solar Power could give a significant contribution to develop a more sustainable energy system. This work is aimed to investigate a Concentrating Solar-Trough plant, having nominal power equal to 100 kWe and exploiting linear parabolic collectors, to generate electric energy by means of Organic Rankine Cycle Turbine. In particular, a

Maria Dicorato; Giuseppe Forte; Mariagiovanna Pisani; Enrico De Tuglie

2010-01-01

380

Experimental comparison of alternative convection suppression arrangements for concentrating integral collector storage solar water heaters  

Microsoft Academic Search

An experimental investigation of an inverted absorber integrated collector storage solar water heater mounted in the tertiary cavity of a compound parabolic concentrator with a secondary cylindrical reflector has been performed under simulated solar conditions. The solar water heaters performance was determined with the aperture parallel to the simulator for a range of transparent baffles positioned at different locations within

M. Smyth; P. McGarrigle; P. C. Eames; B. Norton

2005-01-01

381

Solar thermal system engineering guidebook. Final report 24 sep 82-31 may 83  

Microsoft Academic Search

This report presents a graphical methodology for the preliminary evaluation of solar thermal energy plants by Air Force base civil engineers. The report is organized as a Guidebook with worksheets and nomograms provided for rapid estimation of solar collector area, land area, energy output, and thermal power output of a solar thermal plant. Flat plate, evacuated tube, parabolic trough, and

M. K. Selcuk; S. A. Bluhm

1983-01-01

382

Advances in solar thermal electricity technology  

Microsoft Academic Search

Various advanced solar thermal electricity technologies are reviewed with an emphasis on new technology and new market approaches.In single-axis tracking technology, the conventional parabolic trough collector is the mainstream established technology and is under continued development but is soon to face competition from two linear Fresnel reflector (LFR) technologies, the CLFR and Solarmundo. A Solarmundo prototype has been built in

D. Mills

2004-01-01

383

Solar energy tracking and collector apparatus  

Microsoft Academic Search

An apparatus for tracking and collecting solar energy including at least one collector having elongated reflective surfaces which are parabolic in cross-section. A heat collection and transfer conduit is carried by said collector with said conduit having an inlet at one end and an outlet at the other end. The inlet is connected to an inlet manifold and the outlet

C. B. Marshall; L. A. Marshall

1982-01-01

384

Determination of source terms in a degenerate parabolic equation  

NASA Astrophysics Data System (ADS)

In this paper, we prove Lipschitz stability results for inverse source problems relative to parabolic equations. We use the method introduced by Imanuvilov and Yamamoto in 1998 based on Carleman estimates. What is new here is that we study a class of one-dimensional degenerate parabolic equations. In our model, the diffusion coefficient vanishes at one extreme point of the domain. Instead of the classical Carleman estimates obtained by Fursikov and Imanuvilov for non degenerate equations, we use and extend some recent Carleman estimates for degenerate equations obtained by Cannarsa, Martinez and Vancostenoble. Finally, we obtain Lipschitz stability results in inverse source problems for our class of degenerate parabolic equations both in the case of a boundary observation and in the case of a locally distributed observation.

Cannarsa, P.; Tort, J.; Yamamoto, M.

2010-10-01

385

Shenandoah Solar Total-Energy Project  

NASA Astrophysics Data System (ADS)

The design and construction of the world's first solar total energy plant in the private sector was completed and checkout is underway. During its operational phase, the solar plant will furnish electrical power, process steam, and other thermal energy to a nearby knitwear factory. The solar system consists of a collector field containing 114 parabolic dish collectors which supply thermal energy at 4000 C to drive a 400 kW multistage Rankine cycle turbine generator. Some steam is extracted from the turbine and supplied to the knitwear manufacturing processes. The system will be grid connected. Presented are a description of the system and components being installed; a summary of performance testing of the extraction turbine and of four prototype parabolic dish collectors; and a discussion of design considerations and insights which have general applicability to solar thermal system designs.

Leonard, J. A.; Hunke, R. W.

1982-12-01

386

Rotational Disruption of Comets with Parabolic Orbits  

NASA Astrophysics Data System (ADS)

One of the most fundamental problems in planetary science is the natural lifetime of comets, which is limited by several processes, most notably by spontaneous disruption of the nucleus. While the underlying mechanism is uncertain, rapid rotation is often suspected. To address this problem, I derived the probability of rotational disruption, and investigated it for comets with parabolic orbits as a function of perihelion distance and nucleus size for a range of input parameters. The disruption probability is defined as the ratio of expected change in the rotation rate to the allowable span of the rotation rate, the latter being limited by the critical rotation rate (prograde and retrograde), which I adopted from Davidsson (2001, Icarus 149, 375). The expected change in the rotation rate, resulting from the action of torques generated by mass loss, is calculated following the standard approach (e.g. Drahus et al. 2011, ApJL 734, L4, and ref. therein), but taking into account the suspected decrease of the net torque with an increasing active fraction of the nucleus (Jewitt 1997, EM&P 79, 35; Samarasinha & Mueller 2013, ApJL 775, L10). The sublimation flux is obtained from the standard energy balance equation (e.g. Cowan & AHearn 1979, M&P 21, 155), but I also take into account extinction of sunlight in the dust coma. I find that close to the Sun coma transmission steeply decreases with a decreasing heliocentric distance, resulting in the sublimation flux at a remarkably constant level, and also that coma transmission decreases with an increasing nucleus size, both properties being critically important in the calculation of sublimation flux for large sungrazers. The obtained rotational-disruption probability features several interesting properties. It has a well-defined regime occupied by smaller comets closely approaching the Sun, for which rotational disruption is unavoidable regardless of the original rotation state. Moreover, the probability function offers a very close match to the empirical survival cutoff for long-period comets with perihelia of less than 0.5 AU (Bortle 1991, ICQ 13, 89), independently suggesting that rotational disruption is the primary mechanism responsible for the destruction of comets.

Drahus, Michal

2014-11-01

387

Output Feedback Control of Parabolic PDE Systems with Input Constraints1  

E-print Network

by quasi-linear parabolic PDEs. Examples in- clude tubular reactors, packed-bed reactors, and chemical vapor deposition reactors. Parabolic PDE systems typi- cally involve spatial differential operators

Sontag, Eduardo

388

Property estimation using inverse methods for elliptic and parabolic partial differential equations  

E-print Network

In this work we use inverse methods to estimate flow coefficients in both elliptic and parabolic partial differential equations. An algorithm is developed to solve a one layer problem for elliptic and parabolic partial differential equations...

Parmekar, Sandeep

1994-01-01

389

Current and future costs for parabolic trough and power tower systems in the US market.  

SciTech Connect

NREL's Solar Advisor Model (SAM) is employed to estimate the current and future costs for parabolic trough and molten salt power towers in the US market. Future troughs are assumed to achieve higher field temperatures via the successful deployment of low melting-point, molten-salt heat transfer fluids by 2015-2020. Similarly, it is assumed that molten salt power towers are successfully deployed at 100MW scale over the same time period, increasing to 200MW by 2025. The levelized cost of electricity for both technologies is predicted to drop below 11 cents/kWh (assuming a 10% investment tax credit and other financial inputs outlined in the paper), making the technologies competitive in the marketplace as benchmarked by the California MPR. Both technologies can be deployed with large amounts of thermal energy storage, yielding capacity factors as high as 65% while maintaining an optimum LCOE.

Turchi, Craig (National Renewable Energy Laboratory, Golden, CO); Kolb, Gregory J.; Mehos, Mark Steven (National Renewable Energy Laboratory, Golden, CO); Ho, Clifford Kuofei

2010-08-01

390

Application and Operations Concepts of Large Transmit Phased Array of Parabolic Reflectors  

NASA Technical Reports Server (NTRS)

The primary motive for large transmit array of parabolic reflectors, also known as Uplink Array, was to explore alternate methods in order to replace the large 70m antennas of Deep Space Network (DSN) such that the core capability for emergency support to a troubled spacecraft in deep space is preserved. Given that the Uplink Array is a new technology, the focus has always been on its feasibility and phase calibration techniques, which by itself is quite a challenge. It would be interesting to examine, however, what else could be accomplished by the Uplink Array capability other than the emergency support to a troubled spacecraft in deep space. ... The objective of this paper is to discuss a few application scenarios and the corresponding operation concepts, such as lunar positioning system, high EIRP uplink and the synergies with solar radar, and high power RF beams.

Amoozegar, Farid

2006-01-01

391

A comparison of prototype compound parabolic collector-reactors (CPC) on the road to SOLARDETOX technology.  

PubMed

Solar photocatalytic detoxification of non-biodegradable chlorinated hydrocarbon solvents (NBCS) is carried out in different concentrating and non concentrating devices using TiO2 as a photocatalyst fixed on the inner surface of the reaction tubes or as a slurry catalyst which has to be removed from the treated water. The reaction is most effective using 200 mg/l of TiO2 as a slurry in a non concentrating CPC reactor. The concentrating parabolic trough reactor has a poor activity because of its minor irradiated reactor surface. Catalyst coated glass tubes are less efficient then the used slurry catalyst. Their advantage is that no catalyst has not to be removed from the treated water and there is no loss of activity during treatment. Yet their physical stability is not sufficient to be competitive to the slurry catalyst. Nevertheless the degradation results are very promising and will possibly lead to commercial applications of this technology. PMID:11695470

Funken, K H; Sattler, C; Milow, B; De Oliveira, L; Blanco, J; Fernndez, P; Malato, S; Brunott, M; Dischinge, N; Tratzky, S; Musci, M; de Oliveira, J C

2001-01-01

392

Current and Future Costs for Parabolic Trough and Power Tower Systems in the US Market: Preprint  

SciTech Connect

NREL's Solar Advisor Model (SAM) is employed to estimate the current and future costs for parabolic trough and molten salt power towers in the US market. Future troughs are assumed to achieve higher field temperatures via the successful deployment of low melting-point, molten-salt heat transfer fluids by 2015-2020. Similarly, it is assumed that molten salt power towers are successfully deployed at 100MW scale over the same time period, increasing to 200MW by 2025. The levelized cost of electricity for both technologies is predicted to drop below 11 cents/kWh (assuming a 10% investment tax credit and other financial inputs outlined in the paper), making the technologies competitive in the marketplace as benchmarked by the California MPR. Both technologies can be deployed with large amounts of thermal energy storage, yielding capacity factors as high as 65% while maintaining an optimum LCOE.

Turchi, C.; Mehos, M.; Ho, C. K.; Kolb, G. J.

2010-10-01

393

Microgravity research during aircraft parabolic flights: the 20 ESA campaigns.  

PubMed

Aircraft parabolic flights provide repeated periods of up to 20 seconds of reduced gravity during ballistic flight manoeuvres, preceded and followed by 20 seconds of 1.8 g. Such flights are used to conduct short microgravity investigations in physical and life sciences, to test instrumentation and to train astronauts before a spaceflight. Since 1984, ESA's Microgravity Projects Division has organised 20 parabolic flight campaigns using three different types of aircraft. More than 1700 parabolas have been flown, representing nine and half hours of microgravity in slices of 20 seconds, or equivalently, six low Earth orbits. A total of 235 experiments have been performed using this unique microgravity tool. PMID:14971370

Pletser, V

1995-05-01

394

Accelerating Airy beams with non-parabolic trajectories  

NASA Astrophysics Data System (ADS)

A class of Airy accelerating beams with non-parabolic trajectories are derived by means of a novel application of a conformal transformation originally due to Bateman. It is also shown that the salient features of these beams are very simply incorporated in a solution which is derived by applying a conventional conformal transformation together with a Galilean translation to the basic accelerating Airy beam solution of the two-dimensional paraxial equation. Motivation for the non-parabolic beam trajectories is provided and the effects of finite-energy requirements are discussed.

Besieris, Ioannis M.; Shaarawi, Amr M.

2014-11-01

395

Nonlocal Operators, Parabolic-type Equations, and Ultrametric Random Walks  

E-print Network

In this article we introduce a new type of nonlocal operators and study the Cauchy problem for certain parabolic-type pseudodifferential equations naturally associated to these operators. Some of these equations are the p-adic master equations of certain models of complex systems introduced by Avetisov et al. The fundamental solutions of these parabolic-type equations are transition functions of random walks on the n-dimensional vector space over the field of p-adic numbers. We study some properties of these random walks, including the first passage time.

L. F. Chacn-Cortes; W. A. Ziga-Galindo

2014-08-22

396

Solar Total Energy at Sandia Labs  

Microsoft Academic Search

The Sandia Laboratories' Solar Total Energy Program is described. This program consists of designing, building, installing, and operating a field of concentrating parabolic trough solar collectors which provide energy at 310 C, a 32-kW organic Rankine cycle power plant, and the heating and cooling equipment to utilize the cascaded, low-temperature energy from the turbine\\/generator. Included in the presentation are descriptions

J. A. Leonard

1976-01-01

397

Air Brayton Solar Receiver, phase 1  

NASA Technical Reports Server (NTRS)

A six month analysis and conceptual design study of an open cycle Air Brayton Solar Receiver (ABSR) for use on a tracking, parabolic solar concentrator are discussed. The ABSR, which includes a buffer storage system, is designed to provide inlet air to a power conversion unit. Parametric analyses, conceptual design, interface requirements, and production cost estimates are described. The design features were optimized to yield a zero maintenance, low cost, high efficiency concept that will provide a 30 year operational life.

Zimmerman, D. K.

1979-01-01

398

Line-focus solar thermal energy technology development. FY 79 annual report for Department 4720  

SciTech Connect

The primary role of the Solar Energy Projects Department II (4720) is the development, evaluation, and testing of line-focus solar thermal technology. This report of FY 79 progress and accomplishments is divided into two parts: (1) Component and Subsystem Development including the design and analysis of collector modules, their components, and associated materials and processes, and (2) Systems and Applications Development, involving larger configurations of solar thermal line-focus systems. The emphasis is on parabolic troughs, but significant efforts on hemispherical bowls, compound parabolic collectors, and dishes for the Solar Total Energy Project are also described.

Bergeron, K D; Champion, R L; Hunke, R W [eds.

1980-04-01

399

Midtemperature solar systems test facility predictions for thermal performance based on test data: solar kinetics T-600 solar collector with FEK 244 reflector surface  

SciTech Connect

Sandia National Laboratories, Albuquerque (SNLA), is currently conducting a program to predict the performance and measure the characteristics of commercially available solar collectors that have the potential for use in industrial process heat and enhanced oil recovery applications. The thermal performance predictions for the Solar Kinetics T-600 solar line-focusing parabolic trough collector are presented for three output temperatures at five cities in the US. (WHK)

Harrison, T.D.

1981-04-01

400

Parabolic lines and caustics in weakly anisotropic solids 9iFODY##9DYU\\XN  

E-print Network

117 Parabolic lines and caustics in weakly anisotropic solids 9iFODY##9DYU\\þXN *HRSK@ig.cas.cz Summary The behaviour of parabolic lines and caustics in anisotropic solids can be, in general, very, no parabolic lines appear on the S1 slowness sheet. Consequently, the S1 wave sheet displays no caustics

Cerveny, Vlastislav

401

Fermi Energy in the Non-Parabolic Band Structure of a Carbon Nanotube  

Microsoft Academic Search

The band structure of a carbon nanotube is obtained from the graphene band structure. The band energy of CNT near to the minimum band energy is parabolic. However it is not parabolic in other regions. In the non-parabolic regime the density of states is proportional to a numerical integral that is different from Fermi integrals. The carrier statistics to all

Mohammad Taghi Ahmadi; Jeffrey Frank Webb; Razali Ismail

2009-01-01

402

FERMI ENERGY IN THE NON-PARABOLIC BAND STRUCTURE OF A CARBON NANOTUBE  

Microsoft Academic Search

The band structure of a carbon nanotube is obtained from the graphene band structure. The band energy of CNT near to the minimum band energy is parabolic. However it is not parabolic in other regions. In the non-parabolic regime the density of states is proportional to a numerical integral that is different from Fermi integrals. The carrier statistics to all

Mohammad Taghi Ahmadi; Jeffrey Frank Webb; Razali Ismail

2009-01-01

403

A MODEL REDUCTION APPROACH TO NUMERICAL INVERSION FOR A PARABOLIC PARTIAL DIFFERENTIAL EQUATION  

E-print Network

, and assess its performance with numerical experiments. Key words. Inverse problem, parabolic, CSEM, modelA MODEL REDUCTION APPROACH TO NUMERICAL INVERSION FOR A PARABOLIC PARTIAL DIFFERENTIAL EQUATION a novel numerical inversion algorithm for parabolic partial differential equations, based on model

Borcea, Liliana

404

Build an oven, cook a meal: How solar energy empowered women in Costa Rica  

SciTech Connect

A pilot solar cooking project in the hot, northern province of Guanacaste promises to serve as a model for community groups wanting to build their own solar ovens. An $8,000 (US) grant has been awarded by the Canadian Embassy in Costa Rica to take the Guanacaste project into a second stage in 1990-91. Two construction workshops, with twelve participants in each, are planned in communities near Oriente. Three women from the Oriente group will have paid jobs as organizational facilitators and workshop supervisors. In popular education this is called the multiplier effect - the users of solar cookers construct the ovens themselves, and then instruct others to do the same. 3 refs.

Blankenship, J. (Canadian Univ. Service Organization, San Jose (Costa Rica))

1990-12-01

405

Solar-pumped solid-state lasers  

SciTech Connect

Results are presented for direct solar pumping of a ND:YAG rod laser. Stable CW output of more than 60 W was obtained with a slope efficiency exceeding 2 percent. A compound parabolic concentrator, designed to increase the solar radiation coupled into the laser rod, was used in these experiments. The results are consistent with predictions based on a simple solar-pumped laser model, which is also presented. Using this model, it is shown that existing laser materials with broad-band absorption characteristics (e.g., alexandrite and Nd:Cr:GSGG) have a potential for better than 10 percent overall conversion efficiency when solar pumped.

Weksler, M.; Shwartz, J.

1988-06-01

406

Concentrating Solar Power Program  

NSDL National Science Digital Library

This information resource related to renewable energy has recently been made available by the US Department of Energy. The Concentrating Solar Power Program is researching solar thermal technologies in order to provide future energy, economic, and environmental security for the US. This site provides an overview of the program, the program's strategic plan, and an analysis of the three technologies being researched: the power tower, dish/engine, and parabolic trough systems. Cost and performance analysis results for each technology are included (Adobe Acrobat [.pdf] format only). [Notes: Originally reviewed in conjunction with other resources. To read the full review, link to the archived Scout Report via the Date of Review above. Site formerly known as "Solar Thermal Electric Program (STEP)."

1997-01-01

407

Optical measurements pertaining to Space Station solar dynamic power systems  

NASA Technical Reports Server (NTRS)

The Space Station solar dynamic power system is a hybrid of solar photovoltaic and solar dynamic systems, the latter of which uses a parabolic reflector to collect solar energy. This paper describes analytical results of an off-axis solar illumination on the intensity distribution in arbitrary target planes perpendicular to the axis of a parabolic reflector. Such computational capability would make it possible to predict optical intensity distributions resulting from off-axis angles of incident radiation on such target planes. To validate the computer code, experimental optical measurements were performed on the multifaceted paraboloidal collecor at the Solar Dynamic Test Facility at Rockedyne's Santa Susana Field Laboratory. The experimental data compared reasonably well with the calculated values.

Holly, S.; Springer, T.; Jefferies, K. S.

1987-01-01

408

Galerkin proper orthogonal decomposition methods for parabolic problems  

Microsoft Academic Search

Summary. In this work error estimates for Galerkin proper orthogonal decomposition (POD) methods for linear and certain non-linear\\u000a parabolic systems are proved. The resulting error bounds depend on the number of POD basis functions and on the time discretization.\\u000a Numerical examples are included.

K. Kunisch; S. Volkwein

2001-01-01

409

Runge-Kutta Time Discretization of Fully Nonlinear Parabolic Problems  

E-print Network

Runge-Kutta Time Discretization of Fully Nonlinear Parabolic Problems Mechthild Thalhammer October of the institute Gerhard and Gnther Cesar and Cesreo #12; #12; Abstract In the present work we study Runge-Kutta existence and con- vergence results for Runge-Kutta methods under certain smoothness assumptions

Thalhammer, Mechthild

410

Explicit Runge-Kutta methods for parabolic partial differential equations  

Microsoft Academic Search

Numerical methods for parabolic PDEs have been studied for many years. A great deal of the research focuses on the stability problem in the time integration of the systems of ODEs which result from the spatial discretization. These systems often are stiff and highly expensive to solve due to a huge number of components, in particular for multi-space dimensional problems.

J. G. Verwer

1996-01-01

411

On strongly Petrovski's parabolic SPDEs in arbitrary dimension  

Microsoft Academic Search

In this paper we show that the Cahn-Hilliard stochastic SPDE has a function valued solution in dimension 4 and 5 when the perturbation is driven by a space-correlated Gaussian noise. This is done proving general results on SPDEs with globally Lipschitz coefficients associated with operators on smooth domains of Rd which are parabolic in the sense of Petrovski, and do

C. Cardon-Weber; A. Millet

412

A UNIVERSAL PARABOLIC MAP A. EPSTEIN AND M. YAMPOLSKY  

E-print Network

A UNIVERSAL PARABOLIC MAP A. EPSTEIN AND M. YAMPOLSKY Of all the beautiful developments in modernS]) and Douady-Hubbard [DH2], fol- lowing an important #12;rst step taken earlier by H. Epstein [E, EE]. We?culty in specifying Date: November 17, 2002. 1 #12; 2 A. EPSTEIN AND M. YAMPOLSKY a well-de#12;ned renormalized circle

Yampolsky, Michael

413

A four-lens corrector for parabolic reflectors  

NASA Astrophysics Data System (ADS)

This paper describes the designing of a four-lens corrector system for parabolic mirrors incorporating a final optimization with a computer. An example for the Palomar 5.08 m telescope is worked out, which proves to give smaller image blur circles than Wynne's design [4].

Zhou, Bi-fang

1980-09-01

414

Long-term average performance benefits of parabolic trough improvements  

SciTech Connect

Improved parabolic trough concentrating collectors will result from better design, improved fabrication techniques, and the development and utilization of improved materials. The difficulty of achieving these improvements varies as does their potential for increasing parabolic trough performance. The purpose of this analysis is to quantify the relative merit of various technology advancements in improving the long-term average performance of parabolic trough concentrating collectors. The performance benefits of improvements are determined as a function of operating temperature for north-south, east-west, and polar mounted parabolic troughs. The results are presented graphically to allow a quick determination of the performance merits of particular improvements. Substantial annual energy gains are shown to be attainable. Of the improvements evaluated, the development of stable back-silvered glass reflective surfaces offers the largest performance gain for operating temperatures below 150/sup 0/C. Above 150/sup 0/C, the development of trough receivers that can maintain a vacuum is the most significant potential improvement. The reduction of concentrator slope errors also has a substantial performance benefit at high operating temperatures.

Gee, R.; Gaul, H.W.; Kearney, D.; Rabl, A.

1980-03-01

415

Theory of parabolic pulse generation in tapered Anton I. Latkin  

E-print Network

(e.g., Er-doped fiber amplifiers, Yb- doped fiber, or passive optical fibers with distributed Raman.g., telecommunication signal processing) where high signal power is not required and the most valu- able features are the specific parabolic pulse shape and chirp. An active medium, inevitably, introduces amplified spontaneous

Turitsyn, Sergei K.

416

Parabolic Anderson model with a finite number of moving catalysts  

E-print Network

Parabolic Anderson model with a finite number of moving catalysts F. Castell, O. G¨un and G- actant" u under the influence of a "catalyst" . In the present paper we focus on the case where of particles A and B. A-particles represent "catalysts", B-particles represent "reactants" and the dynamics

Maillard, Grégory

417

The dynamics of parabolic flight: flight characteristics and passenger percepts.  

PubMed

Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 seconds of freefall (0 g) followed by 40 seconds of enhanced force (1.8 g), repeated 30-60 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity. " Despite the aircraft trajectory including large (45) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments. PMID:19727328

Karmali, Faisal; Shelhamer, Mark

2008-09-01

418

The dynamics of parabolic flight: flight characteristics and passenger percepts  

PubMed Central

Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 seconds of freefall (0 g) followed by 40 seconds of enhanced force (1.8 g), repeated 3060 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity. " Despite the aircraft trajectory including large (45) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments. PMID:19727328

Karmali, Faisal; Shelhamer, Mark

2008-01-01

419

Non-Reflecting Boundary Conditions for Parabolic Approximations  

NASA Astrophysics Data System (ADS)

Recent interest has been shown in the formulation and implementation of non-reflecting boundary conditions for use at the upper boundary in atmospheric acoustic propagation modeling codes. We consider both the accuracy and performance of boundary conditions which are alternatives to the traditional use of an artificial absorbing layer for implementations with parabolic equation computations. Comparisons between analytical solutions and finite difference computations using the alternative exact boundary condition demonstrate that the latter effectively treats the upper atmospheric boundary. Comparisons are made between an absorbing layer treatment and the exact non-reflecting boundary condition. Results are presented applying the computational model to propagation through inhomogeneous atmospheres and over surfaces with different impedances. The exact boundary condition is shown to compare favorably with the absorbing layer. The computational efficiency of the alternatives for modeling the upper atmospheric boundary is addressed. Numerical schemes are developed for improving the efficiency of computing the non-local, non-reflecting boundary conditions. The computational burden is relieved through appropriate use of truncation and through analysis of the discretization scheme. The wide-angle parabolic equation is applied to atmospheric acoustic propagation. The wide-angle model using an absorbing layer is compared with the same model using a new exact non-reflecting boundary condition developed for the wide-angle parabolic approximation. Application of the non-reflecting boundary condition to higher-order parabolic approximations is addressed.

Jardine, Richard Joseph

420

On the parabolized Navier-Stokes equations without sublayer assumptions  

Microsoft Academic Search

A new implicit, iteractive method of solving the Parabolized Navier-Stokes (PNS) Equations claims to overcome the elliptic character of the embedded subsonic sublayer by explicitly introducing pressure as an additional state variable. The Bhutta-Lewis approach makes no sublayer pressure assumptions. The validity and basis of that method is explored in this thesis by examining the relevant eigenvalues governing marching stability.

Stephen C. Pluntze

1987-01-01

421

FLOW PARAMETER ESTIMATION USING THE PARABOLIZED NAVIER-STOKES EQUATIONS  

Microsoft Academic Search

The estimation of the inflow parameters from measurements in flow-field is considered in the optimization statement. The flow is assumed to be two dimensional, supersonic, viscous, laminar one governed by the parabolized Navier-Stokes equations. The adjoint problem for the residual gradient calculation is formulated and studied. Both direct and adjoint problems are solved by finite difference method. The calculations of

ALEKSEY K. ALEKSEEV

422

The Planar Parabolic Optical Antenna David T. Schoen,,  

E-print Network

antennas Controlling the far-field emission pattern of nanoscale objects is one of the central goalsThe Planar Parabolic Optical Antenna David T. Schoen,, Toon Coenen, F. Javier Garca de Abajo, Mark L. Brongersma, and Albert Polman*, Stanford University, Stanford, California 94305, United States

Polman, Albert

423

A Discontinuous Galerkin method applied to nonlinear parabolic equations  

Microsoft Academic Search

Semi-discrete and a family of discrete time locally conservative Discontinuous Galerkin procedures are formulated for approximations to nonlinear parabolic equations. For the continuous time approximations a priori L 1 (L 2 ) and L 2 (H 1 ) estimates are derived and similarly, l 1 (L 2 ) and l 2 (H 1 ) for the discrete time schemes. Spatial

Batrice Rivire; Mary F. Wheeler

2000-01-01

424

An Application of Calculus: Optimum Parabolic Path Problem  

ERIC Educational Resources Information Center

A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object

Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali

2009-01-01

425

Performance of solar electric generating systems on the utility grid  

Microsoft Academic Search

The first year of performance of the Solar Electric Generating System I (SEGS I), which has been operating on the Southern California Edison (SCE) grid since December 1984 is discussed. The solar field, comprised of 71,680 m² of Luz parabolic trough line-focus solar collectors, supplies thermal energy at approx. 585°F to the thermal storage tank. This energy is then used

1986-01-01

426

Participation in multilateral effort to develop high performance integrated CPC evacuated collectors. [Compound Parabolic Concentrator (CPC)  

SciTech Connect

The University of Chicago Solar Energy Group has had a continuing program and commitment to develop an advanced evacuated solar collector integrating nonimaging concentration into its design. During the period from 1985--1987, some of our efforts were directed toward designing and prototyping a manufacturable version of an Integrated Compound Parabolic Concentrator (ICPC) evacuated collector tube as part of an international cooperative effort involving six organizations in four different countries. This multilateral'' project made considerable progress towards a commercially practical collector. One of two basic designs considered employed a heat pipe and an internal metal reflector CPC. We fabricated and tested two large diameter (125mm) borosilicate glass collector tubes to explore this concept. The other design also used a large diameter (125mm) glass tube but with a specially configured internal shaped mirror CPC coupled to a U-tube absorber. Performance projections in a variety of systems applications using the computer design tools developed by the International Energy Agency (IEA) task on evacuated collectors were used to optimize the optical and thermal design. The long-term goal of this work continues to be the development of a high efficiency, low cost solar collector to supply solar thermal energy at temperatures up to 250{degree}C. Some experience and perspectives based on our work are presented and reviewed. Despite substantial progress, the stability of research support and the market for commercial solar thermal collectors were such that the project could not be continued. A cooperative path involving university, government and industrial collaboration remains the most attractive near term option for developing a commercial ICPC.

Winston, R.; O'Gallagher, J.J.

1992-05-31

427

IR Spectrometer Using 90-degree Off-axis Parabolic Mirrors  

SciTech Connect

A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light ource at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output IR recording camera. With an initial wavelength range of 15004500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera arrays sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement singlepoint pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.

Robert M. Malone, Richard, G. Hacking, Ian J. McKenna, and Daniel H. Dolan

2008-09-02

428

IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors  

SciTech Connect

A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light Source at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output recording camera. With an initial wavelength range of 15004500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera arrays sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement single-point pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets.

Robert M. Malone, Ian J. McKenna

2008-03-01

429

CHINA'S DUST AFFECTS SOLAR RESOURCE IN THE U.S.: A CASE STUDY Christian A. Gueymard Nels S. Laulainen  

E-print Network

a significant im- pact. Concentrating systems such as parabolic troughs and solar tower plants utilize onlyCHINA'S DUST AFFECTS SOLAR RESOURCE IN THE U.S.: A CASE STUDY Christian A. Gueymard Nels S of how long- range aerosol transport may temporarily affect the U.S. solar resource. Broadband

Oregon, University of

430

Acurex Parabolic Dish Concentrator (PDC-2)  

NASA Technical Reports Server (NTRS)

The design approach, rationale for the selected configuration, and the development status of a cost effective point-focus solar concentrator are discussed. The low-cost concentrator reflective surface design is based on the use of a thin, backsilvered mirror glass reflector bonded to a molded structural plastic substrate. The foundation, support, and drive subassembles are described. A hybrid, two-axis, Sun tracking control system based on microprocessor technology was selected. Coarse synthetic tracking is achieved through a microcomputer-based control system to calculate Sun position for transient periods of cloud cover as well as sundown and sunrise positioning. Accurate active tracking is achieved by two-axis optical sensors. Results of the reflective panel demonstration tests investigating slope error, hail impact survivability, temperature/humidity cycling, longitudinal strength/bending stiffness, and torsional stiffness are discussed.

Overly, P.; Bedard, R.

1982-01-01

431

Solar economy and technology update  

SciTech Connect

The industry, national, and consumer perspectives on solar power are reviewed. With a 30% increase in dealer/installers, and a 30% attrition rate, about 60% of the participants in the market are ''new kids on the block.'' The installed value of the market was $750 million in 1981. There was a 30% decline in volumes, due to the recession, in 1982. As for the national perspective, solar is labor intensive, and generated a billion dollars worth of jobs. As the DOE has abandoned all but high risk ''core technology'' RandD has faltered some. But desiccant heat pumps, polymer collectors, and parabolic collectors are discussed.

Brotherton, T.K.

1983-06-01

432

Fuel from the Sun: Solar commerical and industrial applications for the 1980's  

NASA Astrophysics Data System (ADS)

The use of solar energy for industrial and commercial applications, particularly process heat, is presented. Flat plate, evacuated tube, and parabolic trough solar collectors are described briefly, and their temperature ranges and costs are given. Other solar technologies, including biomass conversion, wind power, solar ponds, photovolttaics, and passive design are also discussed. A checklist is given to help determine the feasibility of a solar heating system for a particular application. Economic aspects of using a solar energy system are discussed. Information is given on the installation and operation of a solar energy system, including the question of solar access.

1981-09-01

433

Research and Development of a Low Cost Solar Collector  

SciTech Connect

This is a Final Technical Report on the Research and Development completed towards the development of a Low Cost Solar Collector conducted under the DOE cost-sharing award EE-0003591. The objective of this project was to develop a new class of solar concentrators with geometries and manufacturability that could significantly reduce the fully installed cost of the solar collector field for concentrated solar thermal power plants. The goal of the project was to achieve an aggressive cost target of $170/m2, a reduction of up to 50% in the total installed cost of a solar collector field as measured against the current industry benchmark of a conventional parabolic trough. The project plan, and the detailed activities conducted under the scope of the DOE Award project addressed all major drivers that affect solar collector costs. In addition to costs, the study also focused on evaluating technical performance of new collector architectures and compared them to the performance of the industry benchmark parabolic trough. The most notable accomplishment of this DOE award was the delivery of a full-scale integrated design, manufacturing and field installation solution for a new class of solar collector architecture which has been classified as the Bi-Planar Fresnel Collector (BPFC) and may be considered as a viable alternative to the conventional parabolic trough, as well as the conventional Fresnel collectors. This was in part accomplished through the design and development, all the way through fabrication and test validation of a new class of Linear Planar Fresnel Collector architecture. This architecture offers a number of key differentiating features which include a planar light-weight frame geometry with small mass-manufacturable elements utilizing flat mirror sections. The designs shows significant promise in reducing the material costs, fabrication costs, shipping costs, and on-site field installation costs compared to the benchmark parabolic trough, as well as the conventional Fresnel collector. The noteworthy design features of the BPFC architecture include the use of relatively cheaper flat mirrors and a design which allows the mirror support beam sections to act as load-bearing structural elements resulting in more than a 36% reduction in the overall structural weight compared to an optimized parabolic trough. Also, it was shown that the utilization of small mass-produced elements significantly lowers mass-production and logistics costs that can more quickly deliver economies of scale, even for smaller installations while also reducing shipping and installation costs. Moreover, unlike the traditional Fresnel trough the BPFC architecture does not require complex articulating drive mechanisms but instead utilizes a standard parabolic trough hydraulic drive mechanism. In addition to the development of the Bi-Planar Fresnel Collector, an optimized conventional space-frame type parabolic trough was also designed, built, analyzed and field-tested during the first phase of this award. The design of the conventional space-frame parabolic collector was refined with extensive FEA and CFD analysis to reduce material costs and re-designed for simpler fabrication and more accurate lower-cost field assembly. This optimized parabolic trough represented an improvement over the state-of-the art of the traditional parabolic trough architecture and also served as a more rigorous and less subjective benchmark that was used for comparison of new candidate design architectures. The results of the expanded 1st phase of the DOE award project showed that both the Optimized Parabolic Trough and the new Bi-Planar Fresnel Collector design concepts failed to meet the primary objectives for the project of achieving a 50% cost reduction from the industry reference total installed cost of $350/m2. Results showed that the BPFC came in at projected total installed cost of $237/m2 representing a 32% savings compared to the industry benchmark conventional parabolic trough. And the cost reduction obtained by the Optimized Parabolic Trough compared to the

Ansari, Asif; Philip, Lee; Thouppuarachchi, Chirath

2012-08-01

434

Application of solar thermal energy to buildings and industry  

SciTech Connect

Flat plate collectors and evacuated tube collectors are described, as are parabolic troughs, Fresnel lenses, and compound parabolic concentrators. Use of solar energy for domestic hot water and for space heating and cooling are discussed. Some useful references and methods of system design and sizing are given. This includes mention of the importance of economic analysis. The suitability of solar energy for industrial use is discussed, and solar ponds, point-focus receivers and central receivers are briefly described. The use of solar energy for process hot water, drying and dehydration, and process steam are examined, industrial process heat field tests by the Department of Energy are discussed, and a solar total energy system in Shenandoah, GA is briefly described. (LEW)

Kutscher, C. F.

1981-05-01

435

Design, cost, and performance comparisons of several solar thermal systems for process heat. Volume 3: Receivers  

NASA Astrophysics Data System (ADS)

The receiver subsystem converts reflected solar radiation into thermal power by heating a working fluid. The cost and performance were estimated for the receiver subsystem for parabolic troughs, parabolic dishes, and central receivers over a wide range of temperatures and power levels for thermal power applications. The fundamental design philosophy employed, the constraints identified, the tradeoffs performed and the cost and performance results obtained for each receiver in the study matrix are described.

Woodard, J. B., Jr.

1981-03-01

436

Physiologic Pressure and Flow Changes During Parabolic Flight (Pilot Study)  

NASA Technical Reports Server (NTRS)

The objective of this study was to obtain measurement of cutaneous tissue perfusion central and peripheral venous pressure, and esophageal and abdominal pressure in human test subjects during parabolic flight. Hemodynamic data recorded during SLS-I and SLS-2 missions have resulted in the paradoxical finding of increased cardiac stroke volume in the presence of a decreased central venous pressure (CVP) following entry in weightlessness. The investigators have proposed that in the absence of gravity, acceleration-induced peripheral vascular compression is relieved, increasing peripheral vascular capacity and flow while reducing central and peripheral venous pressure, This pilot study seeks to measure blood pressure and flow in human test subjects during parabolic flight for different postures.

Pantalos, George; Sharp, M. Keith; Mathias, John R.; Hargens, Alan R.; Watenpaugh, Donald E.; Buckey, Jay C.

1999-01-01

437

Treatment of motion sickness in parabolic flight with buccal scopolamine  

NASA Technical Reports Server (NTRS)

Treatment of acute motion sickness induced by parabolic flight with a preparation of scopolamine placed in the buccal pouch was investigated. Twenty-one subjects flew aboard a KC-135 aircraft operated by NASA which performed parabolic maneuvers resulting in periods of 0-g, 1-g, and 1.8-g. Each subject flew once with a tablet containing scopolamine and once with a placebo in a random order, crossover design. Signs and symptoms of motion sickness were systematically recorded during each parabola by an investigator who was blind to the content of the tablet. Compared with flights using placebo, flights with buccal scopolamine resulted in significantly lower scores for nausea (31-35 percent reduction) and vomiting (50 percent reduction in number of parabolas with vomiting). Side effects of the drug during flight were negligible. It is concluded that buccal scopolamine is more effective than a placebo in treating ongoing motion sickness.

Norfleet, William T.; Degioanni, Joseph J.; Reschke, Millard F.; Bungo, Michael W.; Kutyna, Frank A.; Homick, Jerry L.; Calkins, D. S.

1992-01-01

438

A technique for comparing parabolic trough photovoltaic performance  

NASA Astrophysics Data System (ADS)

An analysis was performed to predict the power outputs of 4- and 7-foot aperture linear parabolic troughs. The analysis was part of a trade-off study to reduce the cost of the BDM 47 kW concentrating PV applications experiment (PRDA-35) by using fewer larger aperture collectors. The key feature of the analysis was the use of laser scans of the troughs to provide individual insolation inputs to cell computer models. The analysis, using the Photovoltaic Transient Analysis Program (PV-TAP), led to the selection of the larger trough for the PRDA system. The techniques detailed in this paper can serve as a valuable tool in predicting the output of proposed collector designs. This paper also presents the results of the trade-off and conclusions pertinent to parabolic troughs in general.

Lambarski, T. J.; Higbie, J. A.; Rogers, C. B.

439

Development and testing of Parabolic Dish Concentrator No. 1  

NASA Technical Reports Server (NTRS)

Parabolic Dish Concentrator No. 1 (PDC-1) is a 12-m-diameter prototype concentrator with low life-cycle costs for use with thermal-to-electric energy conversion devices. The concentrator assembly features panels made of a resin transfer molded balsa core/fiberglass sandwich with plastic reflective film as the reflective surface and a ribbed framework to hold the panels in place. The concentrator assembly tracks in azimuth and elevation on a base frame riding on a circular track. It is shown that the panels do not exhibit the proper parabolic contour. However, thermal gradients were discovered in the panels with daily temperature changes. The PDC-1 has sufficient optical quality to operate satisfactorily in a dish-electric system. The PDC-1 development provides the impetus for creating innovative optical testing methods and valuable information for use in designing and fabricating concentrators of future dish-electric systems.

Dennison, E. W.; Thostesen, T. O.

1984-01-01

440

Solution method of parabolized Navier-Stokes equations  

NASA Astrophysics Data System (ADS)

Laminar and turbulent incompressible flow through curved channels is studied via artificially parabolized Navier-Stokes equations. It is shown how the laminar secondary flow develops if at the inlet of a streamwise curved channel a rigid body vortex moving in the cross section is prescribed. For low Reynolds numbers where no separation is expected, the fully parabolic Navier-Stokes equations can be applied. Using a grid spacing of 21 x 21 points in the cross flow section, the computer time needed for one calculation is less than 30sec on a Cray-1S. A solution method for engineering purposes to calculate turbulent flows in curved three dimensional ducts with variable cross sections was developed. Calculation time on the Cray-1S (21 x 21 grid) is less than 48 sec.

Grundmann, R.

441

Approximate solutions to second order parabolic equations. I: Analytic estimates  

NASA Astrophysics Data System (ADS)

We establish a new type of local asymptotic formula for the Green's function Gt(x,y) of a uniformly parabolic linear operator ?t-L with nonconstant coefficients using dilations and Taylor expansions at a point z =z(x,y) for a function z with bounded derivatives such that z(x,x)=x?RN. Our method is based on dilation at z, Dyson, and Taylor series expansions. We use the Baker-Campbell-Hausdorff commutator formula to explicitly compute the terms in the Dyson series. Our procedure leads to an explicit, elementary, algorithmic construction of approximate solutions to parabolic equations that are accurate to arbitrarity prescribed order in the short-time limit. We establish mapping properties and precise error estimates in the exponentially weighed, Lp-type Sobolev spaces Was,p(RN) that appear in practice.

Constantinescu, Radu; Costanzino, Nick; Mazzucato, Anna L.; Nistor, Victor

2010-10-01

442

Sea urchin fertilization during a KC-135 parabolic flight.  

PubMed

For long-term exposure to space it is crucial to understand the underlying mechanisms for altered physiological functions. We have chosen the sea urchin system to study the effects of microgravity on various cellular processes visible during fertilization and subsequent development. We report here on experiments performed on NASA's KC-135 during parabolic flight trajectories to validate procedures to be implemented as part of the first Aquatic Research Facility Space Shuttle experiment on STS-77. PMID:11543042

Schatten, H; Zoran, S; Levine, H G; Anderson, K; Chakrabarti, A

1999-07-01

443

Galerkin/Runge-Kutta discretizations for semilinear parabolic equations  

NASA Technical Reports Server (NTRS)

A new class of fully discrete Galerkin/Runge-Kutta methods is constructed and analyzed for semilinear parabolic initial boundary value problems. Unlike any classical counterpart, this class offers arbitrarily high, optimal order convergence. In support of this claim, error estimates are proved, and computational results are presented. Furthermore, it is noted that special Runge-Kutta methods allow computations to be performed in parallel so that the final execution time can be reduced to that of a low order method.

Keeling, Stephen L.

1987-01-01

444

A stability analysis for a semilinear parabolic partial differential equation  

NASA Technical Reports Server (NTRS)

The parabolic partial differential equation considered is u sub t = u sub xx + f(u), where minus infinity x plus infinity and o t plus infinity. Under suitable hypotheses pertaining to f, a class of initial data is exhibited: phi(x), minus infinity x plus infinity, for which the corresponding solutions u(x,t) appraoch zero as t approaches the limit of plus infinity. This convergence is uniform with respect to x on any compact subinterval of the real axis.

Chafee, N.

1973-01-01

445

Optimality of the boundary control for nxn parabolic lag system  

NASA Astrophysics Data System (ADS)

Optimal boundary control problem for nxn coupled system of second order parabolic lag partial differential equation with infinitely many variables is considered. By Lions scheme [J.L. Lions, Optimal Control of Systems Governed by Partial Differential Equations, Grundlehren Math. Wiss., vol. 170, Springer-Verlag, 1971], necessary and sufficient condition of optimality for the Neumann problem with quadratic performance functional and constrained control is derived. Finally, several mathematical examples for derived optimality conditions are presented.

Kotarski, W.; El-Saify, H. A.

2006-07-01

446

Second Order of Accuracy Difference Schemes for Ultra Parabolic Equations  

NASA Astrophysics Data System (ADS)

In this paper, our interest is studying the stability of second order difference scheme for the approximate solution of the initial boundary value problem for ultra parabolic equations in an arbitrary Banach space E with a strongly positive operator A. For approximately solving the given problem, the second-order of accuracy difference scheme is presented. Numerical example is given to illustrate the applicability and efficiency of our method.

Ashyralyev, Allaberen; Yilmaz, Serhat

2011-09-01

447

Piecewise parabolic method (PPM) for gas-dynamical simulations  

Microsoft Academic Search

We present the piecewise parabolic method, a higher-order extension of of Godunov's method. There are several new features of this method which distinguish it from other higher-order Godunov-type methods. We use a higher-order spatial interpolation than previously used, which allows for a steeper representation of discontinuities, particularly contact discontinuities. We introduce a simpler and more robust algorithm for calculating the

P. Corlella; PAUL R. WOODWARD

1984-01-01

448

Synergies between optical and physical variables in intercepting parabolic targets  

PubMed Central

Interception requires precise estimation of time-to-contact (TTC) information. A long-standing view posits that all relevant information for extracting TTC is available in the angular variables, which result from the projection of distal objects onto the retina. The different timing models rooted in this tradition have consequently relied on combining visual angle and its rate of expansion in different ways with tau being the most well-known solution for TTC. The generalization of these models to timing parabolic trajectories is not straightforward. For example, these different combinations rely on isotropic expansion and usually assume first-order information only, neglecting acceleration. As a consequence no optical formulations have been put forward so far to specify TTC of parabolic targets with enough accuracy. It is only recently that context-dependent physical variables have been shown to play an important role in TTC estimation. Known physical size and gravity can adequately explain observed data of linear and free-falling trajectories, respectively. Yet, a full timing model for specifying parabolic TTC has remained elusive. We here derive two formulations that specify TTC for parabolic ball trajectories. The first specification extends previous models in which known size is combined with thresholding visual angle or its rate of expansion to the case of fly balls. To efficiently use this model, observers need to recover the 3D radial velocity component of the trajectory which conveys the isotropic expansion. The second one uses knowledge of size and gravity combined with ball visual angle and elevation angle. Taking into account the noise due to sensory measurements, we simulate the expected performance of these models in terms of accuracy and precision. While the model that combines expansion information and size knowledge is more efficient during the late trajectory, the second one is shown to be efficient along all the flight. PMID:23720614

Gmez, Jos; Lpez-Moliner, Joan

2013-01-01

449

Space-Time Adaptive Wavelet Methods for Parabolic Evolution Problems  

E-print Network

(y)-w(x))(v(y)-v(x)) |x-y|3 dxdy, IR3 , X = Y = H 1 2()/R (hypersingular boundary integral equation). · Parabolic, X = Y = H1 0 ()n ? L2,0() for a domain IRn (stat. Stokes problem), · (Bw)(v) = 1 4 (w of partial differential and integral operators, B is close to a sparse matrix, and f is close to sparse. We

Rauhut, Holger

450

Self-Similar Subsolutions and Blowup for Nonlinear Parabolic Equations  

Microsoft Academic Search

For a wide class of nonlinear parabolic equations of the formut??u=F(u,?u), we prove the nonexistence of global solutions for large initial data. We also estimate the maximal existence time. To do so we use a method of comparison with suitable blowing up self-similar subsolutions. As a consequence, we improve several known results onut??u=up, on generalized Burgers' equations, and on other

Philippe Souplet; Fred B Weissler

1997-01-01

451

Radiative Heat Transfer During Atmosphere Entry at Parabolic Velocity  

NASA Technical Reports Server (NTRS)

Stagnation point radiative heating rates for manned vehicles entering the earth's atmosphere at parabolic velocity are presented and compared with corresponding laminar convective heating rates. The calculations were made for both nonlifting and lifting entry trajectories for vehicles of varying nose radius, weight-to-area ratio, and drag. It is concluded from the results presented that radiative heating will be important for the entry conditions considered.

Yoshikawa, Kenneth K.; Wick, Bradford H.

1961-01-01

452

Circulatory filling pressures during transient microgravity induced by parabolic flight  

NASA Technical Reports Server (NTRS)

Theoretical concepts hold that blood in the gravity dependent portion of the body would relocate to more cephalad compartments under microgravity. The result is an increase in blood volume in the thoraic and cardiac chambers. However, experimental data has been somewhat contradictory and nonconclusive. Early studies of peripheral venous pressure and estimates of central venous pressure (CVP) from these data did not show an increase in CVP under microgravity. However, CVP recorded in human volunteers during a parabolic flight revealed an increase in CVP during the microgravity state. On the STS 40 shuttle mission, a payload specialist wore a fluid line that recorded CVP during the first few hours of orbital insertion. These data revealed decreased CVP. When this CVP catheter was tested during parabolic flight in four subjects, two had increased CVP recordings and two had decreased CVP measurements. In 1991, our laboratory performed parabolic flight studies in several chronic-instrumented baboons. It was again noted that centrally recorded right atrial pressure varied with exposure to microgravity, some animals having an increase, and others a decrease.

Latham, Ricky D.; Fanton, John W.; White, C. D.; Vernalis, Mariana N.; Crisman, R. P.; Koenig, S. C.

1993-01-01

453

Sympathetic nerve response to microgravity induced by parabolic flight.  

PubMed

The aim of this study was to clarify how muscle sympathetic nerve activity (MSNA) in humans, which plays an important role in blood pressure control against gravity, is altered under microgravity conditions. Subjects were seated in a jet aircraft with their legs extended. MSNA was recorded microneurographically from the tibial nerve of the sitting subjects with simultaneous monitoring of electrocardiogram, blood pressure, respiration, and intrathoracic blood volume during parabolic flights. In the Air Force training area, the aircraft made parabolas up to 10 times. At the entry to microgravity, intrathoracic blood volume increased, systemic blood pressure was elevated, and MSNA was suppressed. However, this MSNA suppression lasted only 10-15 sec, and then followed by an enhancement to the end of the parabolas. We conclude that MSNA is suppressed at the onset of microgravity during parabolic flight in response to loading of the cardiopulmonary volume receptor due to a cephalad body fluid shift. However, this MSNA suppression is transient during such dynamic gravitational changes as those induced by parabolic flight, probably modulated by arterial baroreceptors. PMID:11541505

Iwase, S; Cui, J; Kitazawa, H; Miyazaki, S; Sugiyama, Y; Kohno, M; Mukai, C; Mano, T

1997-12-01

454

Integrated solar energy system optimization  

NASA Astrophysics Data System (ADS)

The computer program SYSOPT, intended as a tool for optimizing the subsystem sizing, performance, and economics of integrated wind and solar energy systems, is presented. The modular structure of the methodology additionally allows simulations when the solar subsystems are combined with conventional technologies, e.g., a utility grid. Hourly energy/mass flow balances are computed for interconnection points, yielding optimized sizing and time-dependent operation of various subsystems. The program requires meteorological data, such as insolation, diurnal and seasonal variations, and wind speed at the hub height of a wind turbine, all of which can be taken from simulations like the TRNSYS program. Examples are provided for optimization of a solar-powered (wind turbine and parabolic trough-Rankine generator) desalinization plant, and a design analysis for a solar powered greenhouse.

Young, S. K.

1982-11-01

455

Thermal nuclear blast simulation at the National Solar Thermal Test Facility  

Microsoft Academic Search

The National Solar Thermal Test Facility is operated by Sandia National Laboratories and located on Kirtland Air Force Base in Albuquerque, New Mexico. The facility includes a heliostat field and associated receiver tower, two solar furnaces, and two point-focus parabolic concentrators. All can be used for simulating the thermal portion of nuclear pulses. The heliostat field contains 222 computer-controlled mirrors,

C. P. Cameron; C. M. Ghanbari

1989-01-01

456

SOLAR FIBER-OPTIC MINI-DISHES: A NEW APPROACH TO THE EFFICIENT COLLECTION OF SUNLIGHT  

Microsoft Academic Search

A new concept for efficient solar energy concentration and power delivery is proposed one that offers substantial advantages in efficiency, compactness, reduced mechanical loads, and ease of fabrication and installation relative to conventional solar designs. The design exploits the availability of low-attenuation optical fibers, as well as the practical advantages of mass producing highly accurate very small parabolic dishes.

Daniel Feuermann; Jeffrey M. Gordon

1999-01-01

457

Optimisation and Cost Analysis of a Lithium Bromide Absorption Solar Cooling System  

Microsoft Academic Search

SUMMARY This paper presents the optimisation of the various components of a lithium bromide (LiBr) absorption solar cooling system such as the type, slope and area of solar collector and storage tank size. The collector types considered are the flat plate, compound parabolic and evacuated tube collectors. The optimisation is based on an energy benefit analysis, i.e., the amount of

Georgios A. Florides; Soteris A. Kalogirou

2007-01-01

458

Line focus solar thermal central receiver research study. Final report, April 30, 1977March 30, 1979  

Microsoft Academic Search

The results of a study to examine the line focus central receiver alternative for solar thermal generation of electric power on a commercial scale are presented. The baseline concept consists of the following elements: (1) a solar collector (heliostat) whose geometry is the equivalent of a focused parabolic cylinder. The heliostat reflecting surface is composed of an array of flexible

D. G. Di Canio; W. J. Treytl; F. A. Jur; C. D. Watson

1979-01-01

459

Development of concentrating collectors for solar thermal systems  

Microsoft Academic Search

The authors discuss the concentrating solar collectors that are required to generate the elevated temperatures that can be used to power industrial and electric conversion processes efficiently. The development and improvement of a number of cost-effective, highly innovative heliostats and parabolic dish collectors, and supporting design and materials research are reviewed. The authors describe the analytical modeling, evaluation, and testing

John T. Holmes; Daniel J. Alpert; Thomas R. Mancini; L. M. Murphy; P. O. Schissel

1989-01-01

460

State-of-the-art solar trough collector  

Microsoft Academic Search

The Department of Energy and Acurex Corporation have joined in a cooperative agreement to accelerate producibility and commercial availability of major line focus parabolic trough solar collector system components. The Acurex goal is to develop the next generation collector based on 4 years' experience with the current generation. As in the past, the primary applications for the new collector will

D. Youmans; D. Bell; R. Carlton

1981-01-01

461

Solar reflector with flexible sheet tightly secured around form surfaces  

Microsoft Academic Search

A solar trough reflector includes two forms with identical surfaces, preferably convex parabolic curves. The form members are carried on a longitudinal slideway in which at least one is free to slide. Positive mechanical means, such as a threaded screw, moves the slide to adjusted position on a slideway. Gripping means hold a flexible sheet with a reflecting surface tightly

Bronstein

1981-01-01

462

Investigation of evacuated tube heated by solar trough concentrating system  

Microsoft Academic Search

Two types of solar evacuated tube have been used to measure their heating efficiency and temperature with fluids of water and N2 respectively with a parabolic trough concentrator. Experiments demonstrate that both evacuated tubes present a good heat transfer with the fluid of water, the heating efficiency is about 7080%, and the water is easy to boil when liquid rate

M. Li; L. L. Wang

2006-01-01

463

Performance and cost optimisation of small solar power stations  

Microsoft Academic Search

Small solar farm power systems using parabolic trough collectors and power conversion systems following the Rankine principle are discussed. Overall system efficiency is considered in terms of the selection of optimum operational temperature, storage size, and design day; it is noted that collector field efficiency drops with increasing temperature, while power conversion efficiency increases with higher temperature. Attention is also

J. E. Feustel

1979-01-01

464

Cost and performance evaluation of terrestrial solar thermal power systems  

Microsoft Academic Search

A cost optimization model was developed based on relating systems costs to performance and minimizing the system electric energy production costs. The model was applied to systems representing major categories of solar thermal power systems such as the central receiver, the parabolic dish, the line-focusing and the fixed orientation focusing collectors. Several types of engines and energy storage systems were

N. Elgabalawi

1982-01-01

465

About Migration of Asteroids and Comets within Solar System  

Microsoft Academic Search

The paper presents the results of investigation of the dynamical behaviour of small solar system objects with model orbits similar to SOHO comets, assuming their orbits to be near parabolic. The numerical integration of the equation of motion of the objects showed that the bodies periodically change their inclination, eccentricities, and perihelion distances within a rather wide range. During this

E. M. Pittich; N. A. Solovaya

2004-01-01

466

First phase testing of solar thermal engine at United Stirling  

Microsoft Academic Search

The objective of the program is to demonstrate that the Stirling engine is a practical efficient and reliable energy converter when integrated with a parabolic dish concentrator, and that it has the potential of being cost competitive with fossil fueled electric generating systems of today. The engine, with its receiver (solar heat exchanger), alternator and control system, is described.

W. Percival; H. G. Nelving

1981-01-01

467

Heat engine development for solar thermal power systems  

Microsoft Academic Search

The parabolic dish solar collector systems for converting sunlight to electrical power through a heat engine will, require a small heat engine of high performance long lifetime to be competitive with conventional power systems. The most promising engine candidates are Stirling, high temperature Brayton, and combined cycle. Engines available in the current market today do not meet these requirements. The

H. Q. Pham; L. D. Jaffe

1981-01-01

468

Midtemperature solar systems test facility predictions for thermal performance based on test data: Sun-Heet nontracking solar collector  

SciTech Connect

Sandia National Laboratories, Albuquerque (SNLA), is currently conducting a program to predict the performance and measure the characteristics of commercially available solar collectors that have the potential for use in industrial process heat and enhanced oil recovery applications. The thermal performance predictions for the Sun-Heet nontracking, line-focusing parabolic trough collector at five cities in the US are presented. (WHK)

Harrison, T.D.

1981-03-01

469

Air Brayton Solar Receiver, phase 2  

NASA Technical Reports Server (NTRS)

An air Brayton solar receiver (ABSR) is discussed. The ABSR consists of a cylindrical, insulated, offset plate fin heat exchanger which is mounted at the focal plane of a fully tracking parabolic solar collector. The receiver transfer heat from the concentrated solar radiation (which impinges on the inside walls of the heat exchanger) to the working fluid i.e., air. The hot air would then e used to drive a small Brayton cycle heat engine. The engine in turn drives a generator which produces electrical energy. Symmetrical and asymmetrical solar power input into the ABSR are analyzed. The symmetrical cases involve the baseline incident flux and the axially shifted incident fluxes. The asymmetrical cases correspond to the solar fluxes that are obtained by reduced solar input from one half of the concentrator or by receiver offset of plus or minus 1 inch from the concentrator optical axis.

Deanda, L. E.

1981-01-01

470

Design requirements for interfaces in solar energy conversion technologies  

NASA Astrophysics Data System (ADS)

Candidate materials for improving the durability and economics of solar energy conversion systems (SECS) are reviewed. A 30-yr lifetime is regarded as necessary for solar collector and concentrator materials in order to offset the high initial costs of SECS in parabolic dish, heliostat, parabolic trough, flat plate collector, OTEC, solar cell, and wind turbine configurations. The materials are required to transfer a maximum amount of intercepted energy without degrading from exposure to UV radiation, wind, water, dust, and temperature cycling. Glass and mirrored surfaces for reflecting or refracting optical subsystems are currently made from soda-lime, boro- and aluminosilicate, and must resist chemicals, abrasion, and permeability, and have good strength, flexibility, coefficient of expansion, and Young's modulus. Additional concerns are present in photochemical, solar cell, and in substrata components and systems.

Butler, B. L.

1982-04-01

471

Slow Cookers and Food Safety  

MedlinePLUS

... USDA Food Safety and Inspection Service Topics Careers Data Collection and Reports Fact Sheets Food Defense and Emergency ... Site Map A-Z Index Help Topics Careers Data Collection and Reports Fact Sheets Food Defense and Emergency ...

472

The Pressure-Cooker Presidency  

ERIC Educational Resources Information Center

When the AGB task force on the state of the Presidency in American Higher Education was meeting last fall in Washington, D.C., to deliberate about the role of the academic presidency, the Secretary of Education's Commission on the Future of Higher Education convened across town to examine issues ranging from access to affordability to

McLaughlin, Judith Block

2006-01-01

473

Dexterous Manipulation in Microgravity in Parabolic Flights and on ISS  

NASA Astrophysics Data System (ADS)

It has been shown that during exposure to microgravity in parabolic flights the control of interaction forces when manipulating an object adapts partially to the lack of gravity, yet evidence indicates that anticipation of gravity's effects persists in the short term. The motivation for these experiments to be performed in long-duration space flight is to understand how the central nervous system adapts to an environment without gravity and what will be the consequences of long-term adaptation when an individual returns to a normal (Earth) or partial (Moon or Mars) gravitational field. The experiment Dexterous Manipulation in Microgravity (DEX) will target specific questions about the effects of gravity on dexterous manipulation, questions that cannot be addressed in the normal terrestrial environment. Some of the scientific questions have already been studied since nearly ten years and will continue to be addressed in experiments conducted in parabolic flights, during which it will be examined how the nervous system copes with repeated transitions between different gravitational environments. Results from these experiments provide initial data about short-term adaptation to 0g. The experiments proposed for ISS draw from these short-term precursor experiments, but will emphasize long-term adaptation of sensorimotor processes to 0g and re-adaptation to 1g. A first conceptual definition phase of a DEX instrument has been completed under an ESA contract and is now ready to enter into the design and development phase in view of a launch on ISS in the 2013-2014 timeframe. In this paper, the science background will be recalled and several experiments performed during parabolic flights will be presented, showing how these early breadboards testing in microgravity have helped to refine the DEX conceptual design and how it could be used on ISS.

Pletser, V.; Sundblad, P.; Thonnard, J.-L.; Lefevre, P.; McIntyre, J.; Kassel, R.; Derkinderen, W.; Penta, M.; Andre, T.

474

Error Analysis for Discontinuous Galerkin Method for Parabolic Problems  

NASA Technical Reports Server (NTRS)

In the proposal, the following three objectives are stated: (1) A p-version of the discontinuous Galerkin method for a one dimensional parabolic problem will be established. It should be recalled that the h-version in space was used for the discontinuous Galerkin method. An a priori error estimate as well as a posteriori estimate of this p-finite element discontinuous Galerkin method will be given. (2) The parameter alpha that describes the behavior double vertical line u(sub t)(t) double vertical line 2 was computed exactly. This was made feasible because of the explicitly specified initial condition. For practical heat transfer problems, the initial condition may have to be approximated. Also, if the parabolic problem is proposed on a multi-dimensional region, the parameter alpha, for most cases, would be difficult to compute exactly even in the case that the initial condition is known exactly. The second objective of this proposed research is to establish a method to estimate this parameter. This will be done by computing two discontinuous Galerkin approximate solutions at two different time steps starting from the initial time and use them to derive alpha. (3) The third objective is to consider the heat transfer problem over a two dimensional thin plate. The technique developed by Vogelius and Babuska will be used to establish a discontinuous Galerkin method in which the p-element will be used for through thickness approximation. This h-p finite element approach, that results in a dimensional reduction method, was used for elliptic problems, but the application appears new for the parabolic problem. The dimension reduction method will be discussed together with the time discretization method.

Kaneko, Hideaki

2004-01-01

475

Exact analytic flux distributions for two-dimensional solar concentrators.  

PubMed

A new approach for representing and evaluating the flux density distribution on the absorbers of two-dimensional imaging solar concentrators is presented. The formalism accommodates any realistic solar radiance and concentrator optical error distribution. The solutions obviate the need for raytracing, and are physically transparent. Examples illustrating the method's versatility are presented for parabolic trough mirrors with both planar and tubular absorbers, Fresnel reflectors with tubular absorbers, and V-trough mirrors with planar absorbers. PMID:23842256

Fraidenraich, Naum; Henrique de Oliveira Pedrosa Filho, Manoel; Vilela, Olga C; Gordon, Jeffrey M

2013-07-01

476

SOLERAS solar active cooling field test operations  

Microsoft Academic Search

Four small-scale commercial size solar cooling systems being tested in Arizona as part of the SOLERAS program are described, together with 1981 performance summaries. A 63 kW air-cooled Rankine cycle system powered by parabolic troughs is used to cool a one-story office building. The system has both hot and cold storage tanks and uses R-11 fluid. A 49 kW Rankine

J. Williamson; R. Martin

1982-01-01

477

Coolidge solar powered irrigation pumping project  

NASA Astrophysics Data System (ADS)

A 150 kW solar thermal electric power plant which includes over 2100 square meters of parabolic trough type collectors and an organic Rankine cycle turbine engine was constructed on an irrigated farm. The plant is interconnected with the electrical utility grid. Operation is providing an evaluation of equipment performance and operating and maintenance requirements as well as the desirability of an on farm location.

Larson, D. L.

1980-05-01

478

Asymmetrical non-imaging cylindrical solar concentrators  

Microsoft Academic Search

Two types of asymmetrical concentrators, parabolic and nonparabolic, are compared to those with symmetrical designs. Asymmetrical configurations are found to provide many advantages, including: (1) a concentration versus time-of-day relationship which can compensate for projected solar-area fall-off, allowing more uniform energy output when this is desirable, (2) greater operational flexibility, (3) easier adaptation to vacuum-insulated receivers, and (4) possible increased

D. R. Mills; J. E. Giutronich

1978-01-01

479

Piecewise-parabolic methods for astrophysical fluid dynamics  

SciTech Connect

A general description of some modern numerical techniques for the simulation of astrophysical fluid flow is presented. The methods are introduced with a thorough discussion of the especially simple case of advection. Attention is focused on the piecewise-parabolic method (PPM). A description of the SLIC method for treating multifluid problems is also given. The discussion is illustrated by a number of advection and hydrodynamics test problems. Finally, a study of Kelvin-Helmholtz instability of supersonic jets using PPM with SLIC fluid interfaces is presented.

Woodward, P.R.

1983-11-01

480

Third-order superintegrable systems separable in parabolic coordinates  

E-print Network

In this paper, we investigate superintegrable systems which separate in parabolic coordinates and admit a third-order integral of motion. We give the corresponding determining equations and show that all such systems are multi-separable and so admit two second-order integrals. The third-order integral is their Lie or Poisson commutator. We discuss how this situation is different from the Cartesian and polar cases where new potentials were discovered which are not multi-separable and which are expressed in terms of Painlev\\'e transcendents or elliptic functions.

I. Popper; S. Post; P. Winternitz

2012-04-08

481

4-E (energyexergyenvironmentaleconomic) analyses of line-focusing stand-alone concentrating solar power plants  

Microsoft Academic Search

In this study, energyexergyenvironmentaleconomic (4-E) analyses of stand-alone line-focusing concentrating solar power plants are carried out for different plant capacities ranging from 1 to 50 MWe<\\/sub>. Solar power plants based on concentrating power technologies are used to harness the solar radiation effectively. Among the solar power technologies, line-focusing concentrating systems such as linear Fresnel reflector (LFR) and parabolic trough collector

K. Ravi Kumar; K. S. Reddy

2012-01-01

482

A solar thermal cooling and heating system for a building: Experimental and model based performance analysis and design  

Microsoft Academic Search

A solar thermal cooling and heating system at Carnegie Mellon University was studied through its design, installation, modeling, and evaluation to deal with the question of how solar energy might most effectively be used in supplying energy for the operation of a building. This solar cooling and heating system incorporates 52m2 of linear parabolic trough solar collectors; a 16kW double

Ming Qu; Hongxi Yin; David H. Archer

2010-01-01

483

The solvability of the first initial-boundary problem for parabolic and degenerate parabolic equations in domains with a conical point  

SciTech Connect

The first initial-boundary problem for second-order parabolic and degenerate parabolic equations is investigated in a domain with a conical or angular point. The means of attack is already known and uses weighted classes of smooth or integrable functions. Sufficient conditions for a unique solution to exist and for coercive estimates for the solution to be obtained are formulated in terms of the angular measure of the solid angle and the exponent of the weight. It is also shown that if these conditions fail to hold, then the parabolic problem has elliptic properties, that is, it can have a nonzero kernel or can be nonsolvable, and, in the latter case, it is not even a Fredholm problem. A parabolic equation and an equation with some degeneracy or a singularity at a conical point are considered. Bibliography: 49 titles.

Degtyarev, Sergey P [Institute of Applied Mathematics and Mechanics, Ukraine National Academy of Sciences, Donetsk (Ukraine)

2010-09-02

484

Universal solar energy desalination system  

NASA Astrophysics Data System (ADS)

Design considerations to allow site-dependent flexibility in the choice of solar/wind powered desalinization plant configurations are discussed. A prototype design was developed for construction of 6300 cu m per day brackish water treatment in Brownsville, TX. The water is treated to reduce the amount of suspended solids and prevent scaling. A reverse osmosis unit processes the treated liquid to recover water at a ratio of 90%. The power system comprises a parabolic trough solar thermal system with an organic Rankine cycle generator, rock-oil thermal storage, and 200 kW wind turbines. Analysis of the complementarity of the solar and wind subsystems indicates that at any site one system will supplement the other. Energy storage, e.g., battery banks, would increase system costs to unacceptable levels. Climatic conditions will significantly influence the sizing of each segment of the total power system.

Fusco, V. S.

485

RungeKutta approximation of quasilinear parabolic equations Christian Lubich and Alexander Ostermann  

E-print Network

RungeKutta approximation of quasilinear parabolic equations Christian Lubich and Alexander the convergence properties of implicit RungeKutta methods applied to time discretization of parabolic equations and requires algebraic stability of the RungeKutta method. The second one is based on estimates for linear

Tbingen, Universitt

486

New developments in the study of optical parabolic pulses in normally dispersive fibers  

Microsoft Academic Search

We report two recent studies dealing with the evolution of parabolic pulses in normally dispersive fibres. On the one hand, the nonlinear reshaping from a Gaussian intensity profile towards the asymptotic parabolic shape is experimentally investigated in a Raman amplifier. On the other hand, the significant impact of the fourth order dispersion on a passive propagation is theoretically discussed: we

Kamal Hammani; Brandon G. Bale; Sonia Boscolo; Christophe Finot

2011-01-01

487

Controllability results for some nonlinear coupled parabolic systems by one control force  

E-print Network

Controllability results for some nonlinear coupled parabolic systems by one control force Manuel being arbitrary) when the control force acts on a unique equation of the system through an arbitrarily to deal with the null controllability of linear coupled parabolic systems by a unique control force

González Burgos, Manuel

488

Estimation of Sound Source Direction Using Parabolic Reflection Board Tetsuya Takiguchi  

E-print Network

In this paper, a new active microphone with a parabolic reflection board is proposed for estimation of soundEstimation of Sound Source Direction Using Parabolic Reflection Board Tetsuya Takiguchi , Ryoichi Takashima and Yasuo Ariki Organization of Advanced Science and Technology Kobe University 1-1 Rokkodai, Nada

Takiguchi, Tetsuya

489

Parabolic and white-noise approximations for elastic waves in random media  

E-print Network

Parabolic and white-noise approximations for elastic waves in random media Josselin Garnier equations in random media in the parabolic white-noise regime. In this regime, the propagation distance are rapid and can be approximated by a white-noise term. The main motivations for studying the white-noise

Solna, Knut

490

Numerical schemes for a pseudo-parabolic Burgers equation: discontinuous data and long-time behaviour  

E-print Network

Numerical schemes for a pseudo-parabolic Burgers equation: discontinuous data and long Burgers'­type equation that is extended with a third-order term containing mixed derivatives in space. Keywords: pseudo-parabolic equations, Burgers equation, numerical schemes at interfaces, long

Eindhoven, Technische Universiteit

491

Non-parabolic hydrodynamic formulations for the simulation of inhomogeneous semiconductor devices  

NASA Technical Reports Server (NTRS)

Hydrodynamic models are becoming prevalent design tools for small scale devices and other devices in which high energy effects can dominate transport. Most current hydrodynamic models use a parabolic band approximation to obtain fairly simple conservation equations. Interest in accounting for band structure effects in hydrodynamic device simulation has begun to grow since parabolic models can not fully describe the transport in state of the art devices due to the distribution populating non-parabolic states within the band. This paper presents two different non-parabolic formulations of the hydrodynamic model suitable for the simulation of inhomogeneous semiconductor devices. The first formulation uses the Kane dispersion relationship (hk)(exp 2)/2m = W(1 + alpha(W)). The second formulation makes use of a power law ((hk)(exp 2)/2m = xW(sup y)) for the dispersion relation. Hydrodynamic models which use the first formulation rely on the binomial expansion to obtain moment equations with closed form coefficients. This limits the energy range over which the model is valid. The power law formulation readily produces closed form coefficients similar to those obtained using the parabolic band approximation. However, the fitting parameters (x,y) are only valid over a limited energy range. The physical significance of the band non-parabolicity is discussed as well as the advantages/disadvantages and approximations of the two non-parabolic models. A companion paper describes device simulations based on the three dispersion relationships: parabolic, Kane dispersion, and power low dispersion.

Smith, Arlynn W.; Brennan, Kevin F.

1995-01-01

492

Parabolic equation solution of seismo-acoustics problems involving variations in bathymetry and sediment thickness  

E-print Network

Parabolic equation solution of seismo-acoustics problems involving variations in bathymetry to extend this approach to a larger class of seismo-acoustics problems. The variable rotated parabolic equation J. Acoust. Soc. Am. 120, 35343538 2006 handles a sloping fluid-solid interface at the ocean

493

Predictive control of uncertain nonlinear parabolic PDE systems using a Galerkin\\/neural-network-based model  

Microsoft Academic Search

In this paper, a model predictive control (MPC) scheme for a class of parabolic partial differential equation (PDE) systems with unknown nonlinearities, arising in the context of transport-reaction processes, is proposed. A spatial operator of a parabolic PDE system is characterized by a spectrum that can be partitioned into a finite slow and an infinite fast complement. In this view,

Ghazal Montaseri; Mohammad Javad Yazdanpanah

2012-01-01

494

THERMODYNAMICS OF QUANTUM WIRES WITH A PARABOLIC POTENTIAL IN TILTED MAGNETIC FIELDS  

Microsoft Academic Search

The magnetic susceptibility, specific heat and entropy of parabolic quantum wires in tilted magnetic fields is studied. The dependence of the magnetic susceptibility, specific heat and entropy on the magnitude of the magnetic field and the direction of the magnetic field, and parameters of a parabolic wells is shown explicitly. During the past three decades, the physics of low- dimensional

G. B. IBRAGIMOV

495

Verification of Second-Order Sufficient Optimality Conditions for Semilinear Elliptic and Parabolic Control Problems  

Microsoft Academic Search

We study optimal control problems for semilinear parabolic equations subject to control constraints and for semilinear elliptic equations subject to control and state constraints. We quote known second-order sufficient optimality conditions (SSC) from the literature. Both problem classes, the parabolic one with boundary control and the elliptic one with boundary or distributed control, are discretized by a finite difference method.

Hans D. Mittelmann

2001-01-01

496

Classification of Invariant Differential Operators for Non-Compact Lie Algebras via Parabolic Relations  

NASA Astrophysics Data System (ADS)

In the present paper we review the progress of the project of classification and construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we called earlier 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduced recently the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. Thus, we consider the exceptional algebra E7(7) which is parabolically related to the CLA E7(-25). Other interesting examples are the orthogonal algebras so(p, q) all of which are parabolically related to the conformal algebra so(n, 2) with p + q = n + 2, the parabolic subalgebras including the Lorentz subalgebra so(n - 1,1) and its analogs so(p - 1, q - 1). Further we consider the algebras sl(2n, Bbb R) and for n = 2k the algebras su* (4k) which are parabolically related to the CLA su(n,n). Further we consider the algebras sp(r,r) which are parabolically related to the CLA sp(2r, Bbb R). We consider also E6(6) and E6(2) which are parabolically related to the hermitian symmetric case E6(-14),

Dobrev, V. K.

2014-05-01

497

Second law analysis and optimization of a parabolic trough receiver tube for direct steam generation  

NASA Astrophysics Data System (ADS)

Entropy generation in the receiver tube of a parabolic trough solar collector can mainly be attributed to the fluid friction and finite temperature differences. The contribution of each of these components is investigated under different circumstances. Mass flow rates, tube diameters and operating pressures are investigated to obtain good guidelines for receiver tube and plant design. Operating pressures between 3 MPa (saturation temperature of 233.9 C) and 9 MPa (saturation temperature of 303.3 C) were investigated. Results show that small diameters can result in excessive fluid friction, especially when the mass flow rates are high. For most cases, tube diameters beyond 20 mm will exclusively be subject to entropy generation due to finite temperature differences, and entropy generation due to fluid friction will be small to negligible. Increasing the concentration ratio will decrease entropy generation, due to a higher heat flux per unit meter. This will ultimately result in shorter receiver tube lengths. From a simulated annealing optimization it was seen that if the diameter is increased, the entropy generation can be lowered, provided that the concentration ratio is kept constant. However, beyond a certain point gains in minimizing the entropy generation become negligible. The optimal operating pressure will generally increase if the mass flow rate is increased. Finally it was seen that higher operating pressures are more advantageous when the entropy generation minimization is considered in conjunction with the work output.

Nolte, H. C.; Bello-Ochende, T.; Meyer, J. P.

2014-12-01

498

Structural design for high-power parabolic trough concentrator arrays in space  

NASA Astrophysics Data System (ADS)

The design of a support structure for a space-power photovoltaic concentrator is described. The baseline concentrator uses miniaturized parabolic-trough mirror-radiators to illuminate solar cells at concentration ratios in the range from 10-40 x geometrical. Such a concentrator has unique pointing requirements in that high accuracy (2 degrees) is required in the axis of concentration, while the perpendicular axis allows greater pointing errors (10 degrees or more) with minimal power loss. The array structure was designed with the goal of meeting these pointing requirements under the constraints of given mirror lengths, payload-bay packaging envelopes, and operating disturbances. Structural design parameters included structure weight, array aperture efficiency (packing factor), and packaged volumetric efficiency. The proposed structure uses a rectangular grid of graphite composite beams backed by a rigidized truss to form a triangular cross-section. This design has projected specific mass as low as 1 kg/sq m for the structural fraction of the array, and can result in concentrator specific powers exceeding 60 W/kg using current technology.

Stern, T. G.; Hayes, E. W.

499

The Piecewise Parabolic Method for Multidimensional Relativistic Fluid Dynamics  

E-print Network

We present an extension of the Piecewise Parabolic Method to special relativistic fluid dynamics in multidimensions. The scheme is conservative, dimensionally unsplit, and suitable for a general equation of state. Temporal evolution is second-order accurate and employs characteristic projection operators; spatial interpolation is piece-wise parabolic making the scheme third-order accurate in smooth regions of the flow away from discontinuities. The algorithm is written for a general system of orthogonal curvilinear coordinates and can be used for computations in non-cartesian geometries. A non-linear iterative Riemann solver based on the two-shock approximation is used in flux calculation. In this approximation, an initial discontinuity decays into a set of discontinuous waves only implying that, in particular, rarefaction waves are treated as flow discontinuities. We also present a new and simple equation of state which approximates the exact result for the relativistic perfect gas with high accuracy. The strength of the new method is demonstrated in a series of numerical tests and more complex simulations in one, two and three dimensions.

A. Mignone; T. Plewa; G. Bodo

2005-05-10

500

Using Parabolic Equation for Calculation of Beam Impedance  

SciTech Connect

In this paper we develop a new method of parabolic equation (PE) for calculation of both high-frequency and small-angle taper (or collimator) impedances. The applicability of PE in the high-frequency limit is based on the observation that in this case the contribution to impedance comes from the waves that catch up the beam far from the obstacle and propagate at small-angles to the axis of the pipe. One of the most important advantages of PE is that it eliminates the spatial scale of the small wavelength from the problem. As a result, the numerical solution of PE requires coarser spatial meshes. In the paper we focus on the longitudinal impedance for an axisymmetric geometry and assume a perfect conductivity of the walls. We show how the known analytical results which include a small-angle collimator, step-in and step-out transitions, and a pillbox cavity, can be derived within the framework of the parabolic equation.

Stupakov, Gennady; /SLAC

2006-04-07