ERIC Educational Resources Information Center
King, Richard C.
1981-01-01
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)
Atul Ganesh Mohod; Yashawant Prabhakar Khandetod; Sandip Sengar
2010-01-01
India is the largest producer, processor, exporter, and second largest consumer of cashew (Anacardium occidentale L.) in the world. India processed about 11,80,000 million tonnes of raw cashew seeds. The large quantity of cashew shell is unutilized due to the expensive method of oil extraction and liberation of acidic flumes during direct combustion. The parabolic concentrating solar cooker (sk-14) was
NSDL National Science Digital Library
American Association for the Advancement of Science
2009-01-01
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.
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.
Users and disusers of box solar cookers in urban India—
Bashir Ahmad
2001-01-01
The purpose of this study is to understand the reasons behind the continued use or disuse of solar cookers, and to outline the implications from the results of this study for future solar cooker projects. Twenty-eight families in three urban sites in Gujarat, India who have a solar cooker have been interviewed. Their experience with solar cookers and solar cooking
Second Law Analysis for Solar Cookers
H. Hüseyin Öztürk
2004-01-01
This article presents the importance and usefulness of Second Law (exergy) analysis for evaluating and comparing solar cookers in meaningful ways. The thermodynamic considerations required for the development of rational and meaningful methodologies for the evaluation and comparison of the efficiency of the solar cookers were defined. Energy and exergy equations were also developed to obtain energy and exergy efficiencies
NSDL National Science Digital Library
McDonald Observatory
2011-01-01
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.
TESTING AND REPORTING SOLAR COOKER PERFORMANCE
Technology Transfer Automated Retrieval System (TEKTRAN)
This Standard for quantifying solar cooker performance specifies that test results be presented as cooking power, in Watts, normalized for ambient conditions, relative to the temperature difference betweeen cooker contents and ambient air, both as a plot and as a regression equation for no less than...
Solar Week Thursday: Solar Pizza Box Cooker
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 cooker by lining a box with reflective material and adding a translucent cover. 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.
Promotion of solar box cooker technology
Stibravy, R.
1992-09-01
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.
Solar Cooker Pringles Can Lesson
NSDL National Science Digital Library
Orzali, Joe
This classroom learning unit gives students hands-on experience using solar energy. The class will use a Pringles can to cook a hot dog using solar energy. In addition to introducing a practical application of solar energy, this unit will also allow students to think about how clean, renewable energy may be used by people in developing countries. This document may be downloaded in PDF file format.
Solar thermal collector system modeling and testing for novel solar cooker
Foley, Brian, S.B. (Brian M.). Massachusetts Institute of Technology
2014-01-01
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 ...
Cookin' with Sun: Design and Build Solar Cookers
ERIC Educational Resources Information Center
Brand, Lance; Warren, Ande; Fitzgerald, Mike
2006-01-01
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…
Solar cooker and method of assembly
Kerr, B.P.
1980-12-02
A method of assembling from kit components a solar oven and in so doing, teaching the assembler the principals involving insulation, reflection, solar ray conversion to heat, temperature conservation and the fine art of cookery is described.
Shenandoah parabolic dish solar collector
Kinoshita, G.S.
1985-01-01
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.
Twelve years experience with solar cookers: Necessary tools for a clean environment
Nandwani, S.S. [Univ. Nacional Herida (Costa Rica). Dept. de Fisica
1992-12-31
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.
Plane and parabolic solar panels
Sales, J H O
2009-01-01
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.
Plane and parabolic solar panels
J. H. O. Sales; A. T. Suzuki
2009-05-14
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.
Parabolic Trough Solar Thermal Electric Power Plants
Not Available
2003-06-01
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.
Solar parabolic dish technology evaluation report
NASA Astrophysics Data System (ADS)
Lucas, J. W.
1984-04-01
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.
Optimization of parabolic trough solar collectors
A. Rabl; P BENDT; H GAUL
1982-01-01
The results of a detailed optical analysis of parabolic trough solar collectors are summarized by a few universal graphs and curve fits. These graphs enable the designer of parabolic trough collectors to calculate the performance and optimize the design with a simple hand calculator. The method is illustrated by specific examples that are typical of practical applications. The sensitivity of
Heat Transfer Convection in The Cooking of Apple Using a Solar Cooker Box-Type
NASA Astrophysics Data System (ADS)
Terres, H.; Chávez, S.; Lizardi, A.; López, R.; Vaca, M.; Flores, J.; Salazar, A.
2015-01-01
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.
Solar Thermal Power Systems parabolic dish project
NASA Technical Reports Server (NTRS)
Truscello, V. C.
1981-01-01
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.
Building a parabolic solar concentrator prototype
NASA Astrophysics Data System (ADS)
Escobar-Romero, J. F. M.; Montiel, S. Vázquez y.; Granados-Agustín, F.; Cruz-Martínez, V. M.; Rodríguez-Rivera, E.; Martínez-Yáñez, L.
2011-01-01
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.
Parabolic trough solar collectors : design for increasing efficiency
Figueredo, Stacy L. (Stacy Lee), 1981-
2011-01-01
Parabolic trough collectors are a low cost implementation of concentrated solar power technology that focuses incident sunlight onto a tube filled with a heat transfer fluid. The efficiency and cost of the parabolic trough ...
A new parabolic trough solar collector P. Kohlenbach1
and power generation (CHP), CSIRO has built a solar thermal parabolic trough collector field which) power generation system. The parabolic trough collectors have been installed in the National Solar be promoted as an integral part of various solar thermal systems. Active commercialisation of near-term solar
Alignment method for parabolic trough solar concentrators
Diver, Richard B. (Albuquerque, NM)
2010-02-23
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.
Modelling of parabolic trough direct steam generation solar collectors
S. D. Odeh; G. L. Morrison; M. Behnia
1998-01-01
Solar electric generation systems (SEGS) currently in operation are based on parabolic trough solar collectors using synthetic oil heat transfer fluid in the collector loop to transfer thermal energy to a Rankine cycle turbine via a heat exchanger. To improve performance and reduce costs direct steam generation in the collector has been proposed. In this paper the efficiency of parabolic
Elastic approximation for a solar parabolic February 29, 2012
Paris-Sud XI, Université de
energy solutions. Introduction A parabolic trough [8] is a concentrating solar thermal energy collector a working temperature high enough for ecient power generation. The geometric precision and manufacturingElastic approximation for a solar parabolic trough February 29, 2012 Gang Xiao (University of Nice
Proceedings of the Fifth Parabolic Dish Solar Thermal Power Program
J. W. Lucas
1984-01-01
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
Steam engine research for solar parabolic dish
NASA Technical Reports Server (NTRS)
Demler, R. L.
1981-01-01
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.
Solar Thermal Power Plants with Parabolic-Trough Collectors
E. Zarza; L. Valenzuela; J. León
2004-01-01
Parabolic-trough collectors (PTC) are solar concentrating devices suitable to work in the 150°C- 400°C 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
Solar parabolic dish technology annual evaluation report. Fiscal year 1983
Not Available
1984-04-15
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.
Testing the figure of parabolic reflectors for solar concentrators.
Bodenheimer, J S; Eisenberg, N P; Gur, J
1982-12-15
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
Test results, Industrial Solar Technology parabolic trough solar collector
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
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.
Solar steam generating systems using parabolic trough concentrators
A. Thomas
1996-01-01
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
THERMAL ANALYSIS OF PARABOLIC TROUGH SOLAR COLLECTORS FOR ELECTRIC POWER GENERATION
S. D. Odeh; G. L. Morrison; M. Behnia
The performance of parabolic trough solar collectors solar thermal electric generation systems is evaluated for Australian climate conditions. The largest Solar Electric Generation System (SEGS) currently in operation uses a parabolic trough solar collector and synthetic oil in the collector loop. To improve performance and reduce costs, future designs propose direct steam generation in the collector. In this study parabolic
Federal technology alert. Parabolic-trough solar water heating
NONE
1998-04-01
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.
Fast thermal cycling of acetanilide and magnesium chloride hexahydrate for indoor solar cooking
A. A. El-Sebaii; S. Al-Amir; F. M. Al-Marzouki; Adel S. Faidah; A. A. Al-Ghamdi; S. Al-Heniti
2009-01-01
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
hal-00177601,version2-30Oct2007 A closed parabolic trough solar collector
Paris-Sud XI, Université de
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
Parabolic Dish Solar Thermal Power Annual Program Review Proceedings
NASA Technical Reports Server (NTRS)
Lucas, J. W.
1982-01-01
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.
Parabolic trough solar power for competitive U.S. markets
Price, H.W.; Kistner, R.
1999-07-01
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 190. Over the last several years, the parabolic trough industry has focused much of its efforts on international market opportunities. Although the power market in developing countries appears to offer a number of opportunities for parabolic trough technologies due to high growth and the availability of special financial incentives for renewables, these markets are also plagued with many difficulties for developers. In recent years, there has been some renewed interest in the U.S. domestic power market as a results of an emerging green market and green pricing incentives. Unfortunately, many of these market opportunities and incentives focus on smaller, more modular technologies (such as photovoltaics or wind power), and as a result they tend to exclude or are of minimum long-term benefit to large-scale concentrating solar power technologies. This paper looks at what is necessary for large-scale parabolic trough solar power plants to compete with state-of-the-art fossil power technology in a competitive US power market.
Thermoeconomic analysis of a solar parabolic trough collector distillation plant
L. García-Rodríguez; C. Gómez-Camacho
1999-01-01
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
Parabolic-trough solar collectors and their applications
A. Fernández-García; E. Zarza; L. Valenzuela; M. Pérez
2010-01-01
This paper presents an overview of the parabolic-trough collectors that have been built and marketed during the past century, as well as the prototypes currently under development. It also presents a survey of systems which could incorporate this type of concentrating solar system to supply thermal energy up to 400°C, especially steam power cycles for electricity generation, including examples of
Cascaded latent heat storage for parabolic trough solar power plants
Horst Michels; Robert Pitz-Paal
2007-01-01
The current revival of solar thermal electricity generating systems (SEGS) unveils the still existing need of economic thermal energy storages (TES) for the temperature range from 250°C to 500°C. The TES-benchmark for parabolic trough power plants is the direct two tank storage, as it was used at the SEGS I plant near Barstow (USA). With the introduction of expensive synthetic
Parabolic Trough Solar Power for Competitive U.S. Markets
Henry W. Price
1998-11-01
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. Although the power market in developing countries appears to offer a number of opportunities for parabolic trough technologies due to high growth and the availability of special financial incentives for renewables, these markets are also plagued with many difficulties for developers. In recent years, there has been some renewed interest in the U.S. domestic power market as a result of an emerging green market and green pricing incentives. Unfortunately, many of these market opportunities and incentives focus on smaller, more modular technologies (such as photovoltaics or wind power), and as a result they tend to exclude or are of minimum long-term benefit to large-scale concentrating solar power technologies. This paper looks at what is necessary for large-scale parabolic trough solar power plants to compete with state-of-the-art fossil power technology in a competitive U.S. power market.
Performance contracting for parabolic trough solar thermal systems
Brown, H.; Hewett, R.; Walker, A. [National Renewable Energy Lab., Golden, CO (United States); Gee, R.; May, K. [Industrial Solar Technology, Golden, CO (United States)
1997-12-31
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 in an ever widening range of applications. Technical developments in materials and fabrication techniques reduce production cost and expand applications from swimming pool heating and service hot water, to higher-temperature applications such as absorption cooling and process steam. Simultaneously, new financing mechanisms such as a recently awarded US Department of Energy (DOE) Federal Energy Management Program (FEMP) indefinite quantity Energy Savings Performance Contract (Super ESPC) facilitate and streamline implementation of the technology in federal facilities such as prisons and military bases.
Thermal analysis of solar parabolic trough with porous disc receiver
K. Ravi Kumar; K. S. Reddy
2009-01-01
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
Cooking with the Sun. How To Build and Use Solar Cookers.
ERIC Educational Resources Information Center
Halacy, Beth; Halacy, Dan
For those working with solar energy and/or conservation and the careful use of resources, constructing a solar oven can be a fun and useful activity. This book describes the construction and use of solar ovens for cooking. Construction details are provided for two inexpensive solar ovens and a reflector hot plate that can then be used to cook 100…
Thermal buffering of receivers for parabolic dish solar thermal power plants
R. Manvi; T. Fujita; B. C. Gajanana; C. J. Marcus
1980-01-01
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
Irrigation market for solar thermal parabolic dish systems
NASA Technical Reports Server (NTRS)
Habib-Agahi, H.; Jones, S. C.
1981-01-01
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.
Proceedings: Fourth Parabolic Dish Solar Thermal Power Program Review
NASA Technical Reports Server (NTRS)
1983-01-01
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.
THERMAL PERFORMANCE OF A SOLAR COOKER HAVING PHASE CHANGE MATERIAL AS TRANSPARENT INSULATION
V. V. S. Murty; Preeti Kanthed
Efforts were made to study the Thermo-physical properties and to enhance the effective thermal conductivity of the Phase Change Materials (PCMS). Some Phase Change Materials are white, like water in physical appearance in the liquid state and can transmit solar radiation. Efforts have been made recently to study the transmittance of these materials. Latent heat thermal energy storage materials usually
Parabolic Trough Solar Power Plant Simulation Model: Preprint
Price, H.
2003-01-01
As interest for clean renewable electric power technologies grows, a number of parabolic trough power plants of various configurations are being considered for deployment around the globe. It is essential that plant designs be optimized for each specific application. The optimum design must consider the capital cost, operations and maintenance cost, annual generation, financial requirements, and time-of-use value of the power generated. Developers require the tools for evaluating tradeoffs between these various project elements. This paper provides an overview of a computer model that is being used by scientists and developers to evaluate the tradeoff between cost, performance, and economic parameters for parabolic trough solar power plant technologies. An example is included that shows how this model has been used for a thermal storage design optimization.
Parabolic-Dish Solar Concentrators of Film on Foam
Barton, Sean A
2009-01-01
Parabolic and spherical mirrors are constructed of aluminized PET polyester film on urethane foam. During construction, the chosen shape of the mirror is created by manipulating the elastic/plastic behavior of the film with air pressure. Foam is then applied to the film and, once hardened, air pressure is removed. At an f-number of 0.68, preliminary models have an optical angular spread of less than 0.25 degrees, a factor of 3.3 smaller than that for a perfectly spherical mirror. The possibility exists for creating large-lightweight mirrors with excellent shape and stiffness. These "film-on-foam" construction techniques may also be applicable to parabolic-trough solar concentrators but do not appear to be suitable for optical imaging applications because of irregularities in the film.
Thermal storage requirements for parabolic dish solar power plants
NASA Technical Reports Server (NTRS)
Wen, L.; Steele, H.
1980-01-01
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.
Techno-Economic Study of Solar Parabolic Trough-Biomass Hybrid Power Plant
Nipon Ketjoy; Wattanapong Rakwichian
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
Numerical Investigation of Energy-Efficient Receiver for Solar Parabolic Trough Concentrator
K. S. Reddy; K. Ravi Kumar; G. V. Satyanarayana
2008-01-01
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
Solar parabolic dish thermal power systems - Technology and applications
NASA Technical Reports Server (NTRS)
Lucas, J. W.; Marriott, A. T.
1979-01-01
Activities of two projects at JPL in support of DOE's Small Power Systems Program are reported. These two projects are the Point-Focusing Distributed Receiver (PFDR) Technology Project and the Point-Focusing Thermal and Electric Applications (PFTEA) Project. The PFDR Technology Project's major activity is developing the technology of solar concentrators, receivers and power conversion subsystems suitable for parabolic dish or point-focusing distributed receiver power systems. Other PFDR activities include system integration and cost estimation under mass production, as well as the testing of the hardware. The PFTEA Project's first major activity is applications analysis, that is seeking ways to introduce PFDR systems into appropriate user sectors. The second activity is systems engineering and development wherein power plant systems are analyzed for specific applications. The third activity is the installation of a series of engineering experiments in various user environments to obtain actual operating experience
A parabolic dish\\/AMTEC solar thermal power system and its performance evaluation
Shuang-Ying Wu; Lan Xiao; Yiding Cao; You-Rong Li
2010-01-01
This paper proposes a parabolic dish\\/AMTEC solar thermal power system and evaluates its overall thermal–electric 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
Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers
Moens, L.; Blake, D. M.
2008-03-01
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.
Cost\\/performance of solar reflective surfaces for parabolic dish concentrators
F. Bouquet
1980-01-01
Materials for highly reflective surfaces for use in parabolic dish solar concentrators are discussed. Some important factors concerning performance of the mirrors are summarized, and typical costs are treated briefly. Capital investment cost\\/performance ratios for various materials are computed specifically for the double curvature parabolic concentrators using a mathematical model. The results are given in terms of initial investment cost
Mechanical development of the actuation system of a parabolic solar trough
O'Rourke, Conor R. (Conor Rakis)
2011-01-01
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 ...
Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint
Stynes, J. K.; Ihas, B.
2012-04-01
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.
Guidelines for reporting parabolic trough solar electric system performance
Price, H.W.
1997-06-01
The purpose of this activity is to develop a generic methodology which can be used to track and compare the performance of parabolic trough power plants. The approach needs to be general enough to work for all existing and future parabolic trough plant designs, provide meaningful comparisons of year to year performance, and allow for comparisons between dissimilar plant designs. The approach presented here uses the net annual system efficiency as the primary metric for evaluating the performance of parabolic trough power plants. However, given the complex nature of large parabolic trough plants, the net annual system efficiency by itself does not adequately characterize the performance of the plant. The approach taken here is to define a number of additional performance metrics which enable a more comprehensive understanding of overall plant performance.
EUROTROUGH - Parabolic Trough Collector Developed for Cost Efficient Solar Power Generation
Michael Geyer; Rafael Osuna; Antonio Esteban; Wolfgang Schiel; Axel Schweitzer; Eduardo Zarza; Paul Nava; Josef Langenkamp; Eli Mandelberg
e CIEMAT Plataforma Solar, Apartado 22, E-04200 Tabernas (Almería), Spain f DLR Plataforma Solar, Apartado 39, E-04200 Tabernas (Almería), 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
Simulation of solar lithium bromide–water absorption cooling system with parabolic trough collector
M. Mazloumi; M. Naghashzadegan; K. Javaherdeh
2008-01-01
Ahwaz is one of the sweltering cities in Iran where an enormous amount of energy is being consumed to cool residential places in a year. The aim of this research is to simulate a solar single effect lithium bromide–water absorption cooling system in Ahwaz. The solar energy is absorbed by a horizontal N–S parabolic trough collector and stored in an
A. El Fadar; A. Mimet; M. Pérez-García
2009-01-01
This article suggests a numerical study of a continuous adsorption refrigeration system consisting of two adsorbent beds and powered by parabolic trough solar collector (PTC). Activated carbon as adsorbent and ammonia as refrigerant are selected. A predictive model accounting for heat balance in the solar collector components and instantaneous heat and mass transfer in adsorbent bed is presented. The validity
Solar-thermal electric power generation using a system of distributed parabolic trough collectors
J. W. Ramsey; E. M. Sparrow; E. R. G. Eckert
1975-01-01
The paper describes a solar-thermal collection and transport system for electric power generation. The system employs water as the working fluid; steam at 60 bars pressure and 276 C is generated locally by distributed parabolic solar collectors. A transfer loop conveys the steam to a central site at which the power plant is situated. The design of the collector and
Fast Food with Slow Cookers SESSION GOALS
Fast Food with Slow Cookers SESSION GOALS: Participants will learn how to use a slow cooker to help survey instrument (if needed) #12;2 Fast Food with Slow Cookers BEFORE THIS SESSION: 1. Review materials created by Cornell University Cooperative Extension. #12;3 Fast Food with Slow Cookers SESSION 1
Experimental investigation on a parabolic trough solar collector for thermal power generation
QiBin Liu; YaLong Wang; ZhiChao Gao; Jun Sui; HongGuang Jin; HePing Li
2010-01-01
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 collector’s\\u000a efficiency with the
Efficiency improvement of solar cell using compound parabolic concentrator and sun tracking system
Eklas Hossain; Riza Muhida; A. Ali
2008-01-01
This paper presents how the efficiency of solar cell can be increased with the design of compound parabolic concentrator (CPC) and the implementation of sun tracking system. Sun tracking systems is an application of the machine vision (MV) and collaboration with data acquisition (DAQ) to systems by using a webcamera as a sensor and sound card as an output channel
Study of a new solar adsorption refrigerator powered by a parabolic trough collector
A. El Fadar; A. Mimet; A. Azzabakh; M. Pérez-García; J. Castaing
2009-01-01
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
Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field
D. Kearney; U. Herrmann; P. Nava; B. Kelly; R. Mahoney; J. Pacheco; R. Cable; N. Potrovitza; D. Blake; H. Price
2003-01-01
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 SEGS1 plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl\\/diphenyl oxide.
Modeling of the radiation field in a parabolic trough solar photocatalytic reactor
C. A. Arancibia-Bulnes; S. A. Cuevas
2004-01-01
We calculate the distribution of absorbed radiation inside a solar photocatalytic reactor, by means of radiative transfer theory. The reactor configuration is that of a glass tube illuminated by a parabolic trough collector, where the catalyst consists of titanium dioxide micro-particles suspended in water. The calculations are made within the framework of the P1 approximation, which allows to solve analytically
R. Forristall
2003-01-01
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
Reducing the Cost of Energy from Parabolic Trough Solar Power Plants: Preprint
Price, H.; Kearney, D.
2003-01-01
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 from conventional fossil fuel power plants. This paper reviews the current cost of energy and the potential for reducing the cost of energy from parabolic trough solar power plant technology based on the latest technological advancements and projected improvements from industry and sponsored R&D. The paper also looks at the impact of project financing and incentives on the cost of energy.
Use of parabolic trough solar energy collectors for sea-water desalination
Soteris Kalogirou
1998-01-01
The various desalination methods are analysed with respect to their primary energy consumption, sea-water treatment requirement and equipment cost. From this analysis, the multiple-effect boiling evaporator is concluded to be the most suitable method for stimulation by solar energy. The parabolic-trough solar-collector is selected mainly due to its ability to function at high temperatures with high efficiency. The design of
Analysis of the influence of geography and weather on parabolic trough solar collector design
NASA Astrophysics Data System (ADS)
Treadwell, G. W.; Grandjean, N. R.; Biggs, F.
1980-03-01
The potential performance of single-axis tracking parabolic trough solar collectors as a function of optical energy distribution and receiver size was calculated for eleven sites using typical meteorological year input data. A simulation based on the SOLTES code was developed which includes the three dimensional features of a parabolic trough and calculates the thermo-optical tradeoffs. The capability of the thermo-optical model was confirmed by the comparison of calculated results with the experimental results from an all day test of a parabolic trough. The results from this eleven site analysis indicate a potential performance superiority of a north-south horizontal axis trough and, in addition, a high quality collector should be of the same geometric design for all of the sites investigated and probably for all regions of the country.
An analysis of the influence of geography and weather on parabolic trough solar collector design
NASA Astrophysics Data System (ADS)
Treadwell, G. W.; Grandjean, N. R.; Biggs, F.
1980-08-01
The potential performance of single-axis tracking parabolic trough solar collectors as a function of optical energy distribution and receiver size has been calculated for eleven sites using typical meteorological year input data. A simulation based on the SOLTES code was developed which includes the three-dimensional features of a parabolic trough and calculates the thermooptical tradeoffs. The capability of the thermooptical model has been confirmed by the comparison of calculated results with the experimental results from an all-day test of a parabolic trough. The results from this eleven-site analysis indicate a potential performance superiority of a north-south horizontal axis trough and, in addition, a high quality collector should be of the same geometric design for all of the sites investigated and probably for all regions of the country.
Treadwell, G.W.; Grandjean, N.R.; Biggs, F.
1980-08-01
The potential performance of single-axis tracking parabolic trough solar collectors as a function of optical energy distribution and receiver size has been calculated for eleven sites using typical meteorological year input data. A simulation based on the SOLTES code was developed which includes the three-dimensional features of a parabolic trough and calculates the thermooptical tradeoffs. The capability of the thermooptical model has been confirmed by the comparison of calculated results with the experimental results from an all-day test of a parabolic trough. The results from this eleven-site analysis indicate a potential performance superiority of a north-south horizontal axis trough and, in addition, a high quality collector should be of the same geometric design for all of the sites investigated and probably for all regions of the country.
Analysis of the influence of geography and weather on parabolic trough solar collector design
Treadwell, G.W.; Grandjean, N.R.; Biggs, F.
1980-03-01
The potential performance of single-axis tracking parabolic trough solar collectors as a function of optical energy distribution and receiver size has been calculated for eleven sites using typical meteorological year input data. A simulation based on the SOLTES code was developed which includes the three-dimensional features of a parabolic trough and calculates the thermooptical tradeoffs. The capability of the thermooptical model has been confirmed by the comparison of calculated results with the experimental results from an all-day test of a parabolic trough. The results from this eleven-site analysis indicate a potential performance superiority of a north-south horizontal axis trough and, in addition, a high quality (optical error, sigma/sub system/ less than or equal to 0.007 radian) collector should be of the same geometric design for all of the sites investigated and probably for all regions of the country.
Adel M. Al-Nasser
2010-01-01
The study explores the technical and economic feasibility of a thermal solar power generation plant using parabolic trough collectors (Euro Trough) in Jubail Industrial City, Saudi Arabia. Total annual available solar radiation is calculated at 1,970 kWhr. The size of the proposed solar thermal power plant is 50 MW. The designed solar field is composed of 100 loops with a
Modeling of a Parabolic Trough Solar Field for Acceptance Testing: A Case Study
Wagner, M. J.; Mehos, M. S.; Kearney, D. W.; McMahan, A. C.
2011-01-01
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.
A Linear Parabolic Trough Solar Collector Performance Model
Qu, M.; Archer, D.; Masson, S.
2006-01-01
losses, optical losses include the losses related to the physical properties of glass envelope, coating of absorber, and absorber tube. Once the solar insolation has been absorbed by the receiver, the thermal losses are only left contributions..., the model could be used for optimizing PTSC design by varying the size of receiver tube, the size of glass envelope, receiver tube material, coating material and so forth. 2.2 Theory Of Solar Collector A solar collector, actually, is a special kind...
Vanguard I solar parabolic dish-Stirling engine module. Final report, May 28, 1982September 30, 1984
Washom
1984-01-01
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,
Comparison of electrochemical and thermal storage for hybrid parabolic dish solar power plants
H. L. Steele; L. Wen
1981-01-01
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
Comparison of advanced thermal and electrical storage for parabolic dish solar thermal power systems
T. Fujita; G. C. Birur; J. M. Schredder; J. M. Bowyer; H. I. Awaya
1982-01-01
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,
Design and performance characteristics of a parabolic-trough solar-collector system
S. A. Kalogirou; S. Lloyd; J. Ward; P. Eleftheriou
1994-01-01
A comparison of the advantages and disadvantages of concentrating collectors against conventional flat-plate collectors are presented. This is followed by the design of a parabolic-trough solar-collector system, due consideration having been given to collector-aperture and rim-angle optimisation, together with the receiver-diameter selection. The collector characteristic curve gives a test slope of 0Â·441 and a test intercept equal to 0Â·642. The
Forristall, R.
2003-10-01
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.
The parabolic trough power plants Andasol 1 to 3 The largest solar power plants in the world
Laughlin, Robert B.
power plants: Andasol 1 to 3 Regulatory framework in Spain Project partners 4 8 20 22 #12;4 Solar energyThe parabolic trough power plants Andasol 1 to 3 The largest solar power plants in the world Â Technology premiere in Europe Andasol 1 to 3 #12;2 #12;3Andasol 1 to 3 Inhalt Table of contents Solar energy
Wind loads and local pressure distributions on parabolic dish solar collectors
NASA Astrophysics Data System (ADS)
Peterka, J. A.; Derickson, R. G.; Cermak, J. E.
1990-05-01
The research and development described in this document was conducted within the U.S. Department of Energy's Solar Thermal Technology Program. The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and the establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. This report presents the results of wind-tunnel tests supported through the Solar Energy Research Institute (SERI) by the Office of Solar Thermal Technology of the U.S. Department of Energy as part of the SERI research effort on innovative concentrators. As gravity loads on drive mechanisms are reduced through stretched-membrane technology, the wind-load contribution of the required drive capacity increases in percentage. Reduction of wind loads can provide economy in support structure and collector drive. Wind-tunnel tests have been directed at finding methods to reduce wind loads on parabolic dish collectors. The tests investigated the mean and peak forces, moments and local pressure distributions. A significant increase in the understanding and prediction of peak parabolic dish wind loads and their reduction within a field was achieved.
NASA Astrophysics Data System (ADS)
Chong, Kok-Keong; Lim, Chuan-Yang; Keh, Wee-Liang; Fan, Jian-Hau; Rahman, Faidz Abdul
2011-10-01
A novel solar furnace system has been proposed to be consisted of a Nonimaging Focusing Heliostat and a smaller parabolic concentrator. In this configuration, the primary heliostat consists of 11×11 array of concave mirrors with a total reflective area of 121 m2 while the secondary parabolic concentrator has a focal length of 30 cm. To simplify the design and reduce the cost, fixed geometry of the primary heliostat is adopted to omit the requirement of continuous astigmatic correction throughout a year. The overall performance of the novel solar furnace configuration can be optimized if the heliostat's spinning-axis is fixed in the orientation dependent on the latitude angle so that the annual variation of incidence angle is the least, which ranges from 33° to 57°. Case study of the novel solar furnace system has been performed with the use of ray-tracing method to simulate solar flux distribution profile for two different target distances, i.e. 50 m and 100 m. The simulated results have revealed that the maximum solar concentration ratio ranges from 20,530 suns to 26,074 suns for the target distance of 50 m, and ranges from 40,366 suns to 43,297 suns for the target distance of 100 m.
Cost/performance of solar reflective surfaces for parabolic dish concentrators
NASA Technical Reports Server (NTRS)
Bouquet, F.
1980-01-01
Materials for highly reflective surfaces for use in parabolic dish solar concentrators are discussed. Some important factors concerning performance of the mirrors are summarized, and typical costs are treated briefly. Capital investment cost/performance ratios for various materials are computed specifically for the double curvature parabolic concentrators using a mathematical model. The results are given in terms of initial investment cost for reflective surfaces per thermal kilowatt delivered to the receiver cavity for various operating temperatures from 400 to 1400 C. Although second surface glass mirrors are emphasized, first surface, chemically brightened and anodized aluminum surfaces as well as second surface, metallized polymeric films are treated. Conventional glass mirrors have the lowest cost/performance ratios, followed closely by aluminum reflectors. Ranges in the data due to uncertainties in cost and mirror reflectance factors are given.
NASA Astrophysics Data System (ADS)
Muhlen, Luis S. W.; Najafi, Behzad; Rinaldi, Fabio; Marchesi, Renzo
2014-04-01
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.
Optical analysis of parabolic dish concentrators for solar dynamic power systems in space
NASA Technical Reports Server (NTRS)
Jefferies, K. S.
1985-01-01
An optical analysis of a parabolic solar collection system operating in Earth orbit was performed using ray tracing techniques. The analysis included the effects of: (1) solar limb darkening, (2) parametric variation of mirror surface error, (3) parametric variation of mirror rim angle, and (4) parametric variation of alignment and pointing error. This ray tracing technique used numerical integration to combine the effects of rays emanating from different parts of the sun at different intensities with the effects of normally distributed mirror-surface errors to compute the angular intensity distribution of rays leaving the mirror surface. A second numerical integration was then performed over the surface of the parabolic mirror to compute the radial distribution of brightness at the mirror focus. Major results of the analysis included: (1) solar energy can be collected at high temperatures with high efficiency, (2) higher absorber temperatures can be achieved at lower efficiencies, or higher efficiencies can be achieved at lower temperatures, and (3) collection efficiency is near its maximum level across a broad plateau of rim angles from 40 deg to 70 deg.
An optimized model and test of the China's first high temperature parabolic trough solar receiver
Gong, Guangjie; Huang, Xinyan; Wang, Jun; Hao, Menglong [Southeast University, Nanjing (China)
2010-12-15
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)
Test results on parabolic dish concentrators for solar thermal power systems
NASA Astrophysics Data System (ADS)
Jaffe, Leonard D.
1989-01-01
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.
Freeform lens design to achieve 1000X solar concentration with a parabolic trough reflector
NASA Astrophysics Data System (ADS)
Wheelwright, Brian M.; Angel, Roger; Coughenour, Blake
2014-12-01
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.
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Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM)
Turchi, C.
2010-07-01
This report describes a component-based cost model developed for parabolic trough solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), assisted by WorleyParsons Group Inc., for use with NREL's Solar Advisor Model (SAM). This report includes an overview and explanation of the model, two summary contract reports from WorleyParsons, and an Excel spreadsheet for use with SAM. The cost study uses a reference plant with a 100-MWe capacity and six hours of thermal energy storage. Wet-cooling and dry-cooling configurations are considered. The spreadsheet includes capital and operating cost by component to allow users to estimate the impact of changes in component costs.
Cleaning strategies for parabolic-trough solar-collector fields; guidelines for decisions
Bergeron, K.D.; Freese, J.M.
1981-06-01
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.
Particle Emissions from Domestic Gas Cookers
Ayten Yilmaz Wagner; Hans Livbjerg; Per Gravers Kristensen; Peter Glarborg
2010-01-01
The authors experimentally studied the formation of submicron particles from a domestic gas cooker in a compartment free from external particle sources. The effects of fuel (methane, natural gas, odorant-free natural gas), primary aeration, flow rate, and fuel sulphur content on particle emissions were investigated. The experiments confirmed reports from literature that blue burning flames of domestic gas cookers emit
Huang, Weidong; Hu, Peng; Chen, Zeshao
2011-01-01
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.
M. J. Montes; A. Abánades; J. M. Martínez-Val; M. Valdés
2009-01-01
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
Pierre Frebourg; Nipon Ketjoy; Sukruedee Nathakaranakul; Anan Pongtornkulpanich; Wattanapong Rakwichian; Paitoon Laodee
This paper focuses on the feasibility of a relatively new concept of the combination of a solar parabolic trough with a biomass backup system. The study concentrates on the feasibility of this concept in Thailand implemented on a small-scale grid- connected power plant.
Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator
NASA Astrophysics Data System (ADS)
Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.
2013-07-01
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 12°C. 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.
Comparison of electrochemical and thermal storage for hybrid parabolic dish solar power plants
NASA Technical Reports Server (NTRS)
Steele, H. L.; Wen, L.
1981-01-01
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.
Optical testing of a parabolic trough solar collector by a null screen with stitching
NASA Astrophysics Data System (ADS)
Moreno-Oliva, V., I.; Campos-Garcia, M.; Granados-Agustin, F.; Arjona-Pérez, M. J.; Díaz-Uribe, R.; Avendaño-Alejo, M.
2009-06-01
In this work we report a method for testing a parabolic trough solar collector (PTSC) based on the null screen principles. For surfaces with symmetry of revolution a cylindrical null screen is used, now, for testing the PTSC we use a flat null screen. The design of the null screen with ellipsoidal spots is described; its image, which is formed by reflection on the test surface, becomes an exact square array of circular spots if the surface is perfect. Any departure from this geometry is indicative of defects on the surface. The flat null screen design and the surface evaluation algorithm are presented. Here the surface is tested in sections and the evaluation of the shape of the surface is performed with stitching method. Results of the evaluation for a square PTSC with 1000 mm by side (F/0.49) are shown.
Washom, B.J.
1984-09-30
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.
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
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)
NASA Astrophysics Data System (ADS)
Owkes, Jeanmarie Kathleen
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.
Solar Cooking. What We Make. Science and Technology Education in Philippine Society.
ERIC Educational Resources Information Center
Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.
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…
A 40 W cw Nd:YAG solar laser pumped through a heliostat: a parabolic mirror system
NASA Astrophysics Data System (ADS)
Almeida, J.; Liang, D.; Guillot, E.; Abdel-Hadi, Y.
2013-06-01
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 heliostat–parabolic 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 heliostat–parabolic 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.
M. Collares-Pereira; J. M. Gordon; A. Rabl; R. Winston
1991-01-01
A new two-stage optical design is proposed for parabolic trough solar collectors with tubular absorbers. It can boost the concentration ratio by a factor of 2.5 relative to the conventional design, while maintaining the large rim angles (i.e., low nominal f-numbers) that are desirable for practical and economical reasons. The second state involves asymmetric nonimaging concentrators of the CPC type,
Secondary and compound concentrators for parabolic dish solar thermal power systems
NASA Technical Reports Server (NTRS)
Jaffe, L. D.; Poon, P. T.
1981-01-01
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.
Software used with the flux mapper at the solar parabolic dish test site
NASA Technical Reports Server (NTRS)
Miyazono, C.
1984-01-01
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.
Secondary and compound concentrators for parabolic-dish solar-thermal power systems
Jaffe, L.D.; Poon, P.T.
1981-04-15
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.
Design of a single flat null-screen for testing a parabolic trough solar collector
NASA Astrophysics Data System (ADS)
Moreno-Oliva, Víctor Iván; Campos-García, Manuel; Román-Hernández, Edwin; Santiago-Alvarado, Agustín
2014-11-01
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.
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
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)
Resonance in a model for Cooker's sloshing experiment
Bridges, Tom
Resonance in a model for Cooker's sloshing experiment by H. Alemi Ardakani, T.J. Bridges & M Cooker's sloshing experiment is a prototype for studying the dy- namic coupling between fluid sloshing;1 Introduction In Cooker's sloshing experiment [11], a rectangular vessel containing fluid is suspended from
Effect of porous disc receiver configurations on performance of solar parabolic trough concentrator
NASA Astrophysics Data System (ADS)
Ravi Kumar, K.; Reddy, K. S.
2012-03-01
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.
3X compound parabolic concentrating (CPC) solar energy collector. Final technical report
Ballheim, R.W.
1980-04-25
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.
Mahdi Hedayatizadeh; Yahya Ajabshirchi; Faramarz Sarhaddi; Ali Safavinejad; Said Farahat; Hossein Chaji
2012-01-01
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
Andreas Poullikkas
2009-01-01
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
NASA Astrophysics Data System (ADS)
Miao, L.; Kang, Y. P.; Li, C.; Tanemura, S.; Wan, C. L.; Iwamoto, Y.; Shen, Y.; Lin, H.
2015-06-01
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 2m × 2m 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 37°C being produced and stored in the insulated container.
Soteris Kalogirou; Stephen Lloyd; John Ward
1997-01-01
A parabolic trough collector (PTC) system used for steam generation is presented in this paper. PTCs are the preferred type of collectors used for steam generation due to their ability to work at high temperatures with a good efficiency. The modelling program developed called PTCDES is used to predict the quantity of steam produced by the system. The flash vessel
NASA Astrophysics Data System (ADS)
Feliciano-Cruz, Luisa I.
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.
Resonance in a model for Cooker's sloshing experiment
Bridges, Tom
Resonance in a model for Cooker's sloshing experiment -- the extended version -- by H. Alemi 7XH, England Abstract Cooker's sloshing experiment is a prototype for studying the dy- namic coupling between fluid sloshing and vessel motion. It involves a container, partially filled with fluid
NASA Astrophysics Data System (ADS)
Miao, L.; Zhang, M.; Tanemura, S.; Tanaka, T.; Kang, Y. P.; Xu, G.
2012-06-01
We have designed a new solar thermoelectric cogeneration system consisting of an evacuated tubular solar collector (ETSC) with a parabolic trough concentrator (PTC) and thermoelectric modules (TEMs) to supply both thermal energy and electricity. The main design concepts are (1) the hot side of the TEM is bonded to the solar selective absorber installed in an evacuated glass tube, (2) the cold side of the TEM is also bonded to the heat sink, and (3) the outer circulated water is heated by residual solar energy after TEM generation. We present an example solar thermal simulation based on energy balance and heat transfer as used in solar engineering to predict the electrical conversion efficiency and solar thermal conversion efficiency for different values of parameters such as the solar insolation, concentration ratio, and TEM ZT values.
Error analysis of motion transmission mechanisms : design of a parabolic solar trough
Koniski, Cyril (Cyril A.)
2009-01-01
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. ...
Conceptual design of a parabolic dish solar collector using simulation techniques
NASA Technical Reports Server (NTRS)
Gupta, B. P.; Buchholz, R. L.
1976-01-01
The development of solar concentrators in recent years have produced a wide variety of collectors for the utilization of solar energy. This paper presents the simulation techniques used to predict the optical and thermal performance of a paraboloid of revolution type solar collector. Conceptual design of a dish concentrator with a fixed receiver size is obtained by parametrically examining the significant variables.
Science Sampler: A slice of solar cooking
NSDL National Science Digital Library
Pamela Galus
2003-05-01
Using the principles of scientific investigation, students design a solar cooker using materials supplied by the teacher. Students then spend individual time designing a solar cooker on their own. Afterward, students are placed in groups to cooperatively design a cooker. The kids construct their cookers, and then try them out by sun-roasting apples. A report is written to summarize at least three science concepts utilized in their design. Through this engaging and inquiry-based activity, students learn the application of science by transforming insulation to heat energy.
NASA Technical Reports Server (NTRS)
Dehne, Hans J.
1991-01-01
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.
Two-tank molten salt storage for parabolic trough solar power plants
Ulf Herrmann; Bruce Kelly; Henry Price
2004-01-01
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,
Luo, Jun
2014-08-08
concentrating solar power plant. A set of engineering performance, financial and net energy models were developed as tools to predict a plant’s engineering performance, cost and energy payback. The models were validated by comparing the predicted results...
Mechanical development of an actuation system for a parabolic solar trough collector
Carrillo, Juan Felipe (Carrillo Salazar)
2013-01-01
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 ...
Design and analysis of hydraulically driven actuation system For a parabolic solar trough
Popovi?, Katarina, S.B. Massachusetts Institute of Technology
2013-01-01
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 ...
2013-01-01
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
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
Evaluation of solar aided biomass power generation systems with parabolic trough field
HongJuan Hou; YongPing Yang; Eric Hu; JiFeng Song; ChangQing Dong; Jian Mao
2011-01-01
Solar and biomass are both renewable energy resources. Using biomass as fuel is becoming more and more attractive after governments\\u000a increase the tariff for the electricity from the renewable sources. However the costs of power from a biomass power generation\\u000a plant depend greatly on the availability and quality of the biomass resource. The commercialization of solar alone thermal\\u000a power generation
Kelly, B.
2006-07-01
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.
Mehos, M. S.; Wagner, M. J.; Kearney, D. W.
2011-08-01
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.
NSDL National Science Digital Library
The Concord Consortium
2012-05-21
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.
NASA Astrophysics Data System (ADS)
Muir, J. F.; Hogan, R. E., Jr.; Skocypec, R. D.; Buck, R.
1993-07-01
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 proof-of-concept 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
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.
Ramírez, Carlos; León, Noel; García, Héctor; Aguayo, Humberto
2015-06-01
Solar tracking concentrators are optical systems that collect the solar energy flux either in a line or spot using reflective or refractive surfaces. The main problem with these surfaces is their manufacturing complexity, especially at large scales. In this paper, a line-to-spot solar tracking concentrator is proposed. Its configuration allows for a low-cost solar concentrator system. It consists of a parabolic trough collector (PTC) and a two-section PMMA Fresnel lens (FL), both mounted on a two-axis solar tracker. The function of the PTC is to reflect the incoming solar radiation toward a line. Then, the FL, which is placed near the focus, transforms this line into a spot by refraction. It was found that the system can achieve a concentration ratio of 100x and concentrate an average solar irradiance of 518.857W/m^{2} with an average transmittance of 0.855, taking into account the effect of the chromatic aberration. PMID:26072873
Parabolic dish module experiment
NASA Astrophysics Data System (ADS)
1986-03-01
A development test model of the 8-meter Solar Brayton Parabolic Dish Module has been designed, fabricated, and tested. The test model consists of five major subsystems: Sanders ceramic honeycomb solar receiver; LaJet LEC460 solar concentrator; AiRsearch SABC MKIIIA engine, Abacus 8 kW ac inverter; and a Sanders designed and built system controller. Goals of the tests were to integrate subsystem components into a working module, demonstrate the concept, and generate 5 kWe (hybrid) and 4.7 kWe (solar only) input. All subsystem integration goals were successfully achieved, but system performance efficiency was lower than expected. Contributing causes of the lower performance efficiencies have been identified. Modifications needed to restore performance to the required levels and improve the system life cycle cost have been addressed and are the subject of this final report.
NASA Astrophysics Data System (ADS)
Selcuk, M. K.; Fujita, T.
1984-06-01
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.
Parabolic trough collectors for industrial and commercial applications
Gee, R.C.
1997-06-01
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.
NASA Astrophysics Data System (ADS)
Jaffe, Leonard D.
1988-11-01
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.
NASA Technical Reports Server (NTRS)
Jaffe, Leonard D.
1988-01-01
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, L.D.
1988-11-01
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.
Burn and mandible fracture due to pressure cooker explosion.
Gundeslioglu, A Ozlem; Yenidunya, M Oguz
2010-09-01
A burn case of 42-year-old female patient due to pressure cooker explosion associated with mandibular fracture is presented. After early tangential excision of the deep second- and third-degree-burn areas, a split-thickness skin grafting was applied. Open reduction and internal fixation therapy with miniplate system were done for linear symphysis fracture. As much as we know, there was no report in the literature about pressure-cooking burn accompanying mandibular fracture. PMID:20856063
Chung, Ill-Min; Yu, Bo-Ra; Park, Inmyoung; Kim, Seung-Hyun
2014-12-10
This study examined the effects of heat and pressure on the isoflavone content and profiles of soybeans and rice cooked together using an electric rice cooker (ERC) and an electric pressure rice cooker (EPRC). The total isoflavone content of the soybean-rice mixture after ERC and EPRC cooking relative to that before cooking was ?90% in soybeans and 14-15% in rice. Malonylglucosides decreased by an additional ?20% in EPRC-cooked soybeans compared to those cooked using the ERC, whereas glucosides increased by an additional ?15% in EPRC-cooked soybeans compared to those in ERC-cooked soybeans. In particular, malonylgenistin was highly susceptible to isoflavone conversion during soybean-rice cooking. Total genistein and total glycitein contents decreased in soybeans after ERC and EPRC cooking, whereas total daidzein content increased in EPRC-cooked soybeans (p < 0.05). These results may be useful for improving the content of nutraceuticals, such as isoflavones, in soybeans. PMID:25394170
Cooker's sloshing experiment with baffles: a naturally occurring multifold 1: :1 resonance
Bridges, Tom
Cooker's sloshing experiment with baffles: a naturally occurring multifold 1: · · · :1 resonance and fluid sloshing for a container with baffles. 1 Introduction A 1 : 1 resonance strong internal. In this case the question is the effect of vehicle coupling on fluid sloshing. In Cooker's experiment
Saturated steam process with direct steam generating parabolic troughs
M. Eck; E. Zarza
2006-01-01
The direct steam generation (DSG) in parabolic trough collectors is an attractive option regarding the economic improvement of parabolic trough technology for solar thermal electricity generation in the multi Megawatt range. The European DISS project has proven the feasibility of the direct steam generation under real solar conditions in more than 4000 operation hours. Within the European R&D project INDITEP
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.
G. C. Bakos; I. Ioannidis; N. F. Tsagas; I. Seftelis
2001-01-01
PTCs are the preferred type of collector used for steam generation, due to their ability to work at high temperatures with high efficiencies. The results produced from a simulation program, showing the variation of collector's efficiency as a function of heat transfer fluid flux, pipe diameter, solar radiation intensity and active area of the PTC, are presented.
The parabolic Harnack inequality
Novak, Erich
The parabolic Harnack inequality on metric graphs Sebastian Haeseler 1. Basic definitions 2. Volume-doubling properties 3. PoincarÂ´e inequalities 4. The parabolic Harnack inequality 5. Examples The parabolic Harnack inequality on metric graphs Sebastian Haeseler Friedrich-Schiller UniversitÂ¨at Jena 28.09.2009 #12;The
Skocypec, R.D.; Hogan, R.E. Jr.; Muir, J.F.
1991-01-01
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.
Optimal Heat Collection Element Shapes for Parabolic Trough Concentrators
Bennett, C
2007-11-15
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.
Cooking Amount Estimation of Rice Cooker by Signed Mahalanobis Distance
NASA Astrophysics Data System (ADS)
Suzuki, Arata; Sugimoto, Kenji
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.
Solargenix Energy Advanced Parabolic Trough Development
R. C. Gee; M. J. Hale
2005-01-01
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,
Parabolic dish test site: History and operating experience
NASA Technical Reports Server (NTRS)
Selcuk, M. K. (compiler)
1985-01-01
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.
Parabolic dish Stirling module
Washom, B.
1984-03-01
The design, manufacture, and assembly of a commercially designed parabolic dish Stirling 25 kWe module is examined. The cost, expected performance, design uniquenesses, and future commercial potential of this module, which is regarded as the most technically advanced in the parabolic dish industry is discussed.
F. Lippke
1996-01-01
Direct steam generation (DSG) in parabolic troughs was first studied in the early 1980s by Murphy (1982) and Pederson (1982). Intensive research on DSG then started in 1988, when Luz identified this technology as the desired system for a future generation of its power plants. These R and D activities were not terminated by Luz`s demise in 1991, but have
ERIC Educational Resources Information Center
Galus, Pamela
2003-01-01
Presents an inquiry activity in which students design a solar cooking apparatus. Students are also asked to write a paragraph that explains the ways in which science knowledge helped them in the design of their cooker. Includes a grading rubric. (SOE)
J. W. Allen; N. M. Levitz; A. Rabl; K. A. Reed; W. W. Schertz; G. Thodos; R. Winston
1977-01-01
Work on the development of Compound Parabolic Concentrators (CPC) is described. A tenfold concentrator with a cavity receiver was constructed and tested. The optical efficiency was very good (65 percent), but the thermal performance was degraded by heat losses of the cavity receiver. A 20 ft² (1.86 m²) concentrating collector (5.3x) has been tested for thermal and optical performance, and
Parabolic Trough Organic Rankine Cycle Power Plant
Canada, S.; Cohen, G.; Cable, R.; Brosseau, D.; Price, H.
2005-01-01
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.
The Pressure Cooker: A Module on the Properties of Matter. Tech Physics Series.
ERIC Educational Resources Information Center
Technical Education Research Center, Cambridge, MA.
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…
Daiton de Freitas Rezende; Theo Guenter Kieckbusch
2003-01-01
During the heat treatment of canned liquid foods in a spin-cooker, the cylindrical can is horizontally positioned and made to rotate around its longitudinal axis. Though a headspace of about 15% in volume is used, the air bubble is continuously displaced to the top affecting the internal level of turbulence in the liquid phase. For relatively high rotations all liquid
Solar Energy Education. Home economics: student activities. Field test edition
Not Available
1981-03-01
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)
Optimized compact secondary reflectors for parabolic troughs with tubular absorbers
Wolfgang Spirkl; Harald Ries; Julius Muschaweck; Andreas Timinger
1997-01-01
Parabolic trough type solar power plants could reach higher efficiencies by using secondary reflectors, which increase the concentration of the solar irradiance onto the absorber tube. Recently, compact secondary concentrators have been proposed which are constructed according to the edge ray principle; they are composed of an involute part and an edge ray reflector with a form close to a
Chadzitaskos, Goce
2013-01-01
We present a proposal of a new type of telescopes using a rotating parabolic strip as the primary mirror. It is the most principal modification of the design of telescopes from the times of Galileo and Newton. In order to demonstrate the basic idea, the image of an artificial constellation observed by this kind of telescope was reconstructed using the techniques described in this article. As a working model of this new telescope, we have used an assembly of the primary mirror---a strip of acrylic glass parabolic mirror 40 cm long and 10 cm wid shaped as a parabolic cylinder of focal length 1 m---and an artificial constellation, a set of 5 apertures in a distance of 5 m illuminated from behind. In order to reconstruct the image, we made a series of snaps, each after a rotation of the constellation by 15 degrees. Using Matlab we reconstructed the image of the artificial constellation.
TRACTOR CALCULI FOR PARABOLIC GEOMETRIES
ANDREAS CAP; A. ROD GOVER
1999-01-01
Parabolic geometries may be considered as curved analogues of the homogeneous spaces G=P where G is a semisimple Lie group and P G a parabolic subgroup. Conformal geometries and CR geometries are exam- ples of such structures. We present a uniform description of a calculus, called tractor calculus, based on natural bundles with canonical linear connections for all parabolic geometries.
Nontracking parabolic collector apparatus
M. C. Rogers; M. Gill
1984-01-01
A mirror collector having a generally parabolic surface terminating near the vertex in a circular or cylindrical curve, a collector tube composed of a clear glass outer tube for energy admission and for passing an inner fluid, the collector being generally eliptical in nature constructed of copper with a selective absorption coating for receiving heat and positioned so that the
Parabolically connected subgroups
Netai, Igor V [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)
2011-08-31
All reductive spherical subgroups of the group SL(n) are found for which the intersections with every parabolic subgroup of SL(n) are connected. This condition guarantees that open equivariant embeddings of the corresponding homogeneous spaces into Moishezon spaces are algebraic. Bibliography: 6 titles.
Control concepts for direct steam generation in parabolic troughs
Loreto Valenzuela; Eduardo Zarza; Manuel Berenguel; Eduardo F. Camacho
2005-01-01
A new prototype parabolic-trough collector system was erected at the Plataforma Solar de Almer??a (PSA) (1996–1998) to investigate direct steam generation (DSG) in a solar thermal power plant under real solar conditions. The system has been under evaluation for efficiency, cost, control and other parameters since 1999. The main objective of the control system is to obtain steam at constant
Parabolic dish photovoltaic concentrator development
NASA Astrophysics Data System (ADS)
Beninga, K.; Davenport, R.; Featherby, M.; Sandubrae, J.; Walcott, K.
1991-05-01
Science Applications International Corporation (SAIC) and Tactical Fabs, Inc. (TFI) have fabricated a prototype parabolic dish photovoltaic (PV) concentrator system to demonstrate the functionality of this approach. A 1.5 m diameter parabolic dish was fabricated of a polyester/fiberglass composite, with a silvered polymer reflective surface. An innovative receiver cooling system used outward radial flow of cooling water in a narrow passage. This configuration matches the heat transfer capability of the cooling system to the flux profile on the PV receiver, minimizing temperature variations across the receiver. The photovoltaic cells used in the system were a new, TFI-proprietary design. Interleaved contacts form a bi-polar, rear-contact cell configuration. Because the electrical contacts are made on the rear of the cells, cells can be close-packed to form receiver arrays of arbitrary shape and size. Optical testing of the dish concentrator was performed by SAIC, SERI, and Sandia National Labs. The dish concentrator, designed for solar thermal applications, had a tight focal spot but exhibited flux non-uniformities away from the focal plane. Thermal testing of the receiver cooling system was performed with excellent success. Single PV cells, 4-cell blocks, and 144-cell receiver modules were built and tested. The cells successfully demonstrated the TFI design concept, but due to cell processing problems their efficiency was very low. Sources of the processing problems were identified and solutions were proposed, but funding limitations precluded further cell production. Operation of the complete PV dish system was conducted, and the functionality of the system was demonstrated. However, low cell efficiencies and receiver plane flux non-uniformities caused the system performance to be very low. These problems are not generic to the concept, and solutions to them proposed.
HISTORY OF SOLAR ENERGY RESEARCH IN BRAZIL
Neelkanth G. Dhere; Pio C. Lobo; Ricardo Rüther; Leila R. Cruz; José R. T. Branco; Izete Zanesco; Católica Porto; Jorge H. G. Lima
Brazil has large, unelectrified, geographic regions with very high insolation throughout the year. Development of solar energy research in Brazil evolved through establishment of well-equipped laboratories, spread of post-graduate education and basic research during 1958-72, intense applied research on solar thermal viz. collectors, refrigeration, furnaces, cookers, driers, and distillation; and photovoltaics viz. c-Si solar cells, Cu2S, CIGS, CdTe and a-
Session: Parabolic Troughs (Presentation)
Kutscher, C.
2008-04-01
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.
Incidence-angle modifier and average optical efficiency of parabolic trough collectors
H. Gaul; A. Rabl
1980-01-01
The incidence-angle modifier for parabolic troughs is investigated in order to clarify the connection between collector tests and the prediction of long-term energy delivery by collector arrays. The optical efficiency of a parabolic trough collector decreases with incidence angle for several reasons: the decreased transmission of the glazing and the absorption of the absorber; the increased width of the solar
Nontracking parabolic collector apparatus
Rogers, M.C.; Gill, M.
1984-10-09
A mirror collector having a generally parabolic surface terminating near the vertex in a circular or cylindrical curve, a collector tube composed of a clear glass outer tube for energy admission and for passing an inner fluid, the collector being generally eliptical in nature constructed of copper with a selective absorption coating for receiving heat and positioned so that the mirror concentrates substantially all incoming energy upon the central collector tube for providing a concentration factor of about four.
Water Cooled TJ Dense Array Modules for Parabolic Dishes
Loeckenhoff, Ruediger; Kubera, Tim; Rasch, Klaus Dieter [AZUR SPACE Solar Power GmbH, Theresienstr. 2, 74072 Heilbronn (Germany)
2010-10-14
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.
Status of APS 1-Mwe Parabolic Trough Project
Canada, S.; Brosseau, D.; Kolb, G.; Moore, L.; Cable, R.; Price, H.
2005-11-01
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.
The EUCLIDES prototype: An efficient parabolic trough for PV concentration
G. Sala; J. C. Arboiro; A. Luque; J. C. Zamorano; J. C. Minano; C. Dramsch; T. Bruton; D. Cunningham
1996-01-01
The project EUCLIDES, subsidized by the European Union, had the aim of demonstrating the feasibility of cost reduction using reflective parabolic trough solar concentrators. The concentrator is conceived as one axis, horizontal tracking North\\/South oriented array, 72 meters long. The geometric concentration ratio is 32X. A prototype, 24 meters long, has been developed and installed in Madrid, Spain. The overall
The application of parabolic trough technology under Jordanian climate
Omar Badran; Markus Eck
2006-01-01
Parabolic trough solar thermal power plants are a proven technology in the utility scale since mid of the eighties. Between 1984 and 1991 nine power plants with an overall capacity of 354MW have been installed in the Mojave Desert in California. Since, these power plants can be equipped with a thermal storage or a fossil back-up they offer a fully
Analysis and design of two stretched-membrane parabolic dish concentrators
Thomas R. Mancini
1991-01-01
The state-of-the-art of parabolic dish solar concentrators is the faceted, glass-metal dish. The mass production costs of glass-metal dishes may be high because they do not incorporate the innovations of design and materials developed over the last eight years. Therefore, Sandia National Laboratories has undertaken to develop two stretched-membrane parabolic dish concentrators for the Department of Energy's Solar Thermal Program.
Solar thermal technology evaluation, fiscal year 1982. Volume 1: Executive summary
NASA Technical Reports Server (NTRS)
1983-01-01
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.
Analysis and conceptual design of a lunar radiator parabolic shade
NASA Technical Reports Server (NTRS)
Ewert, Michael K.; Clark, Craig S.
1991-01-01
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.
ERIC Educational Resources Information Center
El Zubeir, Z.
1997-01-01
In El Sururab in rural Sudan, solar energy is used for cooking instead of wood. This study explored the efficiency of a hot-box type of solar cooker for storing heat and its effectiveness for different methods of cooking various foods used daily in El Sururab. Forty local women served as a respondent group. (PVD)
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...
L. Schnatbaum
2009-01-01
The solar thermal power plant technology, the opportunities it presents and the developments in the market are outlined. The\\u000a focus is on the technology of parabolic trough power plants, a proven technology for solar power generation on a large scale.\\u000a In a parabolic trough power plant, trough-shaped mirrors concentrate the solar irradiation onto a pipe in the focal line of
Closed loop solar collector system
1981-01-01
A closed loop solar collector system includes a linear concentrating parabolic reflector, a linear vaporizer tube horizontally aligned along the focal line of the parabolic reflector, and a fluid metering assembly attached to the input end of the vaporizer tube for precisely metering a quantity of a vaporizable heat transfer fluid from a supply tank to the vaporizer tube. Solar
Concentrating Solar Power Commercial Application Study
Laughlin, Robert B.
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
Nonimaging secondary concentrators for large rim angle parabolic troughs with tubular absorbers.
Ries, H; Spirkl, W
1996-05-01
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
Parabolized stability equations
NASA Astrophysics Data System (ADS)
Herbert, Thorwald
1994-04-01
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.
Criteria for evaluation of reflective surface for parabolic dish concentrators
NASA Technical Reports Server (NTRS)
Bouquet, F.
1980-01-01
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.
Direct steam generation in parabolic trough concentrators with bimetallic receivers
Vicente Flores; Rafael Almanza
2004-01-01
This document shows the results obtained in direct steam generation for low powers in parabolic trough concentrators with bimetallic Cu–Fe wall receivers. The objective is to study its thermal behavior under transient conditions and stratified two-phase flow. Experimental results in transient state appear considering the variants of mass flows between 60 and 150 kg\\/h, the direction of the solar beam
Composite isogrid structures for parabolic surfaces
NASA Technical Reports Server (NTRS)
Silverman, Edward M. (Inventor); Boyd, Jr., William E. (Inventor); Rhodes, Marvin D. (Inventor); Dyer, Jack E. (Inventor)
2000-01-01
The invention relates to high stiffness parabolic structures utilizing integral reinforced grids. The parabolic structures implement the use of isogrid structures which incorporate unique and efficient orthotropic patterns for efficient stiffness and structural stability.
Solar power system, with high concentration, linear reflective solar panels
1979-01-01
A solar power system with high concentration linear reflective solar panels of the linear parabolic type is described which increases the electrical power output from conventional silicon solar cells and heats water for steam power. The solar power system may be arranged as an all electric type using continuous lines of silicon solar cells located at the apex or focal
Solar thermal parabolic dish energy applications
NASA Technical Reports Server (NTRS)
Pijawka, W.
1981-01-01
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.
ccsd00001178 Parabolic subgroups of Garside groups
the Artin-Tits groups of spherical type. We generalise the well-known notion of a parabolic subgroup of an Artin-Tits group into that of a parabolic subgroup of a Garside group. We also de#12;ne the more general between Artin-Tits groups. We prove that most of the properties of parabolic subgroups extend
RCS computation of airplane using parabolic equation
A. R. Mallahzadeh; M. Soleimani; J. Rashed-Mohassel
2005-01-01
The parabolic equation method gives accurate results in calculation of scattering from objects with dimensions ranging from one to tens of wavelengths. Solving parabolic equation with the marching method needs limited computer storage even for scattering calculations of large targets. In this paper, first the calculation procedure of radar cross section using parabolic equation in three dimensions is studied and
Using Solar Cookers and Gardens to Improve Health in Urban and Rural Areas
R. M. Dow; C. R. Dow
1999-01-01
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
Power converters for parabolic dishes
V. C. Truscello; A. N. Williams
1981-01-01
The development status of receivers and power conversion units to be used with parabolic dish concentrators is presented. Applications are identified, and the key role played by the power converter element of the collector module is emphasized. The electrical output of the 11-meter-diameter dish modules which are being developed varies up to a maximum of about 25 kilowatts, depending on
Electromagnetic waves at parabolic boundaries
Pierre Hillion
1997-01-01
We first discuss the scattering of an electromagnetic plane wave at a perfectly conducting parabolic cylinder when the incident wave travels toward the edge of the cylinder and parallel to its axis. We get in terms of Weber functions an exact solution which is simple enough to make possible a comparison with approximate solutions developed to tackle diffraction at rounded
Parabolic tapers for overmoded waveguides
Doane, J.L.
1983-11-25
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.
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.
Mulimani, V H; Supriya, D
1994-10-01
Three domestic cooking methods were studied in alpha-amylase inhibitory activity in sorghum grains. In all the treatments, overnight soaked seeds lost amylase inhibitory activity much faster. All the three treatments reduced the inhibitory activity. Use of solar cooker for reducing amylase inhibitory activity works out very economically and efficiently. Microwave cooking eliminates amylase inhibitory activity within 5 minutes. PMID:7855094
A Grinding Apparatus For Making A Middle-Size Parabolic Mirror Using The Link Mechanism Method
NASA Astrophysics Data System (ADS)
Shishido, Kora; Sugiura, Masao
1987-01-01
A large solar furnace that has a parabolic mirror with a diameter of 10m, a focal length of 3.2m and a heliostat mirror with an area of 15x15m was made by the authors at T6hoku University in 1962, and subsequently a small solar furnace having a parabolic mirror with a diameter of 1.5m, a focal -length of 0.5m and a heliostat mirror with an area of 2x2m was constructed at T6hoku Gakuin University in 1986. The large solar furnace could melt tungsten with a melting point of 3400°C, and the small solar furnace drove a stirling engine made in West Germany that had a rated power of 400W. The parabolic mirror of the segment type at TohokU University was made by a grinding apparatus that used a cam mechanism, and the parabolic mirror at T6hoku Gakuin University was made by an apparatus (hand-made by students)which employed a link mechanism to draw the parabolic curve. In this paper, the grinding apparatus used for making the segmental parabolic mirror with a diameter of 2-3m and a focal length of 0.5-1.0 m is reported. This mirror was used in a middle-size solar heat engine. The heat engine in this system was a Stirling engine with a rated power of 1-3KW, and the grinding apparatus (the precision parts moved in a linear track ) employed a compact link mechanism.
Cost Effectiveness of Hybrid Solar Powerplants
NASA Technical Reports Server (NTRS)
Wen, L. C.; Steele, H. L.
1983-01-01
Report discusses cost effectiveness of high-temperature thermal storage system for representative parabolic dish solar powerplant. Economic viability of thermal storage system assesses; cost and performance projections made; cost of electricity generated by solar power plant also calculated.
Price, H.; Kearney, D.
1999-01-31
Technology roadmapping is a needs-driven technology planning process to help identify, select, and develop technology alternatives to satisfy a set of market needs. The DOE's Office of Power Technologies' Concentrating Solar Power (CSP) Program recently sponsored a technology roadmapping workshop for parabolic trough technology. The workshop was attended by an impressive cross section of industry and research experts. The goals of the workshop were to evaluate the market potential for trough power projects, develop a better understanding of the current state of the technology, and to develop a conceptual plan for advancing the state of parabolic trough technology. This report documents and extends the roadmap that was conceptually developed during the workshop.
Barker, O.P.
1991-04-23
This patent describes a solar harness system. I comprises a parabolic reflector having a specific theoretical focal point and having a series of focal points for the different colored light rays contained in solar lights; means for supporting the parabolic reflector; a solar harness apparatus, including: solar cells, each having an active surface, with the active surface of each solar cell being substantially parallel to one another and facing the same direction, and with the solar cells being stacked in line behind one another; magnets, with at least one magnet being located between each adjacent solar cell in the cells, each of the magnets being of adequate magnetic power to hold the solar cells in stacked arrangement therewith, without any other support and so as to create solderless contacts with each solar cell in series; means connected to one end of the stacked arrangement of solar cells and magnets for drawing electric current therefrom; means for supporting the harness apparatus at the focal point of a color of the colored light rays in solar light other than the red color focal point.
Progress in solar thermal distributed receiver technology
Leonard, J.A.; Otts, J.V.
1985-01-01
A brief discussion is given on the fundamentals of parabolic dish collectors. Private and Department of Energy supported projects which employ parabolic dish collector systems are described. These projects include: the Distributed Receiver Test Facility, Shenandoah Solar Total Energy Project, Vanguard I, Solar Plant No. 1, the Dish/Stirling Solar Electric Generating System, the Organic Rankine Cycle, and the Solarized Automotive Gas Turbine. Reference is also made towards future research and development. (BCS)
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS
Janson, Svante
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS condition* *s on the coefficients of a parabolic equation for convexity to be preserved. A* * parabolic equation is said to preserve convexity if given a convex initial conditio* *n, any
Parabolic Deligne-Lusztig varieties
Digne, François
2011-01-01
Motivated by the Brou\\'e conjecture on blocks with abelian defect groups for finite reductive groups, we study "parabolic" Deligne-Lusztig varieties and construct on those which occur in the Brou\\'e conjecture an action of a braid monoid, whose action on their $\\ell$-adic cohomology will conjecturally factor trough a cyclotomic Hecke algebra. In order to construct this action, we need to enlarge the set of varieties we consider to varieties attached to a "ribbon category"; this category is a {\\em Garside category}, which plays an important role in our proof, so we devote the first part of our paper to the necessary background on Garside categories.
The cost of integration of parabolic trough CSP plants in isolated Mediterranean power systems
Andreas Poullikkas; Ioannis Hadjipaschalis; George Kourtis
2010-01-01
In this work, a technical and economic analysis concerning the integration of parabolic trough concentrated solar power (CSP) technologies, with or without thermal storage capability, in an existing typical small isolated Mediterranean power generation system, in the absence of a feed-in tariff scheme, is carried out. In addition to the business as usual (BAU) scenario, five more scenarios are examined
Development of a Molten-Salt Thermocline Thermal Storage System for Parabolic Trough Plants
James E. Pacheco; Steven K. Showalter; William J. Kolb
2002-01-01
Thermal storage improves the dispatchability and marketability of parabolic trough power plants allowing them to produce electricity on demand independent of solar collection. One such thermal storage system, a thermocline, uses a single tank containing a fluid with a thermal gradient running vertically through the tank, where hotter fluid (lower density) is at the top of the tank and colder
Simulation of point light concentration with parabolic trough collector
NASA Astrophysics Data System (ADS)
Danylyuk, Andriy; Zettl, Marcus; Lynass, Mark
2010-08-01
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.
Overview of software development at the parabolic dish test site
NASA Technical Reports Server (NTRS)
Miyazono, C. K.
1985-01-01
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.
TRACTOR BUNDLES FOR IRREDUCIBLE PARABOLIC GEOMETRIES
A. Rod Gover
2000-01-01
We use general results on tractor calculi for parabolic geometries that we obtained in a previous article to give a simple and effective characterisation of ar- bitrary normal tractor bundles on manifolds equipped with an irreducible parabolic geometry (also called almost Hermitian symmetric- or AHS-structure in the literat- ure). Moreover, we also construct the corresponding normal adjoint tractor bundle and
Solargenix Energy Advanced Parabolic Trough Development
Gee, R. C.; Hale, M. J.
2005-11-01
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.
T. R. Mancini; G. J. Kolb; M. R. Prairie
1997-01-01
Solar thermal power is produced by three types of concentrating systems, which utilize parabolic troughs, dishes, and heliostats as the solar concentrators. These systems are at various levels of development and commercialization in the United States and in Europe. The U.S. Industry is currently developing these systems for export at the end of this century and at the beginning of
Parabolic curves in Lie groups
Pauley, Michael [School of Mathematics and Statistics, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)
2010-05-15
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.
NSDL National Science Digital Library
Iowa Public Television. Explore More Project
2004-01-01
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.
A. S. Nafey; M. A. Sharaf
2010-01-01
Organic Rankine cycles (ORC) have unique properties that are well suited to solar power generation. In this work design and performance calculations are performed using MatLab\\/SimuLink computational environment. The cycle consists of thermal solar collectors (Flat Plate Solar Collector (FPC), or Parabolic Trough Collector (PTC), or Compound Parabolic Concentrator (CPC)) for heat input, expansion turbine for work output, condenser unit
Eduardo Zarza; Loreto Valenzuela; Javier León; Markus Eck; Klaus Hennecke
The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996-1998), a life-size test facility was implemented at the Plataforma Solar de Almería (PSA) to investigate under real
Safety Risk Management for ESA Parabolic Flights
NASA Astrophysics Data System (ADS)
Malyshev, M.; Desroches, V.; Pletser, V.; Gharib, T.; Gai, F.; Rosier, P.
2012-01-01
This article is intended to inform the Space Safety community on the safety assurance practices employed during European Space Agency (ESA) Parabolic Flight Campaigns (PFC). It describes ESA PFC processes, roles and activities of involved organizations and safety assurance methodologies.
A Process Heat Application Using Parabolic Trough Collector
NASA Astrophysics Data System (ADS)
Y?lmaz, ?brahim Halil; Söylemez, Mehmet Sait; Hayta, Hakan; Yumruta?, Recep
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.
NASA Technical Reports Server (NTRS)
Lathrop, J. W.; Prince, J. L.
1979-01-01
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.
Solar Disinfection of MODS Mycobacterial Cultures in Resource-Poor Settings
Nathavitharana, Ruvandhi; Coronel, Jorge; Moore, David A. J.
2007-01-01
Introduction Safe disposal of TB culture material in which the infectious burden of clinical samples has been greatly amplified is an important challenge in resource-limited settings. The bactericidal capacity of solar cookers has been demonstrated previously for conventional bacteria and contaminated clinical waste. We investigated the use of a simple solar cooker for the sterilization of mycobacterial broth cultures from the microscopic observation drug susceptibility assay (MODS). Methods Simulated TB culture materials were prepared by inoculating 24-well MODS plates with 500 µL of a known concentration of Mycobacterium bovis BCG. In a series of experiments, samples were simultaneously placed inside a box-type solar cooker and control box and removed at timepoints between 15 minutes and 6 hours. Quantitative cultures were performed using retrieved samples to determine sterilization effect. Results All cultures from the control box were positive at or within 1–4 logs of inoculation concentration. Simulated culture plates at concentrations from 103colony-forming-units (CFU)/ml to 107 CFU/ml were completely sterilized after only one hour of cooker exposure, at temperatures between 50–102°C. At 109 CFU/ml (far in excess of diagnostic cultures), it was only possible to recover mycobacterial growth in plates removed after 15 minutes. By 30 minutes all plates were effectively sterilized. Discussion Solar disinfection provides a very effective, safe and low-cost alternative to conventional equipment used for disposal of mycobacterial culture material. Effect of climatic conditions and optimal operating procedure remain to be defined. PMID:17971863
Wind loads on heliostats and parabolic dish collectors
NASA Astrophysics Data System (ADS)
Peterka, J. A.; Tan, Z.; Bienkiewicz, B.; Cermak, J. E.
1988-11-01
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.
Performance of a solar-thermal collector
NASA Technical Reports Server (NTRS)
Higa, W. H.
1975-01-01
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.
Jürgen Dersch; Michael Geyer; Ulf Herrmann; Scott A. Jones; Bruce Kelly; Rainer Kistner; Winfried Ortmanns; Robert Pitz-Paal; Henry Price
2004-01-01
Parabolic trough solar technology has been proven at nine commercial Solar Electric Generating Systems (SEGS) power plants that are operating in the California Mojave desert. These plants utilize steam Rankine cycle power plants, and as a result, most people associate parabolic trough solar technology with steam Rankine cycle power plant technology. Although these plants are clearly optimized for their particular
Current and Future Economics of Parabolic Trough Technology
Price, H.; Mehos, M.; Kutscher, C.; Blair, N.
2007-01-01
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.
A. Y. El-Assy
1988-01-01
Compound Parabolic Concentrators (CPCs) in two-phase flows are studied and their thermal performance is analyzed. New parameters identifying the CPC optical and thermal performance are defined. The limits of operation of CPCs in two-phase flows for saturated fluid exit states are identified as a function of the solar flux and the CPC working parameters such as the working pressure and
A conceptual basis for the design of parabolic troughs for different design environments
H. M. Guven; F. Mistree; R. B. Bannerot
1986-01-01
In this paper, a rational approach for multi-objective design and optimization of parabolic trough solar collectors for different design environments is presented. A macro and micro-level partitioning of the design problem is implemented. In this process, environmental goals, objectives, and limitations are accounted for at the macro-level of design. At the micro-level of design, subsystem designs that were developed at
Chaotic motion of comets in near-parabolic orbit: Mapping aproaches
NASA Astrophysics Data System (ADS)
Liu, Jie; Sun, Yi-Sui
1994-09-01
There exist many comets with near-parabolic orbits in the solar system. Among various theories proposed to explain their origin, the Oort cloud hypothesis seems to be the most reasonable. The theory assumes that there is a cometary cloud at a distance 103 to 107 from the sun and that perturbing forces from planets or stars make orbits of some of these comets become the near-parabolic type. Concerning the evolution of these orbits under planetary perturbations, we can raise the question: Will they stay in the solar system forever or will they escape from it? This is an attractive dynamical problem. If we go ahead by directly solving the dynamical differential equations, we may encounter the difficulty of long-time computation. For the orbits of these comets are near-parabolic and their periods are too long to study on their long-term evolution. With mapping approaches the difficulty will be overcome. In another aspect, the study of this model has special meaning for chaotic dynamics. We know that in the neighborhood of any separatrix i.e. the trajectory with zero frequency of the uperturbed motion of a Hamiltonian system, some chaotic motions have to be expected. Actually, the simplest example of separatrix is the parabolic trajectory of the two-body problem which separates the bounded and unbounded motion. From this point of view, the dynamical study of near-parabolic motion is very important. Petrosky's elegant but more abstract deduction gives a Kepler mapping which describes the dynamics of the cometary motion. In this paper we derive a similar mapping directly and discuss its dynamical characters.
Development status of the PDC-1 Parabolic Dish Concentrator
NASA Technical Reports Server (NTRS)
Thostesen, T.; Soczak, I. F.; Pons, R. L.
1982-01-01
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.
Development status of the PDC-1 Parabolic Dish Concentrator
NASA Astrophysics Data System (ADS)
Thostesen, T.; Soczak, I. F.; Pons, R. L.
1982-07-01
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.
Finite Difference Method for Stochastic Parabolic Equations
NASA Astrophysics Data System (ADS)
Ashyralyev, Allaberen; San, Mehmet Emin
2011-09-01
In the present paper the single step difference schemes for the multi-point non local-boundary value problems for the stochastic parabolic equation are presented. The convergence estimates for the solution of these difference schemes are established. In applications this abstract result permit us to obtain the convergence estimates for the solution of difference schemes for the numerical solution of multi-point non-local boundary value problems for parabolic equations. The theoretical statements for the solution of this difference schemes are supported by the results of numerical experiments.
Nonrelativistic Coulomb Green's function in parabolic coordinates
NASA Astrophysics Data System (ADS)
Blinder, S. M.
1981-02-01
The nonrelativistic Coulomb Green's function G(+)(r1,r2,k) is evaluated by explicit summation over discrete and continuum eigenstates in parabolic coordinates. This completes the derivation of Meixner, who was able to obtain only the r1=0 and r2?? limiting forms of the Green's function. Further progress is made possible by an integral representation for a product of two Whittaker functions given by Buchholz. We obtain the closed form for the Coulomb Green's function previously derived by Hostler, via an analogous summation in spherical polar coordinates. The Rutherford scattering limit of the Green's function is also demonstrated, starting with an integral representation in parabolic coordinates.
Controllable parabolic-cylinder optical rogue wave.
Zhong, Wei-Ping; Chen, Lang; Beli?, Milivoj; Petrovi?, Nikola
2014-10-01
We demonstrate controllable parabolic-cylinder optical rogue waves in certain inhomogeneous media. An analytical rogue wave solution of the generalized nonlinear Schrödinger 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 Schrödinger equation. Such rogue waves may appear in different forms, as the hump and paw profiles. PMID:25375612
Advances in solar cooking: Proceedings of the first world conference on solar cooking
Pejack, E. [ed.
1992-12-31
Population growth and resource depletion have led to a need for new sources of cooking fuel in developing countries. Many poor villagers spend half of their time, or half of their income obtaining cooking fuel. Solar cooking can meet the needs of many of these people. People from eighteen countries met at this world conference to share experiences with design and performance of cookers, food, nutrition and health issues, and information dissemination strategies. A total of 27 individual papers were indexed separately for the data base.
Parabolic PDEs and Deterministic Games Robert V. Kohn
Parabolic PDEs and Deterministic Games Robert V. Kohn Courant Institute, NYU Joint work with Sylvia Serfaty ICIAM07, Zurich, July 2007 Robert V. Kohn Courant Institute, NYU Parabolic PDEs and Deterministic. Kohn Courant Institute, NYU Parabolic PDEs and Deterministic Games #12;Goals and perspective Part 1
Full discretization of distributed control problems for parabolic Franck BOYER
Boyer, Franck
Control of full-discrete parabolic equations #12;EXAMPLES WE HAVE IN MIND THE 1D HEAT EQUATION (S) 8Full discretization of distributed control problems for parabolic equations Franck BOYER joint work'OrlÂ´eans IHP, November 2010 1/ 58 F. Boyer Control of full-discrete parabolic equations #12;OUTLINE 1
A PARABOLIC ALMOST MONOTONICITY FORMULA Introduction In ...
2006-07-07
University and the Royal Institute of Technology, respectively, and they thank the universities ... Finally, let us make a remark on the proof of the parabolic almost monotonic- ... almost monotonicity formula (Theorem III) with more features of the monotonicity ...... Also, the boundedness of both u and (???s)u alone implies.
TRACKING CONTROL OF PARABOLIC Luciano Pandolfi
Pandolfi, Luciano
for the optimal control and the optimal trajectory. Keywords: Regulator problem, distributed systems, boundary, by investigating the tracking problem. This consists in finding a control v to force the output z of a given systemTRACKING CONTROL OF PARABOLIC SYSTEMS Luciano Pandolfi Politecnico di Torino, Dip. di Matematica
Accidental parabolics and relatively hyperbolic groups
François Dahmani; Universitd P. Sabatier
2006-01-01
By constructing, in the relative case, objects analogous to Rips and Sela’s canonical representatives, we prove that the set\\u000a of conjugacy classes of images by morphisms without accidental parabolic, of a finitely presented group in a relatively hyperbolic\\u000a group, is finite.
RCS COMPUTATION OF AIRPLANE USING PARABOLIC EQUATION
A. R. Mallahzadeh; M. Soleimani; J. Rashed-Mohassel
2006-01-01
Abstract—The accurate analysis of scattering from objects with dimensions large compared to the wavelength using rigorous methods (finite element, FDTD, method of moments) with a personal computer is almost impractical. In asymptotic methods, physical optics (PO), geometrical theory of diffraction (GTD), the accurate modeling of the object’s boundary is too cumbersome. The parabolic equation method gives accurate results in calculation
NASA Astrophysics Data System (ADS)
1984-08-01
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.
National University, Canberra, Australia. 2 National Solar Thermal Test Facility, Sandia National. The market competitiveness of solar devices such as parabolic dishes and heliostats is critically governed through precise alignment to the sun. Traditionally, solar tracking was facilitated by mounting live sun
NASA Technical Reports Server (NTRS)
1985-01-01
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.
SunLab: Advancing Concentrating Solar Power Technology
NONE
1998-11-24
Concentrating solar power (CSP) technologies, including parabolic troughs, power towers, and dish/engines, have the potential to provide the world with tens of thousands of megawatts of clean, renewable, cost-competitive power.
Design of and metrological results from a bent parabolic mirror.
Miura, S; Kihara, N; Mashima, K; Miyaji, A; Wakamiya, K; Shiozawa, H; Fukuda, Y; Ichikawa, H
1998-05-01
This article describes the successful design and fabrication of, and metrological results from, an elastically bent parabolic mirror. The mirror is equipped with a bending structure that allows the mirror to be bent meridionally to a parabolic shape. This bent parabolic mirror is the key component of the extremely high-quality monochromators designed for the SPring-8 figure-8 soft X-ray undulator and the 2.0 GeV high-brilliance synchrotron radiation source (VSX). PMID:15263660
Strongly nonlinear parabolic initial-boundary value problems.
Brezis, H; Browder, F E
1979-01-01
An existence and uniqueness result is presented for the solution of a parabolic initial-boundary value problem under Dirichlet null boundary conditions for a general parabolic equation of order 2m with a strongly nonlinear zeroth-order perturbation. This is the parabolic generalization of a class of elliptic results considered earlier by the writers and others and is based upon a new compactness theorem. PMID:16592609
Parabolic Trough VSHOT Optical Characterization in 2005-2006 (Presentation)
Wendelin, T.
2006-02-01
This presentation regarding parabolic trough VSHOT optical characterization describes trough deployment and operation phases including: development, manufacture/installation, and maintenance/operation.
Harrison, T.D.
1981-03-01
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)
Energy 101: Concentrating Solar Power
None
2013-05-29
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.
Parabolic Dish Solar Thermal Power Annual Program Review Proceedings
NASA Technical Reports Server (NTRS)
Holbeck, H. J.
1981-01-01
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.
Environmental responses of solar reflective surfaces
F. L. Bouquet
1983-01-01
An assessment is undertaken of the environmental responses of solar reflective surfaces, with emphasis on dish-type concentrator surfaces exposed to the conditions of Southern California. A generalized mathematical model for specific solar reflective surfaces can be formulated on the basis of either experimental or assumed site degradation\\/corrosion data. In addition, the fabrication parameters of a parabolic reflecting surface and its
Solar operated closed system power generator
deGeus
1978-01-01
A solar operated closed system power generator is provided in which a low boiling fluid is vaporized and superheated by solar energy concentrated within a parabolic reflector upon an elongated boiler which extends along the focus of the reflector. A turbine is connected to the boiler for obtaining power by the expansion of superheated vapor. The expanded vapors are condensed
OUT Success Stories: Solar Trough Power Plants
Jones, J.
2000-08-05
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.
Numerical Schemes for Rough Parabolic Equations
Deya, Aurelien, E-mail: deya@iecn.u-nancy.fr [Universite de Nancy 1, Institut Elie Cartan Nancy (France)
2012-04-15
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.
Spectral methods in time for parabolic problems
NASA Technical Reports Server (NTRS)
Tal-Ezer, H.
1985-01-01
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.
Parabolic connection formulae in quantum mechanics
Chebotarev, L.V. [Case Postale 655, Montreal, Quebec, H2A 3N2 (CANADA)] [Case Postale 655, Montreal, Quebec, H2A 3N2 (CANADA)
1997-04-01
The mathematical structure of the tunnelling state of a quantum particle is established with respect to a large variety of smooth potential barriers, without any restriction upon the particle{close_quote}s coordinate or the barrier penetration integral (the latter is allowed to be arbitrarily small). Complete sufficient conditions for the semiclassical parabolic connection formulae are derived, both with respect to the particle{close_quote}s energy and relative to its coordinates. Explicit error bounds to these formulae are obtained. Extension to the overbarrier range is discussed. {copyright} 1997 Academic Press, Inc.
On the parallel solution of parabolic equations
NASA Technical Reports Server (NTRS)
Gallopoulos, E.; Saad, Youcef
1989-01-01
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.
Superstable Manifolds of Semilinear Parabolic Problems
Nils Ackermann; Thomas Bartsch
2005-01-01
We investigate the dynamics of the semiflow ? induced on H01(?) by the Cauchy problem of the semilinear parabolic equation\\u000a$$\\\\partial_{t}u - \\\\Delta u = f(x, u)$$ on ?. Here\\u000a\\u000a is a bounded smooth domain, and\\u000a\\u000a has subcritical growth in u and satisfies\\u000a\\u000a. In particular we are interested in the case when f is definite superlinear in u. The
GREENHOUSE GAS ANALYSIS OF SOLAR-THERMAL ELECTRICITY GENERATION
M. LENZEN
1999-01-01
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
Gain-scheduled control of a solar power plant
Tor A. Johansen; Kenneth J. Hunt; Idar Petersen
2000-01-01
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
Anqing to the development of solar thermal power generation industry
Shen Junchang; Yu Xianjin; Wu Hanjiang; Sun Bangyan; Dai Zhiguo; Ding Kaiming; Zhang Zhan
2008-01-01
This paper initial on the solar parabolic trough collectors, compact Fresnel linear reflector (CLFR). And they in the integration of fossil-fired power plant Kirchmoser (Germany) Staudinger5 (Germany) Stanwell (Australia) etc., of the application, and China development of solar energy, analyses the possibility, necessity and feasibility of the development of solar energy in Anqing. Seizing the opportunity, to strive for integration
Performance evaluation and simulation of a solar thermal power plant
Eduardo I. Ortiz-Rivera; Luisa I. Feliciano-Cruz
2009-01-01
This paper presents a Simulinkreg Model that has been developed for the performance evaluation and simulation of Solar Power Generating or Solar Thermal Power Plants in Puerto Rico with the Compound Parabolic Concentrator as the solar collector of choice. There are several costly and sophisticated commercial software programs that perform this task but, this tool is aimed at performing initial
THE PARABOLIC JET STRUCTURE IN M87 AS A MAGNETOHYDRODYNAMIC NOZZLE
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
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 Königl. 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 Alfvén 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-Alfvénic 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.
SHEARLAB: A RATIONAL DESIGN OF A DIGITAL PARABOLIC SCALING ALGORITHM
Kutyniok, Gitta
shearlet transform, parabolic scaling, performance measures, software package, tight frames AMS subjectSHEARLAB: A RATIONAL DESIGN OF A DIGITAL PARABOLIC SCALING ALGORITHM GITTA KUTYNIOK, MORTEZA-fold: We firstly develop a digital shearlet theory which is rationally designed in the sense
Optimal Control for Degenerate Parabolic Equations with Logistic Growth*
) of the population to be trapped is the control in our problem. We can treat zero Dirichlet (z = 0) or Neumann (noOptimal Control for Degenerate Parabolic Equations with Logistic Growth* by Suzanne M. Lenhart 1 and Jiongmin Yong 2 Abstract. This paper considers the optimal control of a degenerate parabolic partial dif
Optimal Control for Degenerate Parabolic Equations with Logistic Growth*
(x;t) of the population to be trapped is the control in our problem. We can treat zero Dirichlet (z = 0) or Neumann(no uxOptimal Control for Degenerate Parabolic Equations with Logistic Growth* by Suzanne M. Lenhart1 and Jiongmin Yong2 Abstract. This paper considers the optimal control of a degenerate parabolic partial dif
Parabolic Implosion and Hausdorff Dimension Petals and Dimension
Zinsmeister, Michel
Parabolic Implosion and Hausdorff Dimension I: Petals and Dimension A.Douady, P.Sentenac, M] (part I) and [DSZ] (part II). Parabolic implosion is the name given to the phenomenon of discontinuity litterature this implosion is usually explained in the model case of z 7\\Gamma! z +z 2 , i.e; in the presence
PARABOLIC DELIGNE-LUSZTIG VARIETIES. FRANCOIS DIGNE AND JEAN MICHEL
Paris-Sud XI, Université de
PARABOLIC DELIGNE-LUSZTIG VARIETIES. FRANC¸OIS DIGNE AND JEAN MICHEL Abstract. Motivated by the Brou´e conjecture on blocks with abelian defect groups for finite reductive groups, we study "parabolic of a braid monoid, whose action on their -adic cohomology will conjecturally factor trough a cyclotomic Hecke
Manipulation of dielectric particles with nondiffracting parabolic beams.
Ortiz-Ambriz, Antonio; Gutiérrez-Vega, Julio C; Petrov, Dmitri
2014-12-01
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
Numerical approximation of solution derivatives of singularly perturbed parabolic problems
Numerical approximation of solution derivatives of singularly perturbed parabolic problems J singularly perturbed parabolic problem are generated using a backward Euler method in time and an upwinded. The analysis is also applied to singularly perturbed problems of reaction-diffusion type. AMS Classification
TRACTOR BUNDLES FOR IRREDUCIBLE PARABOLIC Cap & A. Rod Gover
Gover, Rod
TRACTOR BUNDLES FOR IRREDUCIBLE PARABOLIC GEOMETRIES by Andreas #20; Cap & A. Rod Gover Abstract. | We use the general results on tractor calculi for parabolic geometries obtained in [3] to give a simple and e#11;ective characterisation of arbitrary normal tractor bundles on manifolds equipped
Optimal Design of Parabolic Canal Section Bhagu R. Chahar1
Chahar, B. R.
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
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS
Janson, Svante
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS SVANTE JANSON AND JOHAN TYSK Abstract for convexity to be preserved. A parabolic equation is said to preserve convexity if given a convex initial is indeed preserved for solutions, given by the stochastic representation formula, to an equation
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS
Janson, Svante
PRESERVATION OF CONVEXITY OF SOLUTIONS TO PARABOLIC EQUATIONS SVANTE JANSON AND JOHAN TYSK Abstract for convexity to be preserved. A parabolic equation is said to preserve convexity if given a convex initial preserved for solutions, given by the stochastic representation formula, to an equation of the form Ft = a2
Blair, N.; Mehos, M.; Christensen, C.
2008-03-01
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.
Assessment of solar thermal energy market development and macro economic impacts
La Porta
1984-01-01
The objective of this study is to furnish an industry estimate of future sales for the three major solar thermal technologies: parabolic trough, parabolic dish, and central receiver. Along with these market projections, information was also sought on: the impact of varied levels of the federal business energy investment credit; projected displacement of conventional energy; investment capital requirements; and direct
Worker health and safety in solar thermal power systems. IV. Routine failure hazards
A. Z. Ullman; B. B. Sokolow; J. Hill; G. Meunier; H. Busick
1979-01-01
Routine failure events in selected solar thermal power system designs are examined, and their rates of occurrence estimated. The results are used to compare and rank the systems considered. Modules of 1 to 100 MWe are developed based on reference or other near-term designs. Technologies used include parabolic trough, parabolic dish, and central tower focusing; central and distributed power generation;
Utility scale hybrid wind–solar thermal electrical generation: A case study for Minnesota
J. P. Reichling; F. A. Kulacki
2008-01-01
The performance of a hybrid wind–solar 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
Experimental and theoretical study of a solar desalination system located in Cairo, Egypt
Zeinab S. Abdel-Rehim; Ashraf Lasheen
2007-01-01
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
Gain Scheduled Control of a Solar Power Plant Tor A. Johansen1
Johansen, Tor Arne
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
innovati nComponents Makeover Gives Concentrating Solar Power a Boost
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
Solar–geothermal hybrid system
Álvaro Lentz; Rafael Almanza
2006-01-01
The Cerro Prieto Geothermal Power Plant is located in the northwest of Mexico, lat. 32°39?, long. 115°21? in the northern hemisphere. A solar–geothermal hybrid system is proposed in order to increase the steam flow during the present geothermal cycle, adding a solar field of parabolic trough concentrators. Energy is supplied to the geothermal flow from wells in order to increase
Water Use in Parabolic Trough Power Plants: Summary Results from WorleyParsons' Analyses
Turchi, C. S.; Wagner, M. J.; Kutscher, C. F.
2010-12-01
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.
Non-local quasi-linear parabolic equations
NASA Astrophysics Data System (ADS)
Amann, H.
2005-12-01
This is a survey of the most common approaches to quasi-linear parabolic evolution equations, a discussion of their advantages and drawbacks, and a presentation of an entirely new approach based on maximal L_p regularity. The general results here apply, above all, to parabolic initial-boundary value problems that are non-local in time. This is illustrated by indicating their relevance for quasi-linear parabolic equations with memory and, in particular, for time-regularized versions of the Perona-Malik equation of image processing.
Solar concentrator development in the US
NASA Astrophysics Data System (ADS)
Alpert, D. J.; Mancini, T. R.; Houser, R. M.; Crossman, J. W.; Schissel, P.; Carasso, M.; Jorgensen, G.; Scheve, M.
Sandia National Laboratories leads the U.S. Department of Energy's solar concentrator development program in a joint effort with the Solar Energy Research Institute. The goal of DOE's program is to develop, build and test solar concentrators that are low in cost, have high performance, and long lifetimes. Efforts are currently focused on three areas: low-cost heliostats, point-focus parabolic dishes, and durable reflective films. The status and future plans of DOE's program in each area are reviewed.
Solar concentrator development in the US
NASA Astrophysics Data System (ADS)
Alpert, D. J.; Mancini, T. R.; Houser, R. M.; Grossman, J. W.; Schissel, P.; Carasso, M.; Jorgensen, G.; Scheve, M.
1991-03-01
Sandia National Laboratories leads the US Department of Energy's solar concentrator development program in a joint effort with the Solar Energy Research Institute. The goal of DOE's program is to develop, build, and test solar concentrations that are low cost, have high performance, and long lifetimes. Efforts are currently focused on three areas: low-cost heliostats, point-focus parabolic dishes, and durable reflective films. The status and future plans of DOE's program in each area are reviewed.
Solar cooking trends--A preliminary report
Blum, B.L. [Solar Box Cookers International, Sacramento, CA (United States)
1992-12-31
This report discusses early results of research on trends in solar cooking worldwide and the key factors in those trends. It is based on household interviews in Belize, Honduras and Nicaragua and mail surveys from scattered individuals and promotion projects worldwide. Household interviews from six more countries will be included in future reports. Early data indicate that where solar cooking has been introduced an immediate, rapid increase in awareness and interest in solar cooking is followed by slow, sustained growth in actual solar cooking two or three years later, after an incubation period. Access to information and affordable materials for the cookers are important. Individual users and promoters both identify similar key elements for effective promotion projects, but in current projects many are often missing. Even so, successes of these small-scale efforts verify the benefits and acceptability of solar cooking to families in many regions, and should encourage much broader promotion efforts. Future reports will explore various economic, technical, cultural and environmental factors in solar cooking use as guides for larger efforts.
Hattori, Haroldo T
2014-10-10
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
Accelerated stress testing of terrestrial solar cells
NASA Technical Reports Server (NTRS)
Lathrop, J. W.; Hawkins, D. C.; Prince, J. L.; Walker, H. A.
1982-01-01
The development of an accelerated test schedule for terrestrial solar cells is described. This schedule, based on anticipated failure modes deduced from a consideration of IC failure mechanisms, involves bias-temperature testing, humidity testing (including both 85-85 and pressure cooker stress), and thermal-cycle thermal-shock testing. Results are described for 12 different unencapsulated cell types. Both gradual electrical degradation and sudden catastrophic mechanical change were observed. These effects can be used to discriminate between cell types and technologies relative to their reliability attributes. Consideration is given to identifying laboratory failure modes which might lead to severe degradation in the field through second quadrant operation. Test results indicate that the ability of most cell types to withstand accelerated stress testing depends more on the manufacturer's design, processing, and worksmanship than on the particular metallization system. Preliminary tests comparing accelerated test results on encapsulated and unencapsulated cells are described.
Cyclotomic double affine Hecke algebras and affine parabolic category O
M. Varagnolo; E. Vasserot
2010-01-01
Using the orbifold KZ connection we construct a functor from an affine parabolic category O of type A to the category O of a cyclotomic rational double affine Hecke algebra H. Then we give several results concerning this functor.
Laminar Incompressible Flow Past Parabolic Bodies at Angles of Attack
Ercan Erturk; Thomas Corke; Osamah Haddad
2004-01-01
Numerical solutions of a two-dimensional steady laminar incompressible flow over semi-infinite parabolic bodies at angles of attack are obtained. All solutions are found by using a modified numerical approach to solve the time- dependent Navier-Stokes equations. The governing equations are written for the stream function and vorticity variables and are solved on a nonuniform body-fitted parabolic grid. A check of
Siddig A. Omer; David G. Infield
2000-01-01
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
Performance of the Vanguard Solar Dish-Stirling Engine Module. Final report
J. J. Droher; S. E. Squier
1986-01-01
This report summarizes information on the performance of the Vanguard Parabolic Dish\\/Stirling Engine Module during an 18-month period of operational testing (February 1984 through July 1985) at Rancho Mirage, California. The test module consisted of a 10.7-m-diameter parabolic dish to collect and concentrate solar beam radiation, a solar receiver, a four-cylinder Stirling engine using hydrogen as the working gas, an
Performance Study of the Solar Box type Stove using Two Phase Change Materials
NASA Astrophysics Data System (ADS)
Bahal, Beni Madhaw
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 80-100°C and 120-140°C 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.
Optimisation and characterisation of parabolic membrane mirrors
NASA Astrophysics Data System (ADS)
Hellmuth, T.; Khrennikov, K.; Kronast, W.; Huster, R.; Mescheder, U.
2008-04-01
MOEMS-based thin silicon membrane mirrors with a useable diameter of 5mm and fast (up to 1kHz) tunable focal length (80 mm to 1m) have been realized. A ring shaped counter electrode is used to achieve a parabolic membrane deformation by electrostatic forces. A circular kerf at the outer perimeter of the membrane provides a soft suspension to the rim and thus reduces the needed driving voltage. FEM has been used for optimisation of the design, especially of the soft suspension, which is realized by a controlled thinning of the outer rim of the Si-membrane. A critical issue for demanding applications is the membrane distortion induced by material stress and the fabrication process. Membrane residual stress reduction has been obtained by using SOI-technology (c-silicon) and by optimisation of the Al deposition process (Al-coated Si-membrane). For dynamic tests of the optical mirror properties a stroboscopic interferometer has been realized. A pulsed laser diode with a pulse duration of 10?s is used as a light source which is synchronized with the modulated electrical field driving the membrane mirror. The interference pattern is recorded with a CCD and evaluated with conventional phaseshift techniques. The geometry is similar to a Mach-Zehnder interferometer. The reference path length can be varied with a piezoceramic to induce the phase shift.
Parabolic Trough Receiver Heat Loss Testing (Poster)
Price, H.; Netter, J.; Bingham, C.; Kutscher, C.; Burkholder, F.; Brandemuehl, M.
2007-03-01
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.
Photon-Atom Coupling with Parabolic Mirrors
Markus Sondermann; Gerd Leuchs
2014-11-26
Efficient coupling of light to single atomic systems has gained considerable attention over the past decades. This development is driven by the continuous growth of quantum technologies. The efficient coupling of light and matter is an enabling technology for quantum information processing and quantum communication. And indeed, in recent years much progress has been made in this direction. But applications aside, the interaction of photons and atoms is a fundamental physics problem. There are various possibilities for making this interaction more efficient, among them the apparently 'natural' attempt of mode-matching the light field to the free-space emission pattern of the atomic system of interest. Here we will describe the necessary steps of implementing this mode-matching with the ultimate aim of reaching unit coupling efficiency. We describe the use of deep parabolic mirrors as the central optical element of a free-space coupling scheme, covering the preparation of suitable modes of the field incident onto these mirrors as well as the location of an atom at the mirror's focus. Furthermore, we establish a robust method for determining the efficiency of the photon-atom coupling.
Solar disinfection of infectious biomedical waste: a new approach for developing countries.
Chitnis, V; Chitnis, S; Patil, S; Chitnis, D
2003-10-18
Poor developing countries cannot afford expensive technologies such as incineration for management of infectious biomedical waste. We assessed solar heating as an alternative technology. We immersed simulated infectious waste with added challenge bacteria in water in a box-type solar cooker, which was left in the sun for 6 h. In 24 sets of observations, the amount of viable bacteria was reduced by about 7 log. We also tested infectious medical waste with a heavy load of bacteria (10(8)-10(9)/g) from our hospital's burn unit for solar heat disinfection in 20 experiments. Our results showed a similar 7 log reduction in the amount of viable bacteria. Solar heating thus seems to be a cheap method to disinfect infectious medical waste in less economically developed countries. PMID:14575975
Design considerations for heat-pipe solar receivers
Douglas R. Adkins
1990-01-01
Heat pipes are being developed to transfer solar energy from the focal point of a parabolic dish concentrator to the working fluid of Stirling engines. With these receivers, concentrated solar energy that is absorbed on the concave surface of a dome is removed by the evaporation of liquid sodium on the convex side of the dome. Vaporized sodium then condenses
Design considerations for heat-pipe solar receivers
Douglas R. Adkins
1989-01-01
Heat pipes are being developed to transfer solar energy from the focal point of a parabolic dish concentrator to the working fluid of Stirling engines. With these receivers, concentrated solar energy that is absorbed on the concave surface of a dome is removed by the evaporation of liquid sodium on the convex side of the dome. Vaporized sodium then condenses
Felt-metal-wick heat-pipe solar receiver
Charles E. Andraka; Douglas R. Adkins; Timothy A. Moss; Howard M. Cole; Nicos H. Andreas
1994-01-01
Reflux heat-pipe receivers have been identified as a desirable interface to couple a Stirling-cycle engine with a parabolic dish solar concentrator. The reflux receiver provides power nearly isothermally to the engine heater heads while decoupling the heater head design from the solar absorber surface design. The independent design of the receiver and engine heater head leads to higher system efficiency.
Exergetic analysis of a solar thermal power system
Narendra Singh; S. C. Kaushik; R. D. Misra
2000-01-01
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
M. J. Montes; A. Abánades; J. M. Martínez-Val
2009-01-01
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
Double cascade organic Rankine cycle for solar-driven reverse osmosis desalination
Agustín M. Delgado-Torres; Lourdes García-Rodríguez
2007-01-01
This paper deals with the application of parabolic trough solar collectors to a double cascade of organic Rankine cycles for reverse osmosis desalination. Two different solar collectors are operated either with thermal oil or with the organic fluid of the top cycle. The solar thermal system drives a seawater reverse osmosis system with around 1000 m3\\/d of fresh water production
Economic Evaluation of Solar Thermal Power Generation: a Case Study for Indian Conditions
N. Singh; S. C. Kaushik
1995-01-01
This paper presents economic evaluation of solar thermal power generation for Indian conditions. The study incorporates case study of parabolic trough collector technology for power generation in 30 MW scale taking into account various options such as Solar Alone and Solar Hybrid. Sensitivity analysis by varying plant load factor, discount rate and the capital cost etc. has also been carried
A roadmap for parabolic trough progress in large-scale power generation
Kearney, D.W.; Price, H.W.
1999-07-01
In 1998 the US DOE/Sun{sm_bullet}Lab sponsored a workshop to discuss and outline a pathway for sustained deployment of commercial parabolic trough power technology. Including both industry and institutional interests, a plan emerged to move to the next step in trough installations. Backed by over ten years operating experience of 354 MW of trough steam plants in the California Mojave Desert, the plan explored future markets, technology advancements, and improvements in cost-effectiveness. This paper highlights the key conclusions and findings that were subsequently documented in the DOE parabolic trough technology roadmap report. Initially, the cost of trough solar power is expected to be 10--12{cents} kWh, depending on plant configuration. After initial market subsidies by GEF buy-down grants or other special green/renewable financing options, and with the next level of technology development, the cost of trough power should reduce to 6--8{cents} kWh. With further reduction of electricity costs below 6{cents} kWh, projections suggest that achievement of up to 1 gigawatt (GW) installed capacity by 2005 and 5 GW by 2010 are possible.
Advances in solar thermal electricity technology
D. Mills
2004-01-01
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
A solar-Stirling small power system
R. L. Pons
1979-01-01
The paper presents results of an in-depth analysis of a 1 MWe solar power system consisting of multiple parabolic dish concentrators employing Stirling cycle engines for power conversion. The engine, ac generator, cavity receiver and integral sodium pool boiler\\/heat transport system are combined in a single package and mounted at the focus of each concentrator. The output of each concentrator
Small community solar thermal power experiment
A. T. Marriott; T. Kiceniuk
1980-01-01
The first solar thermal power plant specifically designed as an alternate source of electric energy for small communities in this country is now in its second phase of development. As a result of Phase I concept definition studies, a decision was made to pursue a parabolic dish system using distributed generation. Both the design approach and the site selection status
Nondiffracting Accelerating Waves: Weber waves and parabolic momentum
Bandres, Miguel A
2012-01-01
Diffraction is one of the universal phenomena of physics, and a way to overcome it has always represented a challenge for physicists. In order to control diffraction, the study of structured waves has become decisive. Here, we present nondiffracting spatially accelerating solutions of the Maxwell equations: the Weber waves. These nonparaxial waves propagate along a parabolic trajectory while preserving its shape to a good approximation. They are expressed in analytic closed form and naturally separate in forward and backward propagation. We show that the Weber waves are self-healing, can form periodic breather waves, and have a well-defined conserved quantity: the parabolic momentum. We find that our Weber waves for moderate to large values of the parabolic momenta can be described by a modulated Airy function. Because the Weber waves are exact time-harmonic solution of the wave equation, they have implications to many linear wave systems in nature, ranging from acoustic and elastic waves to surface waves in ...
Resonant tunneling in double-barrier parabolic well structures
NASA Astrophysics Data System (ADS)
Neofotistos, George; Diff, Karim; Guo, Hong; Gunton, James D.
1989-04-01
The intrinsic time characteristics of a double-barrier parabolic well structure are studied numerically. One-dimensional structures with AlAs and AlGaAs barrier (and superlattice) material are investigated, and two models are considered: the actual microstructure (graded-superlattice) model and the parabolic-potential-well model. Time-independent results such as quasi-energy levels and their widths are essentially the same for these two models, but their time dependence is considerably different. Although the buildup times for these models are very close, the onset of exponential decay for the resonant state in the parabolic potential well takes place in a very short time, so that the time decay constant is a good measure of the temporal decay. The exponential decay for the actual microstructure occurs at a much later time, with the electron probability amplitude in the well having decreased by orders of magnitude when this behavior is observed.
Basic Parabolic Implosion in Five Days. Michel Zinsmeister, after Adrien Douady.
Zinsmeister, Michel
Basic Parabolic Implosion in Five Days. Michel Zinsmeister, after Adrien Douady. September 4, 1997 that appears there called parabolic implosion. We will see that the discontinuity is very nasty and try
Experimental studies on illposed singularly perturbed boundary value problems for parabolic
Reinhardt, Hans-Jürgen
Experimental studies on illposed singularly perturbed boundary value problems for parabolic. In this paper singularly perturbed parabolic initial-boundary value problems are considered which, in addition a stopping rule. 1. Introduction Singularly perturbed differential equations have the essential feature
Current and Future Costs for Parabolic Trough and Power Tower Systems in the US Market: Preprint
Turchi, C.; Mehos, M.; Ho, C. K.; Kolb, G. J.
2010-10-01
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.
Current and future costs for parabolic trough and power tower systems in the US market.
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
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.
Funken, K H; Sattler, C; Milow, B; De Oliveira, L; Blanco, J; Fernández, P; Malato, S; Brunott, M; Dischinge, N; Tratzky, S; Musci, M; de Oliveira, J C
2001-01-01
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
Line-focus solar thermal energy technology development. FY 79 annual report for Department 4720
Bergeron, K D; Champion, R L; Hunke, R W [eds.
1980-04-01
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.
Parabolic approximation method for fast magnetosonic wave propagation in tokamaks
Phillips, C.K.; Perkins, F.W.; Hwang, D.Q.
1985-07-01
Fast magnetosonic wave propagation in a cylindrical tokamak model is studied using a parabolic approximation method in which poloidal variations of the wave field are considered weak in comparison to the radial variations. Diffraction effects, which are ignored by ray tracing mthods, are included self-consistently using the parabolic method since continuous representations for the wave electromagnetic fields are computed directly. Numerical results are presented which illustrate the cylindrical convergence of the launched waves into a diffraction-limited focal spot on the cyclotron absorption layer near the magnetic axis for a wide range of plasma confinement parameters.
Validation of brain-machine interfaces during parabolic flight.
Millàn, José Del R; Ferrez, Pierre W; Seidl, Tobias
2009-01-01
Here we report on a validation study on brain-machine interfaces (BMIs) performed during the December 2007 ESA parabolic flight campaign. We investigated the feasibility of using BMIs for space applications by performing tests in microgravity. Brain signals were recorded with noninvasive electroencephalography before (calibration sessions) and during the parabolic flights on two subjects with prior BMI experience. The results of our experiments show that an experienced BMI user can achieve stable performance in all gravity conditions examined and, hence, demonstrate the feasibility of operating noninvasive BMIs in space. PMID:19608000
The parabolic trigonometric functions and the Chebyshev radicals
G. Dattoli; M. Migliorati; P. E. Ricci
2011-02-08
The parabolic trigonometric functions have recently been introduced as an intermediate step between circular and hyperbolic functions. They have been shown to be expressible in terms of irrational functions, linked to the solution of third degree algebraic equations. We show the link of the parabolic trigonometric functions with the Chebyshev radicals and also prove that further generalized forms of trigonometric functions, providing the natural solutions of the quintic algebraic equation, can be defined. We also discuss the link of this family of functions with the modular elliptic functions. 1
One-dimensional parabolic-beam photonic crystal laser.
Ahn, Byeong-Hyeon; Kang, Ju-Hyung; Kim, Myung-Ki; Song, Jung-Hwan; Min, Bumki; Kim, Ki-Soo; Lee, Yong-Hee
2010-03-15
We report one-dimensional (1-D) parabolic-beam photonic crystal (PhC) lasers in which the width of the PhC slab waveguide is parabolically tapered. A few high-Q resonant modes are confirmed in the vicinity of the tapered region where Gaussian-shaped photonic well is formed. These resonant modes originate from the dielectric PhC guided mode and overlap with the gain medium efficiently. It is also shown that the far-field radiation profile is closely associated with the symmetry of the structural perturbation. PMID:20389580
Harrison, T.D.
1981-04-01
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)
S. B. Kaplan; A. C. Warren
1986-01-01
We have studied theoretically the magnetoconductance oscillations in a quasi-one-dimensional electron gas with a parabolic transverse confining potential. The solution to Schrödinger's equation is that of a hybrid harmonic oscillator with a frequency omega that depends on both the parabolic potential and the magnetic field B. At B=0, omega equals the classical oscillation frequency of the parabolic potential. In the
ccsd-00001178(version1):24Feb2004 Parabolic subgroups of Garside groups
Boyer, Edmond
the Artin-Tits groups of spherical type. We generalise the well-known notion of a parabolic subgroup of an Artin-Tits group into that of a parabolic subgroup of a Garside group. We also define the more general between Artin-Tits groups. We prove that most of the properties of parabolic subgroups extend
Flux Distribution of a Single-Axis Tracking Parabolic Trough Array with Photovoltaic Receiver
Flux Distribution of a Single-Axis Tracking Parabolic Trough Array with Photovoltaic Receiver G 0200 Australia E-mail: gregory.burgess@anu.edu.au Abstract Single-axis tracking parabolic troughs Long arrays of single-axis tracking parabolic troughs with a fluid filled absorber are a well
Complex Band Structures: From Parabolic to Elliptic Approximation
Ximeng Guan; Donghyun Kim; Krishna C. Saraswat; H.-S. Philip Wong
2011-01-01
We show that the conventional nonparabolic approx- imation of real band structures can be modified and generalized to approximate the complex band structures of common semicon- ductors with a significant improvement of accuracy against the parabolic approximation. The improvement is due to the inherent elliptic nature of the complex band structures in the vicinity of the bandgap, which has a
Orthostatic intolerance and motion sickness after parabolic flight
NASA Technical Reports Server (NTRS)
Schlegel, T. T.; Brown, T. E.; Wood, S. J.; Benavides, E. W.; Bondar, R. L.; Stein, F.; Moradshahi, P.; Harm, D. L.; Fritsch-Yelle, J. M.; Low, P. A.
2001-01-01
Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts.
Nonhomogeneous Linear and Quasilinear Elliptic and Parabolic Boundary Value
Amann, Herbert
in the theory of quasilinear parabolic systems by the modern theory of function spaces, interpolation.), ~--- r is the flux vector, and f r is the production rate for the r th species. With this interpretation' of the species r in the physicochemical context. The flux vector ~--- r of the species r is specified
Orthostatic Intolerance and Motion Sickness After Parabolic Flight
NASA Technical Reports Server (NTRS)
Schlegel, Todd T.; Brown, Troy E.; Wood, Scott J.; Benavides, Edgar W.; Bondar, Roberta L.; Stein, Flo; Moradshahi, Peyman; Harm, Deborah L.; Low, Phillip A.
1999-01-01
Orthostatic intolerance is common in astronauts after prolonged space flight. However, the "push-pull effect" in military aviators suggests that brief exposures to transitions between hypo- and hypergravity are sufficient to induce untoward autonomic cardiovascular physiology in susceptible individuals. We therefore investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy test subjects before and after a seated 2-hr parabolic flight. At the same time, we also investigated relationships between parabolic flight-induced vomiting and changes in orthostatic and autonomic cardiovascular function. After parabolic flight, 8 of 16 subjects could not tolerate a 30-min upright tilt test, compared to 2 of 16 before flight. Whereas new intolerance in non-Vomiters resembled the clinical postural tachycardia syndrome (POTS), new intolerance in Vomiters was characterized by comparatively isolated upright hypocapnia and cerebral vasoconstriction. As a group, Vomiters also had evidence for increased postflight fluctuations in efferent vagal-cardiac nerve traffic occurring independently of any superimposed change in respiration. Results suggest that syndromes of orthostatic intolerance resembling those occurring after space flight can occur after a brief (i.e., 2-hr) parabolic flight.
Anomalous diffusion and dynamical localization in a parabolic map
Tomaz Prosen; Marko Znidaric
2001-03-01
We study numerically classical and quantum dynamics of a piecewise parabolic area preserving map on a cylinder which emerges from the bounce map of elongated triangular billiards. The classical map exhibits anomalous diffusion. Quantization of the same map results in a system with dynamical localization and pure point spectrum.
Long-term average performance benefits of parabolic trough improvements
Gee, R.; Gaul, H.W.; Kearney, D.; Rabl, A.
1980-03-01
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.
Equivalent waveguide model for parabolic index planar segmented waveguides
K. Thyagarajan; V. Mahalakshmi; M. R. Shenoy
1995-01-01
In this paper we outline a simple procedure to obtain an equivalent z-invariant waveguide for a given graded index segmented waveguide. In particular, the proposed model is shown to predict accurately the modal spot size and the effective indices of the fundamental and the first higher order modes of a planar parabolic-index segmented waveguide over the entire range of duty
Moving mesh methods for solving parabolic partial differential equations
Jimack, Peter
Moving mesh methods for solving parabolic partial differential equations R. Marlowa, , M. E. Hubbarda , P. K. Jimacka a School of Computing, University of Leeds, UK Abstract A new adaptive method a moving mesh with continuous finite elements. The evolution of the mesh within the interior of the spatial
Canadian low-gravity research using parabolic aircraft
Glen S. Campbell; L. Vezina; J. F. Aitken
1992-01-01
An active experimental program being implemented by Canada in microgravity, which relies heavily on the use of parabolic aircraft, is discussed. The advantages of zero-gravity aircraft include low cost and quick turnaround. These aircraft have demonstrated their value for prototyping experimental hardware developments planned for flight at other facilities, such as sounding rockets and Shuttle-based carriers which are supported by
Extension of the Piecewise Parabolic Method to Multidimensional Ideal Magnetohydrodynamics
Wenlong Dai; Paul R. Woodward
1994-01-01
An extension of the piecewise parabolic method to treat multidimensional ideal magnetohydrodynamical equations is presented in this paper. The multidimensional scheme is constructed from a one-dimensional functioning code based on the dimensional splitting method originally suggested by Strang. The functioning code is built upon a nonlinear Riemann solver for ideal MHD equations recently developed by the authors. The correctness of
Elliptic and parabolic inequalities with point singularities on the boundary
Galakhov, Evgenii I [Steklov Mathematical Institute, Russian Academy of Sciences, Moscow (Russian Federation)
2009-10-31
It is shown that various quasilinear elliptic and parabolic differential inequalities and systems of such inequalities defined on bounded domains, and which have point singularities on the boundary do not have solutions. The method of nonlinear capacity is used in the proof. Examples show that the conditions obtained by this method cannot be improved in the class of problems under consideration. Bibliography: 14 titles.
Dynamical constants of structured photons with parabolic-cylindrical symmetry
B. M. Rodriguez-Lara; R. Jauregui
2009-05-20
Electromagnetic modes with parabolic-cylindrical symmetry and their dynamical variables are studied both in the classical and quantum realm. As a result, a new dynamical constant for the electromagnetic field is identified and linked to the symmetry operator which supports it.
Solid media thermal storage for parabolic trough power plants
Doerte Laing; Wolf-Dieter Steinmann; Rainer Tamme; Christoph Richter
2006-01-01
For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option regarding investment and maintenance costs. In the project WESPE that is described in this paper, solid media sensible heat storage materials have been researched. Two storage systems with a storage capacity of about 350kWh each
Exact solutions for some nonlinear fractional parabolic partial differential equations
Mahmoud M. El-borai
2008-01-01
A method for solving some nonlinear fractional parabolic partial differential equations is considered.Using this method, new exact solutions are obtained. By introducing suitable transformation, we obtain a system of fractional differential equations. This system will generate the exact solutions. The efficiency of the considered method can be demonstrated for a large variety of equations more general than Burgers, Murrary and
Analytical Dynamics of Parabolic Pulses in Nonlinear Optical Fiber Amplifiers
S. Wabnitz
2007-01-01
The process of attraction of parabolic pulses towards a self-similar profile in weakly dispersive nonlinear fiber-optic amplifiers can be well described by means of a simple analytical model. This approach permits for a rapid evaluation of the achievable pulse compression factor of high energy, strongly chirped pulses that emerge from a fiber amplifier
Resonant tunneling effect through a parabolic quantum well
NASA Astrophysics Data System (ADS)
Sekkal, N.; Aourag, H.; Amrane, N.; Soudini, B.
1995-02-01
We present a theoretical investigation on the resonant tunneling effect in an AlAs double-barrier structure with a AlGaAs central well having a special parabolic geometry. The results are similar to those obtained in a transverse resonant magnetotunneling experiment (with a magnetic field parallel to the interfaces of a square well).
Large Phased Array Radar using Networked Small Parabolic Reflectors
Farid Amoozegar
2006-01-01
Multifunction phased array systems with radar, telecom, and imaging applications have already been established for flat plate phased arrays of dipoles, or waveguides. In this paper the design trades and candidate options for combining the radar and telecom functions of the deep space network (DSN) into a single large transmit array of small parabolic reflectors will be discussed. In particular
On inverse problems for pseudoparabolic and parabolic equations of filtration
A. Sh. Lyubanova; A. Tani
2011-01-01
The inverse problems concerning the identification of the coefficient in the second order terms of linear pseudoparabolic equations of filtration in a fissured rock are investigated. The physical and mathematical justification of possible statements of the inverse problem for pseudoparabolic equations is given. New boundary conditions of overdetermination are discussed. Certain parabolic inverse problems relevant to pseudoparabolic ones are considered.
Symmetry properties of positive solutions of parabolic equations: a survey
Polacik, Peter
Symmetry properties of positive solutions of parabolic equations: a survey P. PolÂ´acik School certain reflectional symmetries, the presented results show how positive solutions reflect the symmetries. Depending on the class of solutions con- sidered, the symmetries for all times or asymptotic symmetries
Low-crosstalk Si arrayed waveguide grating with parabolic tapers.
Ye, Tong; Fu, Yunfei; Qiao, Lei; Chu, Tao
2014-12-29
A silicon arrayed waveguide grating (AWG) with low channel crosstalk was demonstrated by using ultra-short parabolic tapers to connect the AWG's free propagation regions and single-mode waveguides. The tapers satisfied the requirements of low-loss mode conversion and lower channel crosstalk from the coupling of neighboring waveguides in the AWGs. In this work, three different tapers, including parabolic tapers, linear tapers, and exponential tapers, were theoretically analyzed and experimentally investigated for a comparison of their effects when implemented in AWGs. The experimental results showed that the AWG with parabolic tapers had a crosstalk improvement up to 7.1 dB compared with the others. Based on the advantages of parabolic tapers, a 400-GHz 8 × 8 cyclic AWG with 2.4 dB on-chip loss and -17.6~-25.1 dB crosstalk was fabricated using a simple one-step etching process. Its performance was comparable with that of existing AWGs with bi-level tapers, which require complicated two-step etching fabrication processes. PMID:25607158
Solar concentrator with diffuser segments
NASA Astrophysics Data System (ADS)
Esparza, Diego; Moreno, Ivan
2011-08-01
Solar energy systems use concentrating optics with photovoltaic cells for optimizing the performance. Advanced concentrators are designed to maximize both the light collection and the spatial uniformity of radiation. This is important because irradiance uniformity is critical for all types of photovoltaic cells. This is difficult to achieve with traditional concentrators, which are built with polished optical surfaces. In this work we propose a new concept of solar concentrator which uses small diffuser segments in key points to increase the irradiation uniformity. We experimentally demonstrate this new concept by analyzing the effects on both efficiency and irradiance uniformity due to the incorporation of scattering ribbons in a compound parabolic concentrator.
Solar economy and technology update
Brotherton, T.K.
1983-06-01
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.
Economic analysis of large solar power plants
NASA Astrophysics Data System (ADS)
Klaiss, Helmut; Nitsch, Joachim; Geyer, Michael
1987-11-01
The current status and future potential of solar-tower, parabolic-reflector/Stirling-engine, channel-collector, and photovoltaic solar power plants of capacity 10 MWe or more are discussed. Consideration is given to the geographic and technological limitations, initial investment and operating costs, presently operating facilities, market openings, and critical technological challenges controlling future expansion. Numerical data are presented in tables and graphs, and it is concluded that solar power production will soon become economically competitive. It is suggested that the channel collector, at present the most mature and cost-efficient technology, has the least potential for further improvement, and that parabolic/Stirling and photovoltaic systems are probably better suited to smaller applications than to large-scale commercial power production.
Acurex Parabolic Dish Concentrator (PDC-2)
NASA Technical Reports Server (NTRS)
Overly, P.; Bedard, R.
1982-01-01
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.
Research and Development of a Low Cost Solar Collector
Ansari, Asif; Philip, Lee; Thouppuarachchi, Chirath
2012-08-01
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
Application of solar thermal energy to buildings and industry
Kutscher, C. F.
1981-05-01
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)
All-fiber ring Raman laser generating parabolic pulses
NASA Astrophysics Data System (ADS)
Kruglov, V. I.; Méchin, D.; Harvey, J. D.
2010-02-01
We present theoretical and numerical results for an all-fiber laser using self-similar parabolic pulses (“similaritons”) designed to operate using self-similar propagation regimes. The similariton laser features a frequency filter and a Sagnac loop which operate together to generate an integrated all-fiber mode-locked laser. Numerical studies show that this laser generates parabolic pulses with linear chirp in good agreement with analytical predictions. The period for propagating similariton pulses in stable regimes can vary from one to two round trips for different laser parameters. Two-round-trip-period operation in the mode-locked laser appears at bifurcation points for certain cavity parameters. The stability of the similariton regimes has been confirmed by numerical simulations for large numbers of round trips.
Shock wave convergence in water with parabolic wall boundaries
NASA Astrophysics Data System (ADS)
Yanuka, D.; Shafer, D.; Krasik, Ya.
2015-04-01
The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ˜45 kA and rise time of ˜80 ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.
Stable spline methods for parabolic partial differential equations
NASA Astrophysics Data System (ADS)
Lippolis, A.; Napolitano, M.
A classical spline-Crank Nicolson approach (Rubin and Khosla, 1977) applied to a linear parabolic partial differential equation is considered. The marching technique of Napolitano and Vacca (1980) is considered with a view to further developments. A stability analysis is used to verify that a technique of this type is unconditionally unstable and to indicate possible ways of removing the cause of the instability. Two new stable marching techniques, which employ spline interpolating concepts in both the marching and the nonmarching directions, are then presented. A different approach to obtaining stability is then followed, and two stable two-sweep procedures are presented. These use the spline-Crank Nicolson approach as the first step and a spline-spline method, for improving the accuracy of the first-step solution, in the second and final sweep. The case of a three-dimensional and nonlinear parabolic partial differential equation is addressed, and numerial results for the classical Burgers equation are presented.
Eigenstate symmetries and information transfer in parabolic quantum reflectors
NASA Astrophysics Data System (ADS)
Trallero-Giner, C.; Lopez-Richard, V.; Ulloa, S. E.; Marques, G. E.
2009-04-01
We study the quantum mechanical properties of one of the simplest geometrical elements: a parabolic reflector. We study the quantum propagation problem in a two-dimensional mirror, appropriate for electrons on the surface of metals, providing explicit closed solutions for the particle wave functions and the corresponding energy dispersion. Knowledge of nodal lines and distributions highlights the importance of “silent” and “loud” regions where quantum amplitude would be small or large. We further analyze the effects of quantum focusing and reflection for an initial pulse originating at the focus of the parabolic reflector. We find two propagation fronts that persist at long times and away from the focus of the parabola; the reflected front has higher amplitude and exhibits a nearly flat distribution moving at constant speed along the focal axis, reminiscent of a typical optical mirror wave front.
Improved field scanner incorporating parabolic optics. Part 1: simulation.
Sharafutdinova, Galiya; Holdsworth, John; van Helden, Dirk
2009-08-01
An unobstructed afocal scanning system design employing two off-axis parabolic reflectors as relay optics between two flat scan mirrors is proposed and investigated using OSLO optical software. It is found that, with a symmetric arrangement of the parabolic reflectors and appropriate selection of the first scan mirror rotational axis, the system provides linear scan lines at the image surface and excellent point spread function results in all scan positions. The design is functionally equivalent to a single-mirror scan engine and superior in every metric to a comparable dimension spherical mirror arrangement. This design is suited to two-dimensional laser scan engines and for confocal and two-photon microscopy in particular. PMID:19649043
Development and testing of Parabolic Dish Concentrator No. 1
NASA Technical Reports Server (NTRS)
Dennison, E. W.; Thostesen, T. O.
1984-01-01
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.
Treatment of motion sickness in parabolic flight with buccal scopolamine
NASA Technical Reports Server (NTRS)
Norfleet, William T.; Degioanni, Joseph J.; Reschke, Millard F.; Bungo, Michael W.; Kutyna, Frank A.; Homick, Jerry L.; Calkins, D. S.
1992-01-01
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.
Adiabatic nanofocusing of the fundamental modes in plasmonic parabolic potentials
NASA Astrophysics Data System (ADS)
Liu, Wei
2015-07-01
We investigate the adiabatic nanofocusing of the fundamental modes in plasmonic parabolic potentials. The potentials are obtained in the metal-dielectric-metal structure, of which the dielectric layer width is modulated quadratically in the horizontal direction and linearly in the longitudinal direction. In such a structure, light is compressed in both transverse directions due to increasingly stronger parabolic potentials and decreasing dielectric layer width. We show by both closed form analytical descriptions and numerical simulations that there is a critical tapering angle, above which the field could be enhanced. In contrast to previously reported tapered structures in the adiabatic regime without transverse potentials, the structure proposed in this paper shows stronger focusing capability and allows monotonic increasing field enhancement over longer propagation distances.
All-fiber ring Raman laser generating parabolic pulses
Kruglov, V. I.; Mechin, D.; Harvey, J. D. [Physics Department, University of Auckland, Private Bag 92019, Auckland (New Zealand)
2010-02-15
We present theoretical and numerical results for an all-fiber laser using self-similar parabolic pulses ('similaritons') designed to operate using self-similar propagation regimes. The similariton laser features a frequency filter and a Sagnac loop which operate together to generate an integrated all-fiber mode-locked laser. Numerical studies show that this laser generates parabolic pulses with linear chirp in good agreement with analytical predictions. The period for propagating similariton pulses in stable regimes can vary from one to two round trips for different laser parameters. Two-round-trip-period operation in the mode-locked laser appears at bifurcation points for certain cavity parameters. The stability of the similariton regimes has been confirmed by numerical simulations for large numbers of round trips.
PECan A Canadian Parabolic Equation Model for Underwater Sound Propagation
Gary H. Brooke; David J. Thomson; Gordon R. Ebbeson
2001-01-01
PECan is a Canadian N£2D\\/3D parabolic equation (PE) underwater sound propagation model that was developed for matched-fleld processing applications. It is based on standard square-root operator and\\/or propagator approximations that lead to an alternating direction solution of the 3D problem. A 2D split-step Pade approximation is employed for propagation in range. The 3D azimuthal corrections are computed using either a
Galerkin/Runge-Kutta discretizations for semilinear parabolic equations
NASA Technical Reports Server (NTRS)
Keeling, Stephen L.
1987-01-01
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.
Canadian low-gravity research using parabolic aircraft
NASA Astrophysics Data System (ADS)
Campbell, Glen S.; Vezina, L.; Aitken, J. F.
1992-12-01
An active experimental program being implemented by Canada in microgravity, which relies heavily on the use of parabolic aircraft, is discussed. The advantages of zero-gravity aircraft include low cost and quick turnaround. These aircraft have demonstrated their value for prototyping experimental hardware developments planned for flight at other facilities, such as sounding rockets and Shuttle-based carriers which are supported by the Canadian Space Agency.
Synergies between optical and physical variables in intercepting parabolic targets
Gómez, José; López-Moliner, Joan
2013-01-01
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
Receiver behavior in direct steam generation with parabolic troughs
Rafael Almanza; Alvaro Lentz; Gustavo Jiménez
1998-01-01
The receiver behavior of parabolic troughs in direct steam generation (DSG) has been studied under different experimental conditions. When cool water was fed into steel receiver pipes (?=2.54cm), the pipes deflected. This bend advanced like a wave from the inlet to the outlet end, having a deflection of about 6.5cm at the center of each section (2.90m long) in the
Laminar Incompressible Flow Past Parabolic Bodies at Angles of Attack
Ercan Erturk; Thomas Corke; Osamah Haddad
2003-01-01
Numerical solutions of a two-dimensional steady laminar incompressible flow over semi-infinite parabolic bodies at angles of attack are obtained. All solutions are found by using a modified numerical approach to solve the time-dependent Navier-Stokes equations. A check of our solutions to those that exist in the literature at zero angle of attack showed excellent agreement. In addition, at zero angle
Boundary-layer receptivity for a parabolic leading edge
P. W. Hammerton; E. J. Kerschen
1996-01-01
The eect of the nose radius of a body on boundary-layer receptivity is analyzed for the case of a symmetric mean flow past a body with a parabolic leading edge. Asymptotic methods based on large Reynolds number are used, supplemented by numerical results. The Mach number is assumed small, and acoustic free-stream disturbances are consid- ered. The case of free-stream
Conservation Laws and Potential Symmetries of Linear Parabolic Equations
Roman O. Popovych; Michael Kunzinger; Nataliya M. Ivanova
2008-01-01
We carry out an extensive investigation of conservation laws and potential symmetries for the class of linear (1+1)-dimensional\\u000a second-order parabolic equations. The group classification of this class is revised by employing admissible transformations,\\u000a the notion of normalized classes of differential equations and the adjoint variational principle. All possible potential conservation\\u000a laws are described completely. They are in fact exhausted by
A stability analysis for a semilinear parabolic partial differential equation
NASA Technical Reports Server (NTRS)
Chafee, N.
1973-01-01
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.
Optimisation of concentrating solar cell systems with passive and active cooling
J. Blumenberg
1983-01-01
Design considerations for concentrator solar cell arrays for space applications are reviewed, noting the restrictions on total mass that govern system selections. Consideration is given to systems with parabolic mirrors and Si and GaAs solar cells. Passive and active cooling systems for the arrays are discussed, as is the addition of a heat engine with a turbogenerator to utilize part
Fe(III)-solar light induced degradation of diethyl phthalate (DEP) in aqueous solutions
G. Mailhot; M. Sarakha; B. Lavedrine; J. Cáceres; S. Malato
2002-01-01
The degradation of diethyl phthalate (DEP) photoinduced by Fe(III) in aqueous solutions has been investigated under solar irradiation in the compound parabolic collector reactor at Plataforma Solar de Almeria. Hydroxyl radicals OH, responsible of the degradation, are formed via an intramolecular photoredox process in the excited state of Fe(III) aquacomplexes. The primary step of the reaction is mainly due to
A model for optimal sizing of solar thermal hydroelectric power plant
Zvonimir Glasnovi?; Marko Rogoši?; Jure Margeta
2011-01-01
This paper presents the model for optimal sizing of a Solar Thermal (ST) power plant with parabolic collectors, which operates with Pump Storage Hydroelectric (PSH), all for the purpose of providing full energy independence of an isolated consumer. The sustainability of such system is based exclusively on solar energy input (without hybridization with any fossil fuel), as a renewable and
Present state of research on selective coatings for solar-energy converters
M. M. Koltun
1980-01-01
Recent developments in selective surface coatings for solar cells, flat plate and tubular collectors, and parabolic concentrators are reviewed. Solar cells treated with hydrazine hydrate or alkalies produce a surface with relief, which traps up to 97% of the spectrum. Multilayer cells transparent to the IR are noted for space applications; phosphor coatings to convert ultraviolet radiation to visible light
Agustín Manuel Delgado-Torres; Lourdes García-Rodríguez
2007-01-01
In a previous paper the authors analyzed a low power (100 kW) solar organic Rankine cycle (ORC) as the mechanical and thermal energy source for desalination processes. Such a solar ORC is powered by parabolic trough collectors with direct vapor generation (DVG) technology. To this day, however, there are still no commercial implementations of said technology. For this reason, in
Solar power converter with pool boiling receiver and integral heat exchanger
D. B. Osborn; R. L. Pons
1982-01-01
A solar converter is disclosed which has particular applicability at the focal point of a parabolic concentrator. The converter absorbs solar thermal radiation in a cavity type receiver and transports the heat via a secondary fluid to a heat exchanger which contains a primary (I.E., working) fluid used for process heating or to power a heat engine employing either stirling,
Circulatory filling pressures during transient microgravity induced by parabolic flight.
Latham, R D; Fanton, J W; White, C D; Vernalis, M N; Crisman, R P; Koenig, S C
1993-01-01
Theoretical concepts hold that blood in the gravity-dependent portion of the body would relocate to more cephalad compartments under microgravity conditions. The result is an increase in blood volume in the thoracic and cardiac chambers. This increase in central volume shift should result in an increase in central atrial filling pressures. However, experimental data has been somewhat contradictory and nonconclusive to date. Early investigations of peripheral venous pressure and estimates of central venous pressure (CVP) from these data did not show an increase in CVP in the microgravity condition. However, CVP recorded in human volunteers during the parabolic flight by Norsk revealed an increase in CVP during the microgravity state. On the June 1991 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 subjects had increased CVP recordings and two other subjects had decreased CVP measurements. In April 1991, our laboratory performed parabolic flight studies in several chronic-instrumented baboon subjects. It was again noted that centrally recorded right atrial pressure varied with exposure to microgravity, some animals having an increase and others having a decrease. Thus, data presently available has demonstrated a variable response in the mechanism not clearly defined. In April 1992, we determined a test hypothesis relating the possible mechanism of these variable pressure responses to venous pressure-volume relationships. PMID:11537424
Space-DRUMS™ experimental development using parabolic reduced gravity flights
NASA Astrophysics Data System (ADS)
Guigné, J. Y.; Davidson, R.; Millan, D.
2000-01-01
Space-DRUMS™ is a microgravity containerless-processing facility that uses acoustic beams to position large diameter liquid or solid samples within a gas-filled chamber. Its capacity to control the position of large diameter (6 cm) low density solid materials was successfully demonstrated on NASA's DC-9 parabolic aircraft in July 1996; two subsequent flights occurred in 1998 using the KC-135 and A-300 aircraft to further refine the technology used in the system. The working environment for the Space-DRUMS™ facility is the Space Shuttle/Space Station where long duration microgravity experimentation can take place. Since the reduced gravity environment of an A-300 or a KC-135 parabolic flight is much harsher than that of the Space Shuttle in terms of residual acceleration magnitudes experienced by the samples to be held in position; this more extreme environment allows for most Space-DRUMS™ technical payload functionality tests to be conducted. In addition to flight hardware shakedowns, parabolic flights continue to be extensively used to study and evaluate the behavior of candidate-advanced materials proposed for ISS Space-DRUMS™ campaigns. The first samples to be processed in 2001 involve combustion synthesis (also known as SHS-Self-propagating High Temperature Synthesis) of large glass-ceramic and of porous ceramic spheres. Upmassing Space-DRUMS™ for the International Space Station is scheduled for early 2001. .
Solar power water distillation unit
NASA Astrophysics Data System (ADS)
Hameed, Kamran; Muzammil Khan, Muhammad; Shahrukh Ateeq, Ijlal; Omair, Syed Muhammad; Ahmer, Muhammad; Wajid, Abdul
2013-06-01
Clean drinking water is the basic necessity for every human being, but about 1.1 billion people in the world lacked proper drinking water. There are many different types of water purification processes such as filtration, reverse osmosis, ultraviolet radiation, carbon absorption, but the most reliable processes are distillation and boiling. Water purification, such as distillation, is especially important in regions where water resources or tap water is not suitable for ingesting without boiling or chemical treatment. In design project It treats the water by combining different methods such as Filtration, Distillation and a technique called concentrated solar power (CSP). Distillation is literally the method seen in nature, whereby: the sun heats the water on the earth's surface, the water is turned into a vapor (evaporation) and rises, leaving contaminants behind, to form clouds. As the upper atmosphere drops in temperature the vapors cool and convert back to water to form water. In this project distillation is achieved by using a parabolic mirror which boils water at high temperature. Filtration is done by sand filter and carbon filter. First sand filter catches the sand particles and the carbon filter which has granules of active carbon is used to remove odor dissolved gases from water. This is the Pre-treatment of water. The filtered water is then collected in a water container at a focus of parabolic mirror where distillation process is done. Another important feature of designed project is the solar tracking of a parabolic mirror which increases the efficiency of a parabolic mirror [1],[2].
1kW solar Stirling experiment. Final report
Giandomenico
1981-01-01
The objective of this experiment was to demonstrate electrical power generation using a small free-piston Stirling engine and linear alternator in conjunction with a parabolic solar collector. A test bed collector, formerly used at the JPL Table Mountain Observatory, was renovated and used to obtain practical experience and to determine test receiver performance. The collector was mounted on a two-axis
The 1kW solar Stirling experiment
A. Giandomenico
1981-01-01
The objective of this experiment was to demonstrate electrical power generation using a small free-piston Stirling engine and linear alternator in conjunction with a parabolic solar collector. A test bed collector, formerly used at the JPL Table Mountain Observatory, was renovated and used to obtain practical experience and to determine test receiver performance. The collector was mounted on a two-axis
Photonic control of flexible structures---application to a free-floating parabolic membrane shell
Hui-Ru Shih; Horn-Sen Tzou; Wilbur L. Walters Jr.
2009-01-01
In this paper, the photonic control of free-floating flexible parabolic shells using photostrictive actuators is investigated. The parabolic shell of revolution is considered to be one of the most difficult geometries among all shell and non-shell structures. Because of this, an approximate way to estimate the dynamic behavior and light-induced control forces for a photostrictive coupled parabolic shell is presented.
Harrison, T.D.
1981-03-01
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)
Air Brayton Solar Receiver, phase 2
NASA Technical Reports Server (NTRS)
Deanda, L. E.
1981-01-01
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.
Koteras, J.R.
1981-03-01
Results (stresses, displacements, and equivalent slope errors) are presented from finite element analyses made to evaluate a design for a parabolic trough solar concentrator. The concentrator consists of a reflector laminate (made of thin glass bonded to sheet metal backing) which is mechanically formed and bonded to a stiff parabolic support (made of aluminum honeycomb bonded to steel skins) with a 2 meter (6.6 foot) aperture. Analyses were first made to determine a length for the concentrator such that it would meet certain performance and survivability criteria under wind and gravity loadings. These studies were made with a model for the concentrator only. The concentrator model was then combined with a model for a support mechanism, and this combined structure was studied for several wind and gravity loadings. A design characterized by a six meter (twenty foot) long concentrator was found to meet performance criteria and had sufficiently low glass stresses in a 40.23 meter per second ((ninety mile per hour) wind.
Testing of Stirling engine solar reflux heat-pipe receivers
S. Rawlinson; P. Cordeiro; V. Dudley; T. Moss
1993-01-01
Alkali metal heat-pipe receivers have been identified as a desirable interface to couple a Stirling-cycle engine with a parabolic dish solar concentrator. The reflux receiver provides power nearly isothermally to the engine heater heads while de-coupling the heater head design from the solar absorber surface design. The independent design of the receiver and engine heater head leads to high system
Exact analytic flux distributions for two-dimensional solar concentrators.
Fraidenraich, Naum; Henrique de Oliveira Pedrosa Filho, Manoel; Vilela, Olga C; Gordon, Jeffrey M
2013-07-01
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
Piecewise-parabolic methods for astrophysical fluid dynamics
Woodward, P.R.
1983-11-01
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.
A cosmological hydrodynamic code based on the Piecewise Parabolic Method
Claudio Gheller; Ornella Pantano; Lauro Moscardini
1997-01-22
We present a hydrodynamical code for cosmological simulations which uses the Piecewise Parabolic Method (PPM) to follow the dynamics of gas component and an N-body Particle-Mesh algorithm for the evolution of collisionless component. The gravitational interaction between the two components is regulated by the Poisson equation which is solved by a standard FFT procedure. In order to simulate cosmological flows we have introduced several modifications to the original PPM scheme which we describe in detail. Various tests of the code are presented including adiabatic expansion, single and multiple pancake formation and three-dimensional cosmological simulations with initial conditions based on the cold dark matter scenario.
Fuzzy control of parabolic antenna with backlash compensation
NASA Astrophysics Data System (ADS)
Ahmed, Mohammed; Noor, Samsul Bahari B. Mohd
2015-05-01
A fuzzy logic based controller (FLC) was proposed for position control of a parabolic dish antenna system with the major aim of eradicating the effect backlash disturbance which may be present in the system. The disturbance is nonlinear and is capable of generating steady state positional errors. Simulation results obtained using SIMULINK/MATLAB 2012a were compared with those obtained when the controller was proportional-derivative controller (PDC). The fuzzy controller portrays that it has the capability of reducing the noise due to backlash and possibly others more than the proportional-derivative controller.
Parabolic Type Equations and Markov Stochastic Processes on Adeles
Sergii M. Torba; W. A. Zuniga-Galindo
2012-06-22
In this paper we study the Cauchy problem for new classes of parabolic type pseudodifferential equations over the rings of finite adeles and adeles. We show that the adelic topology is metrizable and give an explicit metric. We find explicit representations of the fundamental solutions (the heat kernels). These fundamental solutions are transition functions of Markov processes which are adelic analogues of the Archimedean Brownian motion. We show that the Cauchy problems for these equations are well-posed and find explicit representations of the evolution semigroup and formulas for the solutions of homogeneous and non-homogeneous equations.
Stable patterns for fourth-order parabolic equations
J. B. van den Berg; R. C. Vandervorst
2002-01-01
We consider fourth-order parabolic equations of gradient type. For\\u000athe sake of simplicity, the analysis is carried out for the specific\\u000aequation $u\\\\sb t=-\\\\gamma\\\\ u\\\\sb {xxxx}+\\\\beta u\\\\sb {xx}-F\\\\sp \\\\prime(u)$\\u000awith $(t,x)\\\\in (0,\\\\infty)\\\\times(0, L)$ and $\\\\gamma,\\\\beta>0$ and\\u000awhere $F(u)$ is a bistable potential. We study its stable equilibria\\u000aas a function of the ratio $\\\\gamma\\/beta\\\\sp 2$. As the ratio\\u000a$\\\\gamma\\/beta\\\\sp 2$
Exciton States in a Quantum Dot with Parabolic Confinement
NASA Astrophysics Data System (ADS)
Do?an, Ü.; Sakiro?lu, S.; Yildiz, A.; Akgüngör, K.; Epik, H.; Sökmen, I.; Sari, H.; Ergün, Y.
In this study the electronic eigenstructure of an exciton in a parabolic quantum dot (QD) has been calculated with a high accuracy by using Finite element method (FEM). We have converted the coordinates of electron-light-hole system to relative and center of mass coordinate, then placed the Spherical Harmonics into Schrödinger equation analytically and obtained the Schrödinger equation which depends only on the radial variable. Finally we used FEM with only radial variable in order to get the accurate numerical results. We also showed first 21 energy level spectra of exciton depending on confinement and Coulomb interaction parameters.
Marching grid generation using parabolic partial differential equations
NASA Technical Reports Server (NTRS)
Nakamura, S.
1982-01-01
The feasibility of using parabolic partial differential equations for grid generation is examined. Source terms in the form of a linear interpolation between the current grid and the outer boundary are used in generating a grid for a two-dimensional airfoil flow. Grid generation equations are derived by assuming that grid spacings are locally nonuniform on the computational domain. The grid spacing control method is described in detail, and the local orthogonality of the grid lines is discussed. An O-mesh and an H-mesh generated by the described method are shown.
S. Quoilin; M. Orosz; H. Hemond; V. Lemort
2011-01-01
Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine.The paper describes the design of a
Marco Astolfi; Luca Xodo; Matteo C. Romano; Ennio Macchi
2011-01-01
A combined concentrating solar power system and a geothermal binary plant based on an Organic Rankine Cycle (ORC) is analyzed. Given a supercritical ORC, designed for the optimal utilization of an intermediate enthalpy geothermal source, a solar parabolic trough field was included in the plant, introducing an additional high temperature heat source for the cycle and increasing power production. The
Design, fabrication, and testing of a 30 kW(sub t) screen-wick heat-pipe solar receiver
C. E. Andraka; R. B. Diver; D. A. Wolf
1992-01-01
Heat-Pipe reflux receivers have been identified as a desirable interface to couple a Stirling engine with a parabolic dish solar concentrator. The reflux receiver provides power uniformly and nearly isothermally to the engine heater heads while de-coupling the heater head design from the solar absorber surface design. Therefore, the heat pipe reflux receiver allows the receiver and heater head to
S. Janjai; N. Lamlert; P. Intawee; B. Mahayothee; B. K. Bala; M. Nagle; J. Müller
2009-01-01
This paper presents experimental and simulated performance of a PV-ventilated solar greenhouse dryer for drying of peeled longan and banana. The dryer consists of a parabolic roof structure covered with polycarbonate plates on a concrete floor. Three fans powered by a 50-W PV module ventilate the dryer. To investigate the experimental performances of the solar greenhouse dryer for drying of
Universal solar energy desalination system
NASA Astrophysics Data System (ADS)
Fusco, V. S.
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.
NASA Technical Reports Server (NTRS)
1997-01-01
This artist's rendition depicts the response of the solar wind to the obstacle - the planet Mars - in it's path. A supersonic 'solar wind' consisting of electrically charged particles (ions and electrons) streams off the Sun into space. It is slowed to subsonic speeds in the vicinity of Mars at a parabolic surface called a 'bow shock' upstream of the planet. Here, the magnetic field fluctuates wildly and the flow of the solar wind becomes chaotic. Part of the orbital trajectory of the Mars Global Surveyor is indicated, with MGS approaching the planet just prior to over-flight of the pole.
The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. JPL is an operating division of California Institute of Technology (Caltech).
Degtyarev, Sergey P [Institute of Applied Mathematics and Mechanics, Ukraine National Academy of Sciences, Donetsk (Ukraine)
2010-09-02
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.
On the numerical solution of a two dimensional elliptic-parabolic equation
NASA Astrophysics Data System (ADS)
Gercek, Okan; Zusi, Emel
2012-09-01
In the present article, a numerical method for solving two dimensional elliptic-parabolic equations is studied. A procedure of modified Gauss elimination method is used for solving these difference schemes of two dimensional nonlocal boundary value problem for an elliptic-parabolic equation.
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
The behavior of hyperbolic heat equations' solutions near their parabolic limits
Nagy, Gabriel
The behavior of hyperbolic heat equations' solutions near their parabolic limits Gabriel B. Nagy the relation between the solutions of one parameter families of hyperbolic systems of equations describing heat propa- gation near their parabolic limits, which for these cases are the usual diffusive heat equation
Boyer, Edmond
A FINITE VOLUME SCHEME FOR NONLINEAR DEGENERATE PARABOLIC EQUATIONS MARIANNE BESSEMOULIN-CHATARD AND FRANCIS FILBET Abstract. We propose a second order finite volume scheme for nonlinear degenerate parabolic equations. For some of these models (porous media equation, drift-diffusion system for semiconductors
Leading edge boundary layer receptivitivy to oblique free stream acoustic waves on parabolic bodies
Ercan Erturk
1999-01-01
In this study, the effect of the incidence angle of free strewn acoustic waves on the leading edge boundary layer receptivity of a two dimensional laminar incompressible flow over parabolic bodies is investigated. For this, the full Navier-Stokes equations in parabolic coordinates in streamfunction and vorticity variables were solved numerically. For the receptivity problem a spatial approach is used. With
Discrete Approximations for Singularly Perturbed Boundary Value Problems with Parabolic Layers, II
Paul A. Farrell; Pieter W. Hemker; Grigori I. Shishkin
1996-01-01
In his series of three papers we study singularly perturbed (SP) boundaryvalue problems for equations of elliptic and parabolic type. For smallvalues of the perturbation parameter parabolic boundary and interior layersappear in these problems. If classical discretisation methods are used,the solution of the finite difference scheme and the approximation of thediffusive flux do not converge uniformly with respect to this
Blow-up at the Boundary for Degenerate Semilinear Parabolic Equations
Floater, Michael S.
Blow-up at the Boundary for Degenerate Semilinear Parabolic Equations M. S. Floater Department a superlinear parabolic equation, degenerate in the time derivative. It is shown that the solution may blow up in finite time. Moreover it is proved that for a large class of initial data blow-up occurs at the boundary
Second law analysis and optimization of a parabolic trough receiver tube for direct steam generation
NASA Astrophysics Data System (ADS)
Nolte, H. C.; Bello-Ochende, T.; Meyer, J. P.
2015-06-01
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.
Second law analysis and optimization of a parabolic trough receiver tube for direct steam generation
NASA Astrophysics Data System (ADS)
Nolte, H. C.; Bello-Ochende, T.; Meyer, J. P.
2014-12-01
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.
Parabolic trough collectors for industrial process heat in Cyprus
Soteris A Kalogirou
2002-01-01
The thermal utilization of solar energy is usually confined to domestic hot water systems and somewhat to space heating at temperatures up to 60 °C. Industrial process heat has a considerable potential for solar energy utilization. Cyprus has a small isolated energy system, almost totally dependent on imported fuels to meet its energy demand. The abundance of solar radiation together
Simulation and operation of a solar powered organic Rankine cycle turbine
A. F. Veneruso
1976-01-01
Sandia Laboratories' ERDA-sponsored Solar Total Energy System Test Facility utilizes 814 sq m (8759 sq ft) of solar tracking, east-west oriented, parabolic trough collectors to heat Therminol 66 heat transfer fluid to 316 C (600 F). The energy is stored as sensible heat in a 5246 gal storage tank. The solar-heated fluid is then used to power an organic Rankine
Preliminary assessment of solar organic Rankine cycles for driving a desalination system
Agustín M. Delgado-Torres; Lourdes García-Rodríguez
2007-01-01
A detailed analysis of low power (100 kW) solar-driven Rankine cycles in the medium temperature range has been carried out. Toluene, octamethylcyclotetrasiloxane (D4) and hexamethyldisiloxane (MM) has been considered as working fluids of organic Rankine cycle (ORC). Direct solar vapor generation configuration of solar ORC has been analysed and characterized with LS3 and IND300 parabolic trough collector (PTC) models. The
Shock unsteadiness in a thrust optimized parabolic nozzle
NASA Astrophysics Data System (ADS)
Verma, S. B.
2009-07-01
This paper discusses the nature of shock unsteadiness, in an overexpanded thrust optimized parabolic nozzle, prevalent in various flow separation modes experienced during start up {(? P0 /? t > 0)} and shut down {(? P0/? t < 0)} sequences. The results are based on simultaneously acquired data from real-time wall pressure measurements using Kulite pressure transducers, high-speed schlieren (2 kHz) of the exhaust flow-field and from strain-gauges installed on the nozzle bending tube. Shock unsteadiness in the separation region is seen to increase significantly just before the onset of each flow transition, even during steady nozzle operation. The intensity of this measure ( rms level) is seen to be strongly influenced by relative locations of normal and overexpansion shock, the decrease in radial size of re-circulation zone in the back-flow region, and finally, the local nozzle wall contour. During restricted shock separation, the pressure fluctuations in separation region exhibit periodic characteristics rather than the usually observed characteristics of intermittent separation. The possible physical mechanisms responsible for the generation of flow unsteadiness in various separation modes are discussed. The results are from an experimental study conducted in P6.2 cold-gas subscale test facility using a thrust optimized parabolic nozzle of area-ratio 30.
Using Parabolic Equation for Calculation of Beam Impedance
Stupakov, Gennady; /SLAC
2006-04-07
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.
Experimental testing of the variable rotated elastic parabolic equation.
Simpson, Harry J; Collis, Jon M; Soukup, Raymond J; Collins, Michael D; Siegmann, William L
2011-11-01
A series of laboratory experiments was conducted to obtain high-quality data for acoustic propagation in shallow water waveguides with sloping elastic bottoms. Accurate modeling of transmission loss in these waveguides can be performed with the variable rotated parabolic equation method. Results from an earlier experiment with a flat or sloped slab of polyvinyl chloride (PVC) demonstrated the necessity of accounting for elasticity in the bottom and the ability of the model to produce benchmark-quality agreement with experimental data [J. M. Collis et al., J. Acoust. Soc. Am. 122, 1987-1993 (2007)]. This paper presents results of a second experiment, using two PVC slabs joined at an angle to create a waveguide with variable bottom slope. Acoustic transmissions over the 100-300 kHz band were received on synthetic horizontal arrays for two source positions. The PVC slabs were oriented to produce three different simulated waveguides: flat bottom followed by downslope, upslope followed by flat bottom, and upslope followed by downslope. Parabolic equation solutions for treating variable slopes are benchmarked against the data. PMID:22087895
Anderson, R. [Universal Recycled Water Systems, Orlando, FL (United States); Collier, R. [Enerscope, Inc., Merritt Island, FL (United States)
1996-11-01
Non-potable drinking water is a major problem for much of the world`s population. It has been estimated that from 15 to 20 million children under the age of 5 die from diarrheal conditions brought on by infected drinking water every year. This is equivalent to a fully-loaded DC-10 crashing every ten minutes of every day, 365 days a year. Heat is one of the most effective methods of disinfecting drinking water. Using conventional means of heating water (heating on an open-flamed stove) results in an extremely energy-intensive process. The main obstacle is that for areas of the world where potable water is a problem, fuel supplies are either too expensive, not available, or the source of devastating environmental problems (deforestation). The apparatus described is a solar-powered water disinfection device that can overcome most if not all of the barriers that presently limit technological solutions to drinking water problems. It uses a parabolic trough solar concentrator with a receiver tube that is also a counterflow heat exchanger. The system is totally self-contained utilizing a photovoltaic-powered water pump, and a standard automotive thermostat for water flow control. The system is designed for simplicity, reliability and the incorporation of technology readily accessible in most areas of the world. Experiments at the Florida Solar Energy Center have demonstrated up to 2,500 liters of safe drinking water per day with 28 square meters of solar concentrator.
Pasteurization of naturally contaminated water with solar energy.
Ciochetti, D A; Metcalf, R H
1984-02-01
A solar box cooker (SBC) was constructed with a cooking area deep enough to hold several 3.7-liter jugs of water, and this was used to investigate the potential of using solar energy to pasteurize naturally contaminated water. When river water was heated either in the SBC or on a hot plate, coliform bacteria were inactivated at temperatures of 60 degrees C or greater. Heating water in an SBC to at least 65 degrees C ensures that the water will be above the milk pasteurization temperature of 62.8 degrees C for at least an hour, which appears sufficient to pasteurize contaminated water. On clear or partly cloudy days, with the SBC facing magnetic south in Sacramento, bottom water temperatures of at least 65 degrees C could be obtained in 11.1 liters of water during the 6 weeks on either side of the summer solstice, in 7.4 liters of water from mid-March through mid-September, and in 3.7 liters of water an additional 2 to 3 weeks at the beginning and end of the solar season. Periodic repositioning of the SBC towards the sun, adjusting the back reflective lid, and preheating water in a simple reflective device increased final water temperatures. Simultaneous cooking and heating water to pasteurizing temperatures was possible. Additional uses of the SBC to pasteurize soil and to decontaminate hospital materials before disposal in remote areas are suggested. PMID:6712206
Pasteurization of naturally contaminated water with solar energy.
Ciochetti, D A; Metcalf, R H
1984-01-01
A solar box cooker (SBC) was constructed with a cooking area deep enough to hold several 3.7-liter jugs of water, and this was used to investigate the potential of using solar energy to pasteurize naturally contaminated water. When river water was heated either in the SBC or on a hot plate, coliform bacteria were inactivated at temperatures of 60 degrees C or greater. Heating water in an SBC to at least 65 degrees C ensures that the water will be above the milk pasteurization temperature of 62.8 degrees C for at least an hour, which appears sufficient to pasteurize contaminated water. On clear or partly cloudy days, with the SBC facing magnetic south in Sacramento, bottom water temperatures of at least 65 degrees C could be obtained in 11.1 liters of water during the 6 weeks on either side of the summer solstice, in 7.4 liters of water from mid-March through mid-September, and in 3.7 liters of water an additional 2 to 3 weeks at the beginning and end of the solar season. Periodic repositioning of the SBC towards the sun, adjusting the back reflective lid, and preheating water in a simple reflective device increased final water temperatures. Simultaneous cooking and heating water to pasteurizing temperatures was possible. Additional uses of the SBC to pasteurize soil and to decontaminate hospital materials before disposal in remote areas are suggested. PMID:6712206
Effects of band non-parabolicity on cavity modes in photonic crystals
NASA Astrophysics Data System (ADS)
Lue, N.-Y.; Chen, Y.-S.; Wei, H.-S.; Wu, G. Y.
2013-02-01
We include the effect of band non-parabolicity on photonic defect states within the Wannier theory, which improves the quadratic approximation adopted by Painter et al. [Phys. Rev. B 68, 035214 (2003)] for large-size defects, as well as extends the theory to a wider range of defect size. A 2D hexagonal photonic crystal is considered, and analyzed for the origin and degree of non-parabolicity in the 1st TE band around J-point, and for the effect of non-parabolicity on acceptor type cavity modes. The non-parabolicity is shown to derive primarily from the inherent anisotropy of band dispersion around the point. Overall, with the inclusion of non-parabolicity, (i) mode degeneracy is lowered, (ii) the "binding energy" of a cavity mode is increased, and (iii) the cut-off of defect size for a given cavity mode is reduced, by as much as 35% in certain cases, in comparison with that calculated without the non-parabolicity. A simple "overall effective mass" picture is provided for the understanding of non-parabolicity effects.
Applied research concerning the direct steam generation in parabolic troughs
M. Eck; E. Zarza; M. Eickhoff; J. Rheinländer; L. Valenzuela
2003-01-01
With levelized electricity costs (LEC) of 10–12USCts\\/kWh the well-known SEGS (Solar Electric Generating Systems) plants in California are presently the most successful solar technology for electricity generation [Price and Cable (2001) Proc. ASME Int. Solar Energy Conf. Forum 2001]. The SEGS plants apply a two-circuit system, consisting of the collector circuit and the Rankine cycle of the power block. These
Parabolic dish Stirling module development and test results
Washom, B.
1984-08-01
Private industry and the U.S. Department of Energy are presently cost sharing the design, manufacture and test of a 25 Kwe parabolic dish Stirling module, known as Vanguard. The Vanguard module achieved a world's record sunlight to electric conversion efficiency of 31.6% in February 1984 at the Rancho Mirage, California test site. The module is presently operating daily in sunrise to sunset tests to determine the long term performance and O and M requirements of this distributed receiver system. Each module can be easily integrated into a larger field of modules to provide power generation opportunities from a single 25 Kwe unit for isolated loads to 30 Mwe systems for integrated utility power generation.
Homogenization limit of a parabolic equation with nonlinear boundary conditions
NASA Astrophysics Data System (ADS)
Lou, Bendong
Consider the parabolic equation u=a(u)u+f(u), -1
Three-dimensional rogue waves in nonstationary parabolic potentials
Yan Zhenya [Key Laboratory of Mathematics Mechanization, Institute of Systems Science, AMSS, Chinese Academy of Sciences, Beijing 100080 (China); International Centre for Materials Physics, Chinese Academy of Sciences, Shenyang 110016 (China); Konotop, V. V. [Centro de Fisica Teorica e Computacional and Departamento de Fisica, Faculdade de Cienacias, Universidade de Lisboa, Lisboa 1649-003 (Portugal); Akhmediev, N. [Optical Sciences Group, Research School of Physics and Engineering, Institute of Advanced Studies, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)
2010-09-15
Using symmetry analysis we systematically present a higher-dimensional similarity transformation reducing the (3+1)-dimensional inhomogeneous nonlinear Schroedinger (NLS) equation with variable coefficients and parabolic potential to the (1+1)-dimensional NLS equation with constant coefficients. This transformation allows us to relate certain class of localized exact solutions of the (3+1)-dimensional case to the variety of solutions of integrable NLS equation of the (1+1)-dimensional case. As an example, we illustrated our technique using two lowest-order rational solutions of the NLS equation as seeding functions to obtain rogue wavelike solutions localized in three dimensions that have complicated evolution in time including interactions between two time-dependent rogue wave solutions. The obtained three-dimensional rogue wavelike solutions may raise the possibility of relative experiments and potential applications in nonlinear optics and Bose-Einstein condensates.
Optimal Control of a Parabolic Equation with Dynamic Boundary Condition
Hoemberg, D., E-mail: hoemberg@wias-berlin.de; Krumbiegel, K., E-mail: krumbieg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Nonlinear Optimization and Inverse Problems (Germany); Rehberg, J., E-mail: rehberg@wias-berlin.de [Weierstrass Institute for Applied Mathematics and Stochastics, Partial Differential Equations (Germany)
2013-02-15
We investigate a control problem for the heat equation. The goal is to find an optimal heat transfer coefficient in the dynamic boundary condition such that a desired temperature distribution at the boundary is adhered. To this end we consider a function space setting in which the heat flux across the boundary is forced to be an L{sup p} function with respect to the surface measure, which in turn implies higher regularity for the time derivative of temperature. We show that the corresponding elliptic operator generates a strongly continuous semigroup of contractions and apply the concept of maximal parabolic regularity. This allows to show the existence of an optimal control and the derivation of necessary and sufficient optimality conditions.
A compact representation of drawing movements with sequences of parabolic primitives.
Polyakov, Felix; Drori, Rotem; Ben-Shaul, Yoram; Abeles, Moshe; Flash, Tamar
2009-07-01
Some studies suggest that complex arm movements in humans and monkeys may optimize several objective functions, while others claim that arm movements satisfy geometric constraints and are composed of elementary components. However, the ability to unify different constraints has remained an open question. The criterion for a maximally smooth (minimizing jerk) motion is satisfied for parabolic trajectories having constant equi-affine speed, which thus comply with the geometric constraint known as the two-thirds power law. Here we empirically test the hypothesis that parabolic segments provide a compact representation of spontaneous drawing movements. Monkey scribblings performed during a period of practice were recorded. Practiced hand paths could be approximated well by relatively long parabolic segments. Following practice, the orientations and spatial locations of the fitted parabolic segments could be drawn from only 2-4 clusters, and there was less discrepancy between the fitted parabolic segments and the executed paths. This enabled us to show that well-practiced spontaneous scribbling movements can be represented as sequences ("words") of a small number of elementary parabolic primitives ("letters"). A movement primitive can be defined as a movement entity that cannot be intentionally stopped before its completion. We found that in a well-trained monkey a movement was usually decelerated after receiving a reward, but it stopped only after the completion of a sequence composed of several parabolic segments. Piece-wise parabolic segments can be generated by applying affine geometric transformations to a single parabolic template. Thus, complex movements might be constructed by applying sequences of suitable geometric transformations to a few templates. Our findings therefore suggest that the motor system aims at achieving more parsimonious internal representations through practice, that parabolas serve as geometric primitives and that non-Euclidean variables are employed in internal movement representations (due to the special role of parabolas in equi-affine geometry). PMID:19578429
Nonlocal operators, parabolic-type equations, and ultrametric random walks
Chacón-Cortes, L. F., E-mail: fchaconc@math.cinvestav.edu.mx; Zúñiga-Galindo, W. A., E-mail: wazuniga@math.cinvestav.edu.mx [Centro de Investigacion y de Estudios Avanzados del I.P.N., Departamento de Matematicas, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, Mexico D.F., C.P. 07360 (Mexico)
2013-11-15
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, V. A. and Bikulov, A. Kh., “On the ultrametricity of the fluctuation dynamicmobility of protein molecules,” Proc. Steklov Inst. Math. 265(1), 75–81 (2009) [Tr. Mat. Inst. Steklova 265, 82–89 (2009) (Izbrannye Voprosy Matematicheskoy Fiziki i p-adicheskogo Analiza) (in Russian)]; Avetisov, V. A., Bikulov, A. Kh., and Zubarev, A. P., “First passage time distribution and the number of returns for ultrametric random walks,” J. Phys. A 42(8), 085003 (2009); Avetisov, V. A., Bikulov, A. Kh., and Osipov, V. A., “p-adic models of ultrametric diffusion in the conformational dynamics of macromolecules,” Proc. Steklov Inst. Math. 245(2), 48–57 (2004) [Tr. Mat. Inst. Steklova 245, 55–64 (2004) (Izbrannye Voprosy Matematicheskoy Fiziki i p-adicheskogo Analiza) (in Russian)]; Avetisov, V. A., Bikulov, A. Kh., and Osipov, V. A., “p-adic description of characteristic relaxation in complex systems,” J. Phys. A 36(15), 4239–4246 (2003); Avetisov, V. A., Bikulov, A. H., Kozyrev, S. V., and Osipov, V. A., “p-adic models of ultrametric diffusion constrained by hierarchical energy landscapes,” J. Phys. A 35(2), 177–189 (2002); Avetisov, V. A., Bikulov, A. Kh., and Kozyrev, S. V., “Description of logarithmic relaxation by a model of a hierarchical random walk,” Dokl. Akad. Nauk 368(2), 164–167 (1999) (in Russian). 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.
Offset truss hex solar concentrator
NASA Technical Reports Server (NTRS)
White, John E. (Inventor); Sturgis, James D. (Inventor); Erikson, Raymond J. (Inventor); Waligroski, Gregg A. (Inventor); Scott, Michael A. (Inventor)
1991-01-01
A solar energy concentrator system comprises an offset reflector structure made up of a plurality of solar energy reflector panel sections interconnected with one another to form a piecewise approximation of a portion of a (parabolic) surface of revolution rotated about a prescribed focal axis. Each panel section is comprised of a plurality of reflector facets whose reflective surfaces effectively focus reflected light to preselected surface portions of the interior sidewall of a cylindrically shaped solar energy receiver. The longitudinal axis of the receiver is tilted at an acute angle with respect to the optical axis such that the distribution of focussed solar energy over the interior surface of the solar engine is optimized for dynamic solar energy conversion. Each reflector panel section comprises a flat, hexagonally shaped truss support framework and a plurality of beam members interconnecting diametrically opposed corners of the hexagonal framework recessed within which a plurality of (spherically) contoured reflector facets is disposed. The depth of the framework and the beam members is greater than the thickness of a reflector facet such that a reflector facet may be tilted (for controlling the effective focus of its reflected light through the receiver aperture) without protruding from the panel section.
NONE
1998-04-01
Trough systems predominate among today`s commercial solar power plants. All together, nine trough power plants, also called Solar Energy Generating Systems (SEGS), were built in the 1980s in the Mojave Desert near Barstow, California. These plants have a combined capacity of 354 megawatts (MW) and today generate enough electricity to meet the needs of approximately 500,000 people. Trough systems convert the heat from the sun into electricity. Because of their parabolical shape, troughs can focus the sun at 30--60 times its normal intensity on a receiver pipe located along the focal line of the trough. Synthetic oil captures this heat as the oil circulates through the pipe, reaching temperatures as high as 390 C (735 F). The hot oil is pumped to a generating station and routed through a heat exchanger to produce steam. Finally, electricity is produced in a conventional steam turbine. In addition to operating on solar energy the SEGS plants are configured as hybrids to operate on natural gas on cloudy days or after dark. Natural gas provides 25% of the output of the SEGS plants.
Nonparabolic solar concentrators matching the parabola.
Cooper, Thomas; Schmitz, Max; Good, Philipp; Ambrosetti, Gianluca; Pedretti, Andrea; Steinfeld, Aldo
2014-08-01
We consider the limit of geometric concentration for a focusing concave mirror, e.g., a parabolic trough or dish, designed to collect all radiation within a finite acceptance angle and direct it to a receiver with a flat or circular cross-section. While a concentrator with a parabolic cross-section indeed achieves this limit, it is not the only geometry capable of doing so. We demonstrate that there are infinitely many solutions. The significance of this finding is that geometries which can be more easily constructed than the parabola can be utilized without loss of concentration, thus presenting new avenues for reducing the cost of solar collectors. In particular, we investigate a low-cost trough mirror profile which can be constructed by inflating a stack of thin polymer membranes and show how it can always be designed to match the geometric concentration of a parabola of similar form. PMID:25078162
Heat engine development for solar thermal power systems
NASA Technical Reports Server (NTRS)
Pham, H. Q.; Jaffe, L. D.
1981-01-01
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 development of Stirling and high temperature Brayton for automotive applications was studied which utilizes much of the technology developed in this automotive program for solar power engines. The technical status of the engine candidates is reviewed and the components that may additional development to meet solar thermal system requirements are identified.
Volker Quaschning
2004-01-01
Concentrating solar thermal power and photovoltaics are two major technologies for converting sunlight to electricity. Variations of the annual solar irradiation depending on the site influence their annual efficiency, specific output and electricity generation cost. Detailed technical and economical analyses performed with computer simulations point out differences of solar thermal parabolic trough power plants, non-tracked and two-axis-tracked PV systems. Therefore,
Zamboni-Rached, Michel
2014-01-01
We propose in detail Antennas for generating Non-Diffracting Beams of Microwaves, for instance with frequencies of the order of 10 GHz, obtaining fair results even when having recourse to realistic apertures endowed with reasonable diameters. Our first proposal refers mainly to sets of suitable annular slits, having in mind various possible applications, including remote sensing. Our second proposal --which constitutes one of the main aims of this paper-- refers to the alternative, rather simple, use of a Parabolic Reflector, illuminated by a spherical wave source located on the paraboloid axis but slightly displaced with respect to the Focus of the Paraboloid. Such a parabolic reflector yields "extended focus" (non-diffracting) beams. [OCIS codes: 999.9999; 070.7545; 050.1120; 280.0280; 050.1755; 070.0070; 200.0200. Keywords: Non-Diffracting Waves; Microwaves; Remote sensing; Annular Arrays; Bessel beams; Extended focus; Reflecting paraboloids; Parabolic reflectors; Parabolic antennas].
A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows
S. V. PATANKAR; D. B. SPALDING
1972-01-01
A general, numerical, marching procedure is presented for the calculation of the transport processes in three-dimensional flows characterised by the presence of one coordinate in which physical influences are exerted in only one direction. Such flows give rise to parabolic differential equations and so can be called three-dimensional parabolic flows. The procedure can be regarded as a boundary-layer method. provided
Direct numerical method for an inverse problem of a parabolic partial differential equation
Wenyuan Liao; Mehdi Dehghan; Akbar Mohebbi
2009-01-01
A coefficient inverse problem of the one-dimensional parabolic equation is solved by a high-order compact finite difference method in this paper. The problem of recovering a time-dependent coefficient in a parabolic partial differential equation has attracted considerable attention recently. While many theoretical results regarding the existence and uniqueness of the solution are obtained, the development of efficient and accurate numerical
MOSTAFA BAKHODAY PASKYABI; FARZAN RASHIDI
2005-01-01
In this paper, split step wavelet Galerkin method (SSWGM)is proposed for solving underwater wave propagation in range-independent fluid\\/solid media. Parabolic equation model is applied for transforming elliptic wave to parabolic wave equation that enable us to use marching approaches in numerical algorithms. Wavelet Galerkin method is used to discretize the depth operators by using 1-periodic Daubechies scaling basis as shape
Pavel Valtr; Pavel Pechac
2007-01-01
This paper addresses the use of parabolic equation in radiowave propagation problems involving impedance-boundary modeling. The Fourier split-step technique for solving the parabolic equation provides numerical efficiency but lacks the ability to represent complex boundary conditions. A method that makes use of the domain decomposition technique to solve two-dimensional problems of impedance-boundary modeling using the Fourier split-step technique is introduced.
On a nonlinear elliptic–parabolic integro-differential equation with L 1-data
Volker G. Jakubowski; Petra Wittbold
2004-01-01
We generalize the concept of entropy solutions for parabolic equations with L1-data and consider a class of nonlinear history-dependent degenerated elliptic–parabolic equations including problems with a fractional time derivative such as ???t?(b(v)?b(v0))?diva(x,Dv)=f with Dirichlet boundary conditions and initial condition, where 0
Hybrid ray optics and parabolic equation methods for radar propagation modeling
Herbert V. Hitney
1992-01-01
The radio physical optics (RPO) hybrid propagation model presented uses a combination of ray optics and split-step parabolic equation methods to overcome the high computational cost of pure split-step parabolic equation methods. At ranges of less than 2.5 km, and for all elevation angles above 5 deg, RPO uses a 'flat earth' model that ignores refractive and earth-curvature effects.
Iterative Methods for Solving Nonlinear Parabolic Problem in Pension Saving Management
NASA Astrophysics Data System (ADS)
Koleva, M. N.
2011-11-01
In this work we consider a nonlinear parabolic equation, obtained from Riccati like transformation of the Hamilton-Jacobi-Bellman equation, arising in pension saving management. We discuss two numerical iterative methods for solving the model problem—fully implicit Picard method and mixed Picard-Newton method, which preserves the parabolic characteristics of the differential problem. Numerical experiments for comparison the accuracy and effectiveness of the algorithms are discussed. Finally, observations are given.
Dipole-allowed optical absorption in a parabolic quantum dot with two electrons
Jinsheng Huang; Libin
2008-01-01
Dipole-allowed optical absorption in a parabolic quantum dot with two electrons are studied by using the exact diagonalization techniques and the compact density-matrix approach. Numerical results are presented for typical GaAs parabolic quantum dots. The results show that the total optical absorption coefficient of two electrons in quantum dot is about five times smaller than that of one electron in
Solar Thermal Electricity Generating System
NASA Astrophysics Data System (ADS)
Mishra, Sambeet; Tripathy, Pratyasha
2012-08-01
A Solar Thermal Electricity generating system also known as Solar Thermal Power plant is an emerging renewable energy technology, where we generate the thermal energy by concentrating and converting the direct solar radiationat medium/high temperature (300?C ñ 800?C). The resulting thermal energy is then used in a thermodynamic cycleto produce electricity, by running a heat engine, which turns a generator to make electricity. Solar thermal power is currently paving the way for the most cost-effective solar technology on a large scale and is heading to establish a cleaner, pollution free and secured future. Photovoltaic (PV) and solar thermal technologies are two main ways of generating energy from the sun, which is considered the inexhaustible source of energy. PV converts sunlight directly into electricity whereas in Solar thermal technology, heat from the sun's rays is concentrated to heat a fluid, whose steam powers a generator that produces electricity. It is similar to the way fossil fuel-burning power plants work except that the steam is produced by the collected heat rather than from the combustion of fossil fuels. In order to generate electricity, five major varieties of solar thermal technologies used are:* Parabolic Trough Solar Electric Generating System (SEGS).* Central Receiver Power Plant.* Solar Chimney Power Plant.* Dish Sterling System.* Solar Pond Power Plant.Most parts of India,Asia experiences a clear sunny weather for about 250 to 300 days a year, because of its location in the equatorial sun belt of the earth, receiving fairly large amount of radiation as compared to many parts of the world especially Japan, Europe and the US where development and deployment of solar technologies is maximum.Whether accompanied with this benefit or not, usually we have to concentrate the solar radiation in order to compensate for the attenuation of solar radiation in its way to earthís surface, which results in from 63,2 GW/m2 at the Sun to 1 kW/m2 at Earth¥s surface. The higher the concentration, the higher the temperatures we can achieve when converting solar radiation into thermal energy
Li Jing; Pei Gang; Ji Jie
2010-01-01
The presented low temperature solar thermal electric generation system mainly consists of compound parabolic concentrators (CPC) and the Organic Rankine Cycle (ORC) working with HCFC-123. A novel design is proposed to reduce heat transfer irreversibility between conduction oil and HCFC-123 in the heat exchangers while maintaining the stability of electricity output. Mathematical formulations are developed to study the heat transfer
Gang Pei; Jing Li; Jie Ji
2010-01-01
The innovative configuration of low temperature solar thermal electric generation with regenerative Organic Rankine Cycle (ORC) is designed, mainly consisting of small concentration ratio compound parabolic concentrators (CPC) and the regenerative ORC. Advantages of the innovative configuration such as effectively reducing heat transfer irreversibility and permitting the use of thermal storage with phase change materials (PCMs) are outlined. The numerical
Testing of the United Stirling 4-95 solar Stirling engine on test bed concentrator
H. G. Nelving
1984-01-01
The objectives with the testing, test set-ups, component designs, and the results of the testing of the solar Stirling engine in a parabolic dish system are presented. The most important tests are characterization of receivers, full day performance of complete system, cavity and aperture window test including influence from windeffects, control system tests, radiator system tests and special temperature measurements
Stirling engines for solar power generation in the 50 to 500 kW range
D. Wells; W. Percival; C. Bratt; K. Rosenqvist; J. Berntell
1982-01-01
Qualitative analyses are presented of solar Stirling power modules in terms of the engines, the concentrators, and the interaction between the size and efficiency of the modules with the cost of the system. A test unit with a parabolic dish concentrator has furnished 31.6 kWe using an 1800 rpm, 93% efficient permanent magnet alternator. Operating temperatures were 750 C, and
Thermoeconomic methodology for analysis and optimization of a hybrid solar thermal power plant
A. Baghernejad; M. Yaghoubi
2012-01-01
Energy and exergy studies together with cost analysis for power plants design and multi process chemical industries received much attention recently. In the present study, with second law analysis (based on the exergy concept), thermoeconomic analysis of a 500 kW hybrid solar thermal power plant with parabolic collectors has been simulated. Its applications include the evaluation of utility costs such
Joshua M. Christian; Clifford Kuofei Ho
2010-01-01
Understanding the effects of gravity and wind loads on concentrating solar power (CSP) collectors is critical for performance calculations and developing more accurate alignment procedures and techniques. This paper presents a rigorous finite-element model of a parabolic trough collector that is used to determine the impact of gravity loads on bending and displacements of the mirror facets and support structure.
Comparison of parabolic filtration methods for 3D filtered back projection in pulsed EPR imaging
NASA Astrophysics Data System (ADS)
Qiao, Zhiwei; Redler, Gage; Epel, Boris; Halpern, Howard J.
2014-11-01
Pulse electron paramagnetic resonance imaging (Pulse EPRI) is a robust method for noninvasively measuring local oxygen concentrations in vivo. For 3D tomographic EPRI, the most commonly used reconstruction algorithm is filtered back projection (FBP), in which the parabolic filtration process strongly influences image quality. In this work, we designed and compared 7 parabolic filtration methods to reconstruct both simulated and real phantoms. To evaluate these methods, we designed 3 error criteria and 1 spatial resolution criterion. It was determined that the 2 point derivative filtration method and the two-ramp-filter method have unavoidable negative effects resulting in diminished spatial resolution and increased artifacts respectively. For the noiseless phantom the rectangular-window parabolic filtration method and sinc-window parabolic filtration method were found to be optimal, providing high spatial resolution and small errors. In the presence of noise, the 3 point derivative method and Hamming-window parabolic filtration method resulted in the best compromise between low image noise and high spatial resolution. The 3 point derivative method is faster than Hamming-window parabolic filtration method, so we conclude that the 3 point derivative method is optimal for 3D FBP.
Comparison of Parabolic Filtration Methods for 3D Filtered Back Projection in Pulsed EPR Imaging
Qiao, Zhiwei; Redler, Gage; Epel, Boris; Halpern, Howard J
2015-01-01
Pulse electron paramagnetic resonance imaging (Pulse EPRI) is a robust method for noninvasively measuring local oxygen concentrations in vivo. For 3D tomographic EPRI, the most commonly used reconstruction algorithm is filtered back projection (FBP), in which the parabolic filtration process strongly influences image quality. In this work, we designed and compared 7 parabolic filtration methods to reconstruct both simulated and real phantoms. To evaluate these methods, we designed 3 error criteria and 1 spatial resolution criterion. It was determined that the 2 point derivative filtration method and the two-ramp-filter method have unavoidable negative effects resulting in diminished spatial resolution and increased artifacts respectively. For the noiseless phantom the rectangular-window parabolic filtration method and sinc-window parabolic filtration method were found to be optimal, providing high spatial resolution and small errors. In the presence of noise, the 3 point derivative method and Hamming-window parabolic filtration method resulted in the best compromise between low image noise and high spatial resolution. The 3 point derivative method is faster than Hamming-window parabolic filtration method, so we conclude that the 3 point derivative method is optimal for 3D FBP. PMID:25314081
Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads
Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.
2013-01-01
This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209
Can industry afford solar energy
NASA Astrophysics Data System (ADS)
Kreith, F.; Bezdek, R.
1983-03-01
Falling oil prices and conservation measures have reduced the economic impetus to develop new energy sources, thus decreasing the urgency for bringing solar conversion technologies to commercial readiness at an early date. However, the capability for solar to deliver thermal energy for industrial uses is proven. A year-round operation would be three times as effective as home heating, which is necessary only part of the year. Flat plate, parabolic trough, and solar tower power plant demonstration projects, though uneconomically operated, have revealed engineering factors necessary for successful use of solar-derived heat for industrial applications. Areas of concern have been categorized as technology comparisons, load temperatures, plant size, location, end-use, backup requirements, and storage costs. Tax incentives have, however, supported home heating and not industrial uses, and government subsidies have historically gone to conventional energy sources. Tax credit programs which could lead to a 20% market penetration by solar energy in the industrial sector by the year 2000 are presented.
Conservation Laws and Potential Symmetries of Linear Parabolic Equations
Roman O. Popovych; Michael Kunzinger; Nataliya M. Ivanova
2008-03-07
We carry out an extensive investigation of conservation laws and potential symmetries for the class of linear (1+1)-dimensional second-order parabolic equations. The group classification of this class is revised by employing admissible transformations, the notion of normalized classes of differential equations and the adjoint variational principle. All possible potential conservation laws are described completely. They are in fact exhausted by local conservation laws. For any equation from the above class the characteristic space of local conservation laws is isomorphic to the solution set of the adjoint equation. Effective criteria for the existence of potential symmetries are proposed. Their proofs involve a rather intricate interplay between different representations of potential systems, the notion of a potential equation associated with a tuple of characteristics, prolongation of the equivalence group to the whole potential frame and application of multiple dual Darboux transformations. Based on the tools developed, a preliminary analysis of generalized potential symmetries is carried out and then applied to substantiate our construction of potential systems. The simplest potential symmetries of the linear heat equation, which are associated with single conservation laws, are classified with respect to its point symmetry group. Equations possessing infinite series of potential symmetry algebras are studied in detail.
Evaluation of aerosolized medications during parabolic flight maneuvers
NASA Technical Reports Server (NTRS)
Lloyd, Charles W.; Martin, William J.; Gosbee, John
1991-01-01
The goal was to visually evaluate the effect gravity has on delivery of medications by the use of various aerosol devices. During parabolic flight the same four aerosols were retested as performed in studio ground tests. It appears that the Cetacaine spray and the Ventolin inhaler function without failure during all test. The pump spray (Nostril) appeared to function normally when the container was full, however it appeared to begin to fail to deliver a full mist with larger droplet size when the container was nearly empty. The simple hand spray bottle appeared to work when the container was full and performed progressively worse as the container was emptied. During Apollo flights, it was reported that standard spray bottles did not work well, however, they did not indicate why. It appears that we would also conclude that standard spray bottles do not function as well in zero gravity by failing to produce a normal mist spray. The standard spray bottle allowed the fluid to come out in a narrow fluid stream when held with the nozzle either level or slightly tilted upward.
Parabolic and semiparabolic pulse dynamics in optical fibers
NASA Astrophysics Data System (ADS)
Bose, Navonil; Mukherjee, Sampad; Basu, Mousumi
2015-01-01
Nonlinear pulse dynamics in two stages of different active or passive fibers are investigated in this work. Numerical approach of the symmetrized split step Fourier method is used to solve the nonlinear Schrödinger equation in the presence of fiber gain, nonlinearity, and dispersion. An input Gaussian pulse evolves into a linearly chirped perfect parabolic pulse (PP) when it propagates through a standard normal dispersion decreasing fiber amplifier. At the same time, for an erbium-doped dispersion decreasing fiber amplifier with a similar dispersion variation with length, the semiparabolic pulse (SPP) is produced at the output end of the fiber. To our knowledge, this is shown for the first time. In second stage, the so-obtained perfect PP, SPP, and also a chirp-free perfect PP are fed into the input of several normal dispersion fibers and the comparative pulse evolution is studied in detail with the variations of dispersion coefficient, gain, and nonlinearity. While using these pulses as the input of an anomalous dispersion fiber, our result shows that the linearly chirped PP is most efficient for compressing the pulses with a good quality factor without dropping significant pedestal energy.
VHF parabolic cylinder antenna for incoherent scatter radar research
NASA Astrophysics Data System (ADS)
Hagfors, T.; Kildal, P. S.; Kaercher, H. J.; Liesenkoetter, B.; Schroeer, G.
1982-12-01
A parabolic cylnider reflector antenna has been designed for high-power radar observations of signals scattered from the ionospheric plasma at a frequency of 224 MHz. The antenna is constructed with an offset feed system to reduce aperture blockage. Efficient illumination for circular polarization using crossed dipoles is achieved by means of primary beam forming, which amounts to the construction of a polarization sensitive corner reflector. The measured aperture efficiency is 64%, and the gain 43.6 dB. The antenna can be mechanically steered through 90 deg in the meridian plane, and the beam can be offset from this plane by + or - 21.3 deg by manual phase steering of the 128-element line feed. The width of the aperture is 40 m, and the length 120 m. The reflector is constructed in four 30-m-long sections which can be individually steered. The RF distribution system is such that the two antenna halves can be operated and pointed completely independently. The paper describes the design considerations, the construction, and the testing of the performance of the completed antenna.
High Speed Analysis Of Free Flights With A Parabolic Thruster
Scharring, Stefan; Eckel, Hans-Albert [Institute of Technical Physics, German Aerospace Center, D-70569 Stuttgart, Pfaffenwaldring 38-40 (Germany); Roeser, Hans-Peter [Institute of Space Systems, University of Stuttgart, D-70569 Stuttgart, Pfaffenwaldring 31 (Germany)
2010-05-06
A laser-based rangefinder with high temporal resolution, synchronized with a laser burst, is employed for fast on-site analysis of pulsed free flights. Additional high speed recordings from two different angles of view allow for full 3D-reconstruction of the trajectory and calibration of the rangefinder data. This reveals the whole dynamics of the flyer including the lateral and angular impulse coupling components as well as information on the detonation process. The employment of an ignition pin enhances the reproducibility of the momentum coupling due to a more reliable plasma ignition during the flight. The impact of initial lateral offset is studied and shows beam-riding properties of the parabolic craft within a small range. Back-driving forces are derived and compared with the theoretical model. The flight stability is evaluated with respect to the minimization and compensation of the lateral and angular momentum in a hovering experiment. Stable laser acceleration ranges up to 3 m altitude. Ballistic free flights close to the laboratory ceiling at 7.8 m are reported.
Parabolic Systems with p, q-Growth: A Variational Approach
NASA Astrophysics Data System (ADS)
Bögelein, Verena; Duzaar, Frank; Marcellini, Paolo
2013-10-01
We consider the evolution problem associated with a convex integrand {f : {R}^{Nn}to [0,infty)} satisfying a non-standard p, q-growth assumption. To establish the existence of solutions we introduce the concept of variational solutions. In contrast to weak solutions, that is, mappings {u\\colon ?_T to {R}^n} which solve partial_tu-div Df(Du)=0 weakly in {?_T}, variational solutions exist under a much weaker assumption on the gap q - p. Here, we prove the existence of variational solutions provided the integrand f is strictly convex and 2n/n+2 < p le q < p+1. These variational solutions turn out to be unique under certain mild additional assumptions on the data. Moreover, if the gap satisfies the natural stronger assumption 2le p le q < p+ minbig \\{1,4/n big \\}, we show that variational solutions are actually weak solutions. This means that solutions u admit the necessary higher integrability of the spatial derivative Du to satisfy the parabolic system in the weak sense, that is, we prove that uin L^q_locbig(0,T; W^{1,q}_loc(?,{R}^N)big).
NSDL National Science Digital Library
Integrated Teaching and Learning Program,
Students learn about solar energy and how to calculate the amount of solar energy available at a given location and time of day on Earth. The importance of determining incoming solar energy for solar devices is discussed.
newsletter | contact Share | Solar Lentigo Information for adults A A A This image displays many solar lentigos due to the patient having many sunburns as a child and teenager. Overview A solar lentigo (plural, solar lentigines), also known as a ...
Testing of a Low-Temperature Differential Stirling Engine by Using Actual Solar Energy
Bancha Kongtragool; Somchai Wongwises
2008-01-01
In this article, the construction and performance of a small low-temperature differential Stirling engine is presented. The engine is connected to a small DC generator and tested with actual solar energy by using a parabolic-dish concentrator as a heat source. Engine performance tested with actual solar energy is reported. Variations of engine-generator power output, combined engine and generator efficiency, and
Design of the support structure, drive pedestal, and controls for a solar concentrator
V. R. Goldberg; J. L. Ford; A. E. Anderson
1991-01-01
The glass\\/metal McDonnell-Douglas dish is the state-of-the-art of parabolic dish concentrators. Because of the perceived high production cost of this concentrator, the Department of Energy's Solar Thermal Program is developing stretch membrane technology for large (75 kWt) solar concentrators for integration with receivers and engines in 25 kWe dish-Stirling systems. The objective of this development effort is to reduce the
On Integration of Mirror Collector and Stirling Engine for Solar Power System
B. F. Yousif; Ammar Al-Shalabi; Dirk G. Rilling
\\u000a In the current work, several types of solar collectors, i.e. parabolic, cylindrical, and mirrors, were designed and fabricated.\\u000a The aim of this study is to integrate the optimum collector with Stirling engine in Malacca city, Malaysia. Stirling engine\\u000a was designed using CATIA software. The solar collectors were tested for several sunny days and the temperature in the focus\\u000a point was
Development of solar and micro co-generation power installations on the basis of Stirling engines
K. Makhkamov; V. Trukhov; B. Orunov; A. Korobkov; A. Lejebokov; I. Tursunbaev; E. Orda; V. Chuvichkin; G. Yudin; E. Muhamediev; D. B. Ingham
2000-01-01
In this paper the research activities of the Laboratory for Stirling Engines at the Physical-Technical Institute, Tashkent on the development of solar and micro cogeneration power installations with Stirling engines are described. Schematic sketches and design and performance parameters of a 1 kW dish\\/Stirling engine unit with a parabolic concentrator and of a solar water pump installation, incorporating a Stirling
M. Clausse; K. C. A. Alam; F. Meunier
2008-01-01
This work explores the possibility to perform heating and air-conditioning of state of the art building located near Paris in France. For air-conditioning, enhanced compound parabolic solar collectors are used as a heat source of an adsorption system (methanol\\/activated carbon), while during winter direct coupling with the building is performed.A model describing the adsorption unit, the solar collectors and the
The analysis of residual stress in glass-to-metal seals for solar receiver tube
Dongqiang Lei; Zhifeng Wang; Jian Li
2010-01-01
The solar receiver tube is a key component in the parabolic trough solar thermal power system. Breakage of glass-to-metal sealing is main cause for damages of receivers in existing power plants. The residual stresses that are generated during the cooling process of the seal can decrease the seal strength and induce the breakage of the glass-to-metal sealing. Residual stresses were
Reducing the Cost of Thermal Energy Storage for Parabolic Trough Solar Power Plants
Gawlik, Keith
2013-06-25
Thermal energy storage systems using phase change materials were evaluated for trough systems that use oil, steam, and high temperature salts as heat transfer fluids. A variety of eutectic salts and metal alloys were considered as phase change materials in a cascaded arrangement. Literature values of specific heat, latent heat, density, and other thermophysical properties were used in initial analyses. Testing laboratories were contracted to measure properties for candidate materials for comparison to the literature and for updating the models. A TRNSYS model from Phase 1 was further developed for optimizing the system, including a novel control algorithm. A concept for increasing the bulk thermal conductivity of the phase change system was developed using expanded metal sheets. Outside companies were contracted to design and cost systems using platecoil heat exchangers immersed in the phase change material. Laboratory evaluations of the one-dimensional and three-dimensional behavior of expanded metal sheets in a low conductivity medium were used to optimize the amount of thermal conductivity enhancement. The thermal energy storage systems were compared to baseline conventional systems. The best phase change system found in this project, which was for the high temperature plant, had a projected cost of $25.2 per kWhth, The best system also had a cost that was similar to the base case, a direct two-tank molten salt system.
Advanced solar concentrator development in the United States
NASA Astrophysics Data System (ADS)
Alpert, Daniel J.
Sandia National Laboratories is the lead laboratory for the United States Department of Energy's program to develop, build, and test advanced solar concentrators that are low in cost, have high performance, and demonstrate a long lifetime. The principal focus of DOE's concentrator program is on the development of heliostats for central receiver power plants and point focus parabolic dishes for use with a 25-kWe Stirling engine. The status and future plans of DOE's program in each area are reviewed.
Evaluation of a Line-Concentrating Solar Collector
NASA Technical Reports Server (NTRS)
1982-01-01
45-page report contains results of performance evaluation of line-concentrating solar collector. Collector employs parabolic trough to direct Sunlight to line along its focal axis, along which lies a black-chrome plated receiver tube covered by a glass tube containing still air. Reflective trough has aluminum-mirror surface covered with metallized acrylic film. Array of four collectors, positioned end to end was used for evaluation. Array was driven by single drive mechanism which was controlled by electronic tracking device.
Utility-Scale Concentrating Solar Power and Photovoltaic Projects: A Technology and Market Overview
Mendelsohn, M.; Lowder, T.; Canavan, B.
2012-04-01
Over the last several years, solar energy technologies have been, or are in the process of being, deployed at unprecedented levels. A critical recent development, resulting from the massive scale of projects in progress or recently completed, is having the power sold directly to electric utilities. Such 'utility-scale' systems offer the opportunity to deploy solar technologies far faster than the traditional 'behind-the-meter' projects designed to offset retail load. Moreover, these systems have employed significant economies of scale during construction and operation, attracting financial capital, which in turn can reduce the delivered cost of power. This report is a summary of the current U.S. utility-scale solar state-of-the-market and development pipeline. Utility-scale solar energy systems are generally categorized as one of two basic designs: concentrating solar power (CSP) and photovoltaic (PV). CSP systems can be further delineated into four commercially available technologies: parabolic trough, central receiver (CR), parabolic dish, and linear Fresnel reflector. CSP systems can also be categorized as hybrid, which combine a solar-based system (generally parabolic trough, CR, or linear Fresnel) and a fossil fuel energy system to produce electric power or steam.
Projected techno-economic improvements for advanced solar thermal power plants
NASA Technical Reports Server (NTRS)
Fujita, T.; Manvi, R.; Roschke, E. J.
1979-01-01
The projected characteristics of solar thermal power plants (with outputs up to 10 MWe) employing promising advanced technology subsystems/components are compared to current (or pre-1985) steam-Rankine systems. Improvements accruing to advanced technology development options are delineated. The improvements derived from advanced systems result primarily from achieving high efficiencies via solar collector systems which (1) capture a large portion of the available insolation and (2) concentrate this captured solar flux to attain high temperatures required for high heat engine/energy conversion performance. The most efficient solar collector systems employ two-axis tracking. Attractive systems include the central receiver/heliostat and the parabolic dish.
Results of the parabolic flight tests of the rapunzel deployer
NASA Astrophysics Data System (ADS)
Sabath, D.; Krischke, M.; Kast, W.; Kowalczyk, M.; Kruijff, M.; van der Heide, E.
The tether assisted re-entry of small payloads is a highly interesting tool for space transportation especially for the return of small payloads from Space Station ISSA. The small tether mission Rapunzel was initiated in 1991 by the Institute of Astronautics, TU München and the Kayser-Threde Company, to design a low cost and feasible tether experiment for the verification of the tether assisted re-entry. Together with the Samara State Aerospace University, Russia, a mission concept on a Russian Resurs or Photon capsule was developed. Based on this mission a deployer has been designed, mainly based on technology of the textile industry, which insures high reliability at low cost. Recently a similar configuration is being discussed for the ESA-TSE mission. The main work during the recent time was the development and test of the breadboard model of the deployer system. After successfully completing initial ground tests with the deployer, further tests during the ESA Parabolic Flight campaign in November 1995 were conducted. After a short introduction of the overall mission scenario, the planned configuration in orbit, this paper will present the results of the microgravity test campaign onboard the KC-135 aircraft and compare them with the ground test. The deployer showed a good performance during all tests, including ejection of the end-mass, deployment, and braking. Problems that occurred during the tests will be discussed, and solutions for the detected flaws and the results of the redesign now in progress will be presented. These verifications have shown the feasibility of the concept and will lay the base for the planned development of the flight model of the deployer.
Interband magneto-spectroscopy in InSb square and parabolic quantum wells
NASA Astrophysics Data System (ADS)
Kasturiarachchi, T.; Saha, D.; Pan, X.; Sanders, G. D.; Edirisooriya, M.; Mishima, T. D.; Doezema, R. E.; Stanton, C. J.; Santos, M. B.
2015-06-01
We measure the magneto-optical absorption due to intersubband optical transitions between conduction and valence subband Landau levels in InSb square and parabolic quantum wells. InSb has the narrowest band gap (0.24 eV at low temperature) of the III-V semiconductors leading to a small effective mass (0.014 m0) and a large g-factor (-51). As a result, the Landau level spacing is large at relatively small magnetic fields (<8 T), and one can observe spin-splitting of the Landau levels. We examine two structures: (i) a multiple-square-well structure and (ii) a structure containing multiple parabolic wells. The energies and intensities of the strongest features are well explained by a modified Pidgeon-Brown model based on an 8-band k•p model that explicitly incorporates pseudomorphic strain. The strain is essential for obtaining agreement between theory and experiment. While modeling the square well is relatively straight-forward, the parabolic well consists of 43 different layers of various thickness to approximate a parabolic potential. Agreement between theory and experiment for the parabolic well validates the applicability of the model to complicated structures, which demonstrates the robustness of our model and confirms its relevance for developing electronic and spintronic devices that seek to exploit the properties of the InSb band structure.
Criteria for evaluation of reflective surface for parabolic dish concentrators
F. Bouquet
1980-01-01
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
T. B. Clark
1979-01-01
The technical and economic feasibility of a solar electric power plant for a small community is evaluated and specific system designs for development and demonstration are selected. All systems investigated are defined as point focusing, distributed receiver concepts, with energy conversion at the collector. The preferred system is comprised of multiple parabolic dish concentrators employing Stirling cycle engines for power
NASA Astrophysics Data System (ADS)
Yan, Na; Baas, Andreas
2015-04-01
Parabolic dunes are one of a few common aeolian landforms which are highly controlled by eco-geomorphic interactions. Parabolic dunes, on the one hand, can be developed from highly mobile dune landforms, barchans for instance, in an ameliorated vegetation condition; or on the other hand, they can be reactivated and transformed back into mobile dunes due to vegetation deterioration. The fundamental mechanisms and eco-geomorphic interactions controlling both dune transformations remain poorly understood. To bridge the gap between complex processes involved in dune transformations on a relatively long temporal scale and real world monitoring records on a very limited temporal scale, this research has extended the DECAL model to incorporate 'dynamic' growth functions and the different 'growth' of perennial shrubs between growing and non-growing seasons, informed by field measurements and remote sensing analysis, to explore environmental controls and eco-geomorphic interactions of both types of dune transformation. A non-dimensional 'dune stabilising index' is proposed to capture the interactions between environmental controls (i.e. the capabilities of vegetation to withstand wind erosion and sand burial, the sandy substratum thickness, the height of the initial dune, and the sand transport potential), and establish the linkage between these controls and the geometry of a stabilising dune. An example demonstrates how to use the power-law relationship between the dune stabilising index and the normalised migration distance to assist in extrapolating the historical trajectories of transforming dunes. The modelling results also show that a slight increase in vegetation cover of an initial parabolic dune can significantly increase the reactivation threshold of climatic impact (both drought stress and wind strength) required to reactivate a stabilising parabolic dune into a barchan. Four eco-geomorphic interaction zones that govern a barchan-to-parabolic dune transformation and a parabolic-to-barchan dune transformation have been identified. These zones exhibit different characteristics and dynamics that are sensitive to changes in environmental forces, and can be potentially used as a proxy to monitor the mobility of a dune system.
Numerical performance of the parabolized ADM (PADM) formulation of General Relativity
Vasileios Paschalidis; Jakob Hansen; Alexei Khokhlov
2007-12-11
In a recent paper the first coauthor presented a new parabolic extension (PADM) of the standard 3+1 Arnowitt, Deser, Misner formulation of the equations of general relativity. By parabolizing first-order ADM in a certain way, the PADM formulation turns it into a mixed hyperbolic - second-order parabolic, well-posed system. The surface of constraints of PADM becomes a local attractor for all solutions and all possible well-posed gauge conditions. This paper describes a numerical implementation of PADM and studies its accuracy and stability in a series of standard numerical tests. Numerical properties of PADM are compared with those of standard ADM and its hyperbolic Kidder, Scheel, Teukolsky (KST) extension. The PADM scheme is numerically stable, convergent and second-order accurate. The new formulation has better control of the constraint-violating modes than ADM and KST.
Fan beam generated by a linear-array fed parabolic reflector
NASA Technical Reports Server (NTRS)
Huang, John; Rahmat-Samii, Yahya
1990-01-01
The theoretical background and the results of computer simulations and experimental studies for a parabolic reflector fed by a linear array are detailed. The concept of using a parabolic reflector antenna fed by a small linear array to generate fan-beam patterns is validated. Large angle scan along the broad-beam direction of the fan beam can be achieved by offsetting the linear array laterally. It is both empirically and numerically demonstrated that the array feed must be displaced in the reflector's axial direction to an optimum location from the focal plane in order to achieve the best antenna gain performance. As a result, the linear-array-fed parabolic reflector can be used in place of a long planar array in a multifunctional reflector antenna system.
NASA Astrophysics Data System (ADS)
Shishkin, G. I.; Shishkina, L. P.
2008-04-01
The Dirichlet problem for a system of singularly perturbed reaction-diffusion parabolic equations in a rectangle is considered. The higher order derivatives of the equations are multiplied by a perturbation parameter ?2, where ? takes arbitrary values in the interval (0, 1]. When ? vanishes, the system of parabolic equations degenerates into a system of ordinary differential equations with respect to t. When ? tends to zero, a parabolic boundary layer with a characteristic width ? appears in a neighborhood of the boundary. Using the condensing grid technique and the classical finite difference approximations of the boundary value problem, a special difference scheme is constructed that converges ?-uniformly at a rate of O( N -2ln2 N + N {0/-1}, where N = mathop {min }limits_s N_s , N s + 1 and N 0 + 1 are the numbers of mesh points on the axes x s and t, respectively.
Jing Li; Gang Pei; Yunzhu Li; Jie Ji
2010-01-01
The proposed system mainly consists of flat-plate compound parabolic concentrators (CPCs) integrated with photovoltaic (PV) cells and organic Rankine cycle (ORC). The technologies of CPC, PV cell and ORC are analyzed, and feasibility of the hybrid solar electricity system is demonstrated. Novel configuration for the hybrid electricity generation is carefully designed to react to different operating conditions. Fundamentals of the
Solar Thermal Concept Evaluation
NASA Technical Reports Server (NTRS)
Hawk, Clark W.; Bonometti, Joseph A.
1995-01-01
Concentrated solar thermal energy can be utilized in a variety of high temperature applications for both terrestrial and space environments. In each application, knowledge of the collector and absorber's heat exchange interaction is required. To understand this coupled mechanism, various concentrator types and geometries, as well as, their relationship to the physical absorber mechanics were investigated. To conduct experimental tests various parts of a 5,000 watt, thermal concentrator, facility were made and evaluated. This was in anticipation at a larger NASA facility proposed for construction. Although much of the work centered on solar thermal propulsion for an upper stage (less than one pound thrust range), the information generated and the facility's capabilities are applicable to material processing, power generation and similar uses. The numerical calculations used to design the laboratory mirror and the procedure for evaluating other solar collectors are presented here. The mirror design is based on a hexagonal faceted system, which uses a spherical approximation to the parabolic surface. The work began with a few two dimensional estimates and continued with a full, three dimensional, numerical algorithm written in FORTRAN code. This was compared to a full geometry, ray trace program, BEAM 4, which optimizes the curvatures, based on purely optical considerations. Founded on numerical results, the characteristics of a faceted concentrator were construed. The numerical methodologies themselves were evaluated and categorized. As a result, the three-dimensional FORTRAN code was the method chosen to construct the mirrors, due to its overall accuracy and superior results to the ray trace program. This information is being used to fabricate and subsequently, laser map the actual mirror surfaces. Evaluation of concentrator mirrors, thermal applications and scaling the results of the 10 foot diameter mirror to a much larger concentrator, were studied. Evaluations, recommendations and pit falls regarding the structure, materials and facility design are presented.
Optical Design of Segmented Hexagon Array Solar Mirror
NASA Technical Reports Server (NTRS)
Huegele, Vince
2000-01-01
A segmented array of mirrors was designed for a solar concentrator test stand at MSFC for firing solar thermal propulsion engines. The 144 mirrors each have a spherical surface to approximate a parabolic concentrator when combined into the entire 18-foot diameter array. The mirror segments are aluminum hexagons that had the surface diamond turned and quartz coated. The array focuses sunlight reflected from a heliostat to a 4 inch diameter spot containing 10 kw of power at the 15-foot focal point. The derivation of the surface figure for the respective mirror elements is shown. The alignment process of the array is discussed and test results of the system's performance is given.
Measuring flow properties of wicks for heat pipe solar receivers
NASA Astrophysics Data System (ADS)
Adkins, Douglas R.; Moss, Timothy
1990-01-01
A program is currently under way to develop liquid-metal heat pipes that can transfer energy from the focal point of a parabolic solar concentrator to the heater tubes of one or more Stirling engines. To design high performance wicks for heat-pipe solar receivers, it is necessary to have an accurate assessment of the wick's properties. Procedures for measuring the flow properties of wicks before and after fabrication processes take place are presented in this paper. These testing procedures provide a useful method of determining the validity of a wick design before full-scale testing is attempted.
Bates solar industrial process-steam application: preliminary design review
Not Available
1980-01-07
The design is analyzed for a parabolic trough solar process heat system for a cardboard corrugation fabrication facility in Texas. The program is briefly reviewed, including an analysis of the plant and process. The performance modeling for the system is discussed, and the solar system structural design, collector subsystem, heat transport and distribution subsystem are analyzed. The selection of the heat transfer fluid, and ullage and fluid maintenance are discussed, and the master control system and data acquisition system are described. Testing of environmental degradation of materials is briefly discussed. A brief preliminary cost analysis is included. (LEW)
Generation of 63 fs 4.1 MW peak power pulses from a parabolic fiber amplifier operated beyond
Boyer, Edmond
Generation of 63 fs 4.1 MW peak power pulses from a parabolic fiber amplifier operated beyond of the amplifier beyond the gain bandwidth limit plays a key role on the sufficient recom- pressibility- lated Raman scattering (SRS) [10,11]. For broad spectrum parabolic pulses, third-order dispersion (TOD
Apostolos Psyllos; Constantine Philippopoulos
1993-01-01
The effect of a longitudinal parabolic active metal distribution on the performance of a monolithic converter is reported. On the basis of the results of numerical calculations, the improvement in the performance of the catalytic converter with parabolic axial active material distribution compared with the respective uniform distribution is verified. In addition, in cases where operating conditions fail to light-off
James R. Kuttler; G. Daniel Dockery
1991-01-01
A theoretical foundation for the use of the parabolic wave equation\\/Fourier split-step method for modeling electromagnetic tropospheric propagation is presented. New procedures are used to derive a scalar Helmholtz equation and to subsequently transform to a rectangular coordinate system without requiring approximations. The assumptions associated with reducing the resulting exact Helmholtz equation to the parabolic wave equation that is used
Christara, Christina C.
1 Quadratic spline collocation for onedimensional linear parabolic partial differential equations general linear parabolic partial differential equations (PDEs) in one space dimen sion are developed. The methods combine quadraticspline collocation for the space discretization and classical finite differences
The parabolic approximation for sound propagation in a stratified moving medium
NASA Technical Reports Server (NTRS)
Myers, M. K.; Mcaninch, G. L.
1977-01-01
Propagation of sound in a stratified moving medium is discussed through an extension of the parabolic approximation to the acoustic equations of motion for short wavelengths. The parabolic approximation is related to the theory of geometric acoustics, and it is shown that it yields an improvement in accuracy over geometric theory. Also, the approximation corrects cumulative failures of geometric theory which occur when sound propagates many wavelengths from its source. The theory is illustrated by application to simple examples of quasi-plane wave propagation.