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1

Exergy analysis of the solar cylindrical-parabolic cooker  

Microsoft Academic Search

For the first time the simple solar parabolic cooker (SPC), of the cylindrical trough shape, is analysed from the exergy viewpoint. The paper presents the methodology of detailed exergy analysis of the SPC, the distribution of the exergy losses, and, on the example of the cooker surfaces, explains the general problem of how the exergy loss on any radiating surface,

Richard Petela

2005-01-01

2

A parabolic solar cooker with automatic two axes sun tracking system  

Microsoft Academic Search

A parabolic solar cooker with automatic two axes sun tracking system was designed, constructed, operated and tested to overcome the need for frequent tracking and standing in the sun, facing all concentrating solar cookers with manual tracking, and a programmable logic controller was used to control the motion of the solar cooker. The results of the continuous test – performed

Mohammed S. Al-Soud; Essam Abdallah; Ali Akayleh; Salah Abdallah; Eyad S. Hrayshat

2010-01-01

3

USE OF SOLAR PARABOLIC COOKERS (SK14) IN NEPAL  

Microsoft Academic Search

Solar Cooker is a device that uses only sunlight to cook food and pasteurise water. Solar cooker can be used along with other cooking devices to save cost, fuel and the time spent in gathering fuelwood. Solar cooking enables individual families to do without commercially sold fuel and help save money. In Nepal, supply of energy is one of the

Sama Shrestha

4

Solar Cookers.  

ERIC Educational Resources Information Center

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

King, Richard C.

1981-01-01

5

Experimental determination of energy and exergy efficiency of the solar parabolic-cooker  

Microsoft Academic Search

A simply designed and the low-cost parabolic-type solar cooker (SPC) was made and tested. The energy end exergy efficiencies of the cooker were experimentally evaluated. The experimental time period was from 10:00 to 14:00 solar time. During this period, it was found that the daily average temperature of water in the SPC was 333 K and the daily average difference

Hasan Hüseyin Öztürk

2004-01-01

6

Multi-criteria evaluation of cooking devices with special reference to utility of parabolic solar cooker (PSC) in India  

Microsoft Academic Search

Multi-criteria decision making is an emerging technique for evaluation and policy formulation for renewable energy technology promotion. In this paper, the case of the parabolic solar cooker (PSC), which is a relatively recent innovation, is evaluated with respect to eight prevalent domestic cooking devices in India. Thirty different criteria categorized under technical, economic, environmental, social, behavioral and commercial aspects are

S. D. Pohekar; M. Ramachandran

2006-01-01

7

Solar cooker  

Microsoft Academic Search

A solar unit is described comprising a solar oven having an open end. A generally concave parabolic main reflector is joined to the oven to move therewith and reflect solar radiation away from the oven. The main reflector has a central opening to the oven open end, a generally parabolic convex secondary reflector for reflecting the radiation from the main

Zwach

1987-01-01

8

Cookers for solar homes  

Microsoft Academic Search

Means of piping solar energy into kitchens were investigated. Two different solar cookers utilising the heat-pipe principle were designed, constructed and tested. A cooker utilising an east-west line focusing collector, designated Mecca-1, was developed for this purpose. The second cooker was a flat-plate heat-pipe cooker, Mecca-2. A single heat pipe in each cooker absorbed the energy at the collector, transported

A. M. A. Khalifa; M. Akyurt; M. M. A. Taha

1986-01-01

9

Solar cooker  

SciTech Connect

A solar unit is described comprising a solar oven having an open end. A generally concave parabolic main reflector is joined to the oven to move therewith and reflect solar radiation away from the oven. The main reflector has a central opening to the oven open end, a generally parabolic convex secondary reflector for reflecting the radiation from the main reflector through the central opening to the open end of the oven, means for mounting the secondary reflector on the main reflector for movement, a frame, and means for mounting the oven on the frame for adjustable movement relative to the frame. This permits adjusting the angular position relative to the earth. The last mentioned means includes means for supporting the oven including first and second pairs of pivot members that respectively have a fist pivot axis and a second pivot axis that extends perpendicular to the first pivot axis. The oven extends between each of the first pivot members and each of the second pivot members.

Zwach, D.M.

1987-09-29

10

Solar cooker  

SciTech Connect

A solar cooking device made of a flat array of concentric mirrors tilted to focus at a small area, the array being movable mounted on a stand to be movable around a ball joint and with a carrier for a cooking vessel held by a double crank to be at the focal area of the mirrors.

Long, J. B.; Ware, R. R.

1985-12-31

11

Portable solar cooker  

SciTech Connect

A portable solar cooker of the type having an insulated housing with an oven compartment enclosed therein and associated reflector elements is adapted for cooking with the housing and oven compartment in a tilted or level position. When employing only the tilting mode for tracking the sun, reflecting panels are removably attached to the top of the cooker housing. When there is a need to maintain the oven compartment level while tracking the sun during the cooking operation, the reflecting panels are removably mounted on a pivotal frame connected to a telescoping strip assembly which, in turn, is removably mounted on the topside of the cooker housing.

Way, L.V.

1980-09-02

12

Solar Cookers International  

NSDL National Science Digital Library

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

13

Solar Cookers for Haiti, A Feasibility Study.  

National Technical Information Service (NTIS)

The objectives of the study were to assess the feasibility of applying solar cookers extensively in rural Haiti, and to present a preliminary design for a solar cooker based on Haitian requirements. Two such designs are presented herein. (Color illustrati...

T. E. Bowman J. R. Sharber J. H. Blatt

1977-01-01

14

Solar box-cooker: Part 1-modeling  

Microsoft Academic Search

Thermal models for the solar box-cookers loaded with one, two, or four vessels have been presented. The method of Taha and Eldighidy has been utilized to estimate the enhanced solar irradiance on the cooker due to the flat reflector fitted to the cooker. The coupling of the Taha and Eldighidy method with the thermal models yielded the models for the

T. C. Thulasi Das; S. Karmakar; D. P. Rao

1994-01-01

15

Performance evaluation of three solar concentrating cookers  

Microsoft Academic Search

Three solar concentrating type cookers meant for domestic use were tested for their thermal performance and cooking abilities. Stagnation temperature, water heating and cooking tests were conducted. During the tests, the operational ease and problems in each cooker were evaluated.

N. V Patel; S. K Philip

2000-01-01

16

A novel solar cooker for animal feed  

Microsoft Academic Search

A novel solar cooker for boiling animal feed has been designed, developed and tested. The cooker is made of locally available material of no cost, e.g. clay, wheat husk and horse excreta. The only commercial materials required for its fabrication are glass covers and mild steel absorber plate. The cooker is capable of boiling 2 kg of animal feed per

N. M. Nahar; J. P. Gupta; P. Sharma

1996-01-01

17

Multiple use communal solar cookers  

Microsoft Academic Search

Solar cooking in boarding schools and communal centres in isolated areas demands the heating of large quantities of food. It is generally done in large pots of 30–40 litres. In a previous paper (Saravia et al., Energ??as Renovables y Medio Ambiente, ASADES, 1999, 6, 7–16), the solar cooker presented consisted of two separate units: a concentrator on one side and

Judith Franco; Carlos Cadena; Luis Saravia

2004-01-01

18

Performance study of solar cooker with modified utensil  

Microsoft Academic Search

A performance study of the box-type solar cooker was made with special emphasis on the shape of lid of the utensils used in a solar cooker. The study revealed that the performance of a solar cooker can be improved if a utensil with a concave shape lid is used instead of a plain lid, generally provided with the solar cooker.

A Gaur; O. P Singh; S. K Singh; G. N Pandey

1999-01-01

19

Efficient orientation impacts of box-type solar cooker on the cooker performance  

Microsoft Academic Search

The addition of a plane reflector to a box-type solar cooker increases the obtained cooker temperature and this depends upon the efficient orientation of the cooker. In order to find out the effect of the cooker orientation on its performance, the present analysis is carried out. A method is outlined to find out a reflector performance factor and an orientation

Abdulla H. Algifri; Hussain A. Al-Towaie

2001-01-01

20

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...

21

Modelling of a hot box solar cooker  

Microsoft Academic Search

In this study, the thermal analysis of a hot box solar cooker which is manufactured in ?stanbul Technical University, named as ?.T.U.-2, has been done by using the fourth-order Runge—Kutta method. The results obtained have been given comparatively with the experimental results measured from a cooker.

A Binark; N. Türkmen

1996-01-01

22

Portable solar\\/non-solar cooker  

Microsoft Academic Search

A portable, solar cooker of the type having an insulated housing with an oven compartment and associated reflector elements is adapted for cooking with a portion of the housing removed and using a conventional source of heat such as canned heat, gasfired lantern heat, and the like.

1980-01-01

23

Portable solar/non-solar cooker  

SciTech Connect

A portable, solar cooker of the type having an insulated housing with an oven compartment and associated reflector elements is adapted for cooking with a portion of the housing removed and using a conventional source of heat such as canned heat, gasfired lantern heat, and the like.

Way, L.V.

1980-05-20

24

The Performance of a Solar Cooker in Egypt  

Microsoft Academic Search

A simple, efficient solar cooker was designed and its performance in the Egyptian climate was evaluated. The cooker is of the hot box type with a plane booster mirror reflector. The performance of the cooker was measured experimentally for over 2 years under different working conditions. The test conditions include experiments with and without adjusting the cooker's position for maximum

SAID M. A. IBRAHIM; MEDHAT K. EL-REIDY

1993-01-01

25

The performance of a solar cooker in Egypt  

Microsoft Academic Search

A simple, efficient solar cooker was designed and its performance in the Egyptian climate was evaluated. The cooker is of the hot box type with a plane booster mirror reflector. The performance of the cooker was measured experimentally for over 2 years under different working conditions. The test conditions include experiments with and without adjusting the cooker's position for maximum

S. M. A. Ibrahim; M. K. El-Reidy

2009-01-01

26

The performance of a solar cooker in Egypt  

Microsoft Academic Search

A simple, efficient solar cooker was designed and its performance in the Egyptian climate was evaluated. The cooker is of the hot box type with a plane booster mirror reflector. The performance of the cooker was measured experimentally for over two years under different working conditions. The test conditions included experiments with and without adjusting the cooker's position for maximum

Said M. A. Ibrahim; Medhat K. El-Reidy

1995-01-01

27

Solar cooker use in Delhi: pilot survey of urban households  

Microsoft Academic Search

The objectives, methodology and results of a pilot survey of urban households using box type solar cookers in Delhi are briefly described. Also included are the suggestions of the users for improving the acceptability of the solar cookers.

S. Kumar; T. C. Kandpal; S. C. Mullick

1997-01-01

28

Theoretical and experimental assessment of a double exposure solar cooker  

Microsoft Academic Search

A novel design of solar cooker is introduced in which the absorber is exposed to solar radiation from the top and the bottom sides. A set of plane diffuse reflectors is used to direct the radiation onto the lower side of the absorber plate. The performance of the new cooker and the conventional box type solar cooker is extensively investigated.

Emad H Amer

2003-01-01

29

Solar cooker with latent heat storage: Design and experimental testing  

Microsoft Academic Search

A box-type solar cooker with latent heat storage has been designed and fabricated for the composite climatic conditions of India. The experimental results demonstrate the feasibility of using a phase change material as the storage medium in solar cookers, i.e. it is possible to cook the food even in the evening with a solar cooker having latent heat storage. It

D. Buddhi; L. K. Sahoo

1997-01-01

30

Parametric model of solar cooker performance  

Microsoft Academic Search

This paper presents a model for prediction of the cooking power of a solar cooker based on three controlled parameters (solar intercept area, overall heat loss coefficient, and absorber plate thermal conductivity) and three uncontrolled variables (insolation, temperature difference, and load distribution). The model basis is a fundamental energy balance equation. Coefficients for each term in the model were determined

P. A Funk; D. L Larson

1998-01-01

31

Characterisation and design methods of solar cookers  

Microsoft Academic Search

The use of solar cookers is much needed in many regions with good solar radiation intensity throughout the world. The reasons are economical, as the price of fuel for cooking is no longer affordable by many families; ecological, as in many regions deforestation is also associated with the use of wood as an energy source; and social, as the money

Klemens Schwarzer; Maria Eugênia Vieira da Silva

2008-01-01

32

Promotion of solar box cooker technology  

SciTech Connect

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

Stibravy, R.

1992-09-01

33

SOLARBALL: Extremly light, efficient and low-cost solar cooker  

Microsoft Academic Search

Solar cookers are rather important applications in thermal solar energy conversion. They can be used in rural areas and all over the places where fossil fuels and biomass is no available. There have been already many versions of solar cookers developed but they are in most cases immobile due to its dimensions and weight. In the paper we describe the

S. Medved; B. Megli?; P. Novak

1996-01-01

34

Processing of agricultural products in solar cooker for income generation  

Microsoft Academic Search

Solar cookers are generally used for cooking of food for domestic as well as community places. But solar cooker can also be used in agro based industries e.g. processing of Indian goose berry ( Aanwala ), jujube ( Ber ), for making jam & jelly, chutney and preparation of rose syrups & gulkand from rose and sugar. In this paper

N. M. Nahar; P. Sharma; G. R. Chaudhary

2009-01-01

35

Performance and testing of a hot box storage solar cooker  

Microsoft Academic Search

A hot box solar cooker with used engine oil as a storage material has been designed, fabricated and tested so that cooking can be performed even in the late evening. The performance and testing of a storage solar cooker have been investigated by measuring stagnation temperatures and conducting cooking trials. The maximum stagnation temperature inside the cooking chambers of the

N. M Nahar

2003-01-01

36

Thermal test procedure for a paraboloid concentrator solar cooker  

Microsoft Academic Search

Suitable thermal tests have been identified for performance evaluation of a concentrating solar cooker. These tests provide parameters that characterize the performance of the solar cooker, and are more or less independent of the climatic variables. The overall heat loss factor is obtained from the cooling curve and the optical efficiency factor is determined from the heating curve - both

S. C. Mullick; T. C. Kandpal; S. Kumar

1991-01-01

37

Development of a solar cooker in Brunei Darussalam  

Microsoft Academic Search

A program to develop, test and evaluate a solar cooker was carried out with the primary objective of its suitability as an alternative means of cooking using sun rays. Factors considered in the evaluation of the solar cooker include the maximum temperature attained, time taken to boil rice, time taken to cook a variety of Malay dishes, ease of use,

A. Q. Malik; Hamid Bin Hussen

1996-01-01

38

Thermal performance of a solar pressure cooker based on evacuated tube solar collector  

Microsoft Academic Search

This paper presents the thermal performance of a community type solar pressure cooker based on evacuated tube solar collector. The developed design of solar pressure cooker has separate parts for energy collection and cooking unit and both are coupled by heat exchanger. The paper has presented the performance results of experimental study conducted on solar pressure cooker and a simulation

Rakesh Kumar; R. S Adhikari; H. P Garg; Ashvini Kumar

2001-01-01

39

Solar Cooker Pringles Can Lesson  

NSDL National Science Digital Library

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.

Orzali, Joe

2011-12-12

40

Through the wall solar cooker  

Microsoft Academic Search

This patent describes a solar appliance for extending from the interior of a kitchen through an exterior wall of the building and beyond a predetermined distance in a cantilever manner to receive and concentrate in the appliance outside of the building, solar radiation rays for cooking purposes comprising: a housing, the housing being mounted to extend from a kitchen through

Kerr

1987-01-01

41

Solar box-cooker: Part II-analysis and simulation  

Microsoft Academic Search

Based on the model proposed in the companion paper (Part I), a method is outlined simulation of the solar box-cookers loaded with one, two, or four vessels. The relative importance of various heat-exchange rates in the cooker were examined. The effect of parameters such as the thickness and size of the absorber plate, emissivity of the vessel, insulation thickness, and

T. C. Thulasi Das; S. Karmakar; D. P. Rao

1994-01-01

42

Design and testing of Sudanese solar box cooker  

Microsoft Academic Search

This study aimed at developing a solar box cooker to be used in Sudan. The cooker was designed and fabricated in the workshop of Centre for Energy Studies, Indian Institute of Technology (IIT), Delhi. A series of tests were carried out during nine days to determine the two factors of merits F1 and F2 in order to make comparison of

B. S Mohamed Ali

2000-01-01

43

Simulated performance of thermal storage in a solar cooker  

Microsoft Academic Search

An explicit finite-difference method is used to simulate the thermal performance of short-term thermal storage for a focusing, indoor, institutional, solar cooker. The cooker storage unit consists of a cylindrical solid block. The block is enclosed in a uniform layer of insulation except where there are cavities on the top and bottom surfaces to alllow heating of a pot from

P. Kariuki Nyahoro; Richard R. Johnson; John Edwards

1997-01-01

44

Through the wall solar cooker  

SciTech Connect

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

Kerr, B.P.

1987-04-07

45

The comparison of three types of Indonesian solar box cookers  

Microsoft Academic Search

This paper describes the influences which govern solar box cookers: HS 7534, HS 7033 and the newest design HS 5521. The best of solar cooker, type HS 7033 gave oven temperature of 202°C between 12:00 and 12:45 p.m. on October 7, 1997. Thirty-four units of this type have been field tested since September 1997. It was found that these solar

Herliyani Suharta; A. M. Sayigh; K Abdullah; K Mathew

2001-01-01

46

A thermodynamic review on solar box type cookers  

Microsoft Academic Search

Globally there is profuse literature on the continuous developments of box type solar cookers and solar ovens. A lot of research work has been carried out in recent passed years in the world which clearly shown the utilization of solar energy towards the greatest needs of mankind obviously solar cooking, fuel saving, non-polluting environment and to save and produce electricity.

Abhishek Saxena; Varun; S. P. Pandey; G. Srivastav

2011-01-01

47

The performance of a box-type solar cooker with auxiliary heating  

Microsoft Academic Search

In Bangladesh it is very difficult to use solar cookers during the months when the days are generally cloudy and at times solar cooking becomes impossible. To overcome such problems for a box-type solar cooker, we have used an auxiliary source of energy inside it. This is done with the help of a built-in heating coil inside the cooker or

M. Hussain; K. C. Das; A. Huda

1997-01-01

48

Experimental investigation of a box type solar cooker employing a non-tracking concentrator  

Microsoft Academic Search

The present work aims at development of a box type solar cooker utilizing non-tracking concentrator optics to enhance the solar energy availability in the box of the cooker for efficient cooking. A laboratory model of a box type solar cooker employing a non-tracking concentrator has been designed and fabricated, and its thermal performance has been investigated experimentally. The concentrator, consisting

B. S. Negi; I. Purohit

2005-01-01

49

The development impact of solar cookers: A review of solar cooking impact research in South Africa  

Microsoft Academic Search

Solar cooking is often considered “a solution looking for a problem”. Solar cookers have long been presented as an interesting solution to the world's problem of dwindling fuel wood sources and other environmental problems associated with wood fuel demand for cooking. However, recent GTZ field work in South Africa showed different benefits instead: the use of solar cookers resulted in

Marlett Wentzel; Anastassios Pouris

2007-01-01

50

EVALUATION OF A SOLAR COOKER DESIGN WITH REFLECTORS  

Microsoft Academic Search

Performance\\/ evaluation of a box-type solar cooker employing booster mirrors has been carried out. Utensil water temperature is presented as a function of time, heat transfer coefficients and meteorological parameters. Analytical results are illustrated using meteorological parameters for winter period. Following conclusions were drawn:i) cooking period is reduced due to enhanced solar flux on cooking surface, andii) Consecutive cooking takes

G. N. TIWARI; KAILASH THAKUR; Y. P. YADAV

1990-01-01

51

A new design for an economical, highly efficient, conical solar cooker  

Microsoft Academic Search

In this paper, the concept of the conical focus is revealed, and the design of a solar cooker is explained. The cooker was practically tested for grilling both white and red meat in a record time. A method for obtaining real boiling of water (100°C) using a solar heater is described. The cooker was also tested for oil frying and

Emam Sharaf

2002-01-01

52

Experimental investigation of energy and exergy efficiency of masonry-type solar cooker for animal feed  

Microsoft Academic Search

The performance of a masonry animal feed solar cooker was evaluated in terms of energy and exergy. It is a low-cost cooker made of cement, bricks, glass covers and a mild steel absorber plate. The energy and exergy efficiencies of the animal feed solar cooker were experimentally evaluated. The energy output of this cooker ranges from 1.89 to 49.4 kJ, whereas

N. L. Panwar; Surendra Kothari; S. C. Kaushik

2010-01-01

53

Cookin' with Sun: Design and Build Solar Cookers  

ERIC Educational Resources Information Center

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

Brand, Lance; Warren, Ande; Fitzgerald, Mike

2006-01-01

54

Cookin' with Sun: Design and Build Solar Cookers  

ERIC Educational Resources Information Center

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

Brand, Lance; Warren, Ande; Fitzgerald, Mike

2006-01-01

55

A novel advanced box-type solar cooker  

Microsoft Academic Search

An advanced version of the box-type solar cooker is presented: a fixed cooking vessel in good thermal contact with a conductive absorber plate is set into the glazing; the results are improved thermal performance, easier access to the cooking vessel and less frequent maintenance due to protection of all absorbing and reflecting surfaces. Outdoor tests show that 5 liters of

M. Grupp; P. Montagne; M. Wackernagel

1991-01-01

56

Thermal performance study of box type solar cooker from heating characteristic curves  

Microsoft Academic Search

The top heat losses that constitute the major losses from the box type solar cooker have a strong influence on the thermal performance. To predict or evaluate the thermal performance of a cooker, the top heat loss coefficient Utw for a water loaded cooker must be known. In the present study, several indoor and outdoor experiments were performed on a

Subodh Kumar

2004-01-01

57

Thermal performance of a box-type solar cooker with outer-inner reflectors  

Microsoft Academic Search

A simple mathematical model is presented for a box-type solar cooker with outer-inner reflectors. It is based on analytical solution of the energy-balance equations for different elements of the cooker. The cooker performance is investigated by computer simulation in terms of the cooker efficiency as well as characteristic and specific boiling times. Numerical calculations have been carried out for different

A. A. El-Sebah

1997-01-01

58

Design, development and testing of a large-size solar cooker for animal feed  

Microsoft Academic Search

A large-size solar cooker for animal feed has been designed, developed and tested. The cooker employs locally available materials of low cost, e.g. pearl-millet husk and horse excreata. The commercial materials required for its fabrication are plain glass, mild steel angle and sheet, wood and aluminium sheet cooking utensils. The solar cooker is capable of boiling 10 kg of animal

N. M. Nahar; J. P. Gupta; P. Sharma

1994-01-01

59

Experimental investigation of novel indirect solar cooker with indoor PCM thermal storage and cooking unit  

Microsoft Academic Search

In the present study, a novel indirect solar cooker with outdoor elliptical cross section, wickless heat pipes, flat-plate solar collector and integrated indoor PCM thermal storage and cooking unit is designed, constructed and tested under actual meteorological conditions of Giza, Egypt. Two plane reflectors are used to enhance the insolation falling on the cooker’s collector, while magnesium nitrate hexahydrate (Tm=89°C,

H. M. S. Hussein; H. H. El-Ghetany; S. A. Nada

2008-01-01

60

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

Microsoft Academic Search

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

Hüseyin Kurt; Kemal Atik; Mehmet Özkaymak; Ziyaddin Recebli

2008-01-01

61

SOLAR COOKER ACCEPTANCE IN SOUTH AFRICA: RESULTS OF A COMPARATIVE FIELD-TEST  

Microsoft Academic Search

A one-year comparative field-test of 7 different types of solar cookers, involving 66 families in 3 study areas in South Africa, has been conducted by the South African Department of Minerals and Energy (DME) and the Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Overall, families use solar cookers on 38% of all days and for 35% of all cooked meals; they

E. Biermann; M. Grupp; R. Palmer

1999-01-01

62

Solar cooker and method of assembly  

SciTech Connect

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.

Kerr, B.P.

1980-12-02

63

Solar cooker and method of assembly  

Microsoft Academic Search

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.

Kerr

1980-01-01

64

Design, development and testing of a double reflector hot box solar cooker with a transparent insulation material  

Microsoft Academic Search

A double reflector hot box solar cooker with a Transparent Insulation Material (TIM) has been designed, fabricated, tested and the performance compared with a single reflector hot box solar cooker without TIM. A 40 mm thick honeycomb made of polycarbonate capillaries was encapsulated between two glazing sheets of the cooker to minimise convective losses from the window so that even

N. M Nahar

2001-01-01

65

Experimental testing of a box-type solar cooker using the standard procedure of cooking power  

Microsoft Academic Search

A box-type solar cooker with one (Model I) or four (Model II) cooking pots was constructed and tested under Tanta prevailing weather conditions. Experiments were performed during July 2002 using the cooker with or without load. The obtained results were employed to calculate the two figures of merit, F1 and F2, as well as the utilization efficiency ?u and the

A. A. El-Sebaii; A. Ibrahim

2005-01-01

66

Experimental study of a double exposure solar cooker with finned cooking vessel  

Microsoft Academic Search

A comparative experimental study of a box type solar cooker with two different cooking vessels was conducted, the first one conventional and the second one identical to the first in shape and volume but its external lateral surface provided with fins. Fins are shown to improve the heat transfer from the internal hot air of the cooker towards the interior

Arezki Harmim; Mebarek Boukar; M’hamed Amar

2008-01-01

67

Solar cookers—part-II—cooking vessel with central annular cavity  

Microsoft Academic Search

Cooking vessels used in a solar cooker must be able to transfer the heat trapped in the cooker effectively to the food material. In the preceding paper (Part-I) the advantage of keeping the vessel on lugs was discussed. In the current paper the performance of a cooking vessel with a central annular cavity kept on lugs is discussed. The experiments

A. V. Narasimha Rao; S. Subramanyam

2005-01-01

68

Design and measured performance of a plane reflector augmented box-type solar-energy cooker  

Microsoft Academic Search

The design philosophy, construction and measured performances of a plane-reflector augmented box-type solar-energy cooker are presented. The experimental solar cooker consists of an aluminum plate absorber painted matt black and a double-glazed lid. The bottom and sides are lagged with fibreglass wool insulator. The reflector consists of a wooden-framed commercially available specular plane mirror which is sized to form a

O. V Ekechukwu; N. T Ugwuoke

2003-01-01

69

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

Microsoft Academic Search

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

Subodh Kumar

2005-01-01

70

A truncated pyramid non-tracking type multipurpose domestic solar cooker\\/hot water system  

Microsoft Academic Search

For impressive dissemination of the solar thermal gazettes, it is imperative to keep on changing the device design features so as to cater to the different demands of diverse section of the society. Domestic solar hot water systems are not suitable for cooking and the capacity of domestic solar box type cookers for water heating is very low. We report

Naveen Kumar; Tilak Chavda; H. N. Mistry

2010-01-01

71

Low budget solar cookers: An alternative to diminish the use of wood as a source of fuel  

Microsoft Academic Search

The report shows the results of the Low Budget Solar Cookers less than US$20 designed and developed at the School of Physics seeking to reduce the consumption of wood as an energy source. According to National statistics this source of energy represents 53% of the primary energy consumed in the country.The solar cookers are made with cardboard, glass, aluminum foil

E. M. de Escobar

1996-01-01

72

A TRANSPARENT INSULATION MATERIAL FOR SOLAR COOKERS AND COLLECTORS  

Microsoft Academic Search

A Transparent Insulation Material (TIM) was manufactured from plastic film and shown to reduce the cover normalised heat loss coefficient, U\\/?0 by over 50% relative to a double-glazed cover system. Such a TIM could be made from polyester film to produce a stagnation-proof and cost-effective cooker which would have greater chance of adoption than less efficient cookers currently made. A

M. T. A. TURNER; R. H. MARSHALL; B. J. Brinkworth

1998-01-01

73

The oven receiver: An approach toward the revival of concentrating solar cookers  

Microsoft Academic Search

Concentrating type solar cookers are expected to demonstrate high performance because of the large collection area employed. However, the net amount of heat used is still low. This is greatly attributed to the large amount of heat losses from the bare food pots used. Introducing the oven type concept as an alternative approach for collecting the concentrated solar energy would

M. B. Habeebullah; A. M. Khalifa; I. Olwi

1995-01-01

74

Evaluating the international standard procedure for testing solar cookers and reporting performance  

Microsoft Academic Search

The international standard procedure for testing solar cookers and reporting performance was proposed at the Third World Conference on Solar Cooking (Avinashilingam University, Coimbatore, India, 6–10 January, 1997) and revised by the committee over the following months. The standard sets limits for environmental conditions, specifies test procedures and calls for performance to be reported in terms of cooking power (W).

Paul A. Funk

2000-01-01

75

Top heat-loss factor of double-glazed box-type solar cooker from indoor experiments  

Microsoft Academic Search

The top heat-loss factor (Ut) of a box-type solar cooker varies with plate temperature, wind heat-transfer coefficient and ambient temperature. A method for correlating Ut with these variables is presented for a cooker with double glazing. A set of equations is developed for correlating data obtained in indoor experiments at different plate temperatures and wind speeds.

S. C. Mullick; T. C. Kandpal; Subodh Kumar

1997-01-01

76

Thermal performance of a solar cooker based on an evacuated tube solar collector with a PCM storage unit  

Microsoft Academic Search

The thermal performance of a prototype solar cooker based on an evacuated tube solar collector with phase change material (PCM) storage unit is investigated. The design has separate parts for energy collection and cooking coupled by a PCM storage unit. Solar energy is stored in the PCM storage unit during sunshine hours and is utilized for cooking in late evening\\/night

S. D. Sharma; Takeshi Iwata; Hiroaki Kitano; Kazunobu Sagara

2005-01-01

77

Numerical heat transfer studies of PCMs used in a box-type solar cooker  

Microsoft Academic Search

Theoretical investigations on the phase change materials (PCMs) used as the heat storage media for box-type solar cookers have been conducted in this study. The selected PCMs are magnesium nitrate hexahydrate, stearic acid, acetamide, acetanilide and erythritol. For a two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Different materials

C. R. Chen; Atul Sharma; S. K. Tyagi; D. Buddhi

2008-01-01

78

A natural convection flat-plate collector solar cooker with short term storage  

Microsoft Academic Search

A double-glazed flat-plate collector covered with a selective surface - Maxorb® foil - was used as the power source for a solar cooker. Coconut oil was used as the heat transfer fluid. At the highest part of the thermosyphon loop is an oil bath in which two cooking pots are immersed to facilitate good heat transfer between the working fluid

O. St. C. Headley

1996-01-01

79

Experimental test procedures for determination of the optical efficiency factor of a parabolloid concentrator solar cooker  

Microsoft Academic Search

Three somewhat different experimental test procedures may be employed for the determination of the optical efficiency factor, F??o, of a parabolloid concentrator solar cooker. The procedures are briefly described and typical results presented. The merits and drawbacks of each test procedure are also discussed.

Subodh Kumar; T. C. Kandpal; S. C. Mullick

1996-01-01

80

Oven receiver: An approach toward the revival of concentrating solar cookers  

SciTech Connect

Concentrating type solar cookers are expected to demonstrate high performance because of the large collection area employed. However, the net amount of heat used is still low. This is greatly attributed to the large amount of heat losses from the bare food pots used. Introducing the oven type concept as an alternative approach for collecting the concentrated solar energy would drastically boost the overall cooker efficiency. In this work, the transient heat balance equations were developed for predicting the thermal behavior of an oven type concentrating solar cooker. This simulation was used to show theoretically the great advantage of using a glass-sided oven over the conventional bare receiver pot. The resulting mathematical model was solved using numerical integration. The transient nature of solar radiation and effects of wind speed variation were all taken into consideration. The analysis showed that the oven type receiving pot has both a higher fluid temperature and overall receiver efficiency compared to the bare receiver type, working under similar conditions. 18 refs., 12 figs., 3 tabs.

Habeebullah, M.B.; Khalifa, A.M.; Olwi, I. [King Abdulaziz Univ., Jeddah (Saudi Arabia)

1995-04-01

81

Natural convective heat transfer in trapezoidal enclosure of box-type solar cooker  

Microsoft Academic Search

This paper presents simple thermal analysis to evaluate the natural convective heat transfer coefficient, hc12 for a trapezoidal absorber plate-inner glass cover enclosure of a double-glazed box-type solar cooker. Several indoor simulation experiments in steady state conditions have been performed to measure the temperatures of absorber plate, inner and outer glass covers, ambient air, electrical input supply and wind speed.

Subodh Kumar

2004-01-01

82

A solar cooker using vacuum-tube collectors with integrated heat pipes  

Microsoft Academic Search

A solar cooking system is described which consists of a vacuum-tube collector with integrated long heat pipes directly leading to the oven plate. The cooker was tested during several clear days in Marburg (latitude 51°). The heat-up times were measured under cold- and hot-start conditions. Detailed temperature distributions and their time dependences were measured. The maximum temperature obtained in a

A. Balzar; P. Stumpf; S. Eckhoff; H. Ackermann; M. Grupp

1996-01-01

83

Simplified Methodology for Designing Parabolic Trough Solar Power Plants  

Microsoft Academic Search

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

Ricardo Vasquez Padilla

2011-01-01

84

Parabolic dish collectors - A solar option  

NASA Astrophysics Data System (ADS)

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

Truscello, V. C.

1981-05-01

85

Antireflection Pyrex envelopes for parabolic solar collectors  

NASA Astrophysics Data System (ADS)

Antireflective (AR) coatings, applied to the glass envelopes used in parabolic trough solar collectors around the receiver tube in order to reduce thermal losses, can increase solar transmittance by 7 percent. An AR surface has been formed on Pyrex by first heat treating the glass to cause a compositional phase separation, removing a surface layer after heat treatment through the use of a preetching solution, and finally etching in a solution that contains hydrofluorosilic and ammonium bifluoride acids. AR-coated samples with solar transmittance values of more than 0.97, by comparison to an untreated sample value of 0.91, have been obtained for the 560-630 C range of heat treatment temperatures. Optimum values have also been determined for the other processing parameters.

McCollister, H. L.; Pettit, R. B.

1983-11-01

86

Design, development and performance evaluation of a latent heat storage unit for evening cooking in a solar cooker  

Microsoft Academic Search

In this paper, a PCM storage unit for a solar cooker was designed and developed to store solar energy during sunshine hours. The stored energy was utilised to cook food in the evening. Commercial grade acetamide was used as a latent heat storage material. Cooking experiments were conducted with different loads and loading times during the summer and winter seasons.

S. D Sharma; D Buddhi; R. L Sawhney; Atul Sharma

2000-01-01

87

Solar cookers—cheap technology with high ecological benefits  

Microsoft Academic Search

This study discusses the quality and quantity of energy used for cooking in Costa Rica and in the world as a whole, and then compares the advantages and limitations of solar ovens with conventional firewood and electric stoves. The payback period of a common hot box type solar oven, even if used 6–8 months a year, is around 12–14 months.

Shyam S. Nandwani

1996-01-01

88

Prediction and experimental verification of performance of box type solar cooker – Part I. Cooking vessel with central cylindrical cavity  

Microsoft Academic Search

The performance of conventional box type solar cookers can be improved by better designs of cooking vessels with proper understanding of the heat flow to the material to be cooked. An attempt has been made in this article to arrive at a mathematical model to understand the heat flow process to the cooking vessel and thereby to the food material.

Avala Raji Reddy; A. V. Narasimha Rao

2007-01-01

89

Analysis of Health Aspects, Food Acceptability and Economics Benefits of the Solar Box Cooker in Sierra Leone.  

National Technical Information Service (NTIS)

The report provides the results of a project whose aim was ascertaining the effectiveness of the Solar Box Cooker as an instrument for cooking and pasteurizing water, as well as, the degree to which it and its products are acceptable to the people of Sier...

B. W. Carpenter L. Davis

1990-01-01

90

A feedforward IMC structure for controlling the charging temperature of a TES system of a solar cooker  

Microsoft Academic Search

A feedforward internal model control (IMC) structure for controlling and maintaining the outlet charging temperature of a thermal energy storage (TES) system of a solar cooker is presented. The TES system consists of a packed pebble bed in thermal contact with a heat transfer oil contained in a storage tank. An electrical hot plate simulates the collector\\/concentrator which heats up

A. Mawire; M. McPherson

2008-01-01

91

Design, development, and testing of an improvised solar water-heater-cum-steam-cooker by Fresnel reflecting solar concentrator  

NASA Astrophysics Data System (ADS)

The performance of solar water heater varies depending upon many parameters, such as operating temperature, mass flow rate, solar insolation, collector orientations, solar time, wind conditions, ambient temperature, selectivity of the absorber surface, etc. A Linear Fresnel reflecting concentrator in a planar configuration using commercially available mirror strips of reflectivity approximately 0.7 in conjunction with a reverse flat plate selective and non-selective absorber surface has been designed and developed. The performance studies of the solar water heater-cum-steam cooker have been carried out. The efficiencies of the devices were found to be about 60% and 55% for selective and non-selective surfaces, respectively. This solar energy device can be made useful in the domestic sector by operating it year around in our solar insolation condition.

Khan, M. K.; Khan, Abdul J.

1992-11-01

92

Solar Thermal Parabolic Dish Systems: Technology and Applications.  

National Technical Information Service (NTIS)

This presentation surveys the status and some probable future courses of development of parabolic dish solar collector technology and some of the near-term and long-range applications of the technology. Included are fundamentals of the technology, descrip...

J. A. Leonard

1984-01-01

93

Solar parabolic dish technology annual evaluation report. Fiscal year 1983  

SciTech Connect

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

Not Available

1984-04-15

94

Thermal performance evaluation of a latent heat storage unit for late evening cooking in a solar cooker having three reflectors  

Microsoft Academic Search

In this paper, a phase change material (PCM) storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 °C, latent heat of fusion 222 kJ\\/kg) was used as a latent heat storage material. Evening cooking experiments

D Buddhi; S. D Sharma; Atul Sharma

2003-01-01

95

Test results, Industrial Solar Technology parabolic trough solar collector  

SciTech Connect

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

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

1995-11-01

96

Federal technology alert. Parabolic-trough solar water heating  

SciTech Connect

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

NONE

1998-04-01

97

Gas Turbine/Solar Parabolic Trough Hybrid Designs: Preprint  

SciTech Connect

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

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

2011-03-01

98

Performance contracting for parabolic trough solar thermal systems  

SciTech Connect

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.

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

99

Compound parabolic concentrator technology development to commercial solar detoxification applications  

Microsoft Academic Search

An EC-DGXII BRITE-EURAM-III-financed project called ‘Solar detoxification technology in the treatment of persistent non-biodegradable chlorinated industrial water contaminants’ is described. The objectives are to develop a simple, efficient and commercially competitive solar water treatment technology based on compound parabolic collectors (CPC) enabling design and erection of turnkey installations. A European industrial consortium, SOLARDETOX, representing industry and research in Spain, Portugal,

J Blanco; S Malato; P Fernández; A Vidal; A Morales; P Trincado; J. C Oliveira; C Minero; M Musci; C Casalle; M Brunotte; S Tratzky; N Dischinger; K.-H Funken; C Sattler; M Vincent; M Collares-Pereira; J. F Mendes; C. M Rangel

1999-01-01

100

Simulated energy and exergy analyses of the charging of an oil–pebble bed thermal energy storage system for a solar cooker  

Microsoft Academic Search

Energy balance equations are used to model the solar energy capture (SEC) system and the thermal energy storage (TES) system of a proposed indirect solar cooker. An oil–pebble bed is used as the TES material. Energy and exergy analyses are carried out using two different charging methods to predict the performance of the TES system. The first method charges the

A. Mawire; M. McPherson; R. R. J. van den Heetkamp

2008-01-01

101

Mean wind forces on parabolic-trough solar collectors  

SciTech Connect

The purpose of this study was to investigate characteristics of mean wind loads produced by airflow in and around several configurations of parabolic trough solar collectors with and without a wind fence. Four basic parabolic shapes were investigated as single units and one shape was studied as part of several array fields. One 1:25 scale model of each parabolic shape was constructed for mounting on a force balance to measure two forces and three moments. The effects of several dominant variables were investigated in this study: wind-azimuth (or yaw), trough elevation (or pitch) angle, array field configuration, and protective wind fence characteristics. All measurements were made in a boundary-layer flow developed by the meteorological wind tunnel at the Fluid Dynamics and Diffusion Laboratory of Colorado State University. Results are presented and discussed. (WHK)

Peterka, J.A.; Sinau, J.M.; Cermak, J.E.

1980-05-01

102

Irrigation market for solar thermal parabolic dish systems  

NASA Astrophysics Data System (ADS)

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

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

1981-09-01

103

Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

SciTech Connect

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

Stynes, J. K.; Ihas, B.

2012-04-01

104

Parabolic Trough Solar Power Plant Simulation Model: Preprint  

SciTech Connect

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.

Price, H.

2003-01-01

105

Multi-criteria evaluation of cooking energy alternatives for promoting parabolic solar cooker in India  

Microsoft Academic Search

The policy formulation for cooking energy substitution by renewables is addressed in multi-criteria context. A survey is conducted to know the perceptions of different decision making groups on present dissemination of various cooking energy alternatives in India. Nine cooking energy alternatives are evaluated on 30 different criteria comprising of technical, economic, environmental\\/social, behavioral and commercial issues. Preference Ranking Organization METHod

S. D. Pohekar; M. Ramachandran

2004-01-01

106

Beaming-In On Student-Made Solar Technology  

ERIC Educational Resources Information Center

Completion of a unit on heat energy motivated students to devise their own solar collectors, parabolic solar cookers, and designs for a solar home. Using their solar projects, the students tests hypotheses they might have had concerning heating capacities, insulation values, or energy conversions. (MA)

Chiotelis, Charles L.

1978-01-01

107

Solar cooking: A life-changing idea  

SciTech Connect

Simple, inexpensive solar cookers are being used to make a dramatic difference to women and their families in sunny areas of the world. This article describes the early development of solar cookers, the types of successful solar cookers now available, testing of the cookers, training of people to use the cookers, and the sociological aspects of introducing solar cookers.

Blum, B.L. [Solar Cookers International, Sacramento, CA (United States)

1997-11-01

108

Testing of box-type solar cooker: Second figure of merit F 2 and its variation with load and number of pots  

Microsoft Academic Search

The performance of a box-type solar cooker can be represented in terms of two figures of merit, F1 and F2. The second figure F2 is a controlling factor in the sensible heating of a load. The present work validates F2 by computing this figure from experimental data by two different procedures and comparing the results. An attempt has also been

S. C. Mullick; T. C. Kandpal; Subodh Kumar

1996-01-01

109

Validation of the FLAGSOL parabolic trough solar power plant performance model  

SciTech Connect

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

Price, H.W. [National Renewable Energy Lab., Golden, CO (United States); Svoboda, P. [Flachglas-Solartechnik GmbH, Koeln (Germany); Kearney, D. [Kearney and Associates, Del Mar, CA (United States)

1994-10-01

110

Mechanism of Hydrogen Formation in Solar Parabolic Trough Receivers  

SciTech Connect

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

Moens, L.; Blake, D. M.

2008-03-01

111

Optical characterization of solar furnace system using fixed geometry nonimaging focusing heliostat and secondary parabolic concentrator  

Microsoft Academic Search

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

Kok-Keong Chong; Chuan-Yang Lim; Wee-Liang Keh; Jian-Hau Fan; Faidz Abdul Rahman

2011-01-01

112

Analysis of the Influence of Geography and Weather on Parabolic Trough Solar Collector Design.  

National Technical Information Service (NTIS)

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...

G. W. Treadwell N. R. Grandjean F. Biggs

1980-01-01

113

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

National Technical Information Service (NTIS)

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 elem...

R. Forristall

2003-01-01

114

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

SciTech Connect

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

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

2008-05-01

115

Cooking with the Sun. How To Build and Use Solar Cookers.  

ERIC Educational Resources Information Center

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…

Halacy, Beth; Halacy, Dan

116

Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint  

SciTech Connect

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

Stynes, J. K.; Ihas, B.

2012-04-01

117

Solar box cookers: Towards a decentralized sustainable energy strategy for sub-Saharan Africa  

Microsoft Academic Search

The continued economic decline of sub-Saharan Africa, and the African energy crisis in particular, have received considerable attention in recent literature. Little attention, however, has been given to the assessment of solar power as an environmentally sound and economically viable energy strategy. Considering the increasing fuelwood scarcity and debt incurred through petroleum imports, solar energy provides a welcome alternative to

Ellie R. Carmody; Amin U. Sarkar

1997-01-01

118

Guidelines for reporting parabolic trough solar electric system performance  

SciTech Connect

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.

Price, H.W.

1997-06-01

119

Sandia invention to make parabolic trough solar collector systems more energy efficient  

NSDL National Science Digital Library

This news release, from Sandia National Laboratories, announces the development of a system to align the long parabolic trough mirrors in a solar collector, thereby making it much more efficient. The article contains a description of how such trough solar collector systems and the new mirror alignment devices operate. Images are provided along with an outline of the group's anticipated progress.

2007-09-25

120

Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM).  

National Technical Information Service (NTIS)

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 ...

C. Turchi

2010-01-01

121

Optical analysis of parabolic dish concentrators for solar dynamic power systems in space  

Microsoft Academic Search

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

1985-01-01

122

Parabolic Trough Solar Power Plant Simulation Model: Preprint  

Microsoft Academic Search

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

2003-01-01

123

Handbook for the conceptual design of parabolic trough solar energy systems process heat applications  

Microsoft Academic Search

This report presents the techniques needed to execute conceptual designs of process heat systems employing parabolic trough solar collectors. The design tools are presented in graphical format, and each of 26 SOLMET sites is explicitly represented. The conceptual design resultant from the application of the design charts contained within this handbook approximates the collector area needed to displace a constant

R. W. Harrigan

1981-01-01

124

Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field  

Microsoft Academic Search

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS1 plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl\\/diphenyl oxide.

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

2003-01-01

125

Comparative performance characteristics of cylindrical parabolic and flat plate solar energy collectors  

Microsoft Academic Search

The performance of a flat plate and a cylindrical parabolic focusing solar energy collector were measured concurrently and compared to collector temperatures ranging from 135 to 185 F under Oak Ridge, Tennessee, weather conditions with a view toward their use in a residential total energy system. The flat plate collection system was of conventional design while the focusing collector was

J. W. Tester; R. M. Mayer; A. P. Fraas

1974-01-01

126

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

SciTech Connect

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.

Price, H.; Kearney, D.

2003-01-01

127

An analysis of the influence of geography and weather on parabolic trough solar collector design  

NASA Astrophysics Data System (ADS)

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

128

Analysis of the influence of geography and weather on parabolic trough solar collector design  

NASA Astrophysics Data System (ADS)

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.

Treadwell, G. W.; Grandjean, N. R.; Biggs, F.

1980-03-01

129

Analysis of the influence of geography and weather on parabolic trough solar collector design  

SciTech Connect

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.

Treadwell, G.W.; Grandjean, N.R.; Biggs, F.

1980-03-01

130

Analysis of the influence of geography and weather on parabolic trough solar collector design. [SOLTES code  

SciTech Connect

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

131

Performance and economics of a solar thermal power generation plant in Jubail, Saudi Arabia: Parabolic trough collector  

Microsoft Academic Search

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

Adel M. Al-Nasser

2010-01-01

132

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

Microsoft Academic Search

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

Hang Qu; Xiao Yu; Qinglai Fan; Jun Zhao

2011-01-01

133

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

SciTech Connect

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

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

2011-01-01

134

Near-parabolic cometary flux in the outer solar system  

NASA Astrophysics Data System (ADS)

The flux of near-parabolic comets in the outer planetary region is calculated by adopting the regularized equation of motion which incorporates planetary and galactic perturbations. It is found that the flux is similar to the case of a strong comet shower, derived on the presumption that the Galactic tidal force is not operative. The flux so calculated, together with the capture probability of short-period (SP) comets, makes it possible to estimate the supply rate of SP comets. The estimated rate is 0.002/yr, which is at least one order of magnitude less than that required by observation. Possible sources of SP comets are discussed such as a disintegration of a giant comet, an inner extension of the observed Oort cloud, or the Kuiper belt.

Yabushita, S.; Tsujii, T.

1991-01-01

135

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

SciTech Connect

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

Turchi, C. S.; Ma, Z.

2011-08-01

136

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

Microsoft Academic Search

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

A. Valan Arasu; T. Sornakumar

2008-01-01

137

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

SciTech Connect

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

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

1990-01-01

138

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

Microsoft Academic Search

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

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

2012-01-01

139

Optical characterization of solar furnace system using fixed geometry nonimaging focusing heliostat and secondary parabolic concentrator  

NASA Astrophysics Data System (ADS)

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.

Chong, Kok-Keong; Lim, Chuan-Yang; Keh, Wee-Liang; Fan, Jian-Hau; Rahman, Faidz Abdul

2011-09-01

140

Simulation of the Start-Up Procedure of a Parabolic Trough Collector Field with Direct Solar Steam Generation  

Microsoft Academic Search

Solar thermal power plants are one of the most inter- esting options for renewable electricity production. For a plant based on parabolic trough collectors, the start-up procedure of the solar field in the morning has to be well defined in order to start electricity production as soon as possible. In this paper, the Modelica language is used to describe the

Tobias Hirsch; Markus Eck

141

Cost-effective solar furnace system using fixed geometry Non-Imaging Focusing Heliostat and secondary parabolic concentrator  

Microsoft Academic Search

A novel cost-effective solar furnace system is proposed to be consisted of a Non-Imaging Focusing Heliostat (NIFH) and a much smaller parabolic concentrator. In order to simplify the design and hence leading to the cost reduction, a fixed geometry of the NIFH heliostat is adopted in the novel solar furnace system by omitting the requirement of continuous astigmatic correction throughout

K. K. Chong; C. Y. Lim; C. W. Hiew

2011-01-01

142

Optical analysis of parabolic dish concentrators for solar dynamic power systems in space  

SciTech Connect

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.

Jefferies, K.S.

1985-08-01

143

On the performance of cylindrical parabolic solar concentrators with flat absorbers  

NASA Astrophysics Data System (ADS)

An integral relationship is developed for evaluating the intensity distribution on flat absorbers used with cylindrical parabolic solar concentrators. Calculations are presented for perfect cross-section concentrators using various models, rim angles, off-axis angles and defocusing amounts. Peak concentration ratios are shown to vary as the sine of the rim angle. Off-axis and defocused operations are shown to result in considerable reduced intensities. The effect of surface slope errors is also investigated. Normally distributed surface slop errors with a standard deviation of 0.25 degree are shown to reduce peak intensities by more than a factor of 3.

Evans, D. L.

144

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

Microsoft Academic Search

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

E. J. Hanseth

1981-01-01

145

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

Microsoft Academic Search

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

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

2011-01-01

146

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

NASA Astrophysics Data System (ADS)

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

Steele, H. L.; Wen, L.

1981-11-01

147

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

SciTech Connect

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

Kearney, D.

2011-05-01

148

An anisotropic model of diffuse solar radiation with application to an optimization of compound parabolic collectors  

NASA Astrophysics Data System (ADS)

Based on a simple geometrical description of the sky hemisphere and the magnitude of the horizontal diffuse radiation, a model for estimating diffuse radiation impinging on sloping surfaces was developed. Tests against data show that substantial improvement is achieved over the classical isotropic model for any collector slope or orientation. Improvement is found for instantaneous as well as accumulated data. The application of the model to compound parabolic collectors (CPC) accounts partly for the role played by forward scattered radiation in the total energy they receive. An optimization of CPC's geometrical characteristics is performed for photovoltaic generation in the area of Albany, NY. This calculation is used to assess the relative effects of meteorological conditions and economic assumptions or optimum concentration values, and provides the reader with information pertaining to the variation of the cost of electrical energy produced as a function of the cost of silicon solar cells.

Perez, R. R.

149

Thermal performance of a solar cooker integrated vacuum-tube collector with heat pipes containing different refrigerants  

Microsoft Academic Search

A solar cooking system using vacuum-tube collectors with heat pipes containing a refrigerant as working fluid has been fabricated, and its performance has been analysed experimentally. The experiments were conducted during clear days in July and August of 2002 in Elaz??, Turkey under similar meteorological conditions for three refrigerants and water. Detailed temperature distributions and their time dependences were measured.

Mehmet Esen

2004-01-01

150

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

SciTech Connect

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

Kearney, D.; Mehos, M.

2010-12-01

151

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

SciTech Connect

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

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

2009-12-15

152

New high-flux two-stage optical designs for parabolic solar concentrators  

Microsoft Academic Search

We present a new two-stage optical design for parabolic dish concentrators that can realistically attain close to 90% of the thermodynamic limit to concentration with practical, compact designs (e.g., at parabola rim half-angles of around 45[degrees]). For comparison, the parabolic dish-plus-compound parabolic concentrator secondary design, at this rim angle, achieves no more than 50% of the thermodynamic limit. Our new

R. P. Friedman; J. M. Gordon; H. Ries

1993-01-01

153

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

Microsoft Academic Search

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

Daniel Sauceda; Nicolás Velázquez; Octavio García-Valladares; Ricardo Beltrán

2011-01-01

154

7 CFR 58.709 - Cookers.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

155

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

NASA Astrophysics Data System (ADS)

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

Miyazono, C.

1984-09-01

156

Software used with the flux mapper at the Solar Parabolic Dish Test Site  

SciTech Connect

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 dictated by design constraints of the flux-mapper controller. Early attempts at data acquisition from the flux-mapper controller were not without difficulty. Time and personnel limitations resulted 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 or alternative development are discussed. A listing of the programs used in the analysis is included in an appendix.

Miyazono, C.

1984-09-15

157

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

NASA Astrophysics Data System (ADS)

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

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

158

Comparison of Fresnel lenses and parabolic mirrors as solar energy concentrators.  

PubMed

This paper compares the gain that can be achieved with a one- or two-stage concentrator, when the first stage is a Fresnel lens or a parabolic mirror, as a function of the luminosity of the concentrator. The results show that the achievable gain using a parabolic mirror is greater than that obtained using a flat or roof lens but is lower than that obtained using a curved lens. PMID:20389950

Lorenzo, E; Luque, A

1982-05-15

159

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

Microsoft Academic Search

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

Andreas Poullikkas

2009-01-01

160

Experiments with an Induction Cooker  

ERIC Educational Resources Information Center

The induction cooker is a common appliance nowadays. How does it work? Why is it not possible to use aluminium utensils with it? What experiments can be carried out with it (at different levels) and not only in physics lessons? Searching for the answers to these and other questions is the purpose of this article. (Contains 5 figures.)

Zilavy, Peter

2009-01-01

161

Advances in solar energy technology. Volume 3. Heating, agricultural and photovoltaic applications of solar energy  

SciTech Connect

This volume discusses the heating, agricultural and photovoltaic applications of solar energy, and contains the following chapters, solar cookers, solar desalination, solar food drying, solar-powered water pumps, solar greenhouses, solar cells.

Garg, H.P.

1987-01-01

162

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

ERIC Educational Resources Information Center

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

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

163

Solar energy  

Microsoft Academic Search

Water pumps, solar power stations, air conditioners, fresh-water stills, solar homes, solar cookers, fruit driers, devices for (low temperature) steaming of reinforced concrete members, solar refrigerators, solar hothouses, welding and melting of metals presents a far from complete list of the devices and areas of the possible broad use of solar energy. The first plant of solar equipment is to

G. Y. Umarov; A. A. Yershov

1975-01-01

164

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

Microsoft Academic Search

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

Ulf Herrmann; Bruce Kelly; Henry Price

2004-01-01

165

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

Microsoft Academic Search

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

M. J. Montes; A. Rovira; M. Muñoz; J. M. Martínez-Val

2011-01-01

166

A compound parabolic concentrator  

SciTech Connect

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

Manrique, J.A.

1984-05-01

167

Commercialization of parabolic dish systems  

NASA Astrophysics Data System (ADS)

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

Washom, B.

1982-07-01

168

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

PubMed

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

Singh, Chandan; Chaudhary, Rubina; Gandhi, Kavita

2013-01-22

169

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

SciTech Connect

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

Kelly, B.

2006-07-01

170

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

SciTech Connect

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

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

2011-08-01

171

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

PubMed

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

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

2011-02-23

172

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

SciTech Connect

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

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

2011-09-01

173

Preliminary thermoeconomic analysis of combined parabolic trough solar power and desalination plant in port Safaga (Egypt)  

Microsoft Academic Search

The development of society is strongly dependent on water and electricity. There is an increasing water and energy demand driven by population growth and rising industrial and agricultural production. The combination of concentrated solar power (CSP) and desalination processes has a huge potential for producing both energy and water in arid regions suffering from fresh water scarcity and facing the

J. Blanco; P. Palenzuela; D. Alarcón-Padilla; G. Zaragoza; M. Ibarra

2012-01-01

174

Comparison of advanced engines for parabolic dish solar thermal power plants  

Microsoft Academic Search

A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic

T. Fujita; J. M. Bowyer; B. C. Gajanana

1980-01-01

175

Comparison of advanced engines for parabolic dish solar thermal power plants  

Microsoft Academic Search

A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic

T. Fujita; T. M. Bowyer; B. C. Gajanana

1982-01-01

176

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

Microsoft Academic Search

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L?1 of total organic carbon of each drug in 0.1 M Na2SO4 with 0.5 mM Fe2+ of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single

Eloy Isarain-Chávez; Rosa María Rodríguez; Pere Lluís Cabot; Francesc Centellas; Conchita Arias; José Antonio Garrido; Enric Brillas

2011-01-01

177

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

SciTech Connect

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

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

1993-09-01

178

Goals Study for Technical Development and Economic Evaluation of the Compound Parabolic Concentrator Concept for Solar Energy Collector Applications.  

National Technical Information Service (NTIS)

The Argonne National Laboratories, contracted with Arthur D. Little, Inc. (ADL), to perform a 6 week goal study for the purpose of evaluating the technical applicability and the economic viability of the compound parabolic concentrator (CPC) concept for a...

1975-01-01

179

Design, construction and study of a hybrid solar food processor in the climate of Costa Rica  

Microsoft Academic Search

During the last 25 years, the author has designed, constructed, studied and promoted solar oven, hybrid solar\\/electric oven, solar oven cum drier, solar cooker cum water heater and solar still. In different parts of the world, solar cookers have been made, studied, patented, however, their real uses are very limited due to many reasons—unstable climate, economic, cultural, social and single

Shyam S. Nandwani

2007-01-01

180

Solar Cookers: Test Results and New Designs.  

National Technical Information Service (NTIS)

The availability of fuel for cooking has become a major problem in many developing countries. Increased use of charcoal made from native wood can cause deforestation and loss of agricultural land, and most developing countries lack the fuel distribution s...

T. E. Bowman

1978-01-01

181

Testing thermocline filler materials and molten-salt heat transfer fluids for thermal energy storage systems used in parabolic trough solar power plants.  

SciTech Connect

Parabolic trough power systems that utilize concentrated solar energy to generate electricity are a proven technology. Industry and laboratory research efforts are now focusing on integration of thermal energy storage as a viable means to enhance dispatchability of concentrated solar energy. One option to significantly reduce costs is to use thermocline storage systems, low-cost filler materials as the primary thermal storage medium, and molten nitrate salts as the direct heat transfer fluid. Prior thermocline evaluations and thermal cycling tests at the Sandia National Laboratories' National Solar Thermal Test Facility identified quartzite rock and silica sand as potential filler materials. An expanded series of isothermal and thermal cycling experiments were planned and implemented to extend those studies in order to demonstrate the durability of these filler materials in molten nitrate salts over a range of operating temperatures for extended timeframes. Upon test completion, careful analyses of filler material samples, as well as the molten salt, were conducted to assess long-term durability and degradation mechanisms in these test conditions. Analysis results demonstrate that the quartzite rock and silica sand appear able to withstand the molten salt environment quite well. No significant deterioration that would impact the performance or operability of a thermocline thermal energy storage system was evident. Therefore, additional studies of the thermocline concept can continue armed with confidence that appropriate filler materials have been identified for the intended application.

Kelly, Michael James; Hlava, Paul Frank; Brosseau, Douglas A.

2004-07-01

182

Side-by-side comparisons of evacuated compound parabolic concentrator and flat plate solar collector systems at temperatures of 90 to 100C  

NASA Astrophysics Data System (ADS)

This collector system study is an extension of a previous system study in which Argonne National Laboratory (ANL) compared the performance of three solar energy systems operated side by side for over a year. In the present system study, four solar energy systems were operated side by side for part of a year. Two of the collector systems used commercially available compound parabolic concentrator (CPC) collectors, one used a commercially available flat plate collector, and one used an experimental CPC collector built by The University of Chicago. The collectors were mounted in fixed positions; they did not track the Sun, and their tilt angles were not seasonally adjusted. All of the collector arrays faced south and were tilted at 42 deg with respect to the horizon (to match the 42 deg N latitude at ANL). All four collector systems started each day with their storage temperatures at 90 C. During the day, each system was operated by its own solar controller. At the end of the day, the tanks were mixed and the temperature changes in the tanks were measured. The change in storage energy was calculated from the temperature change, the heat capacity of the storage system, and the pump energy.

Allen, J. W.; Schertz, W. W.; Wantroba, A. S.

1987-03-01

183

DIFFUSION OF INNOVATION: SOLAR OVEN USE IN LESOTHO (AFRICA)  

Microsoft Academic Search

This paper uses a previously published report coupled with recently collected empirical information on the diffusion of solar cookers among the Basotho of Lesotho. Drawing upon diffusion practice and theory, the authors cite several present-day in- stances where diffusion is taking place. The conclusion, however, is unfortunate, in that the outlook for the use of solar cookers and their effective

Roy R. Grund; William N. Grund

184

A modified concentrating type solar oven for outdoor cooking  

Microsoft Academic Search

Solar cookers offer a partial solution to many problems for the poor developing areas of the world. In these regions energy used for cooking sometimes comprises four fifths of the total energy demand. Solar cookers are generally four catagories: direct focusing, oven, ovenfocusing and indirect types. The direct focusing types failed to boil water under windy conditions due to excessive

Khalifa

1983-01-01

185

Criteria for Evaluation of Reflective Surfaces for Parabolic Dish Concentrators.  

National Technical Information Service (NTIS)

A summary of the technology for evaluating reflective surfaces for parabolic solar dishes is presented. Commercial, second-surface glass mirrors are emphasized, but aluminum and metallized polymeric films are also included. Criteria for sealing solar mirr...

F. Bouquet

1980-01-01

186

International Experience in Standards and Labeling Programs for Rice Cookers  

SciTech Connect

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

Zhou, Nan; Zheng, Nina

2008-05-01

187

Assessment of different configurations for combined parabolic-trough (PT) solar power and desalination plants in arid regions  

Microsoft Academic Search

The combination of desalination technology into concentrating solar power (CSP) plants needs to be considered for the planned installation of CSP plants in arid regions. There are interesting synergies between the two technologies, like the possibility of substituting the condenser of the power cycle for a thermal desalination unit. This paper presents a thermodynamic evaluation of different configurations for coupling

Patricia Palenzuela; Guillermo Zaragoza; Diego C. Alarcón-Padilla; Elena Guillén; Mercedes Ibarra; Julián Blanco

2011-01-01

188

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

Microsoft Academic Search

Information about the physical properties of dust clouds and regoliths in the solar sys- tem is mainly provided by remote light scattering observations. Laboratory measure- ments, which avoid multiple scattering on gravity packed layers by elaborate levitation techniques, are required to accurately interpret such observations. The feasibility of light scattering measurements under microgravity conditions, both on dust clouds and on

A. C. Levasseur-Regourd

2002-01-01

189

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

PubMed

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L?¹ of total organic carbon of each drug in 0.1 M Na?SO? with 0.5 mM Fe²? of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single Pt/carbon felt (CF) and boron-doped diamond (BDD)/air-diffusion electrode (ADE) cells and combined Pt/ADE-Pt/CF and BDD/ADE-Pt/CF cells were used. SPEF treatments were more potent with the latter cell, yielding 95-97% mineralization with 100% of maximum current efficiency and energy consumptions of about 0.250 kWh g TOC?¹. However, the Pt/ADE-Pt/CF cell gave much lower energy consumptions of about 0.080 kWh g TOC?¹ with slightly lower mineralization of 88-93%, then being more useful for its possible application at industrial level. The EF method led to a poorer mineralization and was more potent using the combined cells by the additional production of hydroxyl radicals (•OH) from Fenton's reaction from the fast Fe²? regeneration at the CF cathode. Organics were also more rapidly destroyed at BDD than at Pt anode. The decay kinetics of beta-blockers always followed a pseudo first-order reaction, although in SPEF, it was accelerated by the additional production of •OH from the action of UV light of solar irradiation. Aromatic intermediates were also destroyed by hydroxyl radicals. Ultimate carboxylic acids like oxalic and oxamic remained in the treated solutions by EF, but their Fe(III) complexes were photolyzed by solar irradiation in SPEF, thus explaining its higher oxidation power. NO?? was the predominant inorganic ion lost in EF, whereas the SPEF process favored the production of NH?? ion and volatile N-derivatives. PMID:21693380

Isarain-Chávez, Eloy; Rodríguez, Rosa María; Cabot, Pere Lluís; Centellas, Francesc; Arias, Conchita; Garrido, José Antonio; Brillas, Enric

2011-05-31

190

Simulation and evaluation of the coupling of desalination units to parabolic-trough solar power plants in the Mediterranean region  

Microsoft Academic Search

Integrated power and desalination plants (IPDP) may provide a key solution for the pressing freshwater deficit and energy problems in many regions of the world. The current study investigates the potential of low-temperature multi-effect distillation (LT-MED) and thermal vapor compression multi-effect distillation (TVC-MED) coupled with a concentrating solar power (CSP) plant, taking also into account a reverse osmosis (RO) unit

Patricia Palenzuela; Guillermo Zaragoza; Diego Alarcón; Julián Blanco

2011-01-01

191

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

SciTech Connect

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

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

1991-01-01

192

Convection and surface radiation heat losses from modified cavity receiver of solar parabolic dish collector with two-stage concentration  

NASA Astrophysics Data System (ADS)

Numerical analysis of solar dish modified cavity receiver with Cone, CPC and Trumpet reflectors is presented. Three-dimensional modeling is carried out to estimate the convective and radiative heat loss from the receiver for different angles of inclination and operating temperatures. Incorporating reflectors in the modified cavity receiver for second stage concentration, the natural convection heat losses are reduced by 29.23, 19.81 and 19.16%, respectively. The receiver with the trumpet reflector has shown better performance as compared to other configurations.

Reddy, K. S.; Sendhil Kumar, N.

2009-01-01

193

Wind loads on heliostats and parabolic dish collectors  

Microsoft Academic Search

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

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

1988-01-01

194

Entwicklung und Erprobung von solaren Kochern mit und ohne temporaere Speicher und deren thermodynamische Charakterisierung. Schlussbericht. (Development of solar cookers with and without temporary storage and their thermodynamic characterization. Final report).  

National Technical Information Service (NTIS)

In many developing countries timber is the main energy source and the largest portion of energy produced therefrom is used for cooking. With this background information, the Juelich Campus of Fachhochschule Aachen has developed cheap and efficient solar c...

K. Schwarzer W. Bieger N. Ricking A. Meer T. Krings

1992-01-01

195

Parabolic dish Stirling module  

NASA Astrophysics Data System (ADS)

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.

Washom, B.

1984-03-01

196

Optical and Thermal Properties of Compound Parabolic Concentrators.  

National Technical Information Service (NTIS)

Compound Parabolic Concentrators (CPC) are relevant for solar energy collection because they achieve the highest possible concentration for any acceptance angle (tracking requirement). The convective and radiative heat transfer through a CPC are calculate...

A. Rabl

1975-01-01

197

Parabolized Stability Equations.  

National Technical Information Service (NTIS)

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...

T. Herbert

1994-01-01

198

Criteria for evaluation of reflective surfaces for parabolic dish concentrators  

Microsoft Academic Search

A summary of the technology for evaluating reflective surfaces for parabolic solar dishes is presented. Commercial, second-surface glass mirrors 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

Bouquet

1980-01-01

199

Optical and thermal properties of Compound Parabolic Concentrators  

Microsoft Academic Search

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

A. Rabl

1976-01-01

200

Parabolically connected subgroups  

SciTech Connect

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.

Netai, Igor V [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

2011-08-31

201

Distributed neural signals on parabolic cylindrical shells  

NASA Astrophysics Data System (ADS)

Parabolic cylindrical shells are commonly used as key components in communication antennas, space telescopes, solar collectors, etc. This study focuses on distributed modal neural sensing signals on a flexible simply-supported parabolic cylindrical shell panel. The parabolic cylindrical shell is fully laminated with a piezoelectric layer on its outer surface and the piezoelectric layer is segmented into infinitesimal elements (neurons) to investigate the microscopic distributed neural sensing signals. Since the dominant vibration component of the shell is usually the transverse oscillation, a new transverse mode shape function is defined. Two shell cases, i.e., the ratio of the meridian height to the half span distance of a parabola at 1:4 (shallow) and 1:1 (deep), are studied to reveal the curvature effect to the neural sensing signals. Studies suggest that the membrane signal component dominates for lower natural modes and the bending signal component dominates for higher natural modes. The meridional membrane and bending signal components are mostly concentrated on the high-curvature areas, while the longitudinal bending component is mostly concentrated on the relatively flat areas. The concentration behavior becomes more prominent as the parabolic cylindrical shell deepens, primarily resulting from the enhanced membrane effect due to the increased curvature.

Hu, S. D.; Li, H.; Tzou, H. S.

2013-06-01

202

75 FR 41231 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Abengoa Solar Inc...  

Federal Register 2010, 2011, 2012, 2013

...would consist of a concentrated solar power facility including a solar parabolic...parabolic-trough, dry-cooled solar power plant with the option to expand...include up to 20 MW of photovoltaic solar power. The proposed project would...

2010-07-15

203

Direct steam generation in parabolic trough solar power plants: Numerical investigation of the transients and the control of a once-through system  

SciTech Connect

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 been continued by several institutes and companies in Europe as well as in Israel (Dagan et al., 1991, Mueller et al., 1992a, b, 1993, 1994). This paper concerns the dynamic reaction of the water-steam flow. In order to investigate this, a numerical simulation program of the water-steam flow. In order to investigate this, a numerical simulation program was developed at the ZSW. The numerical approach, its verification, and results of an extended study concerning the reaction and the control (ability) of a once-through DSG system at different weather conditions are presented.

Lippke, F. [Center of Solar Energy and Hydrogen Research, Stuttgart (Germany). Solar Thermal Engineering Section

1996-02-01

204

Session: Parabolic Troughs (Presentation)  

SciTech Connect

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

Kutscher, C.

2008-04-01

205

The symmetric parabolic resonance  

NASA Astrophysics Data System (ADS)

The parabolic resonance instability emerges in diverse applications ranging from optical systems to simple mechanical ones. It appears persistently in p-parameter families of near-integrable Hamiltonian systems with n degrees of freedom provided n + p >= 3. Here we study the simplest (n = 2, p = 1) symmetric case. The structure and the phase-space volume of the corresponding instability zones are characterized. It is shown that the symmetric case has six distinct non-degenerate normal forms, and two degenerate ones. In the regular cases, the instability zone has the usual O(\\sqrt{\\varepsilon}) extent in the action direction. However, the phase-space volume of this zone is found to be polynomial in the perturbation parameter ? (and not exponentially small as in the elliptic resonance case). Finally, the extent of the instability zone in some of the degenerate cases is explored. Three applications in which the symmetric parabolic resonance arises are presented and analysed.

Rom-Kedar, V.; Turaev, D.

2010-06-01

206

On Parabolic Whittaker Functions  

NASA Astrophysics Data System (ADS)

We propose the Mellin-Barnes integral representation for a solution to generalized (parabolic) quantum Toda lattice, which presumably describes the S 1 × U N -equivariant Gromov-Witten invariants of the Grassmann variety. Our construction is built on a generalization of the standard Whittaker model for principal series {{U}({gl}_N)}-modules, and its special realization by difference operators. Particularly, our result provides a representation theoretic derivation of the conjectural formula due to Hori and Vafa.

Oblezin, Sergey

2012-09-01

207

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

Microsoft Academic Search

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

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

2009-01-01

208

Status of APS 1-Mwe Parabolic Trough Project  

SciTech Connect

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

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

2005-11-01

209

Optimum Construction of Heating Coil for Domestic Induction Cooker  

NASA Astrophysics Data System (ADS)

The design and optimization of the parameters of heating coil is very important for the analytical analysis of high frequency inverter fed induction cooker. Moreover, accurate prediction of high frequency winding loss (i.e., losses due to skin and proximity effects) is necessary as the induction cooker used in power electronics applications. At high frequency current penetration in the induction coil circuit is very difficult for conducting wire due to skin-effect. To eradicate the skin effect heating coil is made up of bundle conductor i.e., litz wire. In this paper inductances and AC resistances of a litz-wire are calculated and optimized by considering the input parameters like wire type, shape, number of strand, number of spiral turn, number of twist per feet of heating coil and operating frequency. A high frequency half bridge series resonant mirror inverter circuit is used in this paper and taking the optimum values of inductance and ac resistance the circuit is simulated through PSPICE simulations. It has been noticed that the results are feasible enough for real implementation.

Sinha, Dola; Bandyopadhyay, Atanu; Sadhu, Pradip Kumar; Pal, Nitai

2010-10-01

210

Parabolic Quantum Corrals.  

NASA Astrophysics Data System (ADS)

Quantum `mirage' STM experiments by Manoharan et al on metal surfaces have shown that electronic states in an elliptical `quantum corral' can be used to effect non-local perturbations, giving rise to interesting energy signatures in the local density of states away from the perturbing source. We have recently considered different corral geometries. Here, we present our results for different families of confocal parabolas. General solutions of the Schroedinger equation for the interior problem fulfilling Dirichlet (hard wall) boundary conditions are investigated. We show that the Hilbert space of solutions is separated in two sub-spaces of levels with odd and even symmetry. The problem of a closed area bounded by confocal, coaxial parabolas (symmetric case) is also discussed in detail. We perform numerical calculations and study the effects of the parabolic curvatures, especially on the eigenvalues and eigenfunctions of the quantum corral. The density of states for the case of a parabolic quantum mirage is analyzed and related to possible experimental configurations.

Trallero-Giner, Carlos; Ulloa, Sergio E.

2002-03-01

211

Water Cooled TJ Dense Array Modules for Parabolic Dishes  

Microsoft Academic Search

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

Rüdiger Löckenhoff; Tim Kubera; Klaus Dieter Rasch

2010-01-01

212

Power losses in an asymmetric compound parabolic photovoltaic concentrator  

Microsoft Academic Search

An asymmetric compound parabolic photovoltaic concentrator (ACPPVC) of geometrical concentration ratio 2 was designed, developed and evaluated for building façade integration. Despite the two times theoretical concentration, the maximum output power achieved was only 1.62 times that of a similar non-concentrating system for a wide range of solar radiation intensities due to a combination of optical and electrical resistance losses.

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

2007-01-01

213

RATIONAL CURVES AND PARABOLIC GEOMETRIES  

Microsoft Academic Search

The twistor transform of a parabolic geometry has two steps: lift up to a geometry of higher dimension, and then drop to a geometry of lower dimension. The rst step is a functor, but the second requires some compati- bility conditions. Local necessary conditions were uncovered by Andreas Cap (14). I prove necessary and sucient global conditions for complex parabolic

BENJAMIN MCKAY

214

Parabolic telescope and spectrometer combination  

Microsoft Academic Search

The properties of a nonfocusing collimating parabolic telescope are studied in detail by a ray-tracing method. The best optical quality with respect to coma and astigmatism is calculated for rays close to the optical axis of the telescope. For rectangular fields of view the borders are not sharp because of the aberration. A combination of a parabolic telescope and an

G. Schmidtke; P. Henneberg; K.-H. Hager; F. Busch; D. Reinhardt

1980-01-01

215

76 FR 28064 - Notice of Availability of the Final Environmental Impact Statement for Palen Solar I, LLC's Palen...  

Federal Register 2010, 2011, 2012, 2013

...consisting of two parabolic-trough solar thermal power plants, each of which has a ``solar field'' comprised of rows of parabolic mirrors focusing solar energy on collector tubes. The tubes would carry...

2011-05-13

216

A Slice of Solar Cooking.  

ERIC Educational Resources Information Center

|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)|

Galus, Pamela

2003-01-01

217

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

SciTech Connect

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

Not Available

1981-03-01

218

Numerical modeling and experimental testing of a solar grill  

SciTech Connect

The sun provides a free, nonpolluting and everlasting source of energy. Considerable research has been carried out to utilize solar energy for purposes such as water heating, high temperature ovens, and conversion to electrical energy. One of the interesting forms for utilizing solar energy is cooking. The main disadvantage of solar energy systems has been the low efficiency attained in most of its practical applications. It is expected, however, that due to continuing decreases in the availability of other energy sources such as oil and coal, along with the safety problems associated with nuclear energy, man's need for utilization of solar energy will increase, thus leading him to find the ways and means to develop adequate and efficient solar-powered systems. In camps, where tents are used to accommodate people, cooking is done via conventional gas stoves. This usually takes place in extremely crowded areas which become highly fireprone. Solar oven cookers seem to be a viable alternative considering both economy and safety. Among the various forms of solar cookers, the oven-type solar cooker is known to be the best in terms of efficiency. One of the most practical and efficient forms of solar oven cookers is the outdoor portable solar grill (Bar-B-Q), developed by Khalifa et al. The solar grill is a light and portable unit that utilizes solar energy to grill meat. One of the best types of grilling with this cooker is the well-known Shish Kebab or Bar-B-Q. A detailed description for the design of the solar grill is provided as follows. This paper is aimed at providing experimental results and formulating a numerical model for the solar grill. Results of the two approaches are then compared to verify the validity of the numerical simulation. An experimental and theoretical investigation was conducted on the solar grill in order to study the factors that affect its design and performance.

Olwi, I.; Khalifa, A. (King Abdulaziz Univ., Jeddah (Saudi Arabia))

1993-02-01

219

The planar parabolic optical antenna.  

PubMed

One of the simplest and most common structures used for directing light in macroscale applications is the parabolic reflector. Parabolic reflectors are ubiquitous in many technologies, from satellite dishes to hand-held flashlights. Today, there is a growing interest in the use of ultracompact metallic structures for manipulating light on the wavelength scale. Significant progress has been made in scaling radiowave antennas to the nanoscale for operation in the visible range, but similar scaling of parabolic reflectors employing ray-optics concepts has not yet been accomplished because of the difficulty in fabricating nanoscale three-dimensional surfaces. Here, we demonstrate that plasmon physics can be employed to realize a resonant elliptical cavity functioning as an essentially planar nanometallic structure that serves as a broadband unidirectional parabolic antenna at optical frequencies. PMID:23194111

Schoen, David T; Coenen, Toon; García de Abajo, F Javier; Brongersma, Mark L; Polman, Albert

2012-12-07

220

Progress in solar thermal distributed receiver technology  

NASA Astrophysics Data System (ADS)

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 Distribution Receiver Test Facility, Shenandoah Solar Total Energy Project, Vangurd I, Solar Plant No. 1, the Dish/Stirling Solar Electric Generating System, the Organic Rankine Cycle, and the Solarized Automotive Gas Turbine.

Leonard, J. A.; Otts, J. V.

221

A modified concentrating type solar oven for outdoor cooking  

SciTech Connect

Solar cookers offer a partial solution to many problems for the poor developing areas of the world. In these regions energy used for cooking sometimes comprises four fifths of the total energy demand. Solar cookers are generally four catagories: direct focusing, oven, ovenfocusing and indirect types. The direct focusing types failed to boil water under windy conditions due to excessive convection losses from the bare cooking pot placed at the concentrator focus. The oven type cookers, such as Telkes oven, observe the rules of energy conservation and thus are more efficient and less affected by windy weather. However, this oven suffers from two major problems. First, tilting the oven could cause food spillage unless a hinged support is used for the pot. This adds complication to the design of Telkes oven. Second, the solar radiation is added to the pot from the top for high solar altitude angles. This leads to poor heat transfer to the food inside the pot. The advantages of concentrating and oven cookers can be obtained by widding of a point focus concentrator to a new oven type receiver. In this paper the concept and design details of such an oven are introduced. Theoretical and experimental analyses of the developed cooker are given.

Khalifa, A.M.A.

1983-12-01

222

Criteria for evaluation of reflective surfaces for parabolic dish concentrators  

SciTech Connect

A summary of the technology for evaluating reflective surfaces for parabolic solar dishes is presented. Commercial, second-surface glass mirrors 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. The objective of this study is to establish a basis for mirror criteria that eventually may become part of inspection and evaluation techniques for three-dimensional parabolic reflective surfaces. Concentrator support structure, optical tracking, gore alignment, and other important ancillary problems are omitted from this study. A glossary and important references concerning optical criteria are included.

Bouquet, F.

1980-07-15

223

Parabolic telescope and spectrometer combination  

NASA Astrophysics Data System (ADS)

The properties of a nonfocusing collimating parabolic telescope are studied in detail by a ray-tracing method. The best optical quality with respect to coma and astigmatism is calculated for rays close to the optical axis of the telescope. For rectangular fields of view the borders are not sharp because of the aberration. A combination of a parabolic telescope and an echelle-type spectrometer gives very high spectral resolution. Wadsworth, Ebert-Fastie, and other types of spectrometers are equally well suited to be combined with this telescope. For some cases spot diagrams demonstrate the optical performance. In addition, diffraction by the aperture and its implications are discussed.

Schmidtke, G.; Henneberg, P.; Hager, K.-H.; Busch, F.; Reinhardt, D.

1980-06-01

224

Parabolic telescope and spectrometer combination.  

PubMed

The properties of a nonfocusing collimating parabolic telescope are studied in detail by a ray-tracing method. The best optical quality with respect to coma and astigmatism is calculated for rays close to the optical axis of the telescope. For rectangular fields of view the borders are not sharp because of the aberration. A combination of a parabolic telescope and an echelle-type spectrometer gives very high spectral resolution. Wadsworth, Ebert-Fastie, and other types of spectrometers are equally well suited to be combined with this telescope. For some cases spot diagrams demonstrate the optical performance. In addition, diffraction by the aperture and its implications are discussed. PMID:20221130

Schmidtke, G; Henneberg, P; Hager, K H; Busch, F; Reinhardt, D

1980-06-01

225

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

Microsoft Academic Search

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

1980-01-01

226

Utilization of a cylindrical parabolic reflector for desalination of saline water  

Microsoft Academic Search

The performance of a new type of solar still, used for producing drinking water in remote areas, has been investigated. This type consists of a metallic cylindrical parabolic reflector. The reflector was designed to concentrate incident solar radiation on the black outside surface of a tray located on the focal line of the reflector. The tray was lined with blackened

A. N. Minasian; A. A. Al-Karaghouli; S. K. Habeeb

1997-01-01

227

Self-similar parabolic plasmonic beams.  

PubMed

We demonstrate that an interplay between diffraction and defocusing nonlinearity can support stable self-similar plasmonic waves with a parabolic profile. Simplicity of a parabolic shape combined with the corresponding parabolic spatial phase distribution creates opportunities for controllable manipulation of plasmons through a combined action of diffraction and nonlinearity. PMID:23455091

Davoyan, Arthur R; Turitsyn, Sergei K; Kivshar, Yuri S

2013-02-15

228

Solar thermal power plants  

Microsoft Academic Search

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

L. Schnatbaum

2009-01-01

229

Parabolic Equations in Reifenberg Domains  

NASA Astrophysics Data System (ADS)

Natural Sobolev-type estimates are proved for weak solutions of inhomogeneous parabolic equations in divergence form in a bounded cylinder ?*=?×(0,T] which is ?-Reifenberg flat in the space direction. The principal coefficients of the operator are assumed to be in BMO space with their BMO semi-norms small enough.

Byun, Sun-Sig; Wang, Lihe

2005-05-01

230

Fractional dual parabolic cylindrical reflector  

Microsoft Academic Search

Geometrical optics (GO) fields of a fractional dual parabolic cylindrical reflector have been studied around the focusing region using Maslovpsilas method. GO fields contain both co- and cross-polarized components. Considering perfect electric conductor as original case, magnitudes of the GO fields do not depend upon the fractional parameter. For impedance boundary reflector as original case, the field components depend upon

A. Hussain; M. Faryad; Q. A. Naqvi

2008-01-01

231

A Solar High Temperature Kiln.  

National Technical Information Service (NTIS)

The feasibility of using solar energy in developing countries for baking ceramic construction materials was investigated. The solar high temperature kiln is described. It uses two parabolic concentrators which direct available radiation into the baking ch...

N. Huettenhoelscher K. Bergmann

1981-01-01

232

QFT-Based Robust Simmering Control for Domestic Induction Cookers Using an Infrared Sensor  

Microsoft Academic Search

This paper presents a robust simmering control for induction hobs. This kind of process is almost impossible to carry out in a domestic cooker where the pot temperature is unknown. We exploit an analytical model of the cooking process to design a QFT-based controller. The resultant controller satisfies all user requirements such as a quick heating up, an accurate temperature

D. Paesa; C. Franco; S. Llorente; G. Lopez-Nicolas; C. Sagues

2010-01-01

233

A comparative study of resonant inverter topologies used in induction cookers  

Microsoft Academic Search

In this paper, a comparison is performed between four inverter topologies commonly used in induction cookers. The considered topologies are the full-bridge inverter, the half-bridge inverter, and two single-switch inverters. All of them are designed for the same specifications and they are compared in aspects such as power device stresses, efficiency, frequency control and electromagnetic emissions

S. Llorente; F. Monterde; J. M. Burdio; J. Acero

2002-01-01

234

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

ERIC Educational Resources Information Center

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

Technical Education Research Center, Cambridge, MA.

235

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

ERIC Educational Resources Information Center

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

Galleano, Monica; Boveris, Alberto; Puntarulo, Susana

2008-01-01

236

Design, testing and evaluation of a small scale injection cooker for ground corn  

SciTech Connect

A continuous cooker for 0.2 kg/min of ground corn (Zea mays) was developed to match the expected alcohol fuel needs of a 300 ha Iowa farm. A commercial jet cooker (Hydroheater) was used, but the design and implementation of the slurry handling, enzyme dosage, pH adjustment, and automatic control were local. Pure corn starch and corn meal were used as feedstocks. Solids concentrations from 10 to 27% w/w were examined. The feedstocks were hydrolized with ..cap alpha..-amylase at temperatures from 97 to 124/sup 0/C, and saccharified at 60/sup 0/C with amyloglucosidase. Slurry samples at four locations were anlayzed for total reducing sugars (TRS). The same jet cooker was used under laboratory conditions to cook small batches of slurry; saccharification was done as a batch. Problems with the acid and base metering pumps led to poor pH control. The results for both cookers were analyzed using a response surface technique, because pooling all the results was expected to give some indication of the performance of a farm scale cooker operated with unsophisticated controls. The dependent variables were: 1) material efficiency, the fraction of starch converted to TRS, 2) conversion ratio, the ratio of TRS in the output supernatant to the input solids concentration, and 3) energy ratio, the ratio of the higher heating value of the TRS produced to the electrical and steam energy during conversion. The independent variables were solids concentration in the input slurry and the temperature of the cooking process.

Chaplin, J.

1983-01-01

237

Electrostatic parabolic density drift instability  

SciTech Connect

The Vlasov theory of an electrostatic instability driven by a parabolic density gradient is considered. The magnetic field is taken as uniform, and the local approximation is used. The instability grows only for a sufficiently large, positive second derivative of the density. The parametric dependences of the linear growth rate are reported, as well as weakly nonlinear calculations on wave-particle transport due to this instability.

Gary, S.P.; Thomsen, M.F.

1982-01-01

238

Parabolic Throw with Video Model  

NSDL National Science Digital Library

The Parabolic Throw with Video Model overlays an EJS model on a video of a ball being thrown. The video displays 15 frames per second and a vertical calibration bar. The simulation superimposes a trajectory of a red circle with acceleration x'' = -g, where g is the acceleration due to gravity. The user sets the initial conditions and the value of g in order to match the trajectory shown on the video. This model uses the Xuggle video library and is designed to test the EJS video API. A warning message is displayed if Xuggle is not installed. The Parabolic Throw with Video Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_ParabolicThrowWithVideo.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item.

Franciscouembre

2011-12-30

239

Parabolic-Trough Technology Roadmap: A Pathway for Sustained Commercial Development and Deployment of Parabolic-Trough Technology  

SciTech Connect

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.

Price, H.; Kearney, D.

1999-01-31

240

Renewable energy technologies for federal facilities: Solar water heating  

SciTech Connect

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

NONE

1996-05-01

241

TREATMENT OF RICE COOKER WASTEWATER AND RECOVERY OF BY-PRODUCTS BY MEMBRANE MICROFILTRATION  

Microsoft Academic Search

A pilot scale system was used to evaluate the performance of a membrane microfiltration system, rated at 0.1 micron, for the recovery of starches and other solids from rice cooker wastewater produced by a rice processing facility. The first series of tests revealed that a crossflow velocity (V) of 5 m\\/s and a transmembrane pressure (TMP) of 275 kPa were

J. C. Boykin; T. S. Soerens; T. J. Siebenmorgen

242

Non-Formal Environmental Education: The Utilization of Solar Energy for Cooking in a Rural Area in Sudan.  

ERIC Educational Resources Information Center

|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)|

El Zubeir, Z.

1997-01-01

243

Solargenix Energy Advanced Parabolic Trough Development  

SciTech Connect

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

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

2005-11-01

244

Solar photoreactors comparison based on oxalic acid photocatalytic degradation  

Microsoft Academic Search

Solar heterogeneous photocatalytic degradation of oxalic acid in water is carried out in four different solar photoreactors: a parabolic trough concentrator (PC), a tubular collector (TC), a compound parabolic collector (CPC), and a V-trough collector (VC). The reactors operate under equal conditions of solar irradiance, collection surface and fluid flow rate to ensure a better comparison between the systems. The

Erick R. Bandala; Camilo A. Arancibia-Bulnes; Sayra L. Orozco; Claudio A. Estrada

2004-01-01

245

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

Microsoft Academic Search

An economic analysis is presented for a combined parabolic trough solar\\/fossil fuel hybrid power plant. Applications are considered for investor-owned utilities and industries with stockholders and bond purchasers. Annual levelized revenues are calculated, based on the capital cost of equipment, annual operations and maintenance, and a rising cost of fossil fuel. The units of heat are considered as equal in

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

1981-01-01

246

Parabolic density function in sedimentary basin modelling  

Microsoft Academic Search

For modelling sedimentary basins of large thickness from their gravity anomalies, the concept of parabolic density function which explains the variation of true density contrast of the sediments with depth in such basins is introduced inBott's (1960) procedure. The analytical expression the gravity anomaly of a two-dimensional vertical prism with parabolic density contrast needed to estimate the gravity effect of

C. Visweswara Rao; V. Chakravarthi; M. L. Raju

1993-01-01

247

Dispersion managed self-similar parabolic pulses  

Microsoft Academic Search

We describe the propagation of a parabolic self-similar pulse in an anomalous dispersive nonlinear fibre. Given the capacity of a linearly chirped parabolic pulse to retain its typical shape over a short propagation distance, we introduce the concept of dispersion managed self-similar pulses and outline potential benefits in terms of spectral broadening enhancement.

Christophe FINOT

2008-01-01

248

Apparatus for collecting solar beams  

SciTech Connect

There is disclosed a solar beam collector for use in collecting and condensing solar beams to introduce them into light guides or conductors. To ensure that almost all components of the white light and other radiations including ultra-violet and infra-red rays are introduced into the light guides, parabolic mirrors are employed in order to converge all of the solar beams having various wave lengths at the inlet of the light guides, thereby avoiding the problem of chromatic aberration. The solar beam collector is compact in size and comprises a first parabolic mirror for converging the arriving solar beams, a second parabolic mirror for condensing the beams from the first mirror into parallel beams, a third parabolic mirror for converging the parallel beams from the second mirror at a fixed focus, and a light guide having an inlet end placed at the focus of the third mirror.

Mori, K.

1984-04-24

249

QED with a parabolic mirror  

NASA Astrophysics Data System (ADS)

We investigate the quantum electrodynamics of a single two-level atom located at the focus of a parabolic cavity. We first work out the modifications of the spontaneous emission induced by the presence of this boundary in the optical regime, where the dipole and the rotating-wave approximations apply. Furthermore, the single-photon state that leaves the cavity asymptotically is determined. The corresponding time-reversed single-photon quantum state is capable of exciting the atom in this extreme multimode scenario with near-unit probability. Using semiclassical methods, we derive a photon-path representation for the relevant transition amplitudes and show that it constitutes a satisfactory approximation for a wide range of wavelengths.

Alber, G.; Bernád, J. Z.; Stobi?ska, M.; Sánchez-Soto, L. L.; Leuchs, G.

2013-08-01

250

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

National Technical Information Service (NTIS)

Measurements of global and normal incident radiation at the Yanbu, Saudi Arabia solar powered desalination plant site are documented. The use of parabolic, two axis tracking, point focusing solar collectors necessitates the measurement and analysis of the...

1985-01-01

251

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.

2013-06-12

252

A parabolic model for dimple potentials  

NASA Astrophysics Data System (ADS)

We study the truncated parabolic function and demonstrate that it is a representation of the Dirac ? function. We also show that the truncated parabolic function, used as a potential in the Schrödinger equation, has the same bound state spectrum, tunneling and reflection amplitudes as the Dirac ? potential, as the width of the parabola approximates to zero. Dirac ? potential is used to model dimple potentials which are utilized to increase the phase-space density of a Bose–Einstein condensate in a harmonic trap. We show that a harmonic trap with a ? function at the origin is a limiting case of the harmonic trap with a symmetric truncated parabolic potential around the origin. Hence, the truncated parabolic is a better candidate for modeling the dimple potentials.

Cibik Aydin, Melike; Uncu, Haydar; Deniz, Coskun

2013-09-01

253

Safety Risk Management for ESA Parabolic Flights  

NASA Astrophysics Data System (ADS)

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.

Malyshev, M.; Desroches, V.; Pletser, V.; Gharib, T.; Gai, F.; Rosier, P.

2012-01-01

254

Graviresponses of Paramecium biaurelia during parabolic flights  

Microsoft Academic Search

Summary.  The thresholds of graviorientation and gravikinesis in Paramecium biaurelia were investigated during the 5th DLR (German Aerospace Center) parabolic-flight campaign at Bordeaux in June 2003. Parabolic\\u000a flights are a useful tool for the investigation of swimming behaviour in protists at different accelerations. At normal gravity\\u000a (1 g) and hypergravity (1 g to 1.8 g), precision of orientation and locomotion rates

Martin Krause; Richard Bräucker; Ruth Hemmersbach

2006-01-01

255

THE SOLAR OVEN: DEVELOPMENT AND FIELD-TESTING OF USER-MADE DESIGNS IN INDONESIA  

Microsoft Academic Search

This paper considers the design, use, and social acceptance of solar cookers that are constructed by their users. Several generations of oven design are described and their field testing in Indonesia, are reported, the first generation design having been described in a previous paper. The second generation design reached 175°C in oven temperature, and it used only local materials in

Herliyani Suharta; K Abdullah; A Sayigh

1998-01-01

256

Pre- and post-natal exposure of children to EMF generated by domestic induction cookers.  

PubMed

Induction cookers are a type of cooking appliance that uses an intermediate-frequency magnetic field to heat the cooking vessel. The magnetic flux density produced by an induction cooker during operation was measured according to the EN 62233 standard, and the measured values were below the limits set in the standard. The measurements were used to validate a numerical model consisting of three vertically displaced coaxial current loops at 35 kHz. The numerical model was then used to compute the electric field (E) and induced current (J) in 26 and 30 weeks pregnant women and 6 and 11 year old children. Both E and J were found to be below the basic restrictions of the 2010 low-frequency and 1998 ICNRIP guidelines. The maximum computed E fields in the whole body were 0.11 and 0.66 V m(-1) in the 26 and 30 weeks pregnant women and 0.28 and 2.28 V m(-1) in the 6 and 11 year old children (ICNIRP basic restriction 4.25 V m(-1)). The maximum computed J fields in the whole body were 46 and 42 mA m(-2) in the 26 and 30 weeks pregnant women and 27 and 16 mA m(-2) in the 6 and 11 year old children (ICNIRP basic restriction 70 mA m(-2)). PMID:21878710

Kos, Bor; Vali?, Blaž; Miklav?i?, Damijan; Kotnik, Tadej; Gajšek, Peter

2011-08-30

257

Prov Med Branslesats for FV Noedutrustningspackar (Tests of a Mini Cooker for Swedish Air Force Survival Kits).  

National Technical Information Service (NTIS)

Tests have been completed of a solidified alcoholic jelly in order to investigate the suitability for the Swedish Air Force Survival Kits. The tests were carried out as a comparison between a solidified alcoholic jelly, contained in a simple cooker, and a...

B. Fransson C. Spangberg

1983-01-01

258

Solar electric power plants: new prosperity or large-scale losers  

Microsoft Academic Search

The 16 major solar electric power plants incorporate varying technologies: seven use central receiver power towers with fields of heliostats, five use photovoltaics; two use line-focusing parabolic troughs; one includes a conglomeration of parabolic dishes; and one uses a solar pond technology. These various approaches to solar power generation are diminished.

Fausch

2009-01-01

259

Effects of infrared radiation, solar cooking and microwave cooking on alpha-amylase inhibitor in sorghum (Sorghum bicolor L.).  

PubMed

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

Mulimani, V H; Supriya, D

1994-10-01

260

Object oriented modelling and simulation of parabolic trough collectors with modelica  

Microsoft Academic Search

The design of advanced control systems to optimize the overall performance of parabolic trough collectors solar plants with direct steam generation is today a high-priority line of research. This study presents the main development guidelines for dynamic models for use in simulation and control system design for such plants. The models are based in the ThermoFluid thermo-hydraulic modelling framework, developed

L. J. Yebra; M. Berenguel; S. Dormido; E. Zarza

2008-01-01

261

Chaotic motion of comets in near-parabolic orbit: Mapping aproaches  

NASA Astrophysics Data System (ADS)

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.

Liu, Jie; Sun, Yi-Sui

1994-09-01

262

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

Microsoft Academic Search

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

R. M. Dow; C. R. Dow

1999-01-01

263

QUASILINEAR SECOND-ORDER PARABOLIC EQUATIONS WITH MANY INDEPENDENT VARIABLES  

Microsoft Academic Search

CONTENTS § 1. Introduction § 2. A priori estimates for the solutions of linear parabolic equations § 3. A priori estimates for the solutions of quasi-linear parabolic equations § 4. Existence theorems for solutions of the first boundary value problem and Cauchy's problem in the large for quasi-linear parabolic equations § 5. An approximate solution of the boundary value problem

O A Oleinik; S N Kruzhkov

1961-01-01

264

Solar  

NSDL National Science Digital Library

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

Project, Iowa P.

2004-01-01

265

Novel method for making parabolic grating  

Microsoft Academic Search

We introduce the moving-mask method for fabrication of continuous relief grating with parabolic section profile in this paper. The depth of the grating is nearly equal to 4 micrometers , the diffraction orders from -10 to 10 has uniform intensity, such a grating can be used as multi-splitter. The grating can be concave or convex. The method presented in this

Bo Chen; Lu-Rong Guo; Ji-Yue Tang; Ping Xu; Ming-Bao Zhou

1996-01-01

266

Energy-Conserving Parabolic Wave Equations.  

National Technical Information Service (NTIS)

Energy-conserving versions of the parabolic wave equation model used for underwater sound propagation are derived for stratified media and variable coefficients (depth-dependent and range-dependent). The energy-conserving PWE models are first given for ti...

A. Sundstroem

1992-01-01

267

Floquet Bundles for Scalar Parabolic Equations.  

National Technical Information Service (NTIS)

For linear scalar parabolic equations such as Ut = Uxx + a(t,x)Ux + b(t,x)U on a finite interval 0 <= x <= pi, with various boundary conditions, we obtain canonical Floquet solutions Un(t,X). These solutions are characterized by the property that Z(Un(t, ...

S. N. Chow K. Lu J. Mallet-Paret

1993-01-01

268

Upgrades to the Parabolic Equation Model.  

National Technical Information Service (NTIS)

The PE model is a fully range dependent transmission loss algorithm based on a split-step Fourier solution of the standard parabolic approximation. Under this contract, many capabilities have been added to the PE model and they are outlined in this report...

E. Holmes J. Hanna L. Gainey

1988-01-01

269

Qualifying parabolic mirrors with deflectometry  

NASA Astrophysics Data System (ADS)

Phase-measuring deflectometry is a full-field gradient technique that lends itself very well to testing reflective optical surfaces. In the past, the industry's interest has been focussed mainly on the detection of defects and ripples, since it is easy to achieve sensitivity in the nm range. On the other hand, attempts to reconstruct the absolute surface shape from the gradient map have been plagued by systematic errors that accumulate to unacceptable uncertainties during data integration. Recently, thanks to improved measurement and evaluation techniques, the state of the art in absolute surface measurement has reached a level of maturity that allows its practical usage in precision optical manufacturing and qualification systems. We demonstrate the techniques, and the progress, by way of results from mirrors for telescopes, solar concentrators, and precision laboratory assemblies.

Burke, J.; Li, W.; Heimsath, A.; von Kopylow, C.; Bergmann, R. B.

2013-02-01

270

Nanofocusing Parabolic Refractive X-Ray Lenses  

SciTech Connect

Parabolic refractive x-ray lenses with short focal distance can generate intensive hard x-ray microbeams with lateral extensions in the 100nm range even at short distance from a synchrotron radiation source. We have fabricated planar parabolic lenses made of silicon that have a focal distance in the range of a few millimeters at hard x-ray energies. In a crossed geometry, two lenses were used to generate a microbeam with a lateral size of 330nm by 110nm at 25keV in a distance of 41.8m from the synchrotron radiation source. First microdiffraction and fluorescence microtomography experiments were carried out with these lenses. Using diamond as lens material, microbeams with lateral size down to 20nm and below are conceivable in the energy range from 10 to 100keV.

Schroer, C.G.; Kuhlmann, M.; Hunger, U.T.; Guenzler, T.F.; Kurapova, O.; Feste, S.; Lengeler, B. [II. Physikalisches Institut, Aachen University, D-52056 Aachen (Germany); Drakopoulos, M.; Somogyi, A.; Simionovici, A. S.; Snigirev, A.; Snigireva, I. [European Synchrotron Radiation Facility ESRF, BP 220, F-38043 Grenoble (France)

2004-05-12

271

ADI spectral collocation methods for parabolic problems  

NASA Astrophysics Data System (ADS)

We discuss the Crank-Nicolson and Laplace modified alternating direction implicit Legendre and Chebyshev spectral collocation methods for a linear, variable coefficient, parabolic initial-boundary value problem on a rectangular domain with the solution subject to non-zero Dirichlet boundary conditions. The discretization of the problems by the above methods yields matrices which possess banded structures. This along with the use of fast Fourier transforms makes the cost of one step of each of the Chebyshev spectral collocation methods proportional, except for a logarithmic term, to the number of the unknowns. We present the convergence analysis for the Legendre spectral collocation methods in the special case of the heat equation. Using numerical tests, we demonstrate the second order accuracy in time of the Chebyshev spectral collocation methods for general linear variable coefficient parabolic problems.

Bialecki, B.; de Frutos, J.

2010-07-01

272

A solar high temperature kiln  

NASA Astrophysics Data System (ADS)

The feasibility of using solar energy in developing countries for baking ceramic construction materials was investigated. The solar high temperature kiln is described. It uses two parabolic concentrators which direct available radiation into the baking chamber. The Sun tracker has only one axis. Preliminary test results with the prototype kiln were satisfactory.

Huettenhoelscher, N.; Bergmann, K.

1981-11-01

273

Reflectors for solar energy collectors  

Microsoft Academic Search

The disclosure illustrates an improved reflector for a solar energy collector. The reflector is made up of a thin, vacuum formed, elongated, trough like sheet having a reflective parabolic surface for reflecting and focusing solar radiation. A structural sheet conforms to and supports the thin sheet. The structural sheet has a series of integrally formed depressions extending away from the

Uroshevich

1981-01-01

274

Which is the best solar thermal collection technology for electricity generation in north-west India? Evaluation of options using the analytical hierarchy process  

Microsoft Academic Search

This study of concentrating solar thermal power generation sets out to evaluate the main existing collection technologies using the framework of the Analytical Hierarchy Process (AHP). It encompasses parabolic troughs, heliostat fields, linear Fresnel reflectors, parabolic dishes, compound parabolic concentrators and linear Fresnel lenses. These technologies are compared based on technical, economic and environmental criteria. Within these three categories, numerous

J. D. Nixon; P. K. Dey; P. A. Davies

2010-01-01

275

Coma compensation in a parabolized Ebert monochromator.  

PubMed

Coma compensation in a parabolized Ebert monochromator is studied using the plate diagram. It is shown that two different criteria may be used: narrowest images or symmetrical ones; however, both may not be satisfied simultaneously. Symmetrical or narrowest images may be obtained for an extended range of wavelengths with displacement of at least one of the slits. With fixed slits only incomplete compensation may be obtained. PMID:20212647

Gil, M A; Simon, J M

1979-07-01

276

Research and development on a distributed type solar thermal power generation plant  

Microsoft Academic Search

The R&D on a solar thermal power generation system of the plane parabolic type within the framework of the Japanese Sunshine Project is described. This system realizes high concentration of solar energy with a special concentrator module which combines 100 flat plate mirror heliostats of the central tower system with 5 parabolic troughs of the distributed system. A molten salt

I. Sumida; M. Tsukamoto; T. Sakamoto; T. Taki; S. Sato

1983-01-01

277

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

Microsoft Academic Search

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

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

2004-01-01

278

Solar energy concentrator design and operation. Citations from the NTIS data base  

NASA Astrophysics Data System (ADS)

Government funded research on the design and operation of various types of solar energy concentrators is discussed. Abstracts cover the efficiency and optimization of Fresnel lenses, V-through concentrators, flat plate and parabolic reflectors, compound parabolic concentrators used in solar photovoltaic conversion and heliostat systems. A few abstracts deal with heat loss and cost studies.

Hundemann, A. S.

1980-09-01

279

Systematic rotation and receiver location error effects on parabolic trough annual performance  

NASA Astrophysics Data System (ADS)

The effects of systematic geometrical design errors and random optical errors on the accuracy and subsequent economic viability of solar parabolic trough concentrating collectors were studied to enable designers to choose and specify necessary design and material constraints. A three-dimensional numerical model of a parabolic trough was analyzed with the inclusion of errors of pointing and mechanical deformation, and data from a typical meteorological year. System errors determined as percentage standard deviations provided the range of a study for systematic rotation and receiver location errors. The two types of errors were found to produce compounded effects. It is concluded that the designer must choose performance levels which take into account existence of errors, must know to what level the errors can be eliminated and at what cost, and should make provisions for monitoring the day-to-day on-line focus of the troughs.

Treadwell, G. W.; Grandjean, N. R.

1981-11-01

280

Cardiovascular and Valsalva responses during parabolic flight.  

PubMed

We investigated the integrated cardiovascular responses of 15 human subjects to the acute gravitational changes (micro- and hypergravity portions) of parabolic flight. Measurements were made with subjects quietly seated and while subjects performed controlled Valsalva maneuvers. During quiet, seated, parabolic flight, mean arterial pressure increased during the transition into microgravity but decreased as microgravity was sustained. The decrease in mean arterial pressure was accompanied by immediate reflexive increases in heart rate but by absent (or later-than-expected) reflexive increases in total vascular resistance. Mean arterial pressure responses in Valsalva phases IIl, III, and IV were accentuated in hypergravity relative to microgravity (P < 0.01, P < 0.01, and P < 0. 05, respectively), but accentuations differed qualitatively and quantitatively from those induced by a supine-to-seated postural change in 1 G. This study is the first systematic evaluation of temporal and Valsalva-related changes in cardiovascular parameters during parabolic flight. Results suggest that arterial baroreflex control of vascular resistance may be modified by alterations of cardiopulmonary, vestibular, and/or other receptor activity. PMID:9804604

Schlegel, T T; Benavides, E W; Barker, D C; Brown, T E; Harm, D L; DeSilva, S J; Low, P A

1998-11-01

281

Solar energy technology  

Microsoft Academic Search

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

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

1987-01-01

282

Symmetry groups and fundamental solutions for systems of parabolic equations  

NASA Astrophysics Data System (ADS)

In this paper, the relationship between Lie point symmetry and fundamental solution for systems of parabolic equations is explored. It is shown that the fundamental solutions of the systems of parabolic equations admitting certain symmetries can be obtained by inverting the Laplace transformation of the corresponding group-invariant solutions. Several examples are presented to illustrate the approach. Furthermore, the relationship between fundamental solutions for two systems of parabolic equations related by an equivalence transformation is identified.

Kang, Jing; Qu, Changzheng

2012-02-01

283

On the invariants of two dimensional linear parabolic equations  

NASA Astrophysics Data System (ADS)

We consider the most general two dimensional linear parabolic equations. Motivated by the recent work of Ibragimov et al. [1-3] we construct differential invariants, semi-invariants and invariant equations. These results are achieved with the employment of the equivalence group admitted by this class of parabolic equations. We derive those variable coefficient equations of this class of linear parabolic equations that can be mapped into constant coefficient equations. Further applications are presented.

Tsaousi, C.; Sophocleous, C.; Tracinà, R.

2012-09-01

284

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

SciTech Connect

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

Not Available

1985-01-01

285

Surface roughness estimation of a parabolic reflector  

NASA Astrophysics Data System (ADS)

Random surface deviations in a reflector antenna reduce the aperture ef- ficiency. This communication presents a method for estimating the mean surface deviation of a parabolic reflector from a set of measured points. The proposed method takes into account systematic measurement errors, such as the offset between the origin of reference frame and the vertex of the surface, and the misalignment between the surface rotation axis and the measurement axis. The results will be applied to perform corrections to the surface of one of the 30 m diameter radiotelescopes at the Instituto Argentino de Radioastronomía (IAR).

Casco, N. A.

286

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

NASA Astrophysics Data System (ADS)

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

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

1981-11-01

287

The Parabolic Jet Structure in M87 as a Magnetohydrodynamic Nozzle  

NASA Astrophysics Data System (ADS)

The structure and dynamics of the M87 jet from sub-milliarcsec to arcsecond scales are continuously examined. We analyzed the Very Long Baseline Array archival data taken at 43 and 86 GHz to measure the size of very long baseline interferometry (VLBI) cores. Millimeter/sub-millimeter VLBI cores are considered as innermost jet emissions, which has been originally suggested by Blandford & 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 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 ~103 r s, while the upstream trans-Alfvénic flow speed increases linearly as a function of the distance at ~102-103 r s. We here point out that this is the first evidence to identify these features in astrophysical jets. We propose that the M87 jet is magnetically accelerated, but thermally confined by the stratified interstellar medium inside the sphere of gravitational influence of the SMBH potential, which may be a norm in active galactic nucleus jets.

Nakamura, Masanori; Asada, Keiichi

2013-10-01

288

SunLab: Advancing Concentrating Solar Power Technology  

SciTech Connect

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.

NONE

1998-11-24

289

Solar Disinfection of MODS Mycobacterial Cultures in Resource-Poor Settings  

PubMed Central

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.

Nathavitharana, Ruvandhi; Coronel, Jorge; Moore, David A. J.

2007-01-01

290

Analysis of the influence of operational strategies in plant performance using SimulCET, simulation software for parabolic trough power plants  

Microsoft Academic Search

This paper analyzes the influence of operational strategies on the performance of parabolic trough (PT) solar power plants with the aid of SimulCET a computer program for the simulation of the energy behavior of PT plants developed by the National Renewable Energy Centre of Spain (CENER).SimulCET uses state of the art techniques to simulate solar energy absorption and others energy

Javier García-Barberena; Pierre Garcia; Marcelino Sanchez; Manuel J. Blanco; Carlos Lasheras; Asun Padrós; Jaime Arraiza

291

Solar  

Microsoft Academic Search

The dispersion relation for a plasma oscillating in a static magnetic field is derived by the Laplace transform method. The plasma oscillations are found to be unstable in frequency bands around multiples of the gyrofrequency. A numerical application to spot magnetic fields at coronal distances indicates sufficient amplification to make plausible the theory of the origin of solar \\

Hari K. Sen

1952-01-01

292

Experimental Study on A Concentrating Solar Photovoltaic\\/Thermal System  

Microsoft Academic Search

In this work, A single-pass photovoltaic\\/thermal solar system with compound parabolic concentrator(CPC) and fins is designed and its electric-thermal performance over arrange of local conditions is studied by an experimental method. A prototype double-trough compound parabolic concentrator is designed and fabricated. The absorber of the hybrid PV\\/T air system under investigation consists of solar cell model and a block aluminium

Sun Jian; Shi Mingheng

2010-01-01

293

Nonuniform depth grids in parabolic equation solutions.  

PubMed

The parabolic wave equation is solved using a finite-difference solution in depth that involves a nonuniform grid. The depth operator is discretized using Galerkin's method with asymmetric hat functions. Examples are presented to illustrate that this approach can be used to improve efficiency for problems in ocean acoustics and seismo-acoustics. For shallow water problems, accuracy is sensitive to the precise placement of the ocean bottom interface. This issue is often addressed with the inefficient approach of using a fine grid spacing over all depth. Efficiency may be improved by using a relatively coarse grid with nonuniform sampling to precisely position the interface. Efficiency may also be improved by reducing the sampling in the sediment and in an absorbing layer that is used to truncate the computational domain. Nonuniform sampling may also be used to improve the implementation of a single-scattering approximation for sloping fluid-solid interfaces. PMID:23556565

Sanders, William M; Collins, Michael D

2013-04-01

294

Telescopic projective methods for parabolic differential equations  

NASA Astrophysics Data System (ADS)

Projective methods were introduced in an earlier paper [C.W. Gear, I.G. Kevrekidis, Projective Methods for Stiff Differential Equations: problems with gaps in their eigenvalue spectrum, NEC Research Institute Report 2001-029, available from http://www.neci.nj.nec.com/homepages/cwg/projective.pdf Abbreviated version to appear in SISC] as having potential for the efficient integration of problems with a large gap between two clusters in their eigenvalue spectrum, one cluster containing eigenvalues corresponding to components that have already been damped in the numerical solution and one corresponding to components that are still active. In this paper we introduce iterated projective methods that allow for explicit integration of stiff problems that have a large spread of eigenvalues with no gaps in their spectrum as arise in the semi-discretization of PDEs with parabolic components.

Gear, C. W.; Kevrekidis, Ioannis G.

2003-05-01

295

Photogalvanic current in a parabolic well  

NASA Astrophysics Data System (ADS)

We study the in-plane stationary photocurrent in a parabolic potential well. The well has vertical asymmetry due to inhomogeneous distribution of scatterers. The electric field of light has both vertical and in-plane components. The photogalvanic effect originates from the periodic oscillation of electrons in a vertical direction caused by the normal component of the alternating electric field with simultaneous in-plane acceleration/deceleration by the in-plane component of electric field. The problem is considered in classical approximation assuming inhomogeneously-distributed friction. Photocurrent has a resonance character. Resonance occurs at light frequencies close to a characteristic well frequency. The effect of in-plane magnetic field is also studied.

Entin, M. V.; Magarill, L. I.

2013-08-01

296

Solar energy modulator  

SciTech Connect

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

Mcdougal, A.R.; Hale, R.R.

1981-07-01

297

Energy 101: Concentrating Solar Power  

ScienceCinema

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

298

Solar aqua-ammonia absorption refrigerator simulation  

Microsoft Academic Search

Thermodynamic analysis of an Ammonia-water absorption refrigeration cycle performance, using solar energy in the generator, is simulated by means of a PC program. The economic feasibility of the system for ice production is studied in two southern locations of Spain. For the solar energy collection unit, a Compound Parabolic Collector (CPC) is considered. The optimal value of the Coefficient of

E. Elegido; J. M. De Juana; M. A. Herrero

1991-01-01

299

OUT Success Stories: Solar Trough Power Plants  

SciTech Connect

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.

Jones, J.

2000-08-05

300

Optimized solar powered freeze desalination technology  

Microsoft Academic Search

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

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

1981-01-01

301

GREENHOUSE GAS ANALYSIS OF SOLAR-THERMAL ELECTRICITY GENERATION  

Microsoft Academic Search

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

M. LENZEN

1999-01-01

302

Gain-scheduled control of a solar power plant  

Microsoft Academic Search

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

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

2000-01-01

303

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

SciTech Connect

Existing parabolic trough solar collectors are basically sheet metal designs utilizing aluminum or steel as the major structural materials. The relatively high labor content associated with these sheet metal designs has generated an interest in investigating the cost effectiveness of using reinforced plastics as a major structural material for trough solar collectors. This interest is bolstered by a growing desire on the part of industry to identify new material-process combinations which save weight, use less energy, and require less capital equipment and assembly costs. The use of reinforced plastics as the basic material for a line-focus parabolic trough concentrator module is studied. This module constitutes a basic building block with which longer trough rows can be built. The basic part analysis is described including the quantification of key material and part-function relationships. In addition candidate materials and processes are reviewed and, the costs associated with the most attractive combinations defined. Finally, the major conclusions and recommendations are summarized.

Hodge, R. (ed.)

1980-08-01

304

Potential for using parabolic trough collectors to supplement power cycle boilers  

NASA Astrophysics Data System (ADS)

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

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

1981-11-01

305

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

PubMed

We present a detailed design concept and optical performance evaluation of stationary dielectric asymmetric compound parabolic concentrators (DiACPCs) using ray-tracing methods. Three DiACPC designs, DiACPC-55, DiACPC-66, and DiACPC-77, of acceptance half-angles (0° and 55°), (0° and 66°), and (0° and 77°), respectively, are designed in order to optimize the concentrator for building façade photovoltaic applications in northern latitudes (>55 °N). The dielectric concentrator profiles have been realized via truncation of the complete compound parabolic concentrator profiles to achieve a geometric concentration ratio of 2.82. Ray-tracing simulation results show that all rays entering the designed concentrators within the acceptance half-angle range can be collected without escaping from the parabolic sides and aperture. The maximum optical efficiency of the designed concentrators is found to be 83%, which tends to decrease with the increase in incidence angle. The intensity is found to be distributed at the receiver (solar cell) area in an inhomogeneous pattern for a wide range of incident angles of direct solar irradiance with high-intensity peaks at certain points of the receiver. However, peaks become more intense for the irradiation incident close to the extreme acceptance angles, shifting the peaks to the edge of the receiver. Energy flux distribution at the receiver for diffuse radiation is found to be homogeneous within ±12% with an average intensity of 520 W/m². PMID:21743533

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

2011-07-01

306

Mean Values of Subsolutions of Elliptic and Parabolic Equations.  

National Technical Information Service (NTIS)

Integral averages of weak subsolutions (and supersolutions) in Rn of quasilinear elliptic and parabolic equations are investigated. The important feature is that these integral averages are defined in terms of measures that reflect interesting geometric p...

W. P. Ziemer

1982-01-01

307

Benchmark Calculations for Higher-Order Parabolic Equations.  

National Technical Information Service (NTIS)

Benchmark solutions generated with parabolic equation (PE) models are presented for range-dependent underwater acoustic propagation problems involving both penetrable and perfectly reflection ocean bottoms. The solution of the wide-angle PE of Claerbout (...

M. D. Collins

1990-01-01

308

Ocular Torsion in the Weightlessness of Parabolic Flight (Abstract Only),  

National Technical Information Service (NTIS)

Preliminary findings of torsional eyeball displacements (rotational displacements about the optic axis) in parabolic flight that were reported in Spacebound '87 have been confirmed. The more recent experiments have used photographs of both eyes, instead o...

K. E. Money N. M. Kirienko W. H. Johnson D. G. D. Watt C. H. Markham

1988-01-01

309

Parabolic Approximation Method for Fast Magnetosonic Wave Propagation in Tokamaks.  

National Technical Information Service (NTIS)

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 i...

C. K. Phillips F. W. Perkins D. Q. Hwang

1985-01-01

310

Flux-splitting schemes for parabolic equations with mixed derivatives  

NASA Astrophysics Data System (ADS)

Difference schemes of required quality are often difficult to construct as applied to boundary value problems for parabolic equations with mixed derivatives. Specifically, difficulties arise in the design of monotone difference schemes and unconditionally stable locally one-dimensional splitting schemes. In parabolic problems, certain opportunities are offered by restating the problem in question so that the quantities to be determined are fluxes (directional derivatives). The original problem is then rewritten as a boundary value one for a system of equations in flux variables. Weighted schemes for parabolic equations in flux coordinates are examined. Unconditionally stable locally one-dimensional flux schemes that are first- and second-order accurate in time are constructed for a parabolic equation without mixed derivatives. A feature of systems in flux variables for equations with mixed derivatives is that the terms with time derivatives are coupled with each other.

Vabishchevich, P. N.

2013-08-01

311

Parabolized Navier-Stokes Methods for Hypersonic Flows.  

National Technical Information Service (NTIS)

The development and numerical solution of the Parabolized Navier-Stokes (PNS) equations is discussed. Special emphasis is placed on numerical integration algorithms for PNS solvers, most notably recent applications of upwind schemes. Application of this t...

S. L. Lawrence

1992-01-01

312

Parabolized Navier-Stokes Methods for Hypersonic Flows.  

National Technical Information Service (NTIS)

A representative sampling of the techniques used in the integration of the Parabolized Navier-Stokes (PNS) equations is presented. Special atention is given to recent algorithms developed specifically for application to high speed flows, characterized by ...

S. L. Lawrence

1991-01-01

313

Parabolized Navier-Stokes Equations without Sublayer Assumptions.  

National Technical Information Service (NTIS)

A new implicit, iteractive method of solving the Parabolized Navier-Stokes (PNS) Equations claims to overcome the elliptic character of the embedded subsonic sublayer by explicitly introducing pressure as an additional state variable. The Bhutta-Lewis app...

S. C. Pluntze

1987-01-01

314

33. July 1958 PARABOLIC BRICK VAULT IN SERVICE MAGAZINE UNDER ...  

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

33. July 1958 PARABOLIC BRICK VAULT IN SERVICE MAGAZINE UNDER RAVELIN (CIVIL WAR PERIOD) - Fort McHenry National Monument & Historic Shrine, East Fort Avenue at Whetstone Point, Baltimore, Independent City, MD

315

Off-axis parabolic optical relays: almost perfect imaging  

NASA Astrophysics Data System (ADS)

Off-axis parabolic elements have found application in Tera-Hertz imaging and new application in two-photon microscopy scan engines. Both these applications demand spatial and temporal precision in photon location. This modelling work examines how close off-axis parabolic elements are to the perfect image relay by calculating the geometrical performance metrics of spot diagrams, point spread functions and wavefront distortion for different arrangements of off-axis parabolas and a parabolic torus when compared to a close-coupled two mirror scan engine. Results identify the off-axis parabolic elements as a superior scan engine particularly in wide-field scan instruments. When within the optimum beam size versus parabola focus length ratio, the imaging of these systems is superb.

Holdsworth, John L.; Sharafutdinova, Galiya; Sanderson, Michael J.; van Helden, Dirk F.

2011-08-01

316

Optical absorptions in asymmetrical semi-parabolic quantum wells  

NASA Astrophysics Data System (ADS)

Optical absorptions in semi-parabolic quantum wells are investigated. By using density-matrix approach and iterative procedure, the analytical formula of optical absorption coefficients in this semi-parabolic quantum wells are deduced. The numerical results on typical GaAs/AlGaAs materials are calculated. The relations between the optical absorptions and the quantum confinement from the semi-parabolic quantum wells, the incident optical intensity, and the relaxation rate are investigated. The results indicate that the absorption peaks bule-shift and the values of the peaks increase with the enhancement of the parabolic confining frequency. The values of the absorption peaks increase quickly with the increase of the relaxation time. In addition, the total absorption coefficient decrease with the increase of the incident optical intensity.

Yu, X. Q.; Yu, Y. B.

2013-10-01

317

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

SciTech Connect

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

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

2008-03-01

318

Solar electricity generation—A comparative view of technologies, costs and environmental impact  

Microsoft Academic Search

The implementation of solar power plants in regions of high insolation is a promising option for an environmentally compatible electricity supply strategy. Today, approximately 80% of the solar generated electricity is provided by solar thermal power plants, while 20% is supplied by photovoltaic systems. Decision-makers have the choice among the following solar technologies: (1) parabolic trough; (2) central receiver; (3)

Franz Trieb; Ole Langni?; Helmut Klai?

1997-01-01

319

Conditions for economical benefits of the use of solar energy in multi-stage flash distillation  

Microsoft Academic Search

A solar assisted multi-stage flash (MSF) distillation system is economically compared with a conventional energy MSF plant. Moreover, the economical and climatic conditions that make competitive the use of solar energy in MSF plants vs. conventional energy are analyzed. The design arrangement of the solar distillation system considered consists of a solar parabolic trough collector field coupled to a conventional

Lourdes García-Rodríguez; Carlos Gómez-Camacho

1999-01-01

320

Industry warms up to the idea of solar heat. [Solar collector panels supply industrial process heat  

Microsoft Academic Search

General Extrusions, Inc. of Youngstown, Ohio has 100 semi-parabolic collector pannels supplying heat for the company's aluminum anodizing department's hot acid dipping process. The collectors are semi-parabolic panels with limited tracking. All parts of the plant's solar panels are aluminum except for the insulation and acrylic glazing. An oil-based heat transfer fluid is used to eliminate corrosion and protect against

Weimer

1977-01-01

321

Three-dimensional nonparaxial beams in parabolic rotational coordinates.  

PubMed

We introduce a class of three-dimensional nonparaxial optical beams found in a parabolic rotational coordinate system. These beams, representing exact solutions of the nonparaxial Helmholtz equation, have inherent parabolic symmetries. Assisted with a computer-generated holography, we experimentally demonstrate the generation of different modes of these beams. The observed transverse beam patterns along the propagation direction agree well with those from our theoretical predication. PMID:24081092

Deng, Dongmei; Gao, Yuanmei; Zhao, Juanying; Zhang, Peng; Chen, Zhigang

2013-10-01

322

Characterization of a focusing parabolic guide using neutron radiography method  

Microsoft Academic Search

The aim of the investigation was to test the focusing properties of a new type of focusing neutron guide (trumpet) with parabolically shaped walls. The guide has a length of 431mm with an entrance area of 16×16mm2 and an output area of 4×4mm2. The interior surfaces were coated with a supermirror-surface m=3 and due to their parabolic shape it was

Nikolay Kardjilov; Peter Böni; André Hilger; Markus Strobl; Wolfgang Treimer

2005-01-01

323

General theme report: Working session 2, solar thermal systems  

NASA Astrophysics Data System (ADS)

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

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

1991-01-01

324

Solar thermal aircraft  

DOEpatents

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

Bennett, Charles L. (Livermore, CA)

2007-09-18

325

Modular solar food dryers for farm use  

SciTech Connect

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

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

1981-01-01

326

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

NASA Astrophysics Data System (ADS)

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

Nagata, Tomoko; Ishida, Ryohei

327

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

SciTech Connect

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

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

1988-11-01

328

Mixed hyperbolic-second-order-parabolic formulations of general relativity  

SciTech Connect

Two new formulations of general relativity are introduced. The first one is a parabolization of the Arnowitt-Deser-Misner formulation and is derived by the addition of combinations of the constraints and their derivatives to the right-hand side of the Arnowitt-Deser-Misner evolution equations. The desirable property of this modification is that it turns the surface of constraints into a local attractor because the constraint propagation equations become second-order parabolic independently of the gauge conditions employed. This system may be classified as mixed hyperbolic--second-order parabolic. The second formulation is a parabolization of the Kidder-Scheel-Teukolsky formulation and is a manifestly mixed strongly hyperbolic--second-order-parabolic set of equations, bearing thus resemblance to the compressible Navier-Stokes equations. As a first test, a stability analysis of flat space is carried out and it is shown that the first modification exponentially damps and smoothes all constraint-violating modes. These systems provide a new basis for constructing schemes for long-term and stable numerical integration of the Einstein field equations.

Paschalidis, Vasileios [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago Illinois 60637 (United States)

2008-07-15

329

Solar energy for pollution control. Final report, 1 June31 October 1978  

Microsoft Academic Search

A study was conducted to determine which existing or emerging pollution control processes are best suited to make use of solar energy input and to determine the potential benefits of such applications. Pollution control processes were matched with compatible solar energy systems, resulting in the following four combinations: Anaerobic digestion\\/flat-plate collector; Anaerobic digestion\\/parabolic trough concentrator; Baghouse heating\\/parabolic trough concentrator; SOX

P. Overly; C. Franklin

1981-01-01

330

Acurex Parabolic Dish Concentrator (PDC2)  

Microsoft Academic Search

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

P. Overly; R. Bedard

1982-01-01

331

Notes on home-type solar hot water economics  

SciTech Connect

Some things to consider before buying a solar hot water system is first discussed. Approximate savings in energy costs for a family of four with a solar hot water system are given. Buying a solar hot water system with money taken out of a savings account and with money borrowed on a bank card is next discussed. Finally, some comments are given on tracking parabolic through solar collectors vs flat plate collectors for residential systems.

Drumheller, K.

1984-01-01

332

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

SciTech Connect

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

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

2010-10-01

333

Parabolic approximation method for fast magnetosonic wave propagation in tokamaks  

SciTech Connect

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.

Phillips, C.K.; Perkins, F.W.; Hwang, D.Q.

1985-07-01

334

Chaotic dynamics and orbit stability in the parabolic oval billiard.  

PubMed

Chaotic properties of the one-parameter family of oval billiards with parabolic boundaries are investigated. Classical dynamics of such billiard is mixed and depends sensitively on the value of the shape parameter. Deviation matrices of some low period orbits are analyzed. Special attention is paid to the stability of orbits bouncing at the singular joining points of the parabolic arcs, where the boundary curvature is discontinuous. The existence of such orbits is connected with the segmentation of the phase space into two or more chaotic components. The obtained results are illustrated by numerical calculations of the Poincaré sections and compared with the properties of the elliptical stadium billiards. PMID:12366219

Lopac, V; Mrkonji?, I; Radi?, D

2002-09-10

335

Line focus solar thermal central receiver research study  

Microsoft Academic Search

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

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

1979-01-01

336

Photovoltaic Engineering Services Pertinent to Solar Energy Conversion.  

National Technical Information Service (NTIS)

The application of the compound parabolic concentrator (CPC) for use with solar cells has been investigated. Experiments with state-of-the-art Si cells in a CPC and under solar concentration were performed. A theoretical model for calculating the behavior...

R. O. Bell J. C. T. Ho W. Kurth T. Surek

1975-01-01

337

Exergetic analysis of a solar thermal power system  

Microsoft Academic Search

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

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

2000-01-01

338

Object Oriented Modelling of DISS Solar Thermal Power Plant  

Microsoft Academic Search

The design of advanced control systems to optimize the overall performance of Parabolic Trough Collec- tors solar plants with Direct Steam Generation is cur- rently a priority research line at PSA-CIEMAT. The development of dynamic models for use in simulation and control of this type of solar power plant is pre- sented in this article, focused on the DISS experimen-

L. J. Yebra; M. Berenguel; E. Zarza; S. Dormido

339

Felt-metal-wick heat-pipe solar receiver  

Microsoft Academic Search

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.

Charles E. Andraka; Douglas R. Adkins; Timothy A. Moss; Howard M. Cole; Nicos H. Andreas

1994-01-01

340

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

Microsoft Academic Search

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

M. J. Montes; A. Abánades; J. M. Martínez-Val

2009-01-01

341

Midtemperature solar systems test facility predictions for thermal performance based on test data: Acurex solar collector with glass reflector surface  

SciTech Connect

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

Harrison, T.D.

1981-03-01

342

Method of and system for generating energy from solar and wind energy sources  

Microsoft Academic Search

Solar and wind energy sources are combined into a unitary system for generating electrical energy. A solar collector collects solar rays, and these rays are focused by a parabolic mirror before being conducted through a fresnel tube to a container which minimizes thermal exchange with the exterior environment. The thermal energy of the rays within the container is converted to

Hope

1980-01-01

343

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

Microsoft Academic Search

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

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

2010-01-01

344

Object-oriented modelling and simulation of ACUREX solar thermal power plant  

Microsoft Academic Search

Research and development of advanced control systems to optimize the overall performance of parabolic trough collector (PTC) solar power plants is a priority line of research at the CIEMAT (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas - Research Centre for Energy, Environment and Technology). These developments are underway at the CIEMAT's Plataforma Solar de Almera (PSA), a highly specialized solar

L. J. Yebra; M. Berenguel; J. Bonilla; L. Roca; S. Dormido; E. Zarza

2010-01-01

345

Wide field of view imaging with parabolic cylindrical reflectors  

Microsoft Academic Search

Parabolic cylindrical reflectors (PCRs) can have a large field of view, for example a 15 m reflector can access an area of 1° by 120° at 1.4 GHz. It is seen that the radiation pattern is asymmetric. This causes problems in situations where the radiation pattern rotates with time, such as radio astronomy. The rotation of the radiation pattern limits

John D. Bunton

2006-01-01

346

Restrictive padé approximation and parabolic partial differential equations  

Microsoft Academic Search

In this paper, we use the restrictive Pade approximation to approximate the exponential matrix exp(rA). The advantage is that it has the exact value at certain r. We define a new accurate, fast implicit method for the finite difference solution of a parabolic partial differential equations. The stability region is discussed, the obtained results are compared with the exact solution

Hassan N. A. Ismail; Elsayed M. E. Elbarbary

1998-01-01

347

Restrictive taylor's approximation and parabolic partial differential equations  

Microsoft Academic Search

In this paper we construct a restrictive type of Taylor's approximation of the function f(x) with parameter to be determined. It yields more accurate result, and it has the exact value at certain point. We shall develop a new approach for an explicit method to solve the parabolic partial differential equation. This approach will exhibit several advantages features: Highly accurate,

Hassan N. A. Ismail; Elsayed M. E. Elbarbary

2001-01-01

348

Dark Matter Halos and Tidal Effects in Parabolic Galaxy Encounters  

NASA Astrophysics Data System (ADS)

The effect of dark matter halo extent upon tidal disruption occurring in parabolic encounters between identical galaxies modelled as perfect isothermal spheres is investigated and it is found that such galaxies are extremely resistant to the formation of tidal tails in these interactions, independent of both halo extent and rotational velocity.

Capriotti, John David

1998-10-01

349

Compound parabolic concentrator with cavity for tubular absorbers  

DOEpatents

A compond parabolic concentrator with a V-shaped cavity is provided in which an optical receiver is emplaced. The cavity redirects all energy entering between the receiver and the cavity structure onto the receiver, if the optical receiver is emplaced a distance from the cavity not greater than 0.27 r (where r is the radius of the receiver).

Winston, Roland (5217C S. University Ave., Chicago, IL 60615)

1983-01-01

350

Parabolic flight experiments on fluid surfaces and wetting  

Microsoft Academic Search

During parabolic flights of a KC-135 aircraft, experiments were performed on the behaviors of water, gylcerine, and Fluorinert in different containers. Results are presented from studies of liquid menisci in solid edges, the formation of solid edges with differing dihedral angles using arrays of microscope slides and rosette modules, the spreading of water and glycerine in rosette modules, and wetting

D. Langbein; R. Grossbach; W. Heide

1990-01-01

351

Solution of the Parabolized Navier-Stokes Equations.  

National Technical Information Service (NTIS)

Solution of the parabolized Navier-Stokes equation using the stream-function/vorticity method; the velocity/vorticity-gradient method; pressure-uncoupling with the SIVA method; and pressure-uncoupling with the SIMPLE method is summarized. Full-Navier-Stok...

D. B. Spalding

1986-01-01

352

A Discontinuous Galerkin method applied to nonlinear parabolic equations  

Microsoft Academic Search

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

Béatrice Rivière; Mary F. Wheeler

2000-01-01

353

A spatial domain decomposition method for parabolic optimal control problems  

NASA Astrophysics Data System (ADS)

We present a non-overlapping spatial domain decomposition method for the solution of linear-quadratic parabolic optimal control problems. The spatial domain is decomposed into non-overlapping subdomains. The original parabolic optimal control problem is decomposed into smaller problems posed on space-time cylinder subdomains with auxiliary state and adjoint variables imposed as Dirichlet boundary conditions on the space-time interface boundaryE The subdomain problems are coupled through Robin transmission conditions. This leads to a Schur complement equation in which the unknowns are the auxiliary state adjoint variables on the space-time interface boundary. The Schur complement operator is the sum of space-time subdomain Schur complement operators. The application of these subdomain Schur complement operators is equivalent to the solution of an subdomain parabolic optimal control problem. The subdomain Schur complement operators are shown to be invertible and the application of their inverses is equivalent to the solution of a related subdomain parabolic optimal control problem. We introduce a new family of Neumann-Neumann type preconditioners for the Schur complement system including several different coarse grid corrections. We compare the numerical performance of our preconditioners with an alternative approach recently introduced by Benamou.

Heinkenschloss, Matthias; Herty, Michael

2007-04-01

354

Finite difference analysis of electrically large parabolic reflector antennas  

Microsoft Academic Search

A reflector antenna is analyzed using the finite-difference method (FD). The induced current densities on an axially symmetric parabolic reflector are rigorously calculated. The measured equation of invariance (MEI) is used to terminate the FD mesh very close to the reflector surface. To take advantage of the axial symmetry, the theory of coupled-azimuthal potentials (CAPs) is employed. Illustrative results are

Yong-Lun Luo; Kwai-Man Luk; Kenneth K. Mei; Edward Kai-Ning Yung

2002-01-01

355

HOMOGENIZATION RESULTS FOR PARABOLIC PROBLEMS WITH DYNAMICAL BOUNDARY CONDITIONS  

Microsoft Academic Search

The aim of this paper is to study the asymptotic behavior of the solution of a parabolic dynamical boundary-value problem in a periodically perforated domain. The domain is considered to be a fixed bounded open subset ??RN , in which identical and periodically distributed perforations (holes) of size ? are made. In the perforated domain we consider a heat equation,

C. TIMOFTE

2004-01-01

356

Optical Analysis of Point Focus Parabolic Radiation Concentrators.  

National Technical Information Service (NTIS)

A simple formalism is developed for analyzing the optical performance of point focus parabolic radiation concentrators. To account for off-axis aberrations of the parabola, an angular acceptance function is defined as that fraction of a beam of parallel r...

P. Bendt A. Rabl

1980-01-01

357

Stueckelberg Curve-Crossing Phases: The Parabolic Model.  

National Technical Information Service (NTIS)

A discussion of the semiclassical two-channel 'curve-crossing' S matrix is given. The literature is reviewed with reference to Stueckelberg phases as calculated by consistent application of the Zwaan-Stueckelberg phase-integral technique and the parabolic...

D. S. F. Crothers

1975-01-01

358

Migration of parabolic dunes at Aberffraw, Anglesey, north Wales  

NASA Astrophysics Data System (ADS)

Aberffraw is a 1-km-wide and 3-km-long transgressive dunefield that extends inland along a northeast-southwest-trending valley from a southwest-facing beach, Traeth Mawr. The prevailing wind is from the southwest, and both the parabolic dunes and the valley within which they lie are sub-parallel to the prevailing wind. The dunefield at Aberffraw includes two foredune ridges and three rows of active compound parabolic dunes. At the landward end is a lake, Llyn Coron, which has been formed by dunes migrating up the valley and damming the river, Afon Ffraw. Between the parabolic dunes are gently sloping interdune areas with a close cropped vegetation. The parabolic dunes at Aberffraw have been migrating inland across the interdune areas. Rates of parabolic dune migration are derived from three sets of aerial photographs taken in 1940, 1982 and 1993. The aerial photographs have been scanned and manipulated in ArcView GIS software. Registration of the aerial photograph to an Ordnance Survey (OS) map was performed using ground control points (GCPs), common fixed features that are identifiable on both the aerial photographs and the baseline map. Attempts to correct for the inherent distortions of aerial photography were made during registration. Standardising the projection of the photographs to a common baseline allows meaningful spatial analysis, and the dune ridges, trailing edges and areas of bare sand were mapped from each photograph as a series of overlays. Rates of dune migration are calculated from the spatial distance between linear trend lines, parallel to the dune crests and perpendicular to the dune migration orientation, applied to sections of dune ridges for 1940 and 1993. Trend lines were only fitted to sections where continuity of dune form was maintained over the given period. The method provides an improved representation of the actual migration rate as it incorporates the whole of the parabolic dune form, and the whole of the compound dune ridge form into the calculation. It effectively measures the centre point or line of a dune or dune ridge as opposed to the variable positions and orientations of the dune crest noses, which represent maximum migration, rather than the mean. Rates of parabolic dune migration range from a minimum of 0 m year -1 to a maximum of 3.6 m year -1, with an average migration rate of 1 m year -1.

Bailey, S. D.; Bristow, C. S.

2004-04-01

359

Solar thermal power  

SciTech Connect

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 the next one for remote power, village electrification, and grid-connected power. U.S. utilities are not forecasting to need power generation capacity until the middle of the first decade of the 21{sup st} century. At that time, solar thermal electric power systems should be cost competitive with conventional power generation in some unique U.S. markets. In this paper, the authors describe the current status of the development of trough electric, dish/engine, and power tower solar generation systems. 46 refs., 20 figs., 8 tabs.

Mancini, T.R.; Kolb, G.J.; Prairie, M.R. [Sandia National Labs., Albuquerque, NM (United States)

1997-12-31

360

First multi-megawatt solar thermal power plant in India. Foreign trip report, December 5--19, 1992.  

National Technical Information Service (NTIS)

The traveler advised the Indian government regarding the proposed project to build a 30 MW solar parabolic trough power plant near Jodhpur, India. He related the experience gained from operating similar power plants at Kramer Junction, USA, and Indian eng...

G. J. Kolb

1993-01-01

361

Advances in solar thermal electricity technology  

Microsoft Academic Search

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

D. Mills

2004-01-01

362

Focus Control System for Solar Thermal Propulsion.  

National Technical Information Service (NTIS)

Solar thermal propulsion (STP) uses a parabolic concentrator like a large magnifying glass to focus the sun's energy and heat a working fluid such as hydrogen to very high temperatures (3,000 K). The hydrogen is then expelled through a nozzle to produce t...

S. R. Wassom

2000-01-01

363

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

SciTech Connect

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

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

1980-04-01

364

Electromagnetic Casimir forces of parabolic cylinder and knife-edge geometries  

SciTech Connect

An exact calculation of electromagnetic scattering from a perfectly conducting parabolic cylinder is employed to compute Casimir forces in several configurations. These include interactions between a parabolic cylinder and a plane, two parabolic cylinders, and a parabolic cylinder and an ordinary cylinder. To elucidate the effect of boundaries, special attention is focused on the 'knife-edge' limit in which the parabolic cylinder becomes a half-plane. Geometrical effects are illustrated by considering arbitrary rotations of a parabolic cylinder around its focal axis, and arbitrary translations perpendicular to this axis. A quite different geometrical arrangement is explored for the case of an ordinary cylinder placed in the interior of a parabolic cylinder. All of these results extend simply to nonzero temperatures.

Graham, Noah [Department of Physics, Middlebury College, Middlebury, Vermont 05753 (United States); Shpunt, Alexander; Kardar, Mehran [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Emig, Thorsten [Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Bat. 100, Universite Paris-Sud, 91405 Orsay cedex (France); Rahi, Sahand Jamal [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Studies in Physics and Biology, The Rockefeller University, 1230 York Street, New York, New York 10065 (United States); Jaffe, Robert L. [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Theoretical Physics and Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-06-15

365

High capability parabolic equations for elastic media propagation  

NASA Astrophysics Data System (ADS)

Parabolic equation techniques are very efficient and can provide accurate solutions for range-dependent problems, which involve environments that change in the direction of wave propagation. A traditional approach used to handle range dependence is to approximate the medium as a series of range-independent segments in which the factorization leading to the parabolic equation is exact. At the vertical interfaces between these range-independent regions, specific conditions must be applied to accurately march the solution from one region into the next. For elastic media a single-scattering correction [E. T. Kusel et al., J. Acoust. Soc. Am. 121, 808 (2007)] accurately treats solid-solid interfaces, unlike other techniques that have proven successful for fluid media. This thesis is concerned with investigating and improving the accuracy of the single-scattering correction, extending the technique to elastic environments that contain anisotropy, and obtaining new parabolic equation formulations for poro-elastic media. The parabolic equation method with a single-scattering correction allows for accurate modeling of range-dependent environments in elastic layered media. For problems with large contrasts, accuracy and efficiency are gained by subdividing vertical interfaces into a series of two or more single-scattering problems. This approach generates several computational parameters, such as the number of interface slices, an iteration convergence parameter tau, and the number of iterations n for convergence. Using a narrow-angle approximation, the choices of n = 1 and tau = 2 give accurate solutions. Analogous results from the narrow-angle approximation extend to environments with larger variations when slices are used as needed at vertical interfaces. The approach is applied to a generic ocean waveguide that includes the generation of a Rayleigh interface wave. This example is presented in both the frequency and time domains. A parabolic equation for calculating propagation in range-dependent, heterogeneous anisotropic media is developed and benchmarked. Recent progress in elastic parabolic equation development, specifically in the treatment of range dependence and heterogeneous layers, is extended to transversely isotropic (TI) elastic media. Range dependence is incorporated by the single-scattering correction. Depth dependence is treated through appropriate heterogeneous operators in the TI equations of motion. Local relationships for elastic moduli are obtained from the p and s wave speeds at specific angles [A. J. Fredricks et al., Wave Motion 31, 139 (2000)]. The approach is applied to example media consisting of TI and isotropic layers. Results show that isotropic approximations to TI layers break down when shear effects are strong. In addition, homogeneous approximations to heterogeneous layers are shown to be applicable only when the layer is too thin or when heterogeneous gradients are sufficiently small. Otherwise, the depth heterogeneity must be returned for accurate calculations. Improvements of parabolic equations for uid and elastic media are extended to formulate new versions for poro-elastic media, including models for shallow-water sediments. A previous parabolic equation solution for poro-elastic media [M. D. Collins, et al., J. Acoust. Soc. Am. 98, 1645 (1995)] does not produce accurate solutions for environments with two or more poro-elastic layers. One variable formulation developed for elastic media is generalized for a more accurate and capable poro-elastic parabolic equation. Another variable formulation is introduced with horizontal interface conditions that contain no depth derivatives higher than first-order. This characteristic should aid in treating range dependence, since discretized first-order derivatives allow convenient matching across vertical interfaces, in contrast to second-order depth derivatives which do not. Considering range-independent problems, both new formulations are superior to the original for environments containing layered poro-elastic media.

Metzler, Adam Michael

366

Solar-pumped solid-state lasers  

SciTech Connect

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

Weksler, M.; Shwartz, J.

1988-06-01

367

A Class of Degenerate Totally Nonlinear Parabolic Equations  

Microsoft Academic Search

Of concern is the following totally nonlinear parabolic equation, as well as its higher space dimensional analogue \\\\eqalign{u_t(x,t)& =\\\\beta(\\\\phi(x,u_x)u_{xx}+f(x,u,u_x)),\\\\qquad (x,t)\\\\in(0,1)\\\\times(0,\\\\infty)\\\\cr u_x(j,t)&\\\\in(-1)^j\\\\beta_j(u(j,t)),\\\\qquad j=0,1\\\\cr u(x,0)&=u_0(x).\\\\cr} Here ?0and ?1are maximal monotone graphs inR×R, and ?(t) or ??(t) might equal zero for somet, at which the equation is not uniformly parabolic. It is shown by the method of lines and nonlinear operator semigroup theory

Chin-Yuan Lin; Li-Chang Fan

1996-01-01

368

Parabolic antennas as components of communications transmitting systems. II  

NASA Astrophysics Data System (ADS)

Parabolic antennas are used to transmit or send microwaves in the dm, cm, or mm range, and must therefore have a high reflector quality and good dynamic behavior. The essential construction principles of several new parabolic antenna designs are outlined, and the application of these antennas to commercial communications systems is discussed. In particular, the German Experimental Ship antenna is described; this antenna consists of 72 individual reflectors on a circular surface, 1.5 m in diameter. A highly-exact millimeter wavelength 25 m radio-telescope has been developed by American scientists, and a 30 m radio-telescope, the reflector surface of which consists of 420 sandwiched panels, is being designed by German and French engineers. The collinear and Christiansen interferometer antenna systems and the Dutch synthesis radio-telescope are also discussed.

Eschenauer, H.; Ruesel, J.

1981-12-01

369

Energy and exergy analyses on a novel hybrid solar heating, cooling and power generation system for remote areas  

Microsoft Academic Search

In this study, a small scale hybrid solar heating, chilling and power generation system, including parabolic trough solar collector with cavity receiver, a helical screw expander and silica gel–water adsorption chiller, etc., was proposed and extensively investigated. The system has the merits of effecting the power generation cycle at lower temperature level with solar energy more efficiently and can provide

H. Zhai; Y. J. Dai; J. Y. Wu; R. Z. Wang

2009-01-01

370

Gradient Estimates for Parabolic and Elliptic Systems from Linear Laminates  

NASA Astrophysics Data System (ADS)

We establish several gradient estimates for second-order divergence type parabolic and elliptic systems. The coefficients and data are assumed to be Hölder or Dini continuous in the time variable and all but one spatial variable. This type of system arises from the problems of linearly elastic laminates and composite materials. For the proof, we use Campanato's approach in a novel way. Non-divergence type equations under similar conditions are also discussed.

Dong, Hongjie

2012-07-01

371

Parabolic compound refractive lenses for hard x rays  

Microsoft Academic Search

We describe parabolic compound refractive lenses for hard x- rays that are genuine imaging devices similar to glass lenses for visible light. They open considerable possibilities in both full field and scanning x-ray microscopy, microanalysis, and coherent scattering. They can operate in a range from about 2 keV to 100 keV, are robust, and withstand the white beam of a

Christian G. Schroer; Bruno Lengeler; Boris Benner; Marion Kuhlmann; Til F. Guenzler; Johannes Tuemmler; Christoph Rau; Timm Weitkamp; Anatoly A. Snigirev; Irina Snigireva

2001-01-01

372

Elastic stresses in bodies with elliptic, parabolic, and tunnel cracks  

Microsoft Academic Search

The paper gives explicit expressions of the elastic T-stress components T\\u000a I, T\\u000a II, and T\\u000a III for an elliptic crack in an unbounded body under uniform pressure and bending and expressions of all the T-stress components for parabolic and tunnel cracks under uniform loading. These formulas are derived by analyzing the asymptotic\\u000a behavior of the stress components near the

V. S. Kirilyuk; O. I. Levchuk

2007-01-01

373

Gain of parabolic mesh reflector antennas with arbitrary depths  

NASA Astrophysics Data System (ADS)

Analytical expressions for calculating the gain of a parabolic mesh reflector with arbitrary ratio of the focal length to aperture diameter have been derived using the method of averaged boundary conditions. The results are obtained for a dense thin-wire mesh with square cells and ideal electric contacts between conductors at junctions. Specific features of the influence of mesh topology on the gain of reflectors with various depths are considered.

Akimov, V. P.; Glybovsky, S. B.; Dubrovich, V. K.

2013-02-01

374

A PARABOLIC-HYPERBOLIC SYSTEM MODELLING A MOVING CELL  

Microsoft Academic Search

In this article, we study the existence and uniqueness of local solutions for a moving boundary problem governed by a coupled parabolic- hyperbolic system. The results can be applied to cell movement, extending a result obtained by Choi, Groulx, and Lui in 2005. r(0) = 0, f(0) = '0 > 0, w(x,0) = w0(x), (x,0) = (x) (1.4) with w0

FABIANA CARDETTI; YUNG-SZE CHOI

2009-01-01

375

Canadian low-gravity research using parabolic aircraft  

NASA Astrophysics Data System (ADS)

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.

Campbell, Glen S.; Vezina, L.; Aitken, J. F.

1992-12-01

376

Space-time adaptive wavelet methods for parabolic evolution problems  

NASA Astrophysics Data System (ADS)

With respect to space-time tensor-product wavelet bases, parabolic initial boundary value problems are equivalently formulated as bi-infinite matrix problems. Adaptive wavelet methods are shown to yield sequences of approximate solutions which converge at the optimal rate. In case the spatial domain is of product type, the use of spatial tensor product wavelet bases is proved to overcome the so-called curse of dimensionality, i.e., the reduction of the convergence rate with increasing spatial dimension.

Schwab, Christoph; Stevenson, Rob

2009-09-01

377

Photodiode Packaging Technique Using Ball Lens and Offset Parabolic Mirror  

Microsoft Academic Search

In this paper, we demonstrated the use of a photodiode (PD) packaging technique that employs a catadioptric system. This optical system consisted of two components: a BK7 ball lens with a diameter of 1.5 mm that was soldered with glass on a hermetic cap and a plastic-molded offset parabolic mirror with a radius of 550 mu m and an offset

Kiyohide Sakai; Minoru Kawano; Hiroshi Aruga; Shin-Ichi Takagi; Shin-Ichi Kaneko; Jiro Suzuki; Masato Negishi; Yousuke Kondoh; Kei-Ichi Fukuda

2009-01-01

378

A parabolic mirror time-of-flight electron energy analyzer  

Microsoft Academic Search

We have designed and built a high-efficiency time-of-flight electron spectrometer which has the potential to record accurately the angular distribution of the photoemitted electrons. This analyzer uses an electrostatic analog of an optical parabolic mirror to collimate, in an isochronic fashion, half of the electrons emitted from an isotropic point source and measure each electron’s energy by time-of-flight. Results are

D. J. Trevor; L. D. Van Woerkom; R. R. Freeman

1989-01-01

379

Spline collocation for convolutional parabolic boundary integral equations  

Microsoft Academic Search

  \\u000a \\u000a \\u000a Summary. We consider spline collocation methods for a class of parabolic pseudodifferential operators. We show optimal order convergence\\u000a results in a large scale of anisotropic Sobolev spaces. The results cover for example the case of the single layer heat operator\\u000a equation when the spatial domain is a disc.

M. Costabel; J. Saranen

2000-01-01

380

Flexible solar reflectors - II  

SciTech Connect

An analytical design of flexible solar reflectors was presented elsewhere so that a flexible material with suitable mass distribution can be suspended to have the shape of a conic with a definite focus. The simplest among these conics is the circular one. This can be built either using fabric and stitching several folds on it to attain the required mass distribution or using shelf paper and sticking it one on the other. In both cases aluminised plastic can be used as the reflecting material. For more permanent devices, better material needs to be devised. However for experimental models, the authors have used the shelf paper and fabric. The authors attempt two types of reflectors. The first one is a spherical design with a point focus, while the second one is linear focussing device to be used for thermosiphon for heating fluids. Each one is field-tested for its efficiency by measuring the insolation continuously during its operation and also the heat absorbed by the fluid. The fluid used here is water though other fluids can be attempted. The devices can be used as cookers, water heaters, air heaters and heating systems for air conditioners. The heating systems are compared with the conventional ones.

Wagh, A.S.; Chin, P.N.

1983-12-01

381

Ibragimov-type invariants for a system of two linear parabolic equations  

NASA Astrophysics Data System (ADS)

We obtain new semi-invariants for a system of two linear parabolic type partial differential equations (PDEs) in two independent variables under equivalence transformations of the dependent variables only. This is achieved for a class of systems of two linear parabolic type PDEs that correspond to a scalar complex linear (1 + 1) parabolic equation. The complex transformations of the dependent variables which map the complex scalar linear parabolic PDE to itself provide us with real transformations that map the corresponding system of linear parabolic type PDEs to itself with different coefficients in general. The semi-invariants deduced for this class of systems of two linear parabolic type equations correspond to the complex Ibragimov invariants of the complex scalar linear parabolic equation. We also look at particular cases of the system of parabolic type equations when they are uncoupled or coupled in a special manner. Moreover, we address the inverse problem of when systems of linear parabolic type equations arise from analytic continuation of a scalar linear parabolic PDE. Examples are given to illustrate the method implemented.

Mahomed, F. M.; Safdar, M.; Zama, J.

2012-08-01

382

Design of a solar power plant for freeze desalination  

Microsoft Academic Search

A solar-powered seawater desalination plant recently began operating in Yanbu, Saudi Arabia. Design and construction were funded by SOLERAS, a joint effort by the United States and Saudi Arabia to further the development and commercialization of the solar energy. The plant consists of 18 parabolic dish solar collectors with a total reflective surface of 1,445 m² and a thermal output

I. Krepchin; R. Torbin

1987-01-01

383

Nondiffracting accelerating waves: Weber waves and parabolic momentum  

NASA Astrophysics Data System (ADS)

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 a specific class of nondiffracting spatially accelerating solutions of the Maxwell equations: the Weber waves. These nonparaxial waves propagate along parabolic trajectories while approximately preserving their shape. They are expressed in an 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 solutions of the wave equation, they have implications for many linear wave systems in nature, ranging from acoustic, electromagnetic and elastic waves to surface waves in fluids and membranes.

Bandres, Miguel A.; Rodríguez-Lara, B. M.

2013-01-01

384

Concentrating Solar Power Program  

NSDL National Science Digital Library

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

1997-01-01

385

Solar thermal power plants for solar countries — Technology, economics and market potential  

Microsoft Academic Search

Solar power plants are needed to meet the growing electricity demand and at the same time to take care of the shrinking fossil resources and to reduce global CO2 emissions.In the first part of the paper the state of the art and the technical and economical development of the different solar thermal power plants (e.g. parabolic trough, central receiver and

Helmut Klaiß; Rainer Köhne; Joachim Nitsch; Uwe Sprengel

1995-01-01

386

Solar alcohol distillation system. Final report, Septemer 29, 1980-January 31, 1982  

SciTech Connect

Two gallons of alcohol were distilled using the solar distillation system in ten hours of operation. The rate was slower than expected, but this was attributed to two factors: alignment of the solar dish with the sun and proper shape of the parabolic dish. When the alignment varies more than two to three degrees, the systems output slows down drastically. Also, alignment of the parabolic shape of the dish was off slightly and a great deal of the energy was not striking the collector. This was due to deformation of the parabolic dish due to its own weight during assembly. Mathematical calculations show that the dish distance to collector if off more than 1/8 of an inch the efficiency is reduced greatly. More work should be done in the area of tracking and the shaping of the parabolic dish which can be accomplished relatively easy.

Kennedy, B.W.

1982-04-23

387

Parabolic pulse evolution in normally dispersive fiber amplifiers preceding the similariton formation regime  

NASA Astrophysics Data System (ADS)

We show analytically and numerically that parabolic pulses and similaritons are not always synonyms and that a self-phase modulation amplification regime can precede the self-similar evolution. The properties of the recompressed pulses after SPM amplification are investigated. We also demonstrate that negatively chirped parabolic pulses can exhibit a spectral recompression during amplification leading to high-power chirp-free parabolic pulses at the amplifier output.

Finot, Christophe; Parmigiani, Francesca; Petropoulos, Periklis; Richardson, David

2006-04-01

388

Solar economy and technology update  

SciTech Connect

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

Brotherton, T.K.

1983-06-01

389

Research and Development of a Low Cost Solar Collector  

SciTech Connect

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

Ansari, Asif; Philip, Lee; Thouppuarachchi, Chirath

2012-08-01

390

Application of solar thermal energy to buildings and industry  

SciTech Connect

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

Kutscher, C. F.

1981-05-01

391

Line focus solar thermal central receiver research study. Final report, April 30, 1977March 30, 1979  

Microsoft Academic Search

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

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

1979-01-01

392

Analytical and experimental study of total internal reflection prismatic panels for solar energy concentrators  

Microsoft Academic Search

For more than a year, E-Systems has pursued the analysis, design, development and testing of prismatic panels which utilize total internal reflection (TIR) to accomplish the concentration of solar energy. Such panels offer the potential of better performance at lower cost for numerous solar concentrator applications, including heliostats for Central Receiver (Power Tower) electric power plants and various parabolic concentrators.

M. J. Oneill; Y. P. Gupta

1977-01-01

393

Thermal nuclear blast simulation at the National Solar Thermal Test Facility  

Microsoft Academic Search

The National Solar Thermal Test Facility is operated by Sandia National Laboratories and located on Kirtland Air Force Base in Albuquerque, New Mexico. The facility includes a heliostat field and associated receiver tower, two solar furnaces, and two point-focus parabolic concentrators. All can be used for simulating the thermal portion of nuclear pulses. The heliostat field contains 222 computer-controlled mirrors,

C. P. Cameron; C. M. Ghanbari

1989-01-01

394

Summary of engineering-scale experiments for the Solar Detoxification of Water project  

Microsoft Academic Search

This report contains a summary of large-scale experiments conducted at Sandia National Laboratories under the Solar Detoxification of Water project. The objectives of the work performed were to determine the potential of using solar radiation to destroy organic contaminants in water by photocatalysis and to develop the process and improve its performance. For these experiments, we used parabolic troughs to

J. E. Pacheco; L. Yellowhorse

1992-01-01

395

Analysis of light guiding property in light piped based solar concentrator  

Microsoft Academic Search

Recently, many researchers have tried to design a system for indoor illumination because the benefits of solar systems. A simple parabolic reflector is often used to collect sunlight but the efficiency is poor when sunlight isn't incident normally. Therefore, an accurate machine to track sun has to be used. In order to get better tolerance, a light pipe based solar

Allen J. Whang; Chun-Hsien Chuang Jr.; Yi-Yung Chen

2008-01-01

396

Solar alcohol distillation system. Final report, Septemer 29, 1980January 31, 1982  

Microsoft Academic Search

Two gallons of alcohol were distilled using the solar distillation system in ten hours of operation. The rate was slower than expected, but this was attributed to two factors: alignment of the solar dish with the sun and proper shape of the parabolic dish. When the alignment varies more than two to three degrees, the systems output slows down drastically.

1982-01-01

397

Solar Alcohol Distillation System. Final Report, September 29, 1980-January 31, 1982.  

National Technical Information Service (NTIS)

Two gallons of alcohol were distilled using the solar distillation system in ten hours of operation. The rate was slower than expected, but this was attributed to two factors: alignment of the solar dish with the sun and proper shape of the parabolic dish...

B. W. Kennedy

1982-01-01

398

SOLAR FIBER-OPTIC MINI-DISHES: A NEW APPROACH TO THE EFFICIENT COLLECTION OF SUNLIGHT  

Microsoft Academic Search

A new concept for efficient solar energy concentration and power delivery is proposed — one that offers substantial advantages in efficiency, compactness, reduced mechanical loads, and ease of fabrication and installation relative to conventional solar designs. The design exploits the availability of low-attenuation optical fibers, as well as the practical advantages of mass producing highly accurate very small parabolic dishes.

Daniel Feuermann; Jeffrey M. Gordon

1999-01-01

399

Status of JPL's experience with thin 7809 glass for solar energy applications. Report No. 1  

Microsoft Academic Search

Through an agreement with DOE, the Solar Energy Research Institute, Golden, Colorado, has supplied JPL with a shipment of advanced, high-transmittance glass for solar thermal power applications. The glass, Corning Code 7809, is planned for use in advanced parabolic dish designs. The results of both mirror and glass inspection are documented. Surface and bulk defects are identified as well as

Bouquet

1980-01-01

400

Optimisation and Cost Analysis of a Lithium Bromide Absorption Solar Cooling System  

Microsoft Academic Search

SUMMARY This paper presents the optimisation of the various components of a lithium bromide (LiBr) absorption solar cooling system such as the type, slope and area of solar collector and storage tank size. The collector types considered are the flat plate, compound parabolic and evacuated tube collectors. The optimisation is based on an energy benefit analysis, i.e., the amount of

Georgios A. Florides; Soteris A. Kalogirou

2007-01-01

401

Two-temperature Langevin dynamics in a parabolic potential.  

PubMed

We study a planar two-temperature diffusion of a Brownian particle in a parabolic potential. The diffusion process is defined in terms of two Langevin equations with two different effective temperatures in the X and the Y directions. In the stationary regime the system is described by a nontrivial particle position distribution, P(x,y), which we determine explicitly. We show that this distribution corresponds to a nonequilibrium stationary state, characterized by the presence of space-dependent particle currents which exhibit a nonzero rotor. Theoretical results are confirmed by the numerical simulations. PMID:23848650

Dotsenko, Victor; Macio?ek, Anna; Vasilyev, Oleg; Oshanin, Gleb

2013-06-19

402

Piecewise-parabolic methods for astrophysical fluid dynamics  

SciTech Connect

A general description of some modern numerical techniques for the simulation of astrophysical fluid flow is presented. The methods are introduced with a thorough discussion of the especially simple case of advection. Attention is focused on the piecewise-parabolic method (PPM). A description of the SLIC method for treating multifluid problems is also given. The discussion is illustrated by a number of advection and hydrodynamics test problems. Finally, a study of Kelvin-Helmholtz instability of supersonic jets using PPM with SLIC fluid interfaces is presented.

Woodward, P.R.

1983-11-01

403

A New Critical Phenomenon for Semilinear Parabolic Problems  

Microsoft Academic Search

We study the Cauchy problem of the inhomogeneous semilinear parabolic equations ?u+up?ut+w=0 onMn×(0,?) with initial valueu0?0, whereMnis a Riemannian manifold with possibly nonnegative Ricci curvature. There is an exponentp* which is critical in the following sense. When 1p* the problem has a

Qi S. Zhang

1998-01-01

404

Chemically reacting mixtures in terms of degenerated parabolic setting  

NASA Astrophysics Data System (ADS)

The paper analyzes basic mathematical questions for a model of chemically reacting mixtures. We derive a model of several (finite) component compressible gas taking rigorously into account the thermodynamical regime. Mathematical description of the model leads to a degenerate parabolic equation with hyperbolic deviation. The thermodynamics implies that the diffusion terms are non-symmetric, not positively defined, and cross-diffusion effects must be strongly marked. The mathematical goal is to establish the existence of weak solutions globally in time for arbitrary number of reacting species. A key point is an entropy-like estimate showing possible renormalization of the system.

Mucha, P. B.; Pokorný, M.; Zatorska, E.

2013-07-01

405

Runge-Kutta methods for parabolic equations and convolution quadrature  

SciTech Connect

We study the approximation properties of Runge-Kutta time discretizations of linear and semilinear parabolic equations, including incompressible Navier-Stokes equations. We derive asymptotically sharp error bounds and relate the temporal order of convergence, which is generally noninteger, to spatial regularity and the type of boundary conditions. The analysis relies on an interpretation of Runge-Kutta methods as convolution quadratures. In a different context, these can be used as efficient computational methods for the approximation of convolution integrals and integral equations. They use the Laplace transform of the confolution kernal via a discrete operational calculus. 23 refs., 2 tabs.

Lubich, Ch.; Ostermann, A.

1993-01-01

406

Solar concentrator development in the United States  

SciTech Connect

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 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. 29 refs., 7 figs.

Alpert, D.J.; Mancini, T.R.; Houser, R.M.; Crossman, J.W. (Sandia National Labs., Albuquerque, NM (USA)); Schissel, P.; Carasso, M.; Jorgensen, G. (Solar Energy Research Inst., Golden, CO (USA)); Scheve, M. (USDOE, Washington, DC (USA))

1990-01-01

407

Solar concentrator development in the United States  

SciTech Connect

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 is 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. 29 refs., 7 figs.

Alpert, D.J.; Mancini, T.R.; Houser, R.M.; Grossman, J.W. (Sandia National Labs., Albuquerque, NM (United States)); Schissel, P.; Carasso, M.; Jorgensen, G. (Solar Energy Research Inst., Golden, CO (United States)); Scheve, M. (USDOE, Washington, DC (United States))

1991-03-01

408

The Piecewise Parabolic Method for Multidimensional Relativistic Fluid Dynamics  

NASA Astrophysics Data System (ADS)

We present an extension of the piecewise parabolic method to special relativistic fluid dynamics in multidimensions. The scheme is conservative, dimensionally unsplit, and suitable for a general equation of state. Temporal evolution is second-order accurate and employs characteristic projection operators; spatial interpolation is piecewise parabolic making the scheme third-order accurate in smooth regions of the flow away from discontinuities. The algorithm is written for a general system of orthogonal curvilinear coordinates and can be used for computations in non-Cartesian geometries. A nonlinear iterative Riemann solver based on the two-shock approximation is used in flux calculation. In this approximation, an initial discontinuity decays into a set of discontinuous waves only implying that, in particular, rarefaction waves are treated as flow discontinuities. We also present a new and simple equation of state that approximates the exact result for the relativistic perfect gas with high accuracy. The strength of the new method is demonstrated in a series of numerical tests and more complex simulations in one, two, and three dimensions.

Mignone, A.; Plewa, T.; Bodo, G.

2005-09-01

409

Blow-up in semilinear parabolic equations with weak diffusion  

NASA Astrophysics Data System (ADS)

Finite time blow-up in the semilinear reactive-diffusive parabolic equation ?1 = µ?xx + e? is examined in the limit of weak diffusion \\micro\\ll 1parabolic equations that exhibit finite time blow-up in order to reveal the associated focusing structure.

Short, Mark; Kapila, Ashwani K.

1998-09-01

410

a Piecewise Parabolic Method for Barotropic Two-Fluid Flows  

NASA Astrophysics Data System (ADS)

In this paper, a third-order Piecewise Parabolic Method for barotropic two-fluid flows with Tait equation of state is presented. In transition layers between two different fluids, a mixture model system based on the assumption of equilibrium pressure is introduced. It conserves the mass of each fluid, the total momentum and energy of the mixture and is supplemented with an advection equation for the volume fraction of one of the two fluids. To close the model and recover the pressure, a nonbarotropic equation of state describing the thermodynamic properties of the mixture is used. However, in pure barotropic fluid regions, the isentropic version of Euler equations is employed. In addition, the third-order Piecewise Parabolic Method is employed to solve the model equations. The governing equations are first evolved in the Lagrangian coordinate system and then the computed results are mapped onto the fixed Eulerian grid in the following remapping step. As compared with other methods, a remarkable feature of our approach is that the scheme is third-order accurate in smooth regions of the solution and is able to give a steeper representation of discontinuities. Numerical results demonstrate satisfactory performances of this approach.

Zheng, J. G.; Lee, T. S.; Ma, D. J.

411

Altered osteoblast structure and function in parabolic flight  

NASA Astrophysics Data System (ADS)

Introduction Bone loss has a significant impact on astronauts during spaceflight being one of the main obstacles preventing interplanetary missions However the exact mechanism is not well understood In the present study we investigated the effects of acute gravitational changes generated by parabolic flight on the structure and function of osteoblasts ROS17 2 8 carried by airbus A300 Methods The alteration of microfilament cytoskeleton was observed by the Texas red conjugated Phalloidin and Alexa Fluor 488 conjugated DNase I immunofluorescence stain ALP activity and expression COL1A1 expression osteocalcin secrete which presenting the osteoblast function were detected by modified calcium and cobalt method RT-PCR and radioimmunity methods respectively Results The changed gravity induced the reorganization of microfilament cytoskeleton of osteoblast After 3 hours parabolic flight F-actin of osteoblast cytoskeleton became more thickness and directivity whereas G-actin reduced and relatively concentrated at the edge of nucleus observed by confocal fluorescence microscopy This phenomenon is identical with structure alternation observed in hypergravity but the osteoblast function decrease The excretion of osteocalcin the activity and mRNA expression of ALP decrease but the COL1A1 expression has no changes These results were similar to the changes in simulated or real microgravity Conclusion Above results suggest that short time gravity alternative change induce osteoblast structure and function

Zhong-Quan, Dai; Ying-Hui, Li; Fen, Yang; Bai, Ding; Ying-Jun, Tan

412

Using Parabolic Equation for Calculation of Beam Impedance  

SciTech Connect

In this paper we develop a new method of parabolic equation (PE) for calculation of both high-frequency and small-angle taper (or collimator) impedances. The applicability of PE in the high-frequency limit is based on the observation that in this case the contribution to impedance comes from the waves that catch up the beam far from the obstacle and propagate at small-angles to the axis of the pipe. One of the most important advantages of PE is that it eliminates the spatial scale of the small wavelength from the problem. As a result, the numerical solution of PE requires coarser spatial meshes. In the paper we focus on the longitudinal impedance for an axisymmetric geometry and assume a perfect conductivity of the walls. We show how the known analytical results which include a small-angle collimator, step-in and step-out transitions, and a pillbox cavity, can be derived within the framework of the parabolic equation.

Stupakov, Gennady; /SLAC

2006-04-07

413

Restrictive Taylor’s approximation for two dimensions initial boundary value problem for parabolic PDE  

Microsoft Academic Search

Treatment initial boundary value problem for parabolic PDE by finite difference approximation has many difficulties for accuracy and complexity. The restrictive Padé and restrictive Taylor (RT) approximations are discussed in many physical and engineering problems. This work is discussing RT approximation for two dimensions initial boundary value problem for parabolic PDE. We estimate an error upper bound, also we drive

Hassan N. A. Ismail; Elsayed M. E. M. Elbarbary; Ghada S. E. Salem

2004-01-01

414

Parabolic focusing pyrolytic graphite x-ray monochromator (abstract)a)  

Microsoft Academic Search

The results of the experimental testing of the parabolic focusing pyrolytic graphite x-ray monochromator (mono) on the wiggler (2 T) synchrotron radiation (SR) beamline of the VEPP-3 storage ring are presented. The monochromatization and the focusing of x radiation in both vertical and horizontal directions are provided by the optical properties of the parabolic surface of revolution of the properly

I. P. Dolbnya; K. V. Zolotarev; M. A. Sheromov; A. A. Antonov; I. G. Grigoryeva

1995-01-01

415

Boundary variation for non-autonomous parabolic equations with Neumann boundary condition  

NASA Astrophysics Data System (ADS)

We study the behavior of solutions of non-autonomous parabolic equations subject to Neumann boundary condition under perturbation of the domain. We prove the convergence of solutions of parabolic equations under domain perturbation by variational methods using suitable assumptions on the sequence of perturbed domains which also give the convergence of solutions under domain perturbation for elliptic equations.

Ngiamsunthorn, Parinya Sa

2013-09-01

416

What happens to the human heart in space? - Parabolic flights provide some answers  

Microsoft Academic Search

Aircraft parabolic flights provide up to 20 seconds of reduced gravity repeatedly during ballistic flight manoeuvres. They are used to conduct short microgravity investigations in the physical- and life-sciences, to test instrumentation and to train astronauts for forthcoming space flights. The real value of parabolic flights lies, however, in the verification tests that can be conducted prior to taking experiments

André E. Aubert; Frank Beckers; Bart Verheyden; Vladimir Plester

2004-01-01

417

Parabolic Harnack inequality and heat kernel estimates for random walks with long range jumps  

Microsoft Academic Search

We investigate the relationships between the parabolic Harnack inequality, heat kernel estimates, some geometric conditions,\\u000a and some analytic conditions for random walks with long range jumps. Unlike the case of diffusion processes, the parabolic\\u000a Harnack inequality does not, in general, imply the corresponding heat kernel estimates.

Martin T. Barlow; Richard F. Bass; Takashi Kumagai

2009-01-01

418

High Resolution Parabolic Radon Transform by Frequency Domain Method for Eliminating Multiple  

Microsoft Academic Search

Parabolic Radon transform (PRT) is one of the most effective methods to eliminate multiple. Based on model study and programming, the article shows the physical signification of FPRT firstly, then presents the theories and implementation processes about the forward and inverse parabolic Radon transform infrequency domain. It also discusses the aliasing in radon domain, the stability of radon transform, the

Junhua Zhang; Cun Yang; Hui Xu; Haicheng Yu; Lianyu Shan

2008-01-01

419

Enhancement of directivity of source radiation using parabolic cylinder made of left-handed metamaterials  

Microsoft Academic Search

We explore radiation of a line source within a parabolic cylinder made of left-handed metamaterials. The far field radiation patterns show the metamaterial parabolic cylinder can enhance the directivity of the line source radiation. It is found that the focal length and the feature length of the parabola affect the directivity. Further improvement of the directivity is realized by changing

Da-yong Zou; Rui-xin Wu; Ping Chen; Min Liu

2010-01-01

420

Focusing of hard x-rays with SU8 resist planar parabolic refractive lenses  

Microsoft Academic Search

Planar parabolic refractive lenses are one important kind of compound refractive lenses which are used in the third generation synchrotron radiation sources as an x-ray focusing device. In order to test the influence of the number of the individual lens on the transmission and gain, a set of 30 micro-focusing planar parabolic lenses with different number (from 1 to 30)

Chengchao Huang; Baozhong Mu; Zhanshan Wang; Yangchao Tian; Gang Liu; Guoqiang Pan

2009-01-01

421

A numerical approach to resistance reduction of displacement vessels using parabolic waterlines  

Microsoft Academic Search

The addition of parabolic side bulbs at the ship's midbody can significantly reduce the wave-making resistance of a vessel. The parabolic bulbs are strategically placed to create a wave pattern that interacts with the shoulder wave system of the base hull at the desired speed range. This concept was first successfully tested on a coaster tanker and then extended to

Dan Vyselaar; Voytek Klaptocz; S. M. Calisal

2007-01-01

422

Filamentation length for femtosecond laser radiation focused by conic and parabolic lenses  

NASA Astrophysics Data System (ADS)

Special features of filamentation of femtosecond laser radiation focused by parabolic lens and axicon are considered. Based on numerical solution of the nonstationary Schrödinger equation, simple expressions are derived for calculation of the filamentation length for laser radiation focused by the parabolic lens and axicon depending on the radiation power and focal lengths.

Zemljanov, A. A.; Bulygin, A. D.; Minina, O. V.

2013-08-01

423

Field solar E. coli inactivation in the absence and presence of TiO 2: is UV solar dose an appropriate parameter for standardization of water solar disinfection?  

Microsoft Academic Search

Evaluation of solar treatment in the absence and presence of TiO2 has been made to assess its effectiveness in reducing bacterial load with respect to drinking water standards.Field experiments under direct solar radiation were carried out using a compound parabolic collector (CPC) placed at the Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland. Water contaminated with E. coli K12 was

Angela-Guiovana Rincón; Cesar Pulgarin

2004-01-01

424

An Iterative Numerical Method for the Incompressible Mean Flow over Parabolic Bodies.  

NASA Astrophysics Data System (ADS)

A new numerical method for solving the steady incompressible flow over parabolic bodies is presented. This is motivated by the need for obtaining an accurate solution of the basic flow for use in the solution of the unsteady boundary layer flow for determining leading edge receptivity by the method of Haddad & Corke(J. Fluid Mech.), 368, 1998. The method is a solution of the steady, nonlinear Navier-Stokes equations in streamfunction-vorticity form, in parabolic coordinates. A numerical, finite difference iterative technique was developed which is always stable, always convergent, converges to machine-zero accuracy, is very fast, and always converges to the unique solution regardless of the initial conditions for a given physical case. The method will be demonstrated for a family of parabolic bodies at different angles of attack, and compared to other approaches including ADI used by Davis(J. Fluid Mech.), 51, 3, 1972 for parabolic bodies in parabolic coordinates.

Erturk, E.; Corke, T. C.

1998-11-01

425

Simulation of a solar powered vapor compression desalination system (SPRVCD)  

Microsoft Academic Search

This article is concerned with the analysis of a solar powered vapor compression desalination system. It consists of three loops, namely, a collector loop, a power loop, and a vapor compression desalination loop. The system is operated by a parabolic collector trough of concentration 4 and R11 as a working fluid with an optimum boiler firing temperature of 410°K. A

K. A. Fathalah; M. A. Darwish; S. E. Aly

1983-01-01

426

Development of concentrating collectors for solar thermal systems  

SciTech Connect

Concentrating solar collectors are required to generate the elevated temperatures that can be used to efficiently power industrial and electric conversion processes. The development and improvement of cost effective, highly innovative, heliostats and parabolic dish collectors, and supporting design and materials research are reviewed. 28 refs., 8 figs., 1 tab.

Holmes, J.T.; Alpert, D.J.; Mancini, T.R.; Murphy, L.M.; Schissel, P.O.

1989-01-01

427

Photocatalytic destruction of chlorinated solvents in water with solar energy  

Microsoft Academic Search

Sandia National Laboratories and the National Renewable Energy Laboratory are developing a photocatalytic process to destroy organic contaminants in water. Tests with common water pollutants have been conducted at Sandia's Solar Thermal Facility using a near commercial scale, single-axis tracking parabolic trough system with a glass pipe reactor mounted at its focus. Experiments at this scale provide verification of laboratory

J. E. Pacheco; M. R. Prairie; L. Yellowhorse

1993-01-01

428

State-of-the-art solar trough collector  

Microsoft Academic Search

The Department of Energy and Acurex Corporation have joined in a cooperative agreement to accelerate producibility and commercial availability of major line focus parabolic trough solar collector system components. The Acurex goal is to develop the next generation collector based on 4 years' experience with the current generation. As in the past, the primary applications for the new collector will

D. Youmans; D. Bell; R. Carlton

1981-01-01

429

Testing of Stirling engine solar reflux heat-pipe receivers.  

National Technical Information Service (NTIS)

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 ...

S. Rawlinson P. Cordeiro V. Dudley T. Moss

1993-01-01

430

About Migration of Asteroids and Comets within Solar System  

Microsoft Academic Search

The paper presents the results of investigation of the dynamical behaviour of small solar system objects with model orbits similar to SOHO comets, assuming their orbits to be near parabolic. The numerical integration of the equation of motion of the objects showed that the bodies periodically change their inclination, eccentricities, and perihelion distances within a rather wide range. During this

E. M. Pittich; N. A. Solovaya

2004-01-01

431

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

SciTech Connect

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

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

1990-12-01

432

Effects of thermoplastic resin content of anisotropic conductive films on the pressure cooker test reliability of anisotropic conductive film flip-chip assembly  

NASA Astrophysics Data System (ADS)

The flip-chip technology using anisotropic conductive films (ACFs) is gaining growing interest due to its technical advantages such as environmentally friendly, simpler, and lower cost processes. Electrical performances and reliability of ACF flip-chip assembly depend on thermomechanical properties of ACF polymer resins. In this paper, the changes in ACF resin morphology due to the phase separation of thermoplastics, and subsequent changes of physical and mechanical properties were investigated as a function of thermoplastic contents of ACF formulation. Furthermore, the pressure cooker test (PCT) reliability of ACF flip-chip assemblies with various thermoplastic contents was also investigated. As thermoplastic contents increased, coefficient of thermal expansion (CTE) of ACFs increased, and elastic modulus (E?) of ACFs decreased. In contrast, water absorption rate decreased as thermoplastic content increased. As a result, PCT reliability of ACF flip-chip assembly was improved adding up to 50 wt.% content of thermoplastic.

Hwang, J. W.; Yim, M. J.; Paik, K. W.

2005-11-01

433

Air Brayton Solar Receiver, phase 2  

NASA Astrophysics Data System (ADS)

An air Brayton solar receiver (ABSR) is discussed. The ABSR consists of a cylindrical, insulated, offset plate fin heat exchanger which is mounted at the focal plane of a fully tracking parabolic solar collector. The receiver transfer heat from the concentrated solar radiation (which impinges on the inside walls of the heat exchanger) to the working fluid i.e., air. The hot air would then e used to drive a small Brayton cycle heat engine. The engine in turn drives a generator which produces electrical energy. Symmetrical and asymmetrical solar power input into the ABSR are analyzed. The symmetrical cases involve the baseline incident flux and the axially shifted incident fluxes. The asymmetrical cases correspond to the solar fluxes that are obtained by reduced solar input from one half of the concentrator or by receiver offset of plus or minus 1 inch from the concentrator optical axis.

Deanda, L. E.

1981-12-01

434

4-E (energy–exergy–environmental–economic) analyses of line-focusing stand-alone concentrating solar power plants  

Microsoft Academic Search

In this study, energy–exergy–environmental–economic (4-E) analyses of stand-alone line-focusing concentrating solar power plants are carried out for different plant capacities ranging from 1 to 50 MWe<\\/sub>. Solar power plants based on concentrating power technologies are used to harness the solar radiation effectively. Among the solar power technologies, line-focusing concentrating systems such as linear Fresnel reflector (LFR) and parabolic trough collector

K. Ravi Kumar; K. S. Reddy

2012-01-01

435

Eigenmode Structure in Solar-Wind Langmuir Waves  

Microsoft Academic Search

We show that observed spatial- and frequency-domain signatures of intense solar-wind Langmuir waves can be described as eigenmodes trapped in a parabolic density well. Measured solar-wind electric field spectra and waveforms are compared with 1D linear solutions and, in many cases, can be represented by 1 3 low-order eigenstates. To our knowledge, this report is the first observational confirmation of

R. E. Ergun; D. M. Malaspina; Iver H. Cairns; M. V. Goldman; D. L. Newman; P. A. Robinson; S. Eriksson; J. L. Bougeret; C. Briand; S. D. Bale; C. A. Cattell; P. J. Kellogg; M. L. Kaiser

2008-01-01

436

Conceptual design of a glass-reinforced concrete solar collector  

Microsoft Academic Search

An investigation of the properties and characteristics of glassfiber-reinforced concrete (GRC) was made to determine its suitability as a reflector substrate and structure for heliostats and solar collectors. The material properties and characteristics of GRC were established by tests on small flat panels. A conceptual design of a 2-m x 6-m parabolic trough solar collector module and a preliminary production-cost

A. J. Slemmons; D. W. Ploeger; R. Lundgren

1981-01-01

437

Testing of Stirling engine solar reflux heat-pipe receivers  

Microsoft Academic Search

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

S. Rawlinson; P. Cordeiro; V. Dudley; T. Moss

1993-01-01

438

Conceptual design of a glass-reinforced concrete solar collector  

SciTech Connect

An investigation of the properties and characteristics of glassfiber-reinforced concrete (GRC) was made to determine its suitability as a reflector substrate and structure for heliostats and solar collectors. The material properties and characteristics of GRC were established by tests on small flat panels. A conceptual design of a 2-m x 6-m parabolic trough solar collector module and a preliminary production-cost analysis were also completed.

Slemmons, A.J.; Ploeger, D.W.; Lundgren, R.

1981-07-01

439

Solar probe technology challenges  

SciTech Connect

A mission close to the sun is only possible if new spacecraft technologies can be developed and incorporated into a state-of-the-art spacecraft concept. The perihelion goal of 4 solar radii requires a shielded spacecraft that can tolerate the almost 3000 suns solar flux while maintaining the electronics components at room temperature. In addition, the shield surface should sublimate at a rate of less than 3mg/s at perihelion. Many shield configuration designs have been studied and the most promising is a parabolic shape that functions as both a shield and a large high gain antenna. The shield material chosen for this design is a carbon-carbon material with highly emissive surface properties. A mission requirement for a high telecommunications power stems from the expected interference when attempting to transmit data through the solar corona. It is expected that the large carbon-carbon shield/antenna will have a high power gain even at high temperatures and will return adequate telemetry at the X-band radio frequency chosen for the Solar Probe mission. Other key technology needs include a non-nuclear power subsystem that can function in the extreme environments of the mission from Earth to Jupiter and onward to a 4 solar radii perihelion. {copyright} {ital 1996 American Institute of Physics.}

Randolph, J.E.; Miyake, R.N.; Nesmith, B.J. [Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, California 91109 (United States); Dirling, R.B. Jr. [Science Applications International Corporation, Material Technologies Division, 18350 Mt. Langley Street, Fountain Valley, California 92708 (United States); Howard, R.J. [Space Physics Division, Code SS, NASA Headquarters, Washington, District of Columbia 20546 (United States)

1996-03-01

440

Recurrence time distribution in mushroom billiards with parabolic hat  

NASA Astrophysics Data System (ADS)

The recurrence time distribution of mushroom billiards with a parabolic-shaped hat is investigated. Classical dynamics exhibits sharply divided phase space, and the recurrence time distribution obeys the algebraic law like well-known classes of billiards. However, due to the existence of a specific type of marginally unstable periodic orbits that forms a crossing in phase space, the sticky motion occurs not as a simple drift along the straight line. Numerical experiments reveal and also theoretical analyses predict that an exponent for the cumulative recurrence time distribution approaches 2 in the asymptotic regime, but in a relatively small recurrence time scale it significantly deviates from the predicted universality, which is explained by the slowdown behavior around a crossing point of the periodic orbit family.

Tanaka, Hiroyuki; Shudo, Akira

2006-09-01

441

Three-dimensional rogue waves in nonstationary parabolic potentials  

SciTech Connect

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.

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

442

Development effort of Sheet Molding Compound (SMC) parabolic trough panels  

NASA Astrophysics Data System (ADS)

The approach taken to meet the objectives was to design the parabolic panel, fabricate a prototype die, choose an SMC formulation and mold the glass and SMC together into a vertex to rim mirrored panel. The main thrust of the program was to successfully co-mold a mirrored glass sheet with the SMC. Results indicate that mirrored glass sheets, if properly strengthened to withstand the temperature and pressure of the molding process, can be successfully molded with SMC in a single press stroke using standard compression molding techniques. The finalized design of the trough panel is given. The SMC formulation chosen is a low shrink, low profile SMC using 40% by weight one inch chopped glass fibers in a uv stabilized polyester resin matrix. A program to test for the adhesion between mirrored glass sheets and the SMC is discussed briefly.

Kirsch, P. A.; Champion, R. L.

443

Parabolic approximation method for the mode conversion-tunneling equation  

SciTech Connect

The derivation of the wave equation which governs ICRF wave propagation, absorption, and mode conversion within the kinetic layer in tokamaks has been extended to include diffraction and focussing effects associated with the finite transverse dimensions of the incident wavefronts. The kinetic layer considered consists of a uniform density, uniform temperature slab model in which the equilibrium magnetic field is oriented in the z-direction and varies linearly in the x-direction. An equivalent dielectric tensor as well as a two-dimensional energy conservation equation are derived from the linearized Vlasov-Maxwell system of equations. The generalized form of the mode conversion-tunneling equation is then extracted from the Maxwell equations, using the parabolic approximation method in which transverse variations of the wave fields are assumed to be weak in comparison to the variations in the primary direction of propagation. Methods of solving the generalized wave equation are discussed. 16 refs.

Phillips, C.K.; Colestock, P.L.; Hwang, D.Q.; Swanson, D.G.

1987-07-01

444

The third ESA Student Parabolic-Flight Campaign.  

PubMed

Today's students will become tomorrow's workforce and hence they should be involved in the global space programme as early as possible so that they will be motivated to follow space careers and create a space-educated next generation for working within the space domain. Getting students involved in today's space programmes is important not only for the space industry in terms of providing a talented workforce for the future, but also for the general public who will be the future voters and potential political supporters of future European space activities. With this in mind, ESA's Office for Education and Outreach organises and runs many space-related activities for young people in order to stimulate their interest in space in particular and in science in general. One of these activities is the 'Student Parabolic-Flight Campaign'. PMID:15008203

Ockels, W J; Jagger-Meziere, L

2001-02-01

445

Tempered random attractors for parabolic equations in weighted spaces  

NASA Astrophysics Data System (ADS)

This paper deals with the asymptotic behavior of solutions of parabolic equations on unbounded domains which contain stochastic terms as well as non-autonomous deterministic terms. We define a continuous random dynamical system for the equations in weighted Sobolev spaces that allow functions to have certain polynomial growth rate at infinity and hence include all bounded solutions. We prove pullback asymptotic compactness of solutions as well as the existence and uniqueness of tempered random attractors in the weighted spaces. The structures of the tempered attractors are fully characterized by tempered complete solutions. In the case where the non-autonomous deterministic terms are periodic in time, we show that the tempered random attractors are also periodic in time. To overcome the difficulty of non-compactness of Sobolev embeddings on unbounded domains, the idea of uniform pathwise estimates on the tails of solutions is employed to show asymptotic compactness.

Bates, Peter W.; Lu, Kening; Wang, Bixiang

2013-08-01

446

A solution to the problem of invariants for parabolic equations  

NASA Astrophysics Data System (ADS)

The article is devoted to the solution of the invariants problem for the one-dimensional parabolic equations written in the two-coefficient canonical form used recently by N.H. Ibragimov: ut-uxx+a(t,x)ux+c(t,x)u=0. A simple invariant condition is obtained for determining all equations that are reducible to the heat equation by the general group of equivalence transformations. The solution to the problem of invariants is given also in the one-coefficient canonical ut-uxx+c(t,x)u=0. One of the main differences between these two canonical forms is that the equivalence group for the two-coefficient form contains the arbitrary linear transformation of the dependent variable whereas this group for the one-coefficient form contains only a special type of the linear transformations of the dependent variable.

Ibragimov, N. H.; Meleshko, S. V.

2009-06-01

447

Global existence for semilinear parabolic systems via Lyapunov type methods  

Microsoft Academic Search

We consider semilinear parabolic systems of partial differential equations of the form \\u000a \\u000a \\u000a \\u000a \\u000a $u_t \\\\left( {t,x} \\\\right) = D\\\\Delta u\\\\left( {t,x} \\\\right) + f\\\\left( {u\\\\left( {t,x} \\\\right)} \\\\right)t > 0,x \\\\in \\\\Omega$u_t \\\\left( {t,x} \\\\right) = D\\\\Delta u\\\\left( {t,x} \\\\right) + f\\\\left( {u\\\\left( {t,x} \\\\right)} \\\\right)t > 0,x \\\\in \\\\Omega\\u000a \\u000a \\u000a \\u000a ((1))\\u000a \\u000a \\u000a with bounded initial data and homogeneous Neumann boundary conditions, where

Jeff Morgan

448

A polynomial based iterative method for linear parabolic equations  

SciTech Connect

A new polynomial based method (PBM) is developed to integrate multi-dimensional linear parabolic initial-boundary-value problems. It is based on L/sub 2/-approximations to f(z) = (1 - exp(-z))/z, f(0) = 1, over ellipses in the complex plane using expansions of f in Chebychev polynomials. The calculation of the Fourier coefficients requires numerical integration over only a single line segment in the complex plane whose length and orientation depend on the step size and the parabolic operator itself. The simplicity with which these coefficients are obtained rests on special properties of the Chebychev polynomials. Most of the work in PBM consists of matrix-vector multiplications, involving a matrix L which arises from the spatial discretization of the differential operator. To be specific, PBM integrates the semi-discrete problem u/sub t/ = L(t)u + b(t), u,b in R/sup n/ and L in R/sup n x n/, and requires only a modest amount of storage (a few vectors of order n). Due to the analyticity of f it has good convergence properties and compares favorably to other standard methods from the classes of Hopscotch, Alternating Direction Implicit (ADI) and Locally One-Dimensional (LOD) schemes, as measured by the CPU-times required on a single CPU of a CRAY X-MP/24. It is also competitive with Crank-Nicolson which we couple with two proven iterative solvers. I recommend PBM on problems which require fourth order spatial accuracy, problems whose solutions contain significant high-frequency components, and problems whose operators cannot be split conveniently in an ADI or LOD fashion (for example, problems with mixed derivatives). 30 refs., 11 figs., 12 tabs.

Schaefer, M.J.

1987-05-01

449

The small community solar thermal power experiment  

Microsoft Academic Search

Contractors were asked to develop a preferred system concept, to perform sensitivity analyses, and to outline recommended approaches for the follow-on design program of a one-megawatt solar thermal demonstration plant. The systems recommended by the contractors in each of the categories were: (1) McDonnell-Douglas Astronautics Company: Central tower with field of south-facing heliostats; (2) General Electric Company: Field of parabolic

T. Kiceniuk

1981-01-01

450

Invariant differential operators for non-compact Lie algebras parabolically related to conformal Lie algebras  

NASA Astrophysics Data System (ADS)

In the present paper we continue the project of systematic construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we call 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduce the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G ' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. Thus, we consider the exceptional algebra E 7(7) which is parabolically related to the CLA E 7(-25) , the parabolic subalgebras including E 6(6) and E 6(-26). Other interesting examples are the orthogonal algebras so(p, q) all of which are parabolically related to the conformal algebra so( n, 2) with p + q = n + 2, the parabolic subalgebras including the Lorentz subalgebra so( n - 1, 1) and its analogs so( p - 1, q - 1). We consider also E6(6) and E6(2) which are parabolically related to the hermitian symmetric case E6(-14) , the parabolic subalgebras including real forms of sl(6). We also give a formula for the number of representations in the main multiplets valid for CLAs and all algebras that are parabolically related to them. In all considered cases we give the main multiplets of indecomposable elementary representations including the necessary data for all relevant invariant differential operators. In the case of so( p, q) we give also the reduced multiplets. We should stress that the multiplets are given in the most economic way in pairs of shadow fields. Furthermore we should stress that the classification of all invariant differential operators includes as special cases all possible conservation laws and conserved currents, unitary or not.

Dobrev, V. K.

2013-02-01

451

Three-dimensional finite-energy Airy self-accelerating parabolic-cylinder light bullets  

NASA Astrophysics Data System (ADS)

We investigate the propagation of localized three-dimensional spatiotemporal Airy self-accelerating parabolic-cylinder light bullets in a linear medium. In particular, we consider the effects resulting from utilizing initial finite-energy Airy wave packets to accelerate these localized beams in the absence of any external potential. A general localized light bullet solution with the joint Airy pulse characteristics and parabolic-cylinder spatial characteristics is obtained in the Cartesian coordinates, using parabolic-cylinder and Airy functions. Our results show that the localized wave packets can retain their intensity features and still be accelerated over several Rayleigh lengths.

Zhong, Wei-Ping; Beli?, Milivoj R.; Huang, Tingwen

2013-09-01

452

Vortex shedding and galloping of open semi-circular and parabolic cylinders in cross-flow  

NASA Astrophysics Data System (ADS)

An experimental wind-tunnel study was undertaken to investigate the flow-induced vibration behaviour of open semi-circular and parabolic cylinders in cross-flow. The motivation for the research was to investigate the cause of the fatigue failures of a number of parabolic section rotary mixing blades in a large mixing vessel. Results are presented for force coefficients as a function of angle of incidence of the flow, Strouhal number and amplitude response. It is shown that the parabolic cylinder is subject to large amplitude vortex shedding resonance and, when the elastic axis is sufficiently downstream of the section's centre of gravity, galloping instability.

Weaver, D. S.; Veljkovic, I.

2005-11-01

453

Components Makeover Gives Concentrating Solar Power a Boost (Fact Sheet), The Spectrum of Clean Energy Innovation  

SciTech Connect

Parabolic trough technology is the most mature of the various concentrating solar power (CSP) options. But scientists at the National Renewable Energy Laboratory (NREL) continue to make advances on trough systems through innovative research on various components in industrial partnerships with Acciona Solar Power, SkyFuel, Schott Solar, and others. The results are leading to improved system efficiencies and lower costs for CSP plants.

Not Available

2010-12-01

454

Universal solar energy desalination system  

NASA Astrophysics Data System (ADS)

Design considerations to allow site-dependent flexibility in the choice of solar/wind powered desalinization plant configurations are discussed. A prototype design was developed for construction of 6300 cu m per day brackish water treatment in Brownsville, TX. The water is treated to reduce the amount of suspended solids and prevent scaling. A reverse osmosis unit processes the treated liquid to recover water at a ratio of 90%. The power system comprises a parabolic trough solar thermal system with an organic Rankine cycle generator, rock-oil thermal storage, and 200 kW wind turbines. Analysis of the complementarity of the solar and wind subsystems indicates that at any site one system will supplement the other. Energy storage, e.g., battery banks, would increase system costs to unacceptable levels. Climatic conditions will significantly influence the sizing of each segment of the total power system.

Fusco, V. S.

455

Motion Sickness Precipitated in the Weightless Phase of Parabolic Flight by Coriolis Accelerations.  

National Technical Information Service (NTIS)

Nineteen normal persons and three deaf subjects with bilateral loss of labyrinthine function (L-D subjects) were exposed to Coriolis accelerations during the brief periods of weightlessness in parabolic flighy by having them move their heads while rotatin...

A. Graybiel R. S. Kennedy R. S. Kellogg

1969-01-01

456

Examination of wall functions for a Parabolized Navier-Stokes code for supersonic flow.  

National Technical Information Service (NTIS)

Solutions from a Parabolized Navier-Stokes (PNS) code with an algebraic turbulence model are compared with wall functions. The wall functions represent the turbulent flow profiles in the viscous sublayer, thus removing many grid points from the solution p...

T. H. Alsbrooks

1993-01-01

457

Atmospheric Sensitivity and Validation Study of the Variable Terrain Radio Parabolic Equation Model (VTRPE).  

National Technical Information Service (NTIS)

The Variable Terrain Radio Parabolic Equation (VTRPE) computer model is a powerful and flexible program that provides calculations of the radar propagation conditions of the atmosphere. This study quantifies the sensitivity of the VTRPE model to the accur...

M. K. Doggett

1997-01-01

458

Solving Parabolic Integro-Differential Equations by an Explicit Integration Method.  

National Technical Information Service (NTIS)

The numerical integration in time of nonclassical parabolic initial boundary value problems which involve nonlocal integral terms over the spatial domain is described. The integral terms may appear in the boundary conditions and/or on the governing partia...

A. S. Vasudevamurthy J. G. Verwer

1991-01-01

459

Accurate, Stable, Explicit, Parabolized Navier-Stokes Solver for High Speed Flows,  

National Technical Information Service (NTIS)

A stable, accurate, and efficient implementation of MacCormack's explicit algorithm for the Parabolized Navier Stokes equations is demonstrated. The familiar problem of decoding the conservative axial flux vector is solved, resulting in accurate, smooth d...

T. P. Gielda D. S. McRae

1986-01-01

460

Explicit, Upwind Algorithm for Solving the Parabolized Navier-Stokes Equations.  

National Technical Information Service (NTIS)

An explicit, upwind algorithm was developed for the direct (noniterative) integration of the 3-D Parabolized Navier-Stokes (PNS) equations in a generalized coordinate system. The new algorithm uses upwind approximations of the numerical fluxes for the pre...

J. J. Korte

1989-01-01

461

Explicit Upwind Algorithm for Solving the Parabolized Navier-Stokes Equations.  

National Technical Information Service (NTIS)

An explicit, upwind algorithm was developed for the direct (noniterative) integration of the 3-D Parabolized Navier-Stokes (PNS) equations in a generalized coordinate system. The new algorithm uses upwind approximations of the numerical fluxes for the pre...

J. J. Korte

1991-01-01

462

Generalized Directional Gradients, Backward Stochastic Differential Equations and Mild Solutions of Semilinear Parabolic Equations  

SciTech Connect

We study a forward-backward system of stochastic differential equations in an infinite-dimensional framework and its relationships with a semilinear parabolic differential equation on a Hilbert space, in the spirit of the approach of Pardoux-Peng. We prove that the stochastic system allows us to construct a unique solution of the parabolic equation in a suitable class of locally Lipschitz real functions. The parabolic equation is understood in a mild sense which requires the notion of a generalized directional gradient, that we introduce by a probabilistic approach and prove to exist for locally Lipschitz functions.The use of the generalized directional gradient allows us to cover various applications to option pricing problems and to optimal stochastic control problems (including control of delay equations and reaction-diffusion equations),where the lack of differentiability of the coefficients precludes differentiability of solutions to the associated parabolic equations of Black-Scholes or Hamilton-Jacobi-Bellman type.

Fuhrman, Marco [Dipartimento di Matematica, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano (Italy)], E-mail: marco.fuhrman@polimi.it; Tessitore, Gianmario [Dipartimento di Matematica, Universita di Parma, via d'Azeglio 85, 43100 Parma (Italy)], E-mail: gianmario.tessitore@unipr.it

2005-05-15

463

A compact alternate direct implicit difference method for solving parabolic equation of multi-dimension  

Microsoft Academic Search

A compact alternate direct implicit difference method for multi-dimensional parabolic equation is studied in this paper. Firstly, a compact difference scheme is derived by using the operator method and the expression of the truncation error is given. Secondly

Mingshu Ma; Wenjuan Ma; Xiaofeng Wang

2009-01-01

464

Paraborikku Furaito Ni Okeru Egg (Erekutorogasutorogurafi) Sokutei (The Electrogastrogram During Parabolic Flight).  

National Technical Information Service (NTIS)

Motion sickness is a disease caused by vehicles with symptoms of digestive system, as well as pale and cold sweat. It is often observed in parabolic flight which produces microgravity and hypergravity. Recently, Electrogastrography (ECG) has been develope...

Y. Wada H. Suzuki S. Watanabe Y. Kaneoke

1993-01-01

465

Remotely Controlled Steering Gear For A Laser-Driven Rocket With A Parabolic Thruster  

Microsoft Academic Search

A new steering concept for laser-driven parabolic thrusters is presented. As an alternative to the well-tried spin-stabilization, our concept provides rocket stabilization and trajectory control and is suitable for the injection of a laser-driven launcher into a planetary orbit: Angular and lateral momentum components are systematically applied to the rocket by specific variation of the ignition configuration inside the parabolic

Stefan Scharring; Daniela Hoffmann; Hans-Albert Eckel; Hans-Peter Röser

2010-01-01

466

Compact parabolic reflector antenna design with cosecant-squared radiation pattern  

Microsoft Academic Search

This paper deals with the parametric analysis and proper design of parabolic reflector antennas to obtain pencil-beam, cosecant-squared and inverse cosecant- squared radiation patterns for air and coastal surveillance radars. A novel design is introduced to obtain both pencil- beam and cosecant-squared radiation patterns by using the same modified parabolic reflector antenna structure fed by an H-plane horn feeder which

Okan Yurduseven; Ozan Yurduseven

2011-01-01

467

Exact solitons in three-dimensional weakly nonlocal nonlinear time-modulated parabolic law media  

NASA Astrophysics Data System (ADS)

The three-dimensional (3D) nonlocal nonlinear Schrödinger equation (NNLSE) with time-dependent parabolic law nonlinearity and an external potential, describes the propagation of an optical pulse in the weakly nonlocal nonlinear parabolic law media, has been studied analytically. Explicit solutions are constructed by using the Jacobian elliptic equations (JEEs) expansion method. The 3D nonlocal spatial bright and dark optical solitons have been found.

Zhou, Qin; Yao, Duanzheng; Liu, Xiaona; chen, Fang; Ding, Sijing; Zhang, Yafang; Chen, Feng

2013-10-01

468

Binding energy of hydrogenic impurity states in an inverse parabolic quantum well under static external fields  

Microsoft Academic Search

In the present theoretical study, we investigate the influence of external fields (electric and\\/or magnetic) on the binding\\u000a energy of hydrogenic impurities in a GaAs\\/Ga1-xAlxAs inverse parabolic quantum well, in which the parabolicity depends on the Al concentrations at the well center. Our calculations\\u000a have been based on the potential morphing method in the effective mass approximation. The systematic theoretical

S. Baskoutas; A. F. Terzis

2009-01-01

469

Curvilinear parabolic approximation for surface wave transformation with wave–current interaction  

Microsoft Academic Search

The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave–current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper,

Fengyan Shi; James T. Kirby

2005-01-01

470

A parabolic function to modify Thornthwaite estimates of potential evapotranspiration for the eastern United States  

USGS Publications Warehouse

Errors of the Thornthwaite model can be analyzed using adjusted pan evaporation as an index of potential evapotranspiration. An examination of ratios of adjusted pan evaporation to Thornthwaite potential evapotranspiration indicates that the ratios are highest in the winter and lowest during summer months. This trend suggests a parabolic pattern. In this study a parabolic function is used to adjust Thornthwaite estimates of potential evapotranspiration. Forty locations east of the Rocky Mountains are analyzed. -from Author

McCabe, Jr, G. J.

1989-01-01

471

Performance of Infinitely Wide Parabolic and Inclined Slider Bearings Lubricated with Couple Stress or Magnetic Fluids  

NASA Astrophysics Data System (ADS)

The hydrodynamic and magnetohydrodynamic (MHD) lubrication problem of infinitely wide inclined and parabolic slider bearings is solved numerically using the finite element method. The bearing configurations are discretized into three-node isoparametric quadratic elements. Stiffness integrals obtained from the weak form of the governing equations are solved using Gauss quadrature to obtain a finite number of stiffness matrices. The global system of equations obtained from enforcing nodal continuity of pressure for the bearings are solved using the Gauss-Seidel iterative scheme with a convergence criterion of 10-10. Numerical computations reveal that, when compared for similar profile and couple stress parameters, greater pressure builds up in a parabolic slider compared to an inclined slider, indicating a greater wedge effect in the parabolic slider. The parabolic slider bearing is also shown to develop a greater load capacity when lubricated with magnetic fluids. The superior performance of parabolic slider bearing is more pronounced at greater Hartmann numbers for identical bearing structural parameters. It is also shown that when load carrying capacity is the yardstick for comparison, the parabolic slider bearings are superior to the inclined bearings when lubricated with couple stress or magnetic lubricants.

Oladeinde, Mobolaji Humphrey; Akpobi, John Ajokpaoghene

2011-10-01

472

High Speed Analysis Of Free Flights With A Parabolic Thruster  

NASA Astrophysics Data System (ADS)

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.

Scharring, Stefan; Eckel, Hans-Albert; Röser, Hans-Peter

2010-05-01

473

Diffusion phenomenon in the hyperbolic and parabolic regimes  

NASA Astrophysics Data System (ADS)

We discuss the diffusion phenomenon in the parabolic and hyperbolic regimes. New effects related to the finite velocity of the diffusion process are predicted, that can partially explain the strange behavior associated to adsorption phenomenon. For sake of simplicity, the analysis is performed by considering a sample in the shape of a slab limited by two perfectly blocking surfaces, in such a manner that the problem is one-dimensional in the space. Two cases are investigated. In the former, the initial distribution of the diffusing particles is assumed of gaussian type, centered around the symmetry surface in the middle of the sample. In the latter, the initial distribution is localized close to the limiting surfaces. In both cases, we show that the evolution toward to the equilibrium distribution is not monotonic. In particular, close to the limiting surfaces the bulk density of diffusing particles present maxima and minima related to the finite velocity of the diffusion process connected to the second order time derivative in the partial differential equation describing the evolution of the bulk density in the sample.

Sapora, A.; Codegone, M.; Barbero, G.

2013-11-01

474

Ultrafast control of the internuclear distance with parabolic chirped pulses.  

PubMed

Recently, control over the bond length of a diatomic molecule with the use of parabolic chirped pulses was predicted on the basis of numerical calculations [Chang; et al. Phys. Rev. A 2010, 82, 063414]. To achieve the required bond elongation, a laser scheme was proposed that implies population inversion and vibrational trapping in a dissociative state. In this work we identify two regimes where the scheme works, called the strong and the weak adiabatic regimes. We define appropriate parameters to identify the thresholds where the different regimes operate. The strong adiabatic regime is characterized by a quasi-static process that requires longer pulses. The molecule is stabilized at a bond distance and at a time directly controlled by the pulse in a time-symmetrical way. In this work we analyze the degree of control over the period and elongation of the bond as a function of the pulse bandwidth. The weak adiabatic regime implies dynamic deformation of the bond, which allows for larger bond stretch and the use of shorter pulses. The dynamics is anharmonic and not time-symmetrical and the final state is a wave packet in the ground potential. We show how the vibrational energy of the wave packet can be controlled by changing the pulse duration. PMID:22082170

Chang, Bo Y; Shin, Seokmin; Santamaria, Jesus; Sola, Ignacio R

2011-11-15

475

Differential invariants of generic parabolic Monge-Ampère equations  

NASA Astrophysics Data System (ADS)

Some new results on the geometry of classical parabolic Monge-Ampère equations (PMAs) are presented. PMAs are either integrable, or non-integrable according to the integrability of its characteristic distribution. All integrable PMAs are locally equivalent to the equation uxx = 0. We study non-integrable PMAs by associating with each of them a one-dimensional distribution on the corresponding first-order jet manifold, called the directing distribution. According to some property of this distribution, non-integrable PMAs are subdivided into three classes, one generic and two special. Generic PMAs are completely characterized by their directing distributions, and we study canonical models of the latter, projective curve bundles (PCB). A PCB is a one-dimensional sub-bundle of the projectivized cotangent bundle of a four-dimensional manifold. Differential invariants of projective curves composing such a bundle are used to construct a series of contact differential invariants for corresponding PMAs. These give a solution of the equivalence problem for generic PMAs with respect to contact transformations. The introduced invariants measure the nonlinearity of PMAs in an exact manner.

Catalano Ferraioli, D.; Vinogradov, A. M.

2012-07-01

476

The Universality Classes in the Parabolic Anderson Model  

NASA Astrophysics Data System (ADS)

We discuss the long time behaviour of the parabolic Anderson model, the Cauchy problem for the heat equation with random potential onmathbb{Z}d. We consider general i.i.d. potentials and show that exactly four qualitatively different types of intermittent behaviour can occur. These four universality classes depend on the upper tail of the potential distribution: (1) tails at ? that are thicker than the double-exponential tails, (2) double-exponential tails at ? studied by Gärtner and Molchanov, (3) a new class called almost bounded potentials, and (4) potentials bounded from above studied by Biskup and König. The new class (3), which contains both unbounded and bounded potentials, is studied in both the annealed and the quenched setting. We show that intermittency occurs on unboundedly increasing islands whose diameter is slowly varying in time. The characteristic variational formulas describing the optimal profiles of the potential and of the solution are solved explicitly by parabolas, respectively, Gaussian densities. Our analysis of class (3) relies on two large deviation results for the local times of continuous-time simple random walk. One of these results is proved by Brydges and the first two authors in [BHK04], and is also used here to correct a proof in [BK01].

van der Hofstad, Remco; König, Wolfgang; Mörters, Peter

2006-10-01

477

Parabolic Systems with p, q-Growth: A Variational Approach  

NASA Astrophysics Data System (ADS)

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).

Bögelein, Verena; Duzaar, Frank; Marcellini, Paolo

2013-10-01

478

High-order parabolic beam approximation for aero-optics  

SciTech Connect

The parabolic beam equations are solved using high-order compact differences for the Laplacians and Runge-Kutta integration along the beam path. The solution method is verified by comparison to analytical solutions for apertured beams and both constant and complex index of refraction. An adaptive 4th-order Runge-Kutta using an embedded 2nd-order method is presented that has demonstrated itself to be very robust. For apertured beams, the results show that the method fails to capture near aperture effects due to a violation of the paraxial approximation in that region. Initial results indicate that the problem appears to be correctable by successive approximations. A preliminary assessment of the effect of turbulent scales is undertaken using high-order Lagrangian interpolation. The results show that while high fidelity methods are necessary to accurately capture the large scale flow structure, the method may not require the same level of fidelity in sampling the density for the index of refraction. The solution is used to calculate a phase difference that is directly compared with that commonly calculated via the optical path difference. Propagation through a supersonic boundary layer shows that for longer wavelengths, the traditional method to calculate the optical path is less accurate than for shorter wavelengths. While unlikely to supplant more traditional methods for most aero-optics applications, the current method can be used to give a quantitative assessment of the other methods as well as being amenable to the addition of more physics.

White, Michael D., E-mail: Michael.White@wpafb.af.mi [Ohio Aerospace Institute, Wright-Patterson Air Force Base, OH 45433-7512 (United States)

2010-08-01

479

Approximate controllability of a system of parabolic equations with delay  

NASA Astrophysics Data System (ADS)

In this paper we give necessary and sufficient conditions for the approximate controllability of the following system of parabolic equations with delay: where [Omega] is a bounded domain in , D is an n×n nondiagonal matrix whose eigenvalues are semi-simple with nonnegative real part, the control and B[set membership, variant]L(U,Z) with , . The standard notation zt(x) defines a function from [-[tau],0] to (with x fixed) by zt(x)(s)=z(t+s,x), -[tau][less-than-or-equals, slant]s[less-than-or-equals, slant]0. Here [tau][greater-or-equal, slanted]0 is the maximum delay, which is supposed to be finite. We assume that the operator is linear and bounded, and [phi]0[set membership, variant]Z, [phi][set membership, variant]L2([-[tau],0];Z). To this end: First, we reformulate this system into a standard first-order delay equation. Secondly, the semigroup associated with the first-order delay equation on an appropriate product space is expressed as a series of strongly continuous semigroups and orthogonal projections related with the eigenvalues of the Laplacian operator (); this representation allows us to reduce the controllability of this partial differential equation with delay to a family of ordinary delay equations. Finally, we use the well-known result on the rank condition for the approximate controllability of delay system to derive our main result.

Carrasco, Alexander; Leiva, Hugo

2008-09-01

480

Range-dependent reverberation modeling with the parabolic equation  

NASA Astrophysics Data System (ADS)

Propagation and scattering are generally convolved in a waveguide. For scatterers small compared to the wavelength, however, the waveguide Green functions to and from the scatterer can be separated from the free space scattering amplitude [Ratilal et al., J. Acoust. Soc. Am. 112, 1797-1816 (2002)]. In this case, waveguide scattering can be modeled using efficient and accurate range-dependent methods such as the parabolic equation (PE) for the waveguide Green function. This approach is implemented for scattering from small particles in the water column and seabed at arbitrary bistatic orientations. Scenarios investigated involving targets of large impedance contrast include scattering from bubbles and fish schools. When the Rayleigh-Born single scatter approximation is valid, PE-based range-dependent scattering can also be used to scatter from elemental water-column and seabed inhomogeneities. This approach is used to model bistatic reverberation from the water column and seabed including returns arising from both diffuse and discrete scattering processes. The former is associated with smoothly decaying reverberation, the latter with clutter. Also, the possibility that internal waves may lead to discrete seafloor scattering returns by focusing energy on the ocean bottom is also investigated with this model.

Ratilal, Purnima; Lee, Sunwoong; Makris, Nicholas C.

2003-10-01

481

Estimation of the limiting capabilities of an objective having a small angular field, consisting of a single parabolic mirror.  

NASA Astrophysics Data System (ADS)

The image quality, produced by a single parabolic mirror in a small angular field, is examined. The Sommerfeld rule is refined, making it possible to evaluate the possibility of using a parabolic mirror for a fixed magnitude of the acceptable geometrical circle of confusion. Formulas are derived for calculating the maximum wave aberration and the root-mean-square deviation of the wavefront for a parabolic mirror with the effect of coma and astigmatism being considered both separately and in combination.

Budin, V. P.

1991-03-01

482

Technical and economical system comparison of photovoltaic and concentrating solar thermal power systems depending on annual global irradiation  

Microsoft Academic Search

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,

Volker Quaschning

2004-01-01

483

HYPERVELOCITY STARS AND THE RESTRICTED PARABOLIC THREE-BODY PROBLEM  

SciTech Connect

Motivated by detections of hypervelocity stars that may originate from the Galactic center, we revisit the problem of a binary disruption by a passage near a much more massive point mass. The six orders of magnitude mass ratio between the Galactic center black hole (BH) and the binary stars allows us to formulate the problem in the restricted parabolic three-body approximation. In this framework, results can be simply rescaled in terms of binary masses, their initial separation, and the binary-to-black hole mass ratio. Consequently, an advantage over the full three-body calculation is that a much smaller set of simulations is needed to explore the relevant parameter space. Contrary to previous claims, we show that, upon binary disruption, the lighter star does not remain preferentially bound to the black hole. In fact, it is ejected in exactly 50% of the cases. Nonetheless, lighter objects have higher ejection velocities, since the energy distribution is independent of mass. Focusing on the planar case, we provide the probability distributions for disruption of circular binaries and for the ejection energy. We show that even binaries that penetrate deeply into the tidal sphere of the BH are not doomed to disruption, but survive in 20% of the cases. Nor do these deep encounters produce the highest ejection energies, which are instead obtained for binaries arriving to 0.1-0.5 of the tidal radius in a prograde orbit. Interestingly, such deep-reaching binaries separate widely after penetrating the tidal radius, but always approach each other again on their way out from the BH. Finally, our analytic method allows us to account for a finite size of the stars and recast the ejection energy in terms of a minimal possible separation. We find that, for a given minimal separation, the ejection energy is relatively insensitive to the initial binary separation.

Sari, Re'em; Kobayashi, Shiho; Rossi, Elena M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

2010-01-01

484

Cluster eye camera using microlenses on parabolic surface  

NASA Astrophysics Data System (ADS)

There are two main types of imaging systems that exist in nature: the single aperture eye and the compound eye. Usually, cameras and most of artificial imaging systems are similar to the single aperture eye. But compound lenses can be more compact than single lenses. Our design is based on insect compound eyes, which also have a wide field of view (FOV). With the rise of micro-optical techniques, fabricating compound lenses has become easier. The simplest form of a curved microlens array is a parabolic surface. In this paper, we proposed a multi-channel imaging system, which combines the principles of the insect compound eye and the human eye. The optical system enables the reduction of track length of the imaging optics to achieve miniaturization. With the aid of optical engineering software ZEMAX, the multi-channel structure is simulated by a curved microlens array, and we use a Hypergon lens as the main lens to simulate the human eye, which can achieve the purpose of the wide FOV. With this architecture, each microlens of a microlens array transmits a segment of the overall FOV. The partial images that are separately recorded in different channels are stitched together to form the final image of the whole FOV by software processing. A 2.74 mm thin imaging system with 59 channels and 90° FOV is optimized using ZEMAX sequential ray tracing software on a 6.16 mm × 4.62 mm image plane. Finally, we will discuss the simulation results of this system and compare it with the optical cluster eye system and a mobile phone patent.

Shen, Hui-Kai; Su, Guo-Dung J.

2013-10-01

485

Heat engine development for solar thermal power systems  

NASA Astrophysics Data System (ADS)

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.

Pham, H. Q.; Jaffe, L. D.

486

The small community solar thermal power experiment  

NASA Astrophysics Data System (ADS)

Contractors were asked to develop a preferred system concept, to perform sensitivity analyses, and to outline recommended approaches for the follow-on design program of a one-megawatt solar thermal demonstration plant. The systems recommended by the contractors in each of the categories were: (1) McDonnell-Douglas Astronautics Company: Central tower with field of south-facing heliostats; (2) General Electric Company: Field of parabolic dishes with steam piped to a central turbine-generator unit; and (3) Ford Aerospace and Communications Corporation: Field of parabolic dishes with a Stirling cycle engine/generator unit at the focus of each dish. A description of each of the proposed experimental plants is given.

Kiceniuk, T.

1981-05-01

487

Solar trough systems  

SciTech Connect

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.

NONE

1998-04-01

488

An anisotropic model of diffuse solar radiation with application to an optimization of compound parabolic collectors  

Microsoft Academic Search

Based on a simple geometrical description of the sky hemisphere and the magnitude of the horizontal diffuse radiation, a model for estimating diffuse radiation impinging on sloping surfaces was developed. Tests against data show that substantial improvement is achieved over the classical isotropic model for any collector slope or orientation. Improvement is found for instantaneous as well as accumulated data.

R. R. Perez

1983-01-01

489

Curvilinear parabolic approximation for surface wave transformation with wave-current interaction  

SciTech Connect

The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave-current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper, the covariant-contravariant tensor method is used for the curvilinear parabolic approximation. We use the covariant components of the wave number vector and contravariant components of the current velocity vector so that the derivation of the curvilinear equation closely follows the higher-order approximation in rectangular Cartesian coordinates in Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. The resulting curvilinear equation can be easily implemented using the existing model structure and numerical schemes adopted in the Cartesian parabolic wave model [J.T. Kirby, R.A. Dalrymple, F. Shi, Combined Refraction/Diffraction Model REF/DIF 1, Version 2.6. Documentation and User's Manual, Research Report, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware, Newark, 2004]. Several examples of wave simulations in curvilinear coordinate systems, including a case with wave-current interaction, are shown with comparisons to theoretical solutions or measurement data.

Shi Fengyan [Center for Applied Coastal Research, Center for Applied Coastal Research, University of Delaware, Newark, DE 19716 (United States)]. E-mail: fyshi@coastal.udel.edu; Kirby, James T. [Center for Applied Coastal Research, Center for Applied Coastal Research, University of Delaware, Newark, DE 19716 (United States)

2005-04-10

490

Reflections on solar collectors at elevated temperatures \\/260-1000 C  

Microsoft Academic Search

Analytical models are developed for optical efficiencies and requirements of concentrating solar collectors, taking into account factors which affect the potentials for mass production. Reflective polyester films and a process to form large spherical mirrors from glass sheets have been crucial factors for lowering production costs. Microprocessors permit the nearly fully automated operation of parabolic dish point-focus and heliostat-central tower

B. Authier

1982-01-01

491

Asymmetrical cone-type secondary concentrators for Fresnel-type reflectors in solar towers  

Microsoft Academic Search

In solar tower plants, where a rotationally symmetric field of heliostats surrounds the tower, an axisymmetric secondary concentrator such as a Compound Parabolic Concentrator (CPC) or a tailored concentrator or a cone is the obvious choice. For locations at higher latitudes, however, the reflecting area of the heliostats may be used more efficiently if the field of heliostats is located

Wolfgang Spirkl; Andreas Timinger; Harald Ries; Abraham Kribus; J. Muschaweck

1997-01-01

492

Economic Assessment of a Concentrating Solar Power Forecasting System for Participation in the Spanish Electricity Market  

Microsoft Academic Search

Forecasts of power production are necessary for the electricity market participation of Concentrating Solar Power (CSP) plants. Deviations from the production schedule may lead to penalty charges. the mitigation impact on deviation penalties of an electricity production forecasting tool for Therefore, the accuracy of direct normal irradiance (DNI) forecasts is an important issue. This paper elaborates the 50 MWel parabolic

Birk Kraas; Marion Schroedter-Homscheidt; Benedikt Pulvermüller; Reinhard Madlener

2011-01-01

493

A New System to Produce Cooling and Power Using Solar Thermal Energy  

Microsoft Academic Search

A new system to produce cooling and power with the energy obtained from low-temperature as a thermal resource is presented in this work. This resource can be obtained from concentrating solar thermal energy (parabolic trough). This system belongs to the broader class of low temperature, Rankine cycles, which have been shown to be one of the most effective means for

Z. S. Abdel-Rehim

2011-01-01

494

Development and testing of a prototype of absorption heat pump system operated by solar energy  

Microsoft Academic Search

In this study, a prototype of an aqua–ammonia absorption heat pump system (AHP) using solar energy was investigated. The performance tests of the system were performed for the climate condition of Ankara in Turkey. The system has been designed operating with a parabolic slote type collector to obtain the required temperatures. In the experiments, high temperature water obtained from the

Adnan Sözen; Duran Alt?parmak; Hüseyin Usta

2002-01-01

495

Testing of the United Stirling 4-95 solar Stirling engine on test bed concentrator  

Microsoft Academic Search

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

H. G. Nelving

1984-01-01

496

Numerical study of melting of large-diameter crystals using an orbital solar concentrator  

Microsoft Academic Search

The melting of large-diameter crystals using an orbital solar concentrator is studied numerically. In the proposed configuration, a parabolic dish imaging concentrator is used to focus the sun`s radiation onto an ampoule which holds the solid charge material to be processed. The charge will start melting in the vicinity of the focal height, after which it is translated in order

X. K. Lan; J. M. Khodadadi; P. D. Jones; L. Wang

1995-01-01

497

Development of an evacuated receiver for line-focus solar thermal collectors  

Microsoft Academic Search

Acurex Corporation has recently completed the design review, fabrication assembly, and testing of an evacuated receiver for its 3021 parabolic trough solar collector. The receivers were installed at Sandia National Laboratories' Distributed Receiver Test Facility for testing by Sandia. The evacuated receivers are believed to represent a significant improvement in the state of the art of receiver technology and feature

Dehne

1987-01-01

498

Design and Modeling Remote Monitoring System for a Solar Power Plant  

Microsoft Academic Search

In this paper we will analyze and study a solar power plant of a linear parabolic type after introducing it. Monitoring system via the Internet is designed for the plant according to present parameters. Besides studying different dynamics of the Internet as important components we discuss the quality and effectiveness of each Internet parameter in order to explain the Internet

Ali Hosein Arianfar; Mehraban Jahromi; Mohsen Mosalanejad; Bahram Dehghan

2009-01-01

499

Rankline-Brayton engine powered solar thermal aircraft  

DOEpatents

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Bennett, Charles L. (Livermore, CA)

2012-03-13

500

Rankine-Brayton engine powered solar thermal aircraft  

DOEpatents

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

Bennett, Charles L. (Livermore, CA)

2009-12-29