Dépouillements

Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector / Juan Rodriguez in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011001/1-5] Titre : Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector Type de document : texte imprimé Auteurs : Juan Rodriguez, Auteur ; Clido Jorge, Auteur ; Patricia Zuniga, Auteur Année de publication : 2010 Article en page(s) : pp. [011001/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Microorganisms  Photolysis  Ruthenium  Solar  absorber-convertors  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Solar water disinfection was performed using TiO2 and a Ru(II) complex as fixed catalysts located in a compound parabolic collector photoreactor. Studies were performed in the laboratory as well as at a greenfield site. Under laboratory conditions, natural water contaminated with cultured bacteria was photocatalytically treated and the influence of the photolysis as well as of both catalysts was studied. Experiments were performed with contaminated water flowing at 12 l/min; under these conditions, photocatalytic experiments performed with a supported heterogeneous photocatalyst (Ahlstrom paper impregnated with TiO2) showed it to be effective in degrading bacteria in water. The Ru complex catalyst, however, showed no clear evidence for disinfecting water, and its efficiency was comparable to the simple photolysis. Under on-site experiments, bacteria contaminated water from the Yaurisque river at Cusco, Peru was treated. As a general trend, after photocatalytic treatment a reduction in the E-coli population present in water was observed. Whenever disinfection was achieved in the experiments, no regrowth of bacteria was observed after 24 h. However, a reduction in the prototype efficiency was observed both in laboratory and on-site experiments. This was ascribed to aging of the photocatalyst as well as due to the deposition of particles onto its surface. In cases in which incomplete disinfection resulted, a low rate of E-coli growth was observed 24 h after ending the experiment. However, pseudomones seem to be resistant to the treatment. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Solar water disinfection studies with supported TiO2 and polymer-supported Ru (II) sensitizer in a compound parabolic collector [texte imprimé] / Juan Rodriguez, Auteur ; Clido Jorge, Auteur ; Patricia Zuniga, Auteur . - 2010 . - pp. [011001/1-5]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011001/1-5] Mots-clés : Microorganisms  Photolysis  Ruthenium  Solar  absorber-convertors  Titanium  compounds  Water  treatment Index. décimale : 621.47 Résumé : Solar water disinfection was performed using TiO2 and a Ru(II) complex as fixed catalysts located in a compound parabolic collector photoreactor. Studies were performed in the laboratory as well as at a greenfield site. Under laboratory conditions, natural water contaminated with cultured bacteria was photocatalytically treated and the influence of the photolysis as well as of both catalysts was studied. Experiments were performed with contaminated water flowing at 12 l/min; under these conditions, photocatalytic experiments performed with a supported heterogeneous photocatalyst (Ahlstrom paper impregnated with TiO2) showed it to be effective in degrading bacteria in water. The Ru complex catalyst, however, showed no clear evidence for disinfecting water, and its efficiency was comparable to the simple photolysis. Under on-site experiments, bacteria contaminated water from the Yaurisque river at Cusco, Peru was treated. As a general trend, after photocatalytic treatment a reduction in the E-coli population present in water was observed. Whenever disinfection was achieved in the experiments, no regrowth of bacteria was observed after 24 h. However, a reduction in the prototype efficiency was observed both in laboratory and on-site experiments. This was ascribed to aging of the photocatalyst as well as due to the deposition of particles onto its surface. In cases in which incomplete disinfection resulted, a low rate of E-coli growth was observed 24 h after ending the experiment. However, pseudomones seem to be resistant to the treatment. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Field operation and track tests of 1-kW small wind turbine under high wind conditions / Hikaru Matsumiya in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011002/1-8] Titre : Field operation and track tests of 1-kW small wind turbine under high wind conditions Type de document : texte imprimé Auteurs : Hikaru Matsumiya, Auteur ; Ryosuke Ito, Auteur ; Masafumi Kawakami, Auteur Année de publication : 2010 Article en page(s) : pp. [011002/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Smal  wind  turbine  Field  test  Track  test  High  wind  operation  Captureability Index. décimale : 621.47 Résumé : A 1-kW small horizontal-axis wind turbine “Airdolphin,” capable of high wind operation up to 50 m/s without pitch control system, is now under global round robin tests. The present paper reports a series of technical approach including design/analysis, track tests, and field tests conducted in support to the design process. One windy site “Erimo” and one offshore site “Fukushima” were chosen. For example, at “Erimo,” a record of one-day generation was 8.831 kWh on November 13, 2006 (day-averaged wind speed; 11.8 m/s) with 36.8% of capacity factor. An operation data under an attack of typhoon with 50 m/s maximum wind speed demonstrated the technical concepts of high wind operation and safety. A new term “capatureability” as an indicator of WT performance was proposed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Field operation and track tests of 1-kW small wind turbine under high wind conditions [texte imprimé] / Hikaru Matsumiya, Auteur ; Ryosuke Ito, Auteur ; Masafumi Kawakami, Auteur . - 2010 . - pp. [011002/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011002/1-8] Mots-clés : Smal  wind  turbine  Field  test  Track  test  High  wind  operation  Captureability Index. décimale : 621.47 Résumé : A 1-kW small horizontal-axis wind turbine “Airdolphin,” capable of high wind operation up to 50 m/s without pitch control system, is now under global round robin tests. The present paper reports a series of technical approach including design/analysis, track tests, and field tests conducted in support to the design process. One windy site “Erimo” and one offshore site “Fukushima” were chosen. For example, at “Erimo,” a record of one-day generation was 8.831 kWh on November 13, 2006 (day-averaged wind speed; 11.8 m/s) with 36.8% of capacity factor. An operation data under an attack of typhoon with 50 m/s maximum wind speed demonstrated the technical concepts of high wind operation and safety. A new term “capatureability” as an indicator of WT performance was proposed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Solar concentrating systems using small mirror arrays / Joachim Gottsche in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011003/1-4] Titre : Solar concentrating systems using small mirror arrays Type de document : texte imprimé Auteurs : Joachim Gottsche, Auteur ; Bernhard Hoffschmidt, Auteur ; Stefan Schmitz, Auteur Année de publication : 2010 Article en page(s) : pp. [011003/1-4] Note générale : En"rgie Solaire Langues : Anglais (eng) Mots-clés : Concentrating  solar  power  Heliostat  Mirror  array  Ray-tracing Index. décimale : 621.47 Résumé : The cost of solar tower power plants is dominated by the heliostat field making up roughly 50% of investment costs. Classical heliostat design is dominated by mirrors brought into position by steel structures and drives that guarantee high accuracies under wind loads and thermal stress situations. A large fraction of costs is caused by the stiffness requirements of the steel structure, typically resulting in ~20 kg/m2 steel per mirror area. The typical cost figure of heliostats (figure mentioned by Solucar at Solar Paces Conference, Seville, 2006) is currently in the area of 150 [euro]/m2 caused by the increasing price of the necessary raw materials. An interesting option to reduce costs lies in a heliostat design where all moving parts are protected from wind loads. In this way, drives and mechanical layout may be kept less robust, thereby reducing material input and costs. In order to keep the heliostat at an appropriate size, small mirrors (around 10×10 cm2) have to be used, which are placed in a box with a transparent cover. Innovative drive systems are developed in order to obtain a cost-effective design. A 0.5×0.5 m2 demonstration unit will be constructed. Tests of the unit are carried out with a high-precision artificial sun unit that imitates the sun's path with an accuracy of less than 0.5 mrad and creates a beam of parallel light with a divergence of less than 4 mrad. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Solar concentrating systems using small mirror arrays [texte imprimé] / Joachim Gottsche, Auteur ; Bernhard Hoffschmidt, Auteur ; Stefan Schmitz, Auteur . - 2010 . - pp. [011003/1-4]. En"rgie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011003/1-4] Mots-clés : Concentrating  solar  power  Heliostat  Mirror  array  Ray-tracing Index. décimale : 621.47 Résumé : The cost of solar tower power plants is dominated by the heliostat field making up roughly 50% of investment costs. Classical heliostat design is dominated by mirrors brought into position by steel structures and drives that guarantee high accuracies under wind loads and thermal stress situations. A large fraction of costs is caused by the stiffness requirements of the steel structure, typically resulting in ~20 kg/m2 steel per mirror area. The typical cost figure of heliostats (figure mentioned by Solucar at Solar Paces Conference, Seville, 2006) is currently in the area of 150 [euro]/m2 caused by the increasing price of the necessary raw materials. An interesting option to reduce costs lies in a heliostat design where all moving parts are protected from wind loads. In this way, drives and mechanical layout may be kept less robust, thereby reducing material input and costs. In order to keep the heliostat at an appropriate size, small mirrors (around 10×10 cm2) have to be used, which are placed in a box with a transparent cover. Innovative drive systems are developed in order to obtain a cost-effective design. A 0.5×0.5 m2 demonstration unit will be constructed. Tests of the unit are carried out with a high-precision artificial sun unit that imitates the sun's path with an accuracy of less than 0.5 mrad and creates a beam of parallel light with a divergence of less than 4 mrad. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

An evaluation of a high altitude solar radiation platform / S. Redi in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011004/1-8] Titre : An evaluation of a high altitude solar radiation platform Type de document : texte imprimé Auteurs : S. Redi, Auteur ; G. S. Aglietti, Auteur ; A. R. Tatnall, Auteur Année de publication : 2010 Article en page(s) : pp. [011004/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Photovoltaic  power  systems  Solar  absorber-convertors  Solar  power  Solar  radiation Index. décimale : 621.47 Résumé : This paper presents a preliminary assessment of the potential advantage that a high altitude solar collector could bring compared with the traditional ground based photovoltaic systems. This advantage mainly derives from the reduced attenuation of the solar radiation as it travels through the atmosphere especially if clouds are present above the location considered. A sun beam traveling through clear atmosphere is considered first using an existent model to calculate the daily irradiation at different altitudes in clear sky conditions. The results obtained are then integrated with experimental data describing cloud distributions versus altitude, and finally the contribution of the diffused radiation is also included to give a realistic evaluation of the total actual irradiation at a specific altitude. The results are obtained for a specific location in the UK, where the experimental data have been acquired. The general conclusions, however, involving the potential of high altitude solar collectors, can be extended to other countries in Europe with similar climates. Finally, the main issues involved in the design and development of a flying platform for the exploitation of the solar energy are presented and the technical feasibility of the system is discussed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] An evaluation of a high altitude solar radiation platform [texte imprimé] / S. Redi, Auteur ; G. S. Aglietti, Auteur ; A. R. Tatnall, Auteur . - 2010 . - pp. [011004/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011004/1-8] Mots-clés : Photovoltaic  power  systems  Solar  absorber-convertors  Solar  power  Solar  radiation Index. décimale : 621.47 Résumé : This paper presents a preliminary assessment of the potential advantage that a high altitude solar collector could bring compared with the traditional ground based photovoltaic systems. This advantage mainly derives from the reduced attenuation of the solar radiation as it travels through the atmosphere especially if clouds are present above the location considered. A sun beam traveling through clear atmosphere is considered first using an existent model to calculate the daily irradiation at different altitudes in clear sky conditions. The results obtained are then integrated with experimental data describing cloud distributions versus altitude, and finally the contribution of the diffused radiation is also included to give a realistic evaluation of the total actual irradiation at a specific altitude. The results are obtained for a specific location in the UK, where the experimental data have been acquired. The general conclusions, however, involving the potential of high altitude solar collectors, can be extended to other countries in Europe with similar climates. Finally, the main issues involved in the design and development of a flying platform for the exploitation of the solar energy are presented and the technical feasibility of the system is discussed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

A Microsolar collector for hydrogen production by methanol reforming / Raul Zimmerman in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011005/1-5] Titre : A Microsolar collector for hydrogen production by methanol reforming Type de document : texte imprimé Auteurs : Raul Zimmerman, Auteur ; Graham Morrison, Auteur ; Gary Rosengarten, Auteur Année de publication : 2010 Article en page(s) : pp. [011005/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Solar  collector  Microreactor  Solar  hydrogen  Portable  energy  Methanol  reforming Index. décimale : 621.47 Résumé : Proton exchange membrane fuel cells (PEMFCs) are good candidates for portable energy sources with a fast response to load changes, while being compact as a result of their capability to provide a high power density. Hydrogen constitutes the fuel for the PEMFC and can be obtained in situ to avoid transportation and safety problems. An efficient method to produce hydrogen is by methanol steam reforming in a microreactor, an endothermic reaction for which the highest efficiency occurs between 250°C and 300°C. Different methods have been used to reach and maintain these temperatures including electrical heaters and exothermic reactions. We propose to use solar energy to increase the efficiency of the microreactor while taking advantage of a free renewable energy source. The microchannels, where the water-methanol mixture flows, are insulated from the surroundings by a thin vacuum layer coated with a selective material. This coating has a high absorptance for short wavelength incoming radiation and low emittance for infrared radiation, reducing the heat losses. By using these coated insulation layers, the fluid temperature in the microchannels is predicted to be higher than 250°C. Hence, it is expected that the solar-powered microreactor will produce hydrogen with a higher overall efficiency than the present reactors by taking advantage of the solar radiation. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] A Microsolar collector for hydrogen production by methanol reforming [texte imprimé] / Raul Zimmerman, Auteur ; Graham Morrison, Auteur ; Gary Rosengarten, Auteur . - 2010 . - pp. [011005/1-5]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011005/1-5] Mots-clés : Solar  collector  Microreactor  Solar  hydrogen  Portable  energy  Methanol  reforming Index. décimale : 621.47 Résumé : Proton exchange membrane fuel cells (PEMFCs) are good candidates for portable energy sources with a fast response to load changes, while being compact as a result of their capability to provide a high power density. Hydrogen constitutes the fuel for the PEMFC and can be obtained in situ to avoid transportation and safety problems. An efficient method to produce hydrogen is by methanol steam reforming in a microreactor, an endothermic reaction for which the highest efficiency occurs between 250°C and 300°C. Different methods have been used to reach and maintain these temperatures including electrical heaters and exothermic reactions. We propose to use solar energy to increase the efficiency of the microreactor while taking advantage of a free renewable energy source. The microchannels, where the water-methanol mixture flows, are insulated from the surroundings by a thin vacuum layer coated with a selective material. This coating has a high absorptance for short wavelength incoming radiation and low emittance for infrared radiation, reducing the heat losses. By using these coated insulation layers, the fluid temperature in the microchannels is predicted to be higher than 250°C. Hence, it is expected that the solar-powered microreactor will produce hydrogen with a higher overall efficiency than the present reactors by taking advantage of the solar radiation. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Applications of low-speed dynamic-stall model to the NREL airfoils / Wanan Sheng in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011006/1-8] Titre : Applications of low-speed dynamic-stall model to the NREL airfoils Type de document : texte imprimé Auteurs : Wanan Sheng, Auteur ; Roderick A. McD. Galbraith, Auteur ; Frank N. Coton, Auteur Année de publication : 2010 Article en page(s) : pp. [011006/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Aerodynamics  Aerospace  components  Blades  Helicopters  Mach  number  Subsonic  flow  Wind  turbines Index. décimale : 621.47 Résumé : National Renewable Energy Laboratory, USA (NREL) airfoils have been specially developed for wind turbine applications, and projected to yield more annual energy without increasing the maximum power level. These airfoils are designed to have a limited maximum lift and relatively low sensitivity to leading-edge roughness. As a result, these airfoils have quite different leading-edge profiles from airfoils applied to helicopter blades, and thus, quite different dynamic-stall characteristics. Unfortunately for wind turbine aerodynamics, the dynamic-stall models in use are still those specially developed and refined for helicopter applications. A good example is the Leishman–Beddoes dynamic-stall model, which is one of the most popular models in wind turbine applications. The consequence is that the application of such dynamic-stall model to low-speed cases can be problematic. Recently, some specific dynamic-stall models have been proposed or tuned for the cases of low Mach numbers, but their universality needs further validation. This paper considers the application of the modified dynamic low-speed stall model of Sheng et al. (“A Modified Dynamic Stall Model for Low Mach Numbers,” 2008, ASME J. Sol. Energy Eng., 130(3), pp. 031013) to the NREL airfoils. The predictions are compared with the data of the NREL airfoils tested at the Ohio State University. The current research has two objectives: to justify the suitability of the low-speed dynamic-stall model, and to provide the relevant parameters for the NREL airfoils. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Applications of low-speed dynamic-stall model to the NREL airfoils [texte imprimé] / Wanan Sheng, Auteur ; Roderick A. McD. Galbraith, Auteur ; Frank N. Coton, Auteur . - 2010 . - pp. [011006/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011006/1-8] Mots-clés : Aerodynamics  Aerospace  components  Blades  Helicopters  Mach  number  Subsonic  flow  Wind  turbines Index. décimale : 621.47 Résumé : National Renewable Energy Laboratory, USA (NREL) airfoils have been specially developed for wind turbine applications, and projected to yield more annual energy without increasing the maximum power level. These airfoils are designed to have a limited maximum lift and relatively low sensitivity to leading-edge roughness. As a result, these airfoils have quite different leading-edge profiles from airfoils applied to helicopter blades, and thus, quite different dynamic-stall characteristics. Unfortunately for wind turbine aerodynamics, the dynamic-stall models in use are still those specially developed and refined for helicopter applications. A good example is the Leishman–Beddoes dynamic-stall model, which is one of the most popular models in wind turbine applications. The consequence is that the application of such dynamic-stall model to low-speed cases can be problematic. Recently, some specific dynamic-stall models have been proposed or tuned for the cases of low Mach numbers, but their universality needs further validation. This paper considers the application of the modified dynamic low-speed stall model of Sheng et al. (“A Modified Dynamic Stall Model for Low Mach Numbers,” 2008, ASME J. Sol. Energy Eng., 130(3), pp. 031013) to the NREL airfoils. The predictions are compared with the data of the NREL airfoils tested at the Ohio State University. The current research has two objectives: to justify the suitability of the low-speed dynamic-stall model, and to provide the relevant parameters for the NREL airfoils. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Pyrometric temperature measurement in concentrated sunlight with emissivity determination / Nathan B. Crane in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011007/1-8] Titre : Pyrometric temperature measurement in concentrated sunlight with emissivity determination Type de document : texte imprimé Auteurs : Nathan B. Crane, Auteur Année de publication : 2010 Article en page(s) : pp. [011007/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Pyrometer  Solar  heating  Emissivity  Temperature  measurement  Radiative  heating Index. décimale : 621.47 Résumé : Pyrometers are commonly used for high temperature measurement, but their accuracy is often limited by uncertainty in the surface emissivity. Radiation heating introduces additional errors due to the extra light reflected off the measured surface. While many types of specialized equipment have been developed for these measurements, this work presents a method for measuring high temperatures using single color pyrometers when the surface emissivity is unknown. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two pyrometers and is most helpful for improving measurement accuracy of low cost commercial instruments. The temperature measurements of two pyrometers operating at different wavelengths are analyzed across a range of sample temperatures to find the surface emissivity values at each wavelength that minimize the difference in temperature measurements between pyrometers. These are taken as the surface emissivity values, and the initial temperature measurements are corrected using the calculated emissivity values to obtain improved estimates of the surface temperature. When applied to temperature data from a solar furnace, the method significantly decreased the difference in the temperature measurements of two single color pyrometers. Simulated temperature data with both random noise and systematic errors are used to demonstrate that the method successfully converges to surface emissivity values and reduces temperature measurement errors even when subjected to significant errors in the model inputs. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects. It is also useful for temperature measurement of objects with unknown emissivity. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Pyrometric temperature measurement in concentrated sunlight with emissivity determination [texte imprimé] / Nathan B. Crane, Auteur . - 2010 . - pp. [011007/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011007/1-8] Mots-clés : Pyrometer  Solar  heating  Emissivity  Temperature  measurement  Radiative  heating Index. décimale : 621.47 Résumé : Pyrometers are commonly used for high temperature measurement, but their accuracy is often limited by uncertainty in the surface emissivity. Radiation heating introduces additional errors due to the extra light reflected off the measured surface. While many types of specialized equipment have been developed for these measurements, this work presents a method for measuring high temperatures using single color pyrometers when the surface emissivity is unknown. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two pyrometers and is most helpful for improving measurement accuracy of low cost commercial instruments. The temperature measurements of two pyrometers operating at different wavelengths are analyzed across a range of sample temperatures to find the surface emissivity values at each wavelength that minimize the difference in temperature measurements between pyrometers. These are taken as the surface emissivity values, and the initial temperature measurements are corrected using the calculated emissivity values to obtain improved estimates of the surface temperature. When applied to temperature data from a solar furnace, the method significantly decreased the difference in the temperature measurements of two single color pyrometers. Simulated temperature data with both random noise and systematic errors are used to demonstrate that the method successfully converges to surface emissivity values and reduces temperature measurement errors even when subjected to significant errors in the model inputs. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects. It is also useful for temperature measurement of objects with unknown emissivity. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

The Performance of wind turbine smart rotor control approaches during extreme loads / Matthew A. Lackner in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011008/1-8] Titre : The Performance of wind turbine smart rotor control approaches during extreme loads Type de document : texte imprimé Auteurs : Matthew A. Lackner, Auteur ; Gijs A. M. Van Kuik, Auteur Année de publication : 2010 Article en page(s) : pp. [011008/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Blades  Fatigue  Intelligent  control  Machine  control  Rotors  Wind  turbines Index. décimale : 621.47 Résumé : Reducing the loads experienced by wind turbine rotor blades can lower the cost of energy of wind turbines. “Smart rotor control” concepts have emerged as a solution to reduce fatigue loads on wind turbines. In this approach, aerodynamic load control devices are distributed along the span of the blade, and through a combination of sensing, control, and actuation, these devices dynamically control the blade loads. While smart rotor control approaches are primarily focused on fatigue load reductions, extreme loads on the blades may also be critical in determining the lifetime of components, and the ability to reduce these loads as well would be a welcome property of any smart rotor control approach. This research investigates the extreme load reduction potential of smart rotor control devices, namely, trailing edge flaps, in the operation of a 5 MW wind turbine. The controller utilized in these simulations is designed explicitly for fatigue load reductions; nevertheless its effectiveness during extreme loads is assessed. Simple step functions in the wind are used to approximate gusts and investigate the performance of two load reduction methods: individual flap control and individual pitch control. Both local and global gusts are simulated. The results yield important insight into the control approach that is utilized, and also into the differences between using individual pitch control and trailing edge flaps for extreme load reductions. Finally, the limitation of the assumption of quasisteady aerodynamic behavior is assessed. DEWEY : 621.47 ISSN : 1099-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] The Performance of wind turbine smart rotor control approaches during extreme loads [texte imprimé] / Matthew A. Lackner, Auteur ; Gijs A. M. Van Kuik, Auteur . - 2010 . - pp. [011008/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011008/1-8] Mots-clés : Blades  Fatigue  Intelligent  control  Machine  control  Rotors  Wind  turbines Index. décimale : 621.47 Résumé : Reducing the loads experienced by wind turbine rotor blades can lower the cost of energy of wind turbines. “Smart rotor control” concepts have emerged as a solution to reduce fatigue loads on wind turbines. In this approach, aerodynamic load control devices are distributed along the span of the blade, and through a combination of sensing, control, and actuation, these devices dynamically control the blade loads. While smart rotor control approaches are primarily focused on fatigue load reductions, extreme loads on the blades may also be critical in determining the lifetime of components, and the ability to reduce these loads as well would be a welcome property of any smart rotor control approach. This research investigates the extreme load reduction potential of smart rotor control devices, namely, trailing edge flaps, in the operation of a 5 MW wind turbine. The controller utilized in these simulations is designed explicitly for fatigue load reductions; nevertheless its effectiveness during extreme loads is assessed. Simple step functions in the wind are used to approximate gusts and investigate the performance of two load reduction methods: individual flap control and individual pitch control. Both local and global gusts are simulated. The results yield important insight into the control approach that is utilized, and also into the differences between using individual pitch control and trailing edge flaps for extreme load reductions. Finally, the limitation of the assumption of quasisteady aerodynamic behavior is assessed. DEWEY : 621.47 ISSN : 1099-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Wind speed estimation algorithm in the presence of observation noise / Ken Mok in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011009/1-6] Titre : Wind speed estimation algorithm in the presence of observation noise Type de document : texte imprimé Auteurs : Ken Mok, Auteur Année de publication : 2010 Article en page(s) : pp. [011009/1-6] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Angular  velocity  measurement  Maximum  likelihood  estimation  Noise  Stochastic  processes  Wind  turbines Index. décimale : 621.47 Résumé : A stochastic hub-height wind speed estimation algorithm for wind turbines, which requires only the rotor angular velocity measurement in the presence of observation noise is proposed. It is assumed that the power curve and the total inertia of the rotor are known a priori. We use the maximum likelihood estimator to identify the hub-height wind speed, which is formulated as one of the state variables in the nonlinear model. The theory and algorithm are verified by both simulated and experimental data in the presence of measurement noise. The effects of the initial guess, the noise variance, and the time history are discussed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Wind speed estimation algorithm in the presence of observation noise [texte imprimé] / Ken Mok, Auteur . - 2010 . - pp. [011009/1-6]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011009/1-6] Mots-clés : Angular  velocity  measurement  Maximum  likelihood  estimation  Noise  Stochastic  processes  Wind  turbines Index. décimale : 621.47 Résumé : A stochastic hub-height wind speed estimation algorithm for wind turbines, which requires only the rotor angular velocity measurement in the presence of observation noise is proposed. It is assumed that the power curve and the total inertia of the rotor are known a priori. We use the maximum likelihood estimator to identify the hub-height wind speed, which is formulated as one of the state variables in the nonlinear model. The theory and algorithm are verified by both simulated and experimental data in the presence of measurement noise. The effects of the initial guess, the noise variance, and the time history are discussed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Preliminary study on a solar water heater using supercritical carbon dioxide as working fluid / H. Yamaguchi in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011010 /1-6] Titre : Preliminary study on a solar water heater using supercritical carbon dioxide as working fluid Type de document : texte imprimé Auteurs : H. Yamaguchi, Auteur ; N. Sawada, Auteur ; H. Suzuki, Auteur Année de publication : 2010 Article en page(s) : pp. [011010 /1-6] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Solar  water  heater  Carbon  diaxide  Supercritical  fluid  Natural  convection  Heat  transfer Index. décimale : 621.47 Résumé : In this paper, a solar water heater using supercritical carbon dioxide as working fluid is proposed and experimentally studied. For supercritical carbon dioxide, a small change in temperature or pressure can result in large change in density, especially in the state close to the critical point. Thus, natural convective flow of the supercritical carbon dioxide can be easily induced by solar heating or water cooling. Such convective flow absorbs and transports heat to water in solar collector tubes. Motivated by the above idea, an experimental setup was designed, and a solar water heater was tested. The obtained results show that natural convective flow is well induced, and a flow of 1900 Reynolds number can be achieved even in winter, when the lowest level of solar radiation condition occurs. Furthermore, the measured collector and heat recovery efficiencies are 66.0% and 65.0%, respectively. More details of its mechanism are to be studied, and a complete performance analysis is needed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Preliminary study on a solar water heater using supercritical carbon dioxide as working fluid [texte imprimé] / H. Yamaguchi, Auteur ; N. Sawada, Auteur ; H. Suzuki, Auteur . - 2010 . - pp. [011010 /1-6]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011010 /1-6] Mots-clés : Solar  water  heater  Carbon  diaxide  Supercritical  fluid  Natural  convection  Heat  transfer Index. décimale : 621.47 Résumé : In this paper, a solar water heater using supercritical carbon dioxide as working fluid is proposed and experimentally studied. For supercritical carbon dioxide, a small change in temperature or pressure can result in large change in density, especially in the state close to the critical point. Thus, natural convective flow of the supercritical carbon dioxide can be easily induced by solar heating or water cooling. Such convective flow absorbs and transports heat to water in solar collector tubes. Motivated by the above idea, an experimental setup was designed, and a solar water heater was tested. The obtained results show that natural convective flow is well induced, and a flow of 1900 Reynolds number can be achieved even in winter, when the lowest level of solar radiation condition occurs. Furthermore, the measured collector and heat recovery efficiencies are 66.0% and 65.0%, respectively. More details of its mechanism are to be studied, and a complete performance analysis is needed. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Optical characterization of nonimaging planar concentrator for the application in concentrator photovoltaic system / K. K. Chong in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011011/1-9] Titre : Optical characterization of nonimaging planar concentrator for the application in concentrator photovoltaic system Type de document : texte imprimé Auteurs : K. K. Chong, Auteur ; C. W. Wong, Auteur ; F. L. Siaw, Auteur Année de publication : 2010 Article en page(s) : pp. [011011/1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Nonimaging  Solar  concentrator  Concentrator  photovoltaic  Uniform  illumination  Flux  distribution  Ray-tracing Index. décimale : 621.47 Résumé : The design and construction of miniature prototype of nonimaging planar concentrator, which is capable of producing much more uniform spatial irradiance and reasonably high concentration ratio, were presented in the previous paper. In this paper, we further explore the optical characteristics of the new concentrator that is specially designed to be incorporated in concentrator photovoltaic systems. For this study, we have carried out a comprehensive analysis via numerical simulation based on all the important design parameters, i.e., array of facet mirrors, f/D ratio, receiver size, and the effect of sun-tracking error, which lead to the overall optical performance of the new concentrator. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Optical characterization of nonimaging planar concentrator for the application in concentrator photovoltaic system [texte imprimé] / K. K. Chong, Auteur ; C. W. Wong, Auteur ; F. L. Siaw, Auteur . - 2010 . - pp. [011011/1-9]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011011/1-9] Mots-clés : Nonimaging  Solar  concentrator  Concentrator  photovoltaic  Uniform  illumination  Flux  distribution  Ray-tracing Index. décimale : 621.47 Résumé : The design and construction of miniature prototype of nonimaging planar concentrator, which is capable of producing much more uniform spatial irradiance and reasonably high concentration ratio, were presented in the previous paper. In this paper, we further explore the optical characteristics of the new concentrator that is specially designed to be incorporated in concentrator photovoltaic systems. For this study, we have carried out a comprehensive analysis via numerical simulation based on all the important design parameters, i.e., array of facet mirrors, f/D ratio, receiver size, and the effect of sun-tracking error, which lead to the overall optical performance of the new concentrator. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Rapid high temperature solar thermal biomass gasification in a prototype cavity reactor / Paul Lichty in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011012/1-7] Titre : Rapid high temperature solar thermal biomass gasification in a prototype cavity reactor Type de document : texte imprimé Auteurs : Paul Lichty, Auteur ; Christopher Perkins, Auteur ; Bryan Woodruff, Auteur Année de publication : 2010 Article en page(s) : pp. [011012/1-7] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Concentrated  solar  Solar-thermal  Biomass  Solar  reactor  Syngas  Gasification Index. décimale : 621.47 Résumé : High temperature biomass gasification has been performed in a prototype concentrated solar reactor. Gasification of biomass at high temperatures has many advantages compared with historical methods of producing fuels. Enhancements in overall conversion, product composition ratios, and tar reduction are achievable at temperatures greater than 1000°C. Furthermore, the utilization of concentrated solar energy to drive these reactions eliminates the need to consume a portion of the product stream for heating and some of the solar energy is stored as chemical energy in the product stream. Experiments to determine the effects of temperature, gas flow rate, and feed type were conducted at the high flux solar furnace at the National Renewable Energy Laboratory, Golden, CO. These experiments were conducted in a reflective cavity multitube prototype reactor. Biomass type was found to be the only significant factor within a 95% confidence interval. Biomass conversion as high as 68% was achieved on sun. Construction and design considerations of the prototype reactor are discussed as well as initial performance results. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Rapid high temperature solar thermal biomass gasification in a prototype cavity reactor [texte imprimé] / Paul Lichty, Auteur ; Christopher Perkins, Auteur ; Bryan Woodruff, Auteur . - 2010 . - pp. [011012/1-7]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011012/1-7] Mots-clés : Concentrated  solar  Solar-thermal  Biomass  Solar  reactor  Syngas  Gasification Index. décimale : 621.47 Résumé : High temperature biomass gasification has been performed in a prototype concentrated solar reactor. Gasification of biomass at high temperatures has many advantages compared with historical methods of producing fuels. Enhancements in overall conversion, product composition ratios, and tar reduction are achievable at temperatures greater than 1000°C. Furthermore, the utilization of concentrated solar energy to drive these reactions eliminates the need to consume a portion of the product stream for heating and some of the solar energy is stored as chemical energy in the product stream. Experiments to determine the effects of temperature, gas flow rate, and feed type were conducted at the high flux solar furnace at the National Renewable Energy Laboratory, Golden, CO. These experiments were conducted in a reflective cavity multitube prototype reactor. Biomass type was found to be the only significant factor within a 95% confidence interval. Biomass conversion as high as 68% was achieved on sun. Construction and design considerations of the prototype reactor are discussed as well as initial performance results. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Shear induced removal of calcium carbonate scale from polypropylene and copper tubes / Matt Royer in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011013/1-9] Titre : Shear induced removal of calcium carbonate scale from polypropylene and copper tubes Type de document : texte imprimé Auteurs : Matt Royer, Auteur ; Jane H. Davidson, Auteur ; Lorraine F. Francis, Auteur Année de publication : 2010 Article en page(s) : pp. [011013/1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Adhesion  Calcium  compounds  Laminar  flow  Scanning  electron  microscopy  Shear  turbulence Index. décimale : 621.47 Résumé : This paper presents an analytical model and an experimental study of adhesion and fluid shear removal of calcium carbonate scale on polypropylene and copper tubes in laminar and turbulent water flows, with a view toward understanding how scale can be controlled in solar absorbers and heat exchangers. The tubes are first coated with scale and then inserted in a flow-through apparatus. Removal is measured gravimetrically for Reynolds numbers from 525 to 5550, corresponding to wall shear stresses from 0.16 Pa to 6.0 Pa. The evolutionary structure of the scale is visualized with scanning electron microscopy. Consistent with the predictive model, calcium carbonate is more easily removed from polypropylene than copper. In a laminar flow with a wall shear stress of 0.16 Pa, 65% of the scale is removed from polypropylene while only 10% is removed from copper. Appreciable removal of scale from copper requires higher shear stresses. At Reynolds number of 5500, corresponding to a wall shear stress of 6.0 Pa, 30% of the scale is removed from the copper tubes. The results indicate scale will be more easily removed from polypropylene, and by inference other polymeric materials, than from copper by flushing with water. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Shear induced removal of calcium carbonate scale from polypropylene and copper tubes [texte imprimé] / Matt Royer, Auteur ; Jane H. Davidson, Auteur ; Lorraine F. Francis, Auteur . - 2010 . - pp. [011013/1-9]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011013/1-9] Mots-clés : Adhesion  Calcium  compounds  Laminar  flow  Scanning  electron  microscopy  Shear  turbulence Index. décimale : 621.47 Résumé : This paper presents an analytical model and an experimental study of adhesion and fluid shear removal of calcium carbonate scale on polypropylene and copper tubes in laminar and turbulent water flows, with a view toward understanding how scale can be controlled in solar absorbers and heat exchangers. The tubes are first coated with scale and then inserted in a flow-through apparatus. Removal is measured gravimetrically for Reynolds numbers from 525 to 5550, corresponding to wall shear stresses from 0.16 Pa to 6.0 Pa. The evolutionary structure of the scale is visualized with scanning electron microscopy. Consistent with the predictive model, calcium carbonate is more easily removed from polypropylene than copper. In a laminar flow with a wall shear stress of 0.16 Pa, 65% of the scale is removed from polypropylene while only 10% is removed from copper. Appreciable removal of scale from copper requires higher shear stresses. At Reynolds number of 5500, corresponding to a wall shear stress of 6.0 Pa, 30% of the scale is removed from the copper tubes. The results indicate scale will be more easily removed from polypropylene, and by inference other polymeric materials, than from copper by flushing with water. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Theory and manufacturing processes of solar nanoantenna electromagnetic collectors / D. K. Kotter in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011014 /1-9] Titre : Theory and manufacturing processes of solar nanoantenna electromagnetic collectors Type de document : texte imprimé Auteurs : D. K. Kotter, Auteur ; S. D. Novack, Auteur ; W. D. Slafer, Auteur Année de publication : 2010 Article en page(s) : pp. [011014 /1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Nantenna  frequency  selective  surfaces  Nanoscale  modeling  Nanofabrication  Nanoimprinting  Roll-to-roll  manufacturing  Rectenna Index. décimale : 621.47 Résumé : The research described in this paper explores a new and efficient approach for producing electricity from the abundant energy of the sun, using nanoantenna (nantenna) electromagnetic collectors (NECs). NEC devices target midinfrared wavelengths, where conventional photovoltaic (PV) solar cells are inefficient and where there is an abundance of solar energy. The initial concept of designing NECs was based on scaling of radio frequency antenna theory to the infrared and visible regions. This approach initially proved unsuccessful because the optical behavior of materials in the terahertz (THz) region was overlooked and, in addition, economical nanofabrication methods were not previously available to produce the optical antenna elements. This paper demonstrates progress in addressing significant technological barriers including: (1) development of frequency-dependent modeling of double-feedpoint square spiral nantenna elements, (2) selection of materials with proper THz properties, and (3) development of novel manufacturing methods that could potentially enable economical large-scale manufacturing. We have shown that nantennas can collect infrared energy and induce THz currents and we have also developed cost-effective proof-of-concept fabrication techniques for the large-scale manufacture of simple square-loop nantenna arrays. Future work is planned to embed rectifiers into the double-feedpoint antenna structures. This work represents an important first step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity. This could lead to a broadband, high conversion efficiency low-cost solution to complement conventional PV devices. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Theory and manufacturing processes of solar nanoantenna electromagnetic collectors [texte imprimé] / D. K. Kotter, Auteur ; S. D. Novack, Auteur ; W. D. Slafer, Auteur . - 2010 . - pp. [011014 /1-9]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011014 /1-9] Mots-clés : Nantenna  frequency  selective  surfaces  Nanoscale  modeling  Nanofabrication  Nanoimprinting  Roll-to-roll  manufacturing  Rectenna Index. décimale : 621.47 Résumé : The research described in this paper explores a new and efficient approach for producing electricity from the abundant energy of the sun, using nanoantenna (nantenna) electromagnetic collectors (NECs). NEC devices target midinfrared wavelengths, where conventional photovoltaic (PV) solar cells are inefficient and where there is an abundance of solar energy. The initial concept of designing NECs was based on scaling of radio frequency antenna theory to the infrared and visible regions. This approach initially proved unsuccessful because the optical behavior of materials in the terahertz (THz) region was overlooked and, in addition, economical nanofabrication methods were not previously available to produce the optical antenna elements. This paper demonstrates progress in addressing significant technological barriers including: (1) development of frequency-dependent modeling of double-feedpoint square spiral nantenna elements, (2) selection of materials with proper THz properties, and (3) development of novel manufacturing methods that could potentially enable economical large-scale manufacturing. We have shown that nantennas can collect infrared energy and induce THz currents and we have also developed cost-effective proof-of-concept fabrication techniques for the large-scale manufacture of simple square-loop nantenna arrays. Future work is planned to embed rectifiers into the double-feedpoint antenna structures. This work represents an important first step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity. This could lead to a broadband, high conversion efficiency low-cost solution to complement conventional PV devices. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Structural analysis of wind-turbine blades by a generalized timoshenko beam model / Alejandro D. Otero in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011015/1-8] Titre : Structural analysis of wind-turbine blades by a generalized timoshenko beam model Type de document : texte imprimé Auteurs : Alejandro D. Otero, Auteur ; Fernando L. Ponta, Auteur Année de publication : 2010 Article en page(s) : pp. [011015/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Blades  Finite  element  analysis  Wind  turbines Index. décimale : 621.47 Résumé : An important aspect in wind-turbine technology nowadays is to reduce the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid-structure interaction process. A fundamental step in that direction is the implementation of structural models capable of capturing the complex features of innovative prototype blades, so that they can be tested at realistic full-scale conditions with a reasonable computational cost. To this end, we developed a code based on a modified implementation of the variational-asymptotic beam sectional (VABS) technique proposed by Hodges et al. VABS has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam, allowing accurate modeling of the 3D structure of the blade as a 1D finite-element problem. In this paper, we report some recent results we have obtained by applying our code to full-scale composite laminate wind-turbine blades, analyzing the fundamental vibrational modes and the stress load in normal operational conditions. DEWEY : 621.47 ISSN : 1099-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Structural analysis of wind-turbine blades by a generalized timoshenko beam model [texte imprimé] / Alejandro D. Otero, Auteur ; Fernando L. Ponta, Auteur . - 2010 . - pp. [011015/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011015/1-8] Mots-clés : Blades  Finite  element  analysis  Wind  turbines Index. décimale : 621.47 Résumé : An important aspect in wind-turbine technology nowadays is to reduce the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid-structure interaction process. A fundamental step in that direction is the implementation of structural models capable of capturing the complex features of innovative prototype blades, so that they can be tested at realistic full-scale conditions with a reasonable computational cost. To this end, we developed a code based on a modified implementation of the variational-asymptotic beam sectional (VABS) technique proposed by Hodges et al. VABS has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam, allowing accurate modeling of the 3D structure of the blade as a 1D finite-element problem. In this paper, we report some recent results we have obtained by applying our code to full-scale composite laminate wind-turbine blades, analyzing the fundamental vibrational modes and the stress load in normal operational conditions. DEWEY : 621.47 ISSN : 1099-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

Simulation and experimental analysis of a solar driven absorption chiller with partially wetted evaporator / Jan Albers in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011016/1-8] Titre : Simulation and experimental analysis of a solar driven absorption chiller with partially wetted evaporator Type de document : texte imprimé Auteurs : Jan Albers, Auteur ; Giovanni Nurzia, Auteur ; Felix Ziegler, Auteur Année de publication : 2010 Article en page(s) : pp. [011016/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Cooling  Heat  exchangers  Refrigerants  Solar  absorber-convertors Index. décimale : 621.47 Résumé : The efficient operation of a solar cooling system strongly depends on the chiller behavior under part load conditions, since driving energy and cooling load are never constant. For this reason, the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collector has been analyzed under part load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled, and cooling water is done by lumped and distributed UA values for the main heat exchangers. In addition to an analytical evaporator model—which is described in detail—experimental correlations for UA values have been used for the condenser, generator, and solution heat exchanger. For the absorber, a basic model based on the Nusselt theory has been employed. The evaporator model was developed, taking into account the distribution of refrigerant on the tube bundle, as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and coefficient of performance (COP) is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless, the results of this investigation can be used to improve control strategies for new and existing solar cooling systems. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Simulation and experimental analysis of a solar driven absorption chiller with partially wetted evaporator [texte imprimé] / Jan Albers, Auteur ; Giovanni Nurzia, Auteur ; Felix Ziegler, Auteur . - 2010 . - pp. [011016/1-8]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [011016/1-8] Mots-clés : Cooling  Heat  exchangers  Refrigerants  Solar  absorber-convertors Index. décimale : 621.47 Résumé : The efficient operation of a solar cooling system strongly depends on the chiller behavior under part load conditions, since driving energy and cooling load are never constant. For this reason, the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collector has been analyzed under part load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled, and cooling water is done by lumped and distributed UA values for the main heat exchangers. In addition to an analytical evaporator model—which is described in detail—experimental correlations for UA values have been used for the condenser, generator, and solution heat exchanger. For the absorber, a basic model based on the Nusselt theory has been employed. The evaporator model was developed, taking into account the distribution of refrigerant on the tube bundle, as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and coefficient of performance (COP) is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless, the results of this investigation can be used to improve control strategies for new and existing solar cooling systems. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

A Solar trough concentrator for pill-box flux distribution over a CPV panel / R. Bader in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [014501/1-4] Titre : A Solar trough concentrator for pill-box flux distribution over a CPV panel Type de document : texte imprimé Auteurs : R. Bader, Auteur ; A. Steinfeld, Auteur Année de publication : 2010 Article en page(s) : pp. [014501/1-4] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Focal  planes  Mirrors  Monte  Carlo  methods  Ray  tracing  Solar  absorber-convertors Index. décimale : 621.47 Résumé : An integral methodology is formulated to analytically derive the exact profile of a solar trough concentrator that delivers a uniform radiative flux distribution over a flat rectangular target area at the focal plane. The Monte Carlo ray-tracing technique is applied to verify the analytical solution and investigate the effect of sun shape and mirror surface imperfections on the radiation uniformity and spillage. This design is pertinent to concentrating photovoltaics at moderate mean solar flux concentration ratios of up to 50 suns. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] A Solar trough concentrator for pill-box flux distribution over a CPV panel [texte imprimé] / R. Bader, Auteur ; A. Steinfeld, Auteur . - 2010 . - pp. [014501/1-4]. Energie Solaire Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 1 (Janvier 2010) . - pp. [014501/1-4] Mots-clés : Focal  planes  Mirrors  Monte  Carlo  methods  Ray  tracing  Solar  absorber-convertors Index. décimale : 621.47 Résumé : An integral methodology is formulated to analytically derive the exact profile of a solar trough concentrator that delivers a uniform radiative flux distribution over a flat rectangular target area at the focal plane. The Monte Carlo ray-tracing technique is applied to verify the analytical solution and investigate the effect of sun shape and mirror surface imperfections on the radiation uniformity and spillage. This design is pertinent to concentrating photovoltaics at moderate mean solar flux concentration ratios of up to 50 suns. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]

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