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Ajouter le résultat dans votre panierProgress in understanding factors governing the sodium manganese ferrite thermochemical cycle / C. Alvani in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 3 (Août 2010)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031001/1-5]
Titre : Progress in understanding factors governing the sodium manganese ferrite thermochemical cycle Type de document : texte imprimé Auteurs : C. Alvani, Auteur ; M. Bellusci, Auteur ; A. la Barbera, Auteur Année de publication : 2011 Article en page(s) : pp. [031001/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Manganese ferrite Thermochemical cycle Hydrogen production Water splitting Index. décimale : 621.47 Résumé : The mixed sodium manganese ferrite thermochemical cycle for sustainable hydrogen production is reviewed. Both the hydrogen production step and the reaction that leads to the regeneration of initial reactants are described as multistep reactions. The chemical cyclability of the reactive system has been demonstrated at 750°C.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Progress in understanding factors governing the sodium manganese ferrite thermochemical cycle [texte imprimé] / C. Alvani, Auteur ; M. Bellusci, Auteur ; A. la Barbera, Auteur . - 2011 . - pp. [031001/1-5].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031001/1-5]
Mots-clés : Manganese ferrite Thermochemical cycle Hydrogen production Water splitting Index. décimale : 621.47 Résumé : The mixed sodium manganese ferrite thermochemical cycle for sustainable hydrogen production is reviewed. Both the hydrogen production step and the reaction that leads to the regeneration of initial reactants are described as multistep reactions. The chemical cyclability of the reactive system has been demonstrated at 750°C.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp.[031002/1-8]
Titre : A Low temperature solar thermochemical power plant with CO2 recovery using methanol-fueled chemical looping combustion Type de document : texte imprimé Auteurs : Hui Hong, Auteur ; Tao Han, Auteur ; HongGuang Jin, Auteur Année de publication : 2011 Article en page(s) : pp.[031002/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Solar thermochemical Methanol-fueled chemical-looping combustion Inherent CO2 capture Index. décimale : 621.47 Résumé : A novel solar-hybrid gas turbine combined cycle was proposed. The cycle integrates methanol-fueled chemical-looping combustion and solar thermal energy at around 200°C, and it was investigated with the aid of the energy-utilization diagram (EUD). Solar thermal energy, at approximately 150°C–300°C, is utilized to drive the reduction in Fe2O3 with methanol in the reduction reactor, and is converted into chemical energy associated with the solid fuel FeO. Then it is released as high-temperature thermal energy during the oxidation of FeO in the oxidation reactor to generate electricity through the combined cycle. As a result, the exergy efficiency of the proposed solar thermal cycle may reach 58.4% at a turbine inlet temperature of 1400°C, and the net solar-to-electric efficiency would be expected to be 22.3%. The promising results obtained here indicate that this solar-hybrid combined cycle not only offers a new approach for highly efficient use of middle-and-low temperature solar thermal energy to generate electricity, but also provides the possibility of simultaneously utilizing renewable energy and alternative fuel for CO2 capture with low energy penalty.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] A Low temperature solar thermochemical power plant with CO2 recovery using methanol-fueled chemical looping combustion [texte imprimé] / Hui Hong, Auteur ; Tao Han, Auteur ; HongGuang Jin, Auteur . - 2011 . - pp.[031002/1-8].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp.[031002/1-8]
Mots-clés : Solar thermochemical Methanol-fueled chemical-looping combustion Inherent CO2 capture Index. décimale : 621.47 Résumé : A novel solar-hybrid gas turbine combined cycle was proposed. The cycle integrates methanol-fueled chemical-looping combustion and solar thermal energy at around 200°C, and it was investigated with the aid of the energy-utilization diagram (EUD). Solar thermal energy, at approximately 150°C–300°C, is utilized to drive the reduction in Fe2O3 with methanol in the reduction reactor, and is converted into chemical energy associated with the solid fuel FeO. Then it is released as high-temperature thermal energy during the oxidation of FeO in the oxidation reactor to generate electricity through the combined cycle. As a result, the exergy efficiency of the proposed solar thermal cycle may reach 58.4% at a turbine inlet temperature of 1400°C, and the net solar-to-electric efficiency would be expected to be 22.3%. The promising results obtained here indicate that this solar-hybrid combined cycle not only offers a new approach for highly efficient use of middle-and-low temperature solar thermal energy to generate electricity, but also provides the possibility of simultaneously utilizing renewable energy and alternative fuel for CO2 capture with low energy penalty.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031003/1-7]
Titre : Influence of measurement equipment on the uncertainty of performance data from test loops for concentrating solar collectors Type de document : texte imprimé Auteurs : Nicole Janotte, Auteur ; Eckhard Lüpfert, Auteur ; Robert Pitz-Paal, Auteur Année de publication : 2011 Article en page(s) : pp. [031003/1-7] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Parabolic trough Extended prototype testing Efficiency Thermal measurement Measurement uncertainty Combined uncertainty Qualification Index. décimale : 621.47 Résumé : Parabolic trough concentrating collectors play a major role in the energy efficiency and economics of concentrating solar power plants. Therefore, existing collector systems are constantly enhanced and new types were developed. Thermal performance testing is one step generally required in the course of their testing and qualification. For outdoor tests of prototypes, a heat transfer fluid loop (single collector or entire loop) needs to be equipped with measurement sensors for inlet, outlet, and ambient temperature as well as irradiance, wind speed, and mass or volumetric flow rate to evaluate the heat balance. Assessing the individual measurement uncertainties and their impact on the combined uncertainty of the desired measurement quantity one obtains the significance of the testing results. The method has been applied to a set of EuroTrough collector tests performed at Plataforma Solar de Almería, Spain. Test results include the uncertainty range of the resulting modeling function and exemplify the effects of sensors and their specifications on the parameters leading to an uncertainty of ±1.7% points for the optical collector efficiency. The measurement uncertainties of direct normal irradiance and mass flow rate are identified as determining uncertainty contributions and indicate room for improvement. Extended multiple sensor deployment and improved calibration procedures are the key to further reducing measurement uncertainty and hence increasing testing significance.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Influence of measurement equipment on the uncertainty of performance data from test loops for concentrating solar collectors [texte imprimé] / Nicole Janotte, Auteur ; Eckhard Lüpfert, Auteur ; Robert Pitz-Paal, Auteur . - 2011 . - pp. [031003/1-7].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031003/1-7]
Mots-clés : Parabolic trough Extended prototype testing Efficiency Thermal measurement Measurement uncertainty Combined uncertainty Qualification Index. décimale : 621.47 Résumé : Parabolic trough concentrating collectors play a major role in the energy efficiency and economics of concentrating solar power plants. Therefore, existing collector systems are constantly enhanced and new types were developed. Thermal performance testing is one step generally required in the course of their testing and qualification. For outdoor tests of prototypes, a heat transfer fluid loop (single collector or entire loop) needs to be equipped with measurement sensors for inlet, outlet, and ambient temperature as well as irradiance, wind speed, and mass or volumetric flow rate to evaluate the heat balance. Assessing the individual measurement uncertainties and their impact on the combined uncertainty of the desired measurement quantity one obtains the significance of the testing results. The method has been applied to a set of EuroTrough collector tests performed at Plataforma Solar de Almería, Spain. Test results include the uncertainty range of the resulting modeling function and exemplify the effects of sensors and their specifications on the parameters leading to an uncertainty of ±1.7% points for the optical collector efficiency. The measurement uncertainties of direct normal irradiance and mass flow rate are identified as determining uncertainty contributions and indicate room for improvement. Extended multiple sensor deployment and improved calibration procedures are the key to further reducing measurement uncertainty and hence increasing testing significance.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031004/1-4]
Titre : Truncation of the secondary concentrator (CPC) as means to cost effective beam-down system Type de document : texte imprimé Auteurs : Akiba Segal, Auteur ; Michael Epstein, Auteur Année de publication : 2011 Article en page(s) : pp. [031004/1-4] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Optics Solar energy concentrators Solar power stations Index. décimale : 621.47 Résumé : A central solar plant based on beam-down optics is composed of a field of heliostats, a tower reflector (hyperboloid mirror), and a ground receiver interfaced at its aperture with one or a cluster of secondary concentrators (compound parabolic concentrator). In previous publications, a method was presented, illustrating the correlation between the tower reflector position and its size on one hand and the geometry, dimensions, and reflective area of the secondary concentrator on the other hand, both related to the heliostat field reflective area. Obviously, when one wishes to reduce the size of a tower reflector by locating it closer to the upper focal point, the image created at the lower focus will be broader, resulting in a larger secondary ground concentrator. The present paper describes a method for substantial decrease in the dimensions of the ground secondary concentrator cluster (and, implicitly, the concentrator's area) via truncation and some geometrical corrections without significant sacrifice of the optical performance. This offers a method for cost effective design of future central solar plants, utilizing the beam-down optics.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Truncation of the secondary concentrator (CPC) as means to cost effective beam-down system [texte imprimé] / Akiba Segal, Auteur ; Michael Epstein, Auteur . - 2011 . - pp. [031004/1-4].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031004/1-4]
Mots-clés : Optics Solar energy concentrators Solar power stations Index. décimale : 621.47 Résumé : A central solar plant based on beam-down optics is composed of a field of heliostats, a tower reflector (hyperboloid mirror), and a ground receiver interfaced at its aperture with one or a cluster of secondary concentrators (compound parabolic concentrator). In previous publications, a method was presented, illustrating the correlation between the tower reflector position and its size on one hand and the geometry, dimensions, and reflective area of the secondary concentrator on the other hand, both related to the heliostat field reflective area. Obviously, when one wishes to reduce the size of a tower reflector by locating it closer to the upper focal point, the image created at the lower focus will be broader, resulting in a larger secondary ground concentrator. The present paper describes a method for substantial decrease in the dimensions of the ground secondary concentrator cluster (and, implicitly, the concentrator's area) via truncation and some geometrical corrections without significant sacrifice of the optical performance. This offers a method for cost effective design of future central solar plants, utilizing the beam-down optics.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031005/1-9]
Titre : Impacts of climate change in degree days and energy demand in coastal California Type de document : texte imprimé Auteurs : B. Lebassi, Auteur ; J. E. Gonzalez, Auteur ; D. Fabris, Auteur Année de publication : 2011 Article en page(s) : pp. [031005/1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Climatology Meteorology Power stations Index. décimale : 621.47 Résumé : An analysis of 1970–2005 observed summer daily maximum and minimum temperatures in two California air basins showed concurrent daytime coastal cooling and inland warming. To study the impacts of these results on energy consumption, summer cooling degree day (CDD) and winter heating degree day (HDD) trends were analyzed via these temperatures. The 2 m level air temperatures consisted of data from 159 locations in California, each with daily minimum and maximum values. Primary data sources included Cooperative Weather Station Network sites, first order National Weather Service stations, and military weather stations. An analysis of the CDD and HDD data has been undertaken for California, in general, and the San Francisco Bay Area and South Coast Air Basin, in particular, as the source of data for an analysis of energy-demand trends. Regional climate fluctuations have considerable effects on surface temperatures, which in turn affect CDD and HDD values. An asymmetric increase in summer CDD values between coastal and inland regions of California was found during the last 35 years, while winter HDD values showed decreases in most of California. In general, coastal areas experienced decreases of CDD, while inland regions experienced increases. The summer asymmetric increases in CDD is attributed to intensified sea breeze flows, which suggests increases in cold marine air intrusions over coastal land masses due to an increased regional sea breeze potential, which ventilates coastal areas, helps reduce maximum temperatures, and contributes to CDD decreases. An analysis of energy demands in the two air basins supports these climatological findings.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Impacts of climate change in degree days and energy demand in coastal California [texte imprimé] / B. Lebassi, Auteur ; J. E. Gonzalez, Auteur ; D. Fabris, Auteur . - 2011 . - pp. [031005/1-9].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031005/1-9]
Mots-clés : Climatology Meteorology Power stations Index. décimale : 621.47 Résumé : An analysis of 1970–2005 observed summer daily maximum and minimum temperatures in two California air basins showed concurrent daytime coastal cooling and inland warming. To study the impacts of these results on energy consumption, summer cooling degree day (CDD) and winter heating degree day (HDD) trends were analyzed via these temperatures. The 2 m level air temperatures consisted of data from 159 locations in California, each with daily minimum and maximum values. Primary data sources included Cooperative Weather Station Network sites, first order National Weather Service stations, and military weather stations. An analysis of the CDD and HDD data has been undertaken for California, in general, and the San Francisco Bay Area and South Coast Air Basin, in particular, as the source of data for an analysis of energy-demand trends. Regional climate fluctuations have considerable effects on surface temperatures, which in turn affect CDD and HDD values. An asymmetric increase in summer CDD values between coastal and inland regions of California was found during the last 35 years, while winter HDD values showed decreases in most of California. In general, coastal areas experienced decreases of CDD, while inland regions experienced increases. The summer asymmetric increases in CDD is attributed to intensified sea breeze flows, which suggests increases in cold marine air intrusions over coastal land masses due to an increased regional sea breeze potential, which ventilates coastal areas, helps reduce maximum temperatures, and contributes to CDD decreases. An analysis of energy demands in the two air basins supports these climatological findings.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031006/1-5]
Titre : Mechanism of hydrogen formation in solar parabolic trough receivers Type de document : texte imprimé Auteurs : Luc Moens, Auteur ; Daniel M. Blake, Auteur Année de publication : 2011 Article en page(s) : pp. [031006/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Parabolic trough receives Hydrogen Heat transfer fluid Diphenyl oxide Biphenyl Index. décimale : 621.47 Résumé : 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 (HTFs) 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 buildup 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, which are the two constituents of Therminol VP-1.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Mechanism of hydrogen formation in solar parabolic trough receivers [texte imprimé] / Luc Moens, Auteur ; Daniel M. Blake, Auteur . - 2011 . - pp. [031006/1-5].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031006/1-5]
Mots-clés : Parabolic trough receives Hydrogen Heat transfer fluid Diphenyl oxide Biphenyl Index. décimale : 621.47 Résumé : 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 (HTFs) 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 buildup 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, which are the two constituents of Therminol VP-1.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031007/1-7]
Titre : The SnO2/Sn carbothermic cycle for splitting water and production of hydrogen Type de document : texte imprimé Auteurs : Michael Epstein, Auteur ; Irina Vishnevetsky, Auteur ; Alexander Berman, Auteur Année de publication : 2011 Article en page(s) : pp. [031007/1-7] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Carboreduction of metal oxide Metal hydrolysis Tin dioxide thermochemical cycle Index. décimale : 621.47 Résumé : The carboreduction in SnO2 to produce Sn and its hydrolysis with steam to generate hydrogen were studied. The SnO2/C/Sn system has several advantages compared with the most advanced cycle considered so far, which is the ZnO/C/Zn system. The most significant one is the lower reduction temperatures (850–900°C for the SnO2 versus 1100–1150°C for the ZnO). The rate of carbothermal reduction was studied experimentally. SnO2 powder (300 mesh, 99.9% purity) was reduced with beech charcoal and graphite using a thermogravimetric analysis apparatus and fixed bed flow reactor at a temperature range of 800–1000°C. Optimal temperature range for the reduction with beech charcoal is 875–900°C. The reaction time needed to reach conversion of SnO2 close to 100% is 5–10 min in this temperature range. The transmission electron microscopy results show that after cooling, the product of carboreduction contains mainly metallic Sn with a particle size of 1–3 µm. The hydrolysis step is crucial to the success of the entire cycle. Reactions between the steam and solid tin having as powder structure similar to the reduced one were performed at a temperature range of 350–600°C. Results of both the reduction and hydrolysis reactions are presented in addition to thermodynamic analysis of this cycle.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] The SnO2/Sn carbothermic cycle for splitting water and production of hydrogen [texte imprimé] / Michael Epstein, Auteur ; Irina Vishnevetsky, Auteur ; Alexander Berman, Auteur . - 2011 . - pp. [031007/1-7].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031007/1-7]
Mots-clés : Carboreduction of metal oxide Metal hydrolysis Tin dioxide thermochemical cycle Index. décimale : 621.47 Résumé : The carboreduction in SnO2 to produce Sn and its hydrolysis with steam to generate hydrogen were studied. The SnO2/C/Sn system has several advantages compared with the most advanced cycle considered so far, which is the ZnO/C/Zn system. The most significant one is the lower reduction temperatures (850–900°C for the SnO2 versus 1100–1150°C for the ZnO). The rate of carbothermal reduction was studied experimentally. SnO2 powder (300 mesh, 99.9% purity) was reduced with beech charcoal and graphite using a thermogravimetric analysis apparatus and fixed bed flow reactor at a temperature range of 800–1000°C. Optimal temperature range for the reduction with beech charcoal is 875–900°C. The reaction time needed to reach conversion of SnO2 close to 100% is 5–10 min in this temperature range. The transmission electron microscopy results show that after cooling, the product of carboreduction contains mainly metallic Sn with a particle size of 1–3 µm. The hydrolysis step is crucial to the success of the entire cycle. Reactions between the steam and solid tin having as powder structure similar to the reduced one were performed at a temperature range of 350–600°C. Results of both the reduction and hydrolysis reactions are presented in addition to thermodynamic analysis of this cycle.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031008/1-12]
Titre : Analysis of wind turbine vibrations based on SCADA data Type de document : texte imprimé Auteurs : Andrew Kusiak, Auteur ; Zijun Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. [031008/1-12] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Data mining Frequency-domain analysis Neural nets Poles and towers Power engineering computing SCADA systems Sensitivity analysis Vibrations Wavelet transforms Wind turbines Index. décimale : 621.47 Résumé : Vibrations of a wind turbine have a negative impact on its performance. Mitigating this undesirable impact requires knowledge of the relationship between the vibrations and other wind turbine parameters that could be potentially modified. Three approaches for ranking the impact importance of measurable turbine parameters on the vibrations of the drive train and the tower are discussed. They include the predictor importance analysis, the global sensitivity analysis, and the correlation coefficient analysis versed in data mining and statistics. To decouple the impact of wind speed on the vibrations of the drive train and the tower, the analysis is performed on data sets with narrow speed ranges. Wavelet analysis is applied to filter noisy accelerometer data. To exclude the impact malfunctions on the vibration analysis, the data are analyzed in a frequency domain. Data-mining algorithms are used to build models with turbine parameters of interest as inputs, and the vibrations of drive train and tower as outputs. The performance of each model is thoroughly evaluated based on metrics widely used in the wind industry. The neural network algorithm outperforms other classifiers and is considered to be the most promising approach to study wind turbine vibrations.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Analysis of wind turbine vibrations based on SCADA data [texte imprimé] / Andrew Kusiak, Auteur ; Zijun Zhang, Auteur . - 2011 . - pp. [031008/1-12].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031008/1-12]
Mots-clés : Data mining Frequency-domain analysis Neural nets Poles and towers Power engineering computing SCADA systems Sensitivity analysis Vibrations Wavelet transforms Wind turbines Index. décimale : 621.47 Résumé : Vibrations of a wind turbine have a negative impact on its performance. Mitigating this undesirable impact requires knowledge of the relationship between the vibrations and other wind turbine parameters that could be potentially modified. Three approaches for ranking the impact importance of measurable turbine parameters on the vibrations of the drive train and the tower are discussed. They include the predictor importance analysis, the global sensitivity analysis, and the correlation coefficient analysis versed in data mining and statistics. To decouple the impact of wind speed on the vibrations of the drive train and the tower, the analysis is performed on data sets with narrow speed ranges. Wavelet analysis is applied to filter noisy accelerometer data. To exclude the impact malfunctions on the vibration analysis, the data are analyzed in a frequency domain. Data-mining algorithms are used to build models with turbine parameters of interest as inputs, and the vibrations of drive train and tower as outputs. The performance of each model is thoroughly evaluated based on metrics widely used in the wind industry. The neural network algorithm outperforms other classifiers and is considered to be the most promising approach to study wind turbine vibrations.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031009/1-13]
Titre : The impacts of climate changes on the renewable energy resources in the Caribbean region Type de document : texte imprimé Auteurs : M. E. Angeles, Auteur ; J. E. Gonzalez, Auteur ; D. J. Erickson III, Auteur Année de publication : 2011 Article en page(s) : pp. [031009/1-13] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : IPCC PCM RAMS Climate change Future Caribbean insolation Future Caribbean wind speed Index. décimale : 621.47 Résumé : Assessment of renewable energy resources such as surface solar radiation and wind current has great relevance in the development of local and regional energy policies. This paper examines the variability and availability of these resources as a function of possible climate changes for the Caribbean region. Global climate changes have been reported in the last decades, causing changes in the atmospheric dynamics, which affects the net solar radiation balance at the surface and the wind strength and direction. For this investigation, the future climate changes for the Caribbean are predicted using the parallel climate model (PCM) and it is coupled with the numerical model regional atmospheric modeling system (RAMS) to simulate the solar and wind energy spatial patterns changes for the specific case of the island of Puerto Rico. Numerical results from PCM indicate that the Caribbean basin from 2041 to 2055 will experience a slight decrease in the net surface solar radiation (with respect to the years 1996–2010), which is more pronounced in the western Caribbean sea. Results also indicate that the easterly winds have a tendency to increase in its magnitude, especially from the years 2070 to 2098. The regional model showed that important areas to collect solar energy are located in the eastern side of Puerto Rico, while the more intense wind speed is placed around the coast. A future climate change is expected in the Caribbean that will result in higher energy demands, but both renewable energy sources will have enough intensity to be used in the future as alternative energy resources to mitigate future climate changes.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] The impacts of climate changes on the renewable energy resources in the Caribbean region [texte imprimé] / M. E. Angeles, Auteur ; J. E. Gonzalez, Auteur ; D. J. Erickson III, Auteur . - 2011 . - pp. [031009/1-13].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031009/1-13]
Mots-clés : IPCC PCM RAMS Climate change Future Caribbean insolation Future Caribbean wind speed Index. décimale : 621.47 Résumé : Assessment of renewable energy resources such as surface solar radiation and wind current has great relevance in the development of local and regional energy policies. This paper examines the variability and availability of these resources as a function of possible climate changes for the Caribbean region. Global climate changes have been reported in the last decades, causing changes in the atmospheric dynamics, which affects the net solar radiation balance at the surface and the wind strength and direction. For this investigation, the future climate changes for the Caribbean are predicted using the parallel climate model (PCM) and it is coupled with the numerical model regional atmospheric modeling system (RAMS) to simulate the solar and wind energy spatial patterns changes for the specific case of the island of Puerto Rico. Numerical results from PCM indicate that the Caribbean basin from 2041 to 2055 will experience a slight decrease in the net surface solar radiation (with respect to the years 1996–2010), which is more pronounced in the western Caribbean sea. Results also indicate that the easterly winds have a tendency to increase in its magnitude, especially from the years 2070 to 2098. The regional model showed that important areas to collect solar energy are located in the eastern side of Puerto Rico, while the more intense wind speed is placed around the coast. A future climate change is expected in the Caribbean that will result in higher energy demands, but both renewable energy sources will have enough intensity to be used in the future as alternative energy resources to mitigate future climate changes.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031010/1-9]
Titre : Trailing edge noise model validation and application to airfoil optimization Type de document : texte imprimé Auteurs : F. Bertagnolio, Auteur ; H. Aa. Madsen, Auteur ; C. Bak, Auteur Année de publication : 2011 Article en page(s) : pp. [031010/1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Aerodynamics Noise abatement Noise measurement Optimisation Wind turbines Index. décimale : 621.47 Résumé : The aim of this article is twofold. First, an existing trailing edge noise model is validated by comparing with airfoil surface pressure fluctuations and far field sound pressure levels measured in three different experiments. The agreement is satisfactory in one case but poor in two other cases. Nevertheless, the model reproduces the main tendencies observed in the measurements with respect to varying flow conditions. Second, the model is implemented into an airfoil design code that is originally used for aerodynamic optimization. An existing wind turbine airfoil is optimized in order to reduce its noise emission, trying at the same time to preserve some of its aerodynamic and geometric characteristics. The new designs are characterized by less cambered airfoils and flatter suction sides. The resulting noise reductions seem to be mainly achieved by a reduction in the turbulent kinetic energy across the boundary layer near the trailing edge and to a lesser extent by a smaller boundary layer displacement thickness.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Trailing edge noise model validation and application to airfoil optimization [texte imprimé] / F. Bertagnolio, Auteur ; H. Aa. Madsen, Auteur ; C. Bak, Auteur . - 2011 . - pp. [031010/1-9].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031010/1-9]
Mots-clés : Aerodynamics Noise abatement Noise measurement Optimisation Wind turbines Index. décimale : 621.47 Résumé : The aim of this article is twofold. First, an existing trailing edge noise model is validated by comparing with airfoil surface pressure fluctuations and far field sound pressure levels measured in three different experiments. The agreement is satisfactory in one case but poor in two other cases. Nevertheless, the model reproduces the main tendencies observed in the measurements with respect to varying flow conditions. Second, the model is implemented into an airfoil design code that is originally used for aerodynamic optimization. An existing wind turbine airfoil is optimized in order to reduce its noise emission, trying at the same time to preserve some of its aerodynamic and geometric characteristics. The new designs are characterized by less cambered airfoils and flatter suction sides. The resulting noise reductions seem to be mainly achieved by a reduction in the turbulent kinetic energy across the boundary layer near the trailing edge and to a lesser extent by a smaller boundary layer displacement thickness.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031011/1-11]
Titre : An experimental data based correction method of biomass gasification equilibrium modeling Type de document : texte imprimé Auteurs : L. Damiani, Auteur ; A. Trucco, Auteur Année de publication : 2011 Article en page(s) : pp. [031011/1-11] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Biomass gasification Matleb-simulink Equilibrium simulation model Index. décimale : 621.47 Résumé : This paper presents a modified equilibrium simulation model for biomass gasification performance prediction. The model, implemented in the MATLAB-SIMULINK® environment, is able to calculate the reactor main operating parameters such as reaction temperature, gas composition, gas flow rate and solid product (typically charcoal). The comparison of model output with experimental data puts in evidence the insufficient precision of equilibrium models due to their incapability of taking into account the nonequilibrium effects always present in the gasification process. To obtain a better prediction of measured values, the pure equilibrium model has been modified on the basis of literature experimental data, introducing semi-empirical relations with the aim to consider the most meaningful effects of nonequilibrium. The results demonstrate that this modification leads to an increased precision of the model in reproducing experimental data.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] An experimental data based correction method of biomass gasification equilibrium modeling [texte imprimé] / L. Damiani, Auteur ; A. Trucco, Auteur . - 2011 . - pp. [031011/1-11].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031011/1-11]
Mots-clés : Biomass gasification Matleb-simulink Equilibrium simulation model Index. décimale : 621.47 Résumé : This paper presents a modified equilibrium simulation model for biomass gasification performance prediction. The model, implemented in the MATLAB-SIMULINK® environment, is able to calculate the reactor main operating parameters such as reaction temperature, gas composition, gas flow rate and solid product (typically charcoal). The comparison of model output with experimental data puts in evidence the insufficient precision of equilibrium models due to their incapability of taking into account the nonequilibrium effects always present in the gasification process. To obtain a better prediction of measured values, the pure equilibrium model has been modified on the basis of literature experimental data, introducing semi-empirical relations with the aim to consider the most meaningful effects of nonequilibrium. The results demonstrate that this modification leads to an increased precision of the model in reproducing experimental data.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031012/1-8]
Titre : Incorporating uncertainty into probabilistic performance models of concentrating solar power plants Type de document : texte imprimé Auteurs : Clifford K. Ho, Auteur ; Gregory J. Kolb, Auteur Année de publication : 2011 Article en page(s) : pp. [031012/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Probability Solar power stations Index. décimale : 621.47 Résumé : A method for applying probabilistic models to concentrating solar-thermal power plants is described in this paper. The benefits of using probabilistic models include quantification of uncertainties inherent in the system and characterization of their impact on system performance and economics. Sensitivity studies using stepwise regression analysis can identify and rank the most important parameters and processes as a means to prioritize future research and activities. The probabilistic method begins with the identification of uncertain variables and the assignment of appropriate distributions for those variables. Those parameters are then sampled using a stratified method (Latin hypercube sampling) to ensure complete and representative sampling from each distribution. Models of performance, reliability, and cost are then simulated multiple times using the sampled set of parameters. The results yield a cumulative distribution function that can be used to quantify the probability of exceeding (or being less than) a particular value. Two examples, a simple cost model and a more detailed performance model of a hypothetical 100-MWe power tower, are provided to illustrate the methods.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Incorporating uncertainty into probabilistic performance models of concentrating solar power plants [texte imprimé] / Clifford K. Ho, Auteur ; Gregory J. Kolb, Auteur . - 2011 . - pp. [031012/1-8].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031012/1-8]
Mots-clés : Probability Solar power stations Index. décimale : 621.47 Résumé : A method for applying probabilistic models to concentrating solar-thermal power plants is described in this paper. The benefits of using probabilistic models include quantification of uncertainties inherent in the system and characterization of their impact on system performance and economics. Sensitivity studies using stepwise regression analysis can identify and rank the most important parameters and processes as a means to prioritize future research and activities. The probabilistic method begins with the identification of uncertain variables and the assignment of appropriate distributions for those variables. Those parameters are then sampled using a stratified method (Latin hypercube sampling) to ensure complete and representative sampling from each distribution. Models of performance, reliability, and cost are then simulated multiple times using the sampled set of parameters. The results yield a cumulative distribution function that can be used to quantify the probability of exceeding (or being less than) a particular value. Two examples, a simple cost model and a more detailed performance model of a hypothetical 100-MWe power tower, are provided to illustrate the methods.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031013/1-6]
Titre : Considerations for the design of solar-thermal chemical processes Type de document : texte imprimé Auteurs : Janna Martinek, Auteur ; Melinda Channel, Auteur ; Allan Lewandowski, Auteur Année de publication : 2011 Article en page(s) : pp. [031013/1-6] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Carnot cycle Enthalpy Nickel compounds Ray tracing Solar energy conversion Zinc compounds Index. décimale : 621.47 Résumé : A methodology is presented for the design of solar thermal chemical processes. The solar receiver efficiency for the high temperature step, defined herein as the ratio of the enthalpy change resulting from the process occurring in the receiver to the solar energy input, is limited by the solar energy absorption efficiency. When using this definition of receiver efficiency, both the optimal reactor temperature for a given solar concentration ratio and the solar concentration required to achieve a given temperature and efficiency shift to lower values than those dictated by the Carnot limitation on the system efficiency for the conversion of heat to work. Process and solar field design considerations were investigated for ZnO and NiFe2O4 “ferrite” spinel water splitting cycles with concentration ratios of roughly 2000, 4000, and 8000 suns to assess the implications of using reduced solar concentration. Solar field design and determination of field efficiency were accomplished using ray trace modeling of the optical components. Annual solar efficiency increased while heliostat area decreased with increasing concentration due to shading and blocking effects. The heliostat fields designed using system efficiency for the conversion of heat to work were found to be overdesigned by up to 21% compared with those designed using the receiver efficiency alone. Overall efficiencies of 13–20% were determined for a “ferrite” based water splitting process with thermal reduction conversions in the range of 35–100%.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Considerations for the design of solar-thermal chemical processes [texte imprimé] / Janna Martinek, Auteur ; Melinda Channel, Auteur ; Allan Lewandowski, Auteur . - 2011 . - pp. [031013/1-6].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031013/1-6]
Mots-clés : Carnot cycle Enthalpy Nickel compounds Ray tracing Solar energy conversion Zinc compounds Index. décimale : 621.47 Résumé : A methodology is presented for the design of solar thermal chemical processes. The solar receiver efficiency for the high temperature step, defined herein as the ratio of the enthalpy change resulting from the process occurring in the receiver to the solar energy input, is limited by the solar energy absorption efficiency. When using this definition of receiver efficiency, both the optimal reactor temperature for a given solar concentration ratio and the solar concentration required to achieve a given temperature and efficiency shift to lower values than those dictated by the Carnot limitation on the system efficiency for the conversion of heat to work. Process and solar field design considerations were investigated for ZnO and NiFe2O4 “ferrite” spinel water splitting cycles with concentration ratios of roughly 2000, 4000, and 8000 suns to assess the implications of using reduced solar concentration. Solar field design and determination of field efficiency were accomplished using ray trace modeling of the optical components. Annual solar efficiency increased while heliostat area decreased with increasing concentration due to shading and blocking effects. The heliostat fields designed using system efficiency for the conversion of heat to work were found to be overdesigned by up to 21% compared with those designed using the receiver efficiency alone. Overall efficiencies of 13–20% were determined for a “ferrite” based water splitting process with thermal reduction conversions in the range of 35–100%.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031014/1-5]
Titre : A Direct steam generation solar power plant with integrated thermal storage Type de document : texte imprimé Auteurs : Jurgen Birnbaum, Auteur ; Markus Eck, Auteur ; Markus Fichtner, Auteur Année de publication : 2011 Article en page(s) : pp. [031014/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Solar thermal power plant Direct steam generation Thermal storage Index. décimale : 621.47 Résumé : For the future market potential of parabolic trough power plants with direct steam generation (DSG), it is beneficial to integrate a thermal storage system. Heat storage media based on phase change materials offer heat transfer at constant temperatures needed for the evaporation process. Different options for a plant layout are presented and discussed. The interactions between the three subsystems—solar field, power block, and thermal storage—are analyzed, and boundary conditions arising from the thermal storage system are identified. Compared with a system without storage the number of operating points increases significantly since different combinations of storage charge and discharge operations go along with a varying power output of the solar field. It is shown that the large number of theoretical operating points can be reduced to a subset with practical relevance. Depending on the live steam parameters a reheat is necessary within the power block. Compared with parabolic trough fields with a single phase heat transfer medium such as oil, a special heat exchanger configuration is needed for a DSG plant. Different alternatives based on available technologies are presented and evaluated.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] A Direct steam generation solar power plant with integrated thermal storage [texte imprimé] / Jurgen Birnbaum, Auteur ; Markus Eck, Auteur ; Markus Fichtner, Auteur . - 2011 . - pp. [031014/1-5].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031014/1-5]
Mots-clés : Solar thermal power plant Direct steam generation Thermal storage Index. décimale : 621.47 Résumé : For the future market potential of parabolic trough power plants with direct steam generation (DSG), it is beneficial to integrate a thermal storage system. Heat storage media based on phase change materials offer heat transfer at constant temperatures needed for the evaporation process. Different options for a plant layout are presented and discussed. The interactions between the three subsystems—solar field, power block, and thermal storage—are analyzed, and boundary conditions arising from the thermal storage system are identified. Compared with a system without storage the number of operating points increases significantly since different combinations of storage charge and discharge operations go along with a varying power output of the solar field. It is shown that the large number of theoretical operating points can be reduced to a subset with practical relevance. Depending on the live steam parameters a reheat is necessary within the power block. Compared with parabolic trough fields with a single phase heat transfer medium such as oil, a special heat exchanger configuration is needed for a DSG plant. Different alternatives based on available technologies are presented and evaluated.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031015/1-8]
Titre : Electricity generation from a compound parabolic concentrator coupled to a thermoelectric module Type de document : texte imprimé Auteurs : Chigbo A. Mgbemene, Auteur ; John Duffy, Auteur ; Hongwei Sun, Auteur Année de publication : 2011 Article en page(s) : pp. [031015/1-8] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Electric power generation Solar energy concentrators Thermoelectric conversion Index. décimale : 621.47 Résumé : Generating electricity from the sun using a combination of a compound parabolic concentrator (CPC) and a thermoelectric module (TEM) has been studied. The system was modeled, analyzed, and tested. The model equations and the methodology used for the demonstration are presented and experimentally validated. The experimental setup comprised a manually fabricated CPC placed on a commercially available TEM. The results showed that the combination can generate and sustain enough power for a small appliance. It was also shown that there is enough dissipated heat from the system, which could be harnessed for additional uses. The cost is still high, about $35/Wp, but if credit is given for the thermal energy the initial cost goes down.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Electricity generation from a compound parabolic concentrator coupled to a thermoelectric module [texte imprimé] / Chigbo A. Mgbemene, Auteur ; John Duffy, Auteur ; Hongwei Sun, Auteur . - 2011 . - pp. [031015/1-8].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031015/1-8]
Mots-clés : Electric power generation Solar energy concentrators Thermoelectric conversion Index. décimale : 621.47 Résumé : Generating electricity from the sun using a combination of a compound parabolic concentrator (CPC) and a thermoelectric module (TEM) has been studied. The system was modeled, analyzed, and tested. The model equations and the methodology used for the demonstration are presented and experimentally validated. The experimental setup comprised a manually fabricated CPC placed on a commercially available TEM. The results showed that the combination can generate and sustain enough power for a small appliance. It was also shown that there is enough dissipated heat from the system, which could be harnessed for additional uses. The cost is still high, about $35/Wp, but if credit is given for the thermal energy the initial cost goes down.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031016/1-9]
Titre : PV-electrolyzer plant : models and optimization procedure Type de document : texte imprimé Auteurs : P. Artuso, Auteur ; Zuccari, F., Auteur ; A. Dell'Era, Auteur Année de publication : 2011 Article en page(s) : pp. [031016/1-9] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Hydrogen production Optimisation Photovoltaic power systems Index. décimale : 621.47 Résumé : The work focused on the analysis of the connection between a photovoltaic (PV) plant and an electrolyzer for hydrogen production. On the basis of PV-plant and electrolyzer experimental data, the effectiveness of the models adopted in the simulation program has been verified in order to choose the best model and, eventually, modify some parameters. By running the simulations, the procedure to optimize the PV-plant and the electrolyzer combination has been established. In fact, the simulation results might be considered to size an electrolyzer as small as possible, which is able to exploit up to the maximum power actually produced by the PV-plant during a working year. This criterion allows minimizing the overall plant costs. Furthermore, the possibility of deleting the maximum power point tracker and the dc/dc converter has been analyzed. On the basis of the obtained results, this opportunity is preferable to avoid the energy losses in the power control system; and it is convenient even from an economic point of view, considering that the electronic device costs are comparable with the PV-plant ones.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] PV-electrolyzer plant : models and optimization procedure [texte imprimé] / P. Artuso, Auteur ; Zuccari, F., Auteur ; A. Dell'Era, Auteur . - 2011 . - pp. [031016/1-9].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031016/1-9]
Mots-clés : Hydrogen production Optimisation Photovoltaic power systems Index. décimale : 621.47 Résumé : The work focused on the analysis of the connection between a photovoltaic (PV) plant and an electrolyzer for hydrogen production. On the basis of PV-plant and electrolyzer experimental data, the effectiveness of the models adopted in the simulation program has been verified in order to choose the best model and, eventually, modify some parameters. By running the simulations, the procedure to optimize the PV-plant and the electrolyzer combination has been established. In fact, the simulation results might be considered to size an electrolyzer as small as possible, which is able to exploit up to the maximum power actually produced by the PV-plant during a working year. This criterion allows minimizing the overall plant costs. Furthermore, the possibility of deleting the maximum power point tracker and the dc/dc converter has been analyzed. On the basis of the obtained results, this opportunity is preferable to avoid the energy losses in the power control system; and it is convenient even from an economic point of view, considering that the electronic device costs are comparable with the PV-plant ones.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031017/1-7]
Titre : An air-based cavity-receiver for solar trough concentrators Type de document : texte imprimé Auteurs : Bartelt, Roman, Auteur ; Maurizio Barbato, Auteur ; Andrea Pedretti, Auteur Année de publication : 2011 Article en page(s) : pp. [031017/1-7] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Cavity resonators Convection Heat conduction Heat transfer Monte Carlo methods Solar absorber-convertors Solar radiation Index. décimale : 621.47 Résumé : A cylindrical cavity-receiver containing a tubular absorber that uses air as the heat transfer fluid is proposed for a novel solar trough concentrator design. A numerical heat transfer model is developed to determine the receiver's absorption efficiency and pumping power requirement. The 2D steady-state energy conservation equation coupling radiation, convection, and conduction heat transfer is formulated and solved numerically by finite volume techniques. The Monte Carlo ray-tracing and radiosity methods are applied to establish the solar radiation distribution and radiative exchange within the receiver. Simulations were conducted for a 50 m-long and 9.5 m-wide collector section with 120°C air inlet temperature, and air mass flows in the range 0.1–1.2 kg/s. Outlet air temperatures ranged from 260°C to 601°C, and corresponding absorption efficiencies varied between 60% and 18%. Main heat losses integrated over the receiver length were due to reflection and spillage at the receiver's windowed aperture, amounting to 13% and 9% of the solar power input, respectively. The pressure drop along the 50 m module was in the range 0.23–11.84 mbars, resulting in isentropic pumping power requirements of 6.45×10−4−0.395% of the solar power input.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] An air-based cavity-receiver for solar trough concentrators [texte imprimé] / Bartelt, Roman, Auteur ; Maurizio Barbato, Auteur ; Andrea Pedretti, Auteur . - 2011 . - pp. [031017/1-7].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [031017/1-7]
Mots-clés : Cavity resonators Convection Heat conduction Heat transfer Monte Carlo methods Solar absorber-convertors Solar radiation Index. décimale : 621.47 Résumé : A cylindrical cavity-receiver containing a tubular absorber that uses air as the heat transfer fluid is proposed for a novel solar trough concentrator design. A numerical heat transfer model is developed to determine the receiver's absorption efficiency and pumping power requirement. The 2D steady-state energy conservation equation coupling radiation, convection, and conduction heat transfer is formulated and solved numerically by finite volume techniques. The Monte Carlo ray-tracing and radiosity methods are applied to establish the solar radiation distribution and radiative exchange within the receiver. Simulations were conducted for a 50 m-long and 9.5 m-wide collector section with 120°C air inlet temperature, and air mass flows in the range 0.1–1.2 kg/s. Outlet air temperatures ranged from 260°C to 601°C, and corresponding absorption efficiencies varied between 60% and 18%. Main heat losses integrated over the receiver length were due to reflection and spillage at the receiver's windowed aperture, amounting to 13% and 9% of the solar power input, respectively. The pressure drop along the 50 m module was in the range 0.23–11.84 mbars, resulting in isentropic pumping power requirements of 6.45×10−4−0.395% of the solar power input.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034501/1-4]
Titre : A Solar thermal electrolytic reactor for studying the production of metals from their oxides Type de document : texte imprimé Auteurs : P. Krenzke, Auteur ; K. Krueger, Auteur ; N. Leonard, Auteur Année de publication : 2011 Article en page(s) : pp. [034501/1-4] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Chemical reactors Electrolysis Electrolytic devices Metallurgical industries Solar cells Index. décimale : 621.47 Résumé : A solar thermal electrolytic reactor was developed for studying at a 10 kW scale how a solar reactor's electrolytic cell design and operating variables influence the performance of a solar process for producing metals from their oxides. Current versus voltage maps as well as current versus time for specified voltages were obtained for the electrolysis of ZnO and MgO within the temperature range of 1200–1500 K and various electrolytic cell configurations. An example of a map is presented. The data from maps and steady-state runs were used to illustrate how we quantify the influence of the cell's operating temperature and current density on process performance. We also illustrate how one design variable, the cell's electrolyte, influences process performance.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] A Solar thermal electrolytic reactor for studying the production of metals from their oxides [texte imprimé] / P. Krenzke, Auteur ; K. Krueger, Auteur ; N. Leonard, Auteur . - 2011 . - pp. [034501/1-4].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034501/1-4]
Mots-clés : Chemical reactors Electrolysis Electrolytic devices Metallurgical industries Solar cells Index. décimale : 621.47 Résumé : A solar thermal electrolytic reactor was developed for studying at a 10 kW scale how a solar reactor's electrolytic cell design and operating variables influence the performance of a solar process for producing metals from their oxides. Current versus voltage maps as well as current versus time for specified voltages were obtained for the electrolysis of ZnO and MgO within the temperature range of 1200–1500 K and various electrolytic cell configurations. An example of a map is presented. The data from maps and steady-state runs were used to illustrate how we quantify the influence of the cell's operating temperature and current density on process performance. We also illustrate how one design variable, the cell's electrolyte, influences process performance.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034502/1-7]
Titre : Negatively buoyant plume flow in a baffled heat exchanger Type de document : texte imprimé Auteurs : Sandra K. S. Boetcher, Auteur ; F. A. Kulacki, Auteur ; Jane H. Davidson, Auteur Année de publication : 2011 Article en page(s) : pp. [034502/1-7] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Thermal stores Immersed heat exchanger Negatively buoyant flow Index. décimale : 621.47 Résumé : A numerical simulation of transient two-dimensional negatively buoyant flow into a straight baffle situated below an isothermal circular cylinder in an initially isothermal enclosure is presented for both an adiabatic and a highly conducting baffle for Rayleigh numbers from 106 to 107. Results show the effects of baffle offset, width, and length on the point where viscous flow develops and on velocity profiles within the baffle. Results are interpreted to guide the design of straight baffles to reduce destruction of stratification in thermal stores using an immersed heat exchanger. The preferred geometry is a low-conductivity baffle of width equal to the effective width of the heat exchanger and 15 or more cylinder diameters in length to ensure nearly fully developed flow at the baffle outlet.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Negatively buoyant plume flow in a baffled heat exchanger [texte imprimé] / Sandra K. S. Boetcher, Auteur ; F. A. Kulacki, Auteur ; Jane H. Davidson, Auteur . - 2011 . - pp. [034502/1-7].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034502/1-7]
Mots-clés : Thermal stores Immersed heat exchanger Negatively buoyant flow Index. décimale : 621.47 Résumé : A numerical simulation of transient two-dimensional negatively buoyant flow into a straight baffle situated below an isothermal circular cylinder in an initially isothermal enclosure is presented for both an adiabatic and a highly conducting baffle for Rayleigh numbers from 106 to 107. Results show the effects of baffle offset, width, and length on the point where viscous flow develops and on velocity profiles within the baffle. Results are interpreted to guide the design of straight baffles to reduce destruction of stratification in thermal stores using an immersed heat exchanger. The preferred geometry is a low-conductivity baffle of width equal to the effective width of the heat exchanger and 15 or more cylinder diameters in length to ensure nearly fully developed flow at the baffle outlet.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034503/1-5]
Titre : Two-step optimization for wind turbine blade with probability approach Type de document : texte imprimé Auteurs : Ki-Hak Lee, Auteur ; Kyu-Hong Kim, Auteur ; Dong-Ho Lee, Auteur Année de publication : 2011 Article en page(s) : pp. [034503/1-5] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Blades Optimisation Probability Wind turbines Index. décimale : 621.47 Résumé : A horizontal-axis wind turbine blade is designed using two step optimization procedures with probability approach. For the efficient management of the multiple design variables required for the blade design, the design procedure is divided into two optimization steps. In step 1, the diameter and rotating speed of a blade are determined and design points are extracted from the design space. In step 2-1, blade shapes are optimized by using the strip theory with the minimum energy loss method. The capacity factor and the cost model for each optimized blade shape are calculated in steps 2-2 and 2-3, respectively. To find the global optimum point in the design space, the space is modified into a highly possible region through the use of the probability approach.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...] [article] Two-step optimization for wind turbine blade with probability approach [texte imprimé] / Ki-Hak Lee, Auteur ; Kyu-Hong Kim, Auteur ; Dong-Ho Lee, Auteur . - 2011 . - pp. [034503/1-5].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 3 (Août 2010) . - pp. [034503/1-5]
Mots-clés : Blades Optimisation Probability Wind turbines Index. décimale : 621.47 Résumé : A horizontal-axis wind turbine blade is designed using two step optimization procedures with probability approach. For the efficient management of the multiple design variables required for the blade design, the design procedure is divided into two optimization steps. In step 1, the diameter and rotating speed of a blade are determined and design points are extracted from the design space. In step 2-1, blade shapes are optimized by using the strip theory with the minimum energy loss method. The capacity factor and the cost model for each optimized blade shape are calculated in steps 2-2 and 2-3, respectively. To find the global optimum point in the design space, the space is modified into a highly possible region through the use of the probability approach.
DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO00013200 [...]
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