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Auteur Richard B. Diver |
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Ajouter le résultat dans votre panier Faire une suggestion Affiner la rechercheConceptual design of a 2× trough for use within salt and oil-based parabolic trough power plants / Gregory J. Kolb in Transactions of the ASME. Journal of solar energy engineering, Vol. 132 N° 4 (Novembre 2010)
Titre : Conceptual design of a 2× trough for use within salt and oil-based parabolic trough power plants Type de document : texte imprimé Auteurs : Gregory J. Kolb, Auteur ; Richard B. Diver, Auteur Année de publication : 2011 Article en page(s) : pp. [041003/1-6] Note générale : Energie Solaire Langues : Anglais (eng) Mots-clés : Parabolic trough Large aperture Molten salt Optics Economics Index. décimale : 621.47 Résumé : Recent studies in the United States suggest that parabolic trough levelized energy costs (LECs) can be reduced 10–15% through integration of a large salt energy storage system coupled with the direct heating of molten salt in the solar field. While noteworthy, this relatively small predicted improvement may not justify the increased technical risks. Examples of potential issues include increased design complexity, higher maintenance costs, and salt freezing in the solar field. To make a compelling argument for development of this new system, we believe that additional technical advances beyond that previously reported will be required to achieve significant LEC reduction, greater than 25%. The new technical advances described include the development of a high-concentration trough that has double aperture and optical concentration of current technology. This trough is predicted to be more cost-effective than current technology because its cost ($/m2) and thermal losses (W/m2) are significantly lower. Recent trough optical performance improvements, such as more accurate facets and better alignment techniques, suggest a 2× trough is possible. Combining this new trough with a new low-melting point salt now under development suggests that a LEC cost reduction of ~25% is possible for a 50 MW, 2× salt plant relative to a conventional (1×) 50 MW oil plant. However, the 2× trough will also benefit plants that use synthetic oil in the field. A LEC comparison of 2× plants at sizes 200 MW shows only a 6% advantage of salt over oil.
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° 4 (Novembre 2010) . - pp. [041003/1-6][article] Conceptual design of a 2× trough for use within salt and oil-based parabolic trough power plants [texte imprimé] / Gregory J. Kolb, Auteur ; Richard B. Diver, Auteur . - 2011 . - pp. [041003/1-6].
Energie Solaire
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 132 N° 4 (Novembre 2010) . - pp. [041003/1-6]
Mots-clés : Parabolic trough Large aperture Molten salt Optics Economics Index. décimale : 621.47 Résumé : Recent studies in the United States suggest that parabolic trough levelized energy costs (LECs) can be reduced 10–15% through integration of a large salt energy storage system coupled with the direct heating of molten salt in the solar field. While noteworthy, this relatively small predicted improvement may not justify the increased technical risks. Examples of potential issues include increased design complexity, higher maintenance costs, and salt freezing in the solar field. To make a compelling argument for development of this new system, we believe that additional technical advances beyond that previously reported will be required to achieve significant LEC reduction, greater than 25%. The new technical advances described include the development of a high-concentration trough that has double aperture and optical concentration of current technology. This trough is predicted to be more cost-effective than current technology because its cost ($/m2) and thermal losses (W/m2) are significantly lower. Recent trough optical performance improvements, such as more accurate facets and better alignment techniques, suggest a 2× trough is possible. Combining this new trough with a new low-melting point salt now under development suggests that a LEC cost reduction of ~25% is possible for a 50 MW, 2× salt plant relative to a conventional (1×) 50 MW oil plant. However, the 2× trough will also benefit plants that use synthetic oil in the field. A LEC comparison of 2× plants at sizes 200 MW shows only a 6% advantage of salt over oil.
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Titre : Influence of film cooling unsteadiness on turbine blade leading edge heat flux Type de document : texte imprimé Auteurs : James L. Rutledge, Auteur ; Paul I. King, Auteur ; Richard B. Diver, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Hot gas path Turbine engine Heat transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Film cooling in the hot gas path of a gas turbine engine can protect components from the high temperature main flow, but it generally increases the heat transfer coefficient h partially offsetting the benefits in reduced adiabatic wall temperature. We are thus interested in adiabatic effectiveness eta and h which are combined in a formulation called net heat flux reduction (NHFR). Unsteadiness in coolant flow may arise due to inherent unsteadiness in the external flow or be intentionally introduced for flow control. In previous work it has been suggested that pulsed cooling flow may, in fact, offer benefits over steady blowing in either improving NHFR or reducing the mass flow requirements for matched NHFR. In this paper we examine this hypothesis for a range of steady and pulsed blowing conditions. We use a new experimental technique to analyze unsteady film cooling on a semicircular cylinder simulating the leading edge of a turbine blade. The average NHFR with pulsed and steady film cooling is measured and compared for a single coolant hole located 21.5° downstream from the leading edge stagnation line, angled 20° to the surface and 90° to the streamwise direction. We show that for moderate blowing ratios at blade passing frequencies, steady film flow yields better NHFR. At higher coolant flow rates beyond the optimum steady blowing ratio, however, pulsed film cooling can be advantageous. We present and demonstrate a prediction technique for unsteady blowing at frequencies similar to the blade passing frequency that only requires the knowledge of steady flow behavior. With this important result, it is possible to predict when pulsing would be beneficial or detrimental. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000007 [...]
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 7 (Juillet 2012) . - 10 p.[article] Influence of film cooling unsteadiness on turbine blade leading edge heat flux [texte imprimé] / James L. Rutledge, Auteur ; Paul I. King, Auteur ; Richard B. Diver, Auteur . - 2012 . - 10 p.
Génie mécanique
Langues : Anglais (eng)
in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 7 (Juillet 2012) . - 10 p.
Mots-clés : Hot gas path Turbine engine Heat transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Film cooling in the hot gas path of a gas turbine engine can protect components from the high temperature main flow, but it generally increases the heat transfer coefficient h partially offsetting the benefits in reduced adiabatic wall temperature. We are thus interested in adiabatic effectiveness eta and h which are combined in a formulation called net heat flux reduction (NHFR). Unsteadiness in coolant flow may arise due to inherent unsteadiness in the external flow or be intentionally introduced for flow control. In previous work it has been suggested that pulsed cooling flow may, in fact, offer benefits over steady blowing in either improving NHFR or reducing the mass flow requirements for matched NHFR. In this paper we examine this hypothesis for a range of steady and pulsed blowing conditions. We use a new experimental technique to analyze unsteady film cooling on a semicircular cylinder simulating the leading edge of a turbine blade. The average NHFR with pulsed and steady film cooling is measured and compared for a single coolant hole located 21.5° downstream from the leading edge stagnation line, angled 20° to the surface and 90° to the streamwise direction. We show that for moderate blowing ratios at blade passing frequencies, steady film flow yields better NHFR. At higher coolant flow rates beyond the optimum steady blowing ratio, however, pulsed film cooling can be advantageous. We present and demonstrate a prediction technique for unsteady blowing at frequencies similar to the blade passing frequency that only requires the knowledge of steady flow behavior. With this important result, it is possible to predict when pulsing would be beneficial or detrimental. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000007 [...] Exemplaires
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Titre : Methodology to assess potential glint and glare hazards from concentrating solar power plants : analytical models and experimental validation Type de document : texte imprimé Auteurs : Clifford K. Ho, Auteur ; Cheryl M. Ghanbari, Auteur ; Richard B. Diver, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : Solar energy Langues : Anglais (eng) Mots-clés : Eye protection Health hazards Optical elements Solar absorber-convertors energy concentrators power stations Sunlight Index. décimale : 621.47 Résumé : With a growing number of concentrating solar power systems being designed and developed, the potential impact of glint and glare from concentrating solar collectors and receivers is receiving increased attention as a potential hazard or as a distraction for motorists, pilots, and pedestrians. This paper provides analytical methods to evaluate the irradiance originating from specularly and diffusely reflecting sources as a function of distance and characteristics of the source. Sample problems are provided for both specular and diffuse sources, and validation of the models is performed via testing. In addition, a summary of safety metrics is compiled from the literature to evaluate the potential hazards of calculated irradiances from glint and glare for short-term exposures. Previous safety metrics have focused on prevention of permanent eye damage (e.g., retinal burn). New metrics used in this paper account for temporary after-image, which can occur at irradiance values several orders of magnitude lower than the irradiance values required for irreversible eye damage. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000133000003 [...]
in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 3 (N° Spécial) (Août 2011) . - 09 p.[article] Methodology to assess potential glint and glare hazards from concentrating solar power plants : analytical models and experimental validation [texte imprimé] / Clifford K. Ho, Auteur ; Cheryl M. Ghanbari, Auteur ; Richard B. Diver, Auteur . - 2012 . - 09 p.
Solar energy
Langues : Anglais (eng)
in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 3 (N° Spécial) (Août 2011) . - 09 p.
Mots-clés : Eye protection Health hazards Optical elements Solar absorber-convertors energy concentrators power stations Sunlight Index. décimale : 621.47 Résumé : With a growing number of concentrating solar power systems being designed and developed, the potential impact of glint and glare from concentrating solar collectors and receivers is receiving increased attention as a potential hazard or as a distraction for motorists, pilots, and pedestrians. This paper provides analytical methods to evaluate the irradiance originating from specularly and diffusely reflecting sources as a function of distance and characteristics of the source. Sample problems are provided for both specular and diffuse sources, and validation of the models is performed via testing. In addition, a summary of safety metrics is compiled from the literature to evaluate the potential hazards of calculated irradiances from glint and glare for short-term exposures. Previous safety metrics have focused on prevention of permanent eye damage (e.g., retinal burn). New metrics used in this paper account for temporary after-image, which can occur at irradiance values several orders of magnitude lower than the irradiance values required for irreversible eye damage. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000133000003 [...] Exemplaires
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