Documents disponibles écrits par cet auteur

Air-sand heat exchanger for high-temperature storage / Shashikant Warerkar in Transactions of the ASME. Journal of solar energy engineering, Vol. 133 N° 2 (Mai 2011) 

Public ISBD [article]  in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 2 (Mai 2011) . - 07 p. Titre : Air-sand heat exchanger for high-temperature storage Type de document : texte imprimé Auteurs : Shashikant Warerkar, Auteur ; Stefan Schmitz, Auteur ; Joachim Goettsche, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Solar energy Langues : Anglais (eng) Mots-clés : Furnaces  Heat  exchangers  High-temperature  techniques  Power  generation  economics  Quartz  Sand  Solar  power  Solar  power  stations  Specific  heat  Steel  industry  Thermal  energy  storage  Thermal  stability Index. décimale : 621.47 Résumé : In view of rising energy prices and an increasing share of power generated by renewable energy sources, the importance of energy storage is growing. In the framework of this project, a thermal energy storage concept for solar power towers is being developed, in which quartz sand serves as a storage medium. Sand is suitable due to its properties such as high thermal stability, specific heat capacity, and low-cost availability. Compared with storages based on ceramic bodies, the use of sand promises to reduce costs of energy storage and thus to reduce the costs of electricity generation. In addition, the storage concept could be applicable in the steel industry. The central element of the storage concept is an air-sand heat exchanger, which is presently under development. This paper describes simulation results and measurements of the heat exchanger prototype. It includes sand flow behavior and experience with different porous walls as well as up-scaling options. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000133000002 [...] [article] Air-sand heat exchanger for high-temperature storage [texte imprimé] / Shashikant Warerkar, Auteur ; Stefan Schmitz, Auteur ; Joachim Goettsche, Auteur . - 2012 . - 07 p. Solar energy Langues : Anglais (eng) in Transactions of the ASME. Journal of solar energy engineering > Vol. 133 N° 2 (Mai 2011) . - 07 p. Mots-clés : Furnaces  Heat  exchangers  High-temperature  techniques  Power  generation  economics  Quartz  Sand  Solar  power  Solar  power  stations  Specific  heat  Steel  industry  Thermal  energy  storage  Thermal  stability Index. décimale : 621.47 Résumé : In view of rising energy prices and an increasing share of power generated by renewable energy sources, the importance of energy storage is growing. In the framework of this project, a thermal energy storage concept for solar power towers is being developed, in which quartz sand serves as a storage medium. Sand is suitable due to its properties such as high thermal stability, specific heat capacity, and low-cost availability. Compared with storages based on ceramic bodies, the use of sand promises to reduce costs of energy storage and thus to reduce the costs of electricity generation. In addition, the storage concept could be applicable in the steel industry. The central element of the storage concept is an air-sand heat exchanger, which is presently under development. This paper describes simulation results and measurements of the heat exchanger prototype. It includes sand flow behavior and experience with different porous walls as well as up-scaling options. DEWEY : 621.47 ISSN : 0199-6231 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JSEEDO000133000002 [...]

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 [...]