TY - CHAP A1 - Ahlbrink, N. A1 - Alexopoulos, Spiros A1 - Andersson, J. A1 - Belhomme, B. A1 - Teixeira Boura, Cristiano José A1 - Gall, J. A1 - Hirsch, T. T1 - viCERP - the Virtual Institute of Central Receiver Power Plant T2 - MATHMOD 2009 - 6th Vienna International Conference on Mathematical Modelling : February 11 - 13, 2009, Vienna, Austria. ARGESIM Report. No. 35 Y1 - 2009 SN - 978-3-901608-35-3 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Alexopoulos, Spiros A1 - Hoffschmidt, Bernhard T1 - Advances in solar tower technology JF - Wiley interdisciplinary reviews : Energy and Environment : WIREs Y1 - 2017 U6 - https://doi.org/10.1002/wene.217 SN - 2041-840X VL - 6 IS - 1 SP - 1 EP - 19 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Alexopoulos, Spiros T1 - Simulation model for the transient process behaviour of solar aluminium recycling in a rotary kiln JF - Applied Thermal Engineering Y1 - 2015 U6 - https://doi.org/10.1016/j.applthermaleng.2015.01.007 SN - 1359-4311 N1 - Autor im Original: Spiridon O. Alexopoulos VL - 78 SP - 387 EP - 396 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Alexopoulos, Spiros T1 - Biogas systems: basics, biogas multifunction, principle of fermentation and hybrid application with a solar tower for the treatment of waste animal manure JF - Journal of Engineering Science and Technology Review N2 - Two of the main environmental problems of today’s society are the continuously increasing production of organic wastes as well as the increase of carbon dioxide in the atmosphere and the related green house effect. A way to solve these problems is the production of biogas. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes and agricultural residues, converts these substrates into electricity and heat and offers a natural fertiliser for agriculture. The microbiological process of decomposition of organic matter, in the absence of oxygen takes place in reactors, called digesters. Biogas can be used as a fuel in a gas turbine or burner and can be used in a hybrid solar tower system offering a solution for waste treatment of agricultural and animal residues. A solar tower system consists of a heliostat field, which concentrates direct solar irradiation on an open volumetric central receiver. The receiver heats up ambient air to temperatures of around 700°C. The hot air’s heat energy is transferred to a steam Rankine cycle in a heat recovery steam generator (HRSG). The steam drives a steam turbine, which in turn drives a generator for producing electricity. In order to increase the operational hours of a solar tower power plant, a heat storage system and/ or hybridization may be considered. The advantage of solar-fossil hybrid power plants, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. On sunny days the hybrid system operates in a solar-only mode with the central receiver and on cloudy days and at night with the gas turbine only. As an alternative to methane gas, environmentally neutral biogas can be used for operating the gas turbine. Hence, the hybrid system is operated to 100% from renewable energy sources Y1 - 2012 SN - 1791-2377 N1 - Special Issue on Renewable Energy Systems VL - 5 IS - 4 SP - 48 EP - 55 ER - TY - CHAP A1 - El Moussaoui, Noureddine A1 - Kassmi, Khalil A1 - Alexopoulos, Spiros A1 - Schwarzer, Klemens A1 - Chayeb, Hamid A1 - Bachiri, Najib T1 - Simulation studies on a new innovative design of a hybrid solar distiller MSDH alimented with a thermal and photovoltaic energy T2 - Materialstoday: Proceedings N2 - In this paper, we present the structure, the simulation the operation of a multi-stage, hybrid solar desalination system (MSDH), powered by thermal and photovoltaic (PV) (MSDH) energy. The MSDH system consists of a lower basin, eight horizontal stages, a field of four flat thermal collectors with a total area of 8.4 m2, 3 Kw PV panels and solar batteries. During the day the system is heated by thermal energy, and at night by heating resistors, powered by solar batteries. These batteries are charged by the photovoltaic panels during the day. More specifically, during the day and at night, we analyse the temperature of the stages and the production of distilled water according to the solar irradiation intensity and the electric heating power, supplied by the solar batteries. The simulations were carried out in the meteorological conditions of the winter month (February 2020), presenting intensities of irradiance and ambient temperature reaching 824 W/m2 and 23 °C respectively. The results obtained show that during the day the system is heated by the thermal collectors, the temperature of the stages and the quantity of water produced reach 80 °C and 30 Kg respectively. At night, from 6p.m. the system is heated by the electric energy stored in the batteries, the temperature of the stages and the quantity of water produced reach respectively 90 °C and 104 Kg for an electric heating power of 2 Kw. Moreover, when the electric power varies from 1 Kw to 3 Kw the quantity of water produced varies from 92 Kg to 134 Kg. The analysis of these results and their comparison with conventional solar thermal desalination systems shows a clear improvement both in the heating of the stages, by 10%, and in the quantity of water produced by a factor of 3. Y1 - 2021 U6 - https://doi.org/10.1016/j.matpr.2021.03.115 SN - 2214-7853 N1 - The Fourth edition of the International Conference on Materials & Environmental Science (ICMES 2020), virtual conference, November 18-28, 2020, Morocco VL - 45 IS - 8 SP - 7653 EP - 7660 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Alexopoulos, Spiros T1 - Biomass technology and bio-fuels: Heating/cooling and power T2 - Renewable energy systems : theory, innovations, and intelligent applications / eds.: Socrates Kaplanis and Eleni Kaplani Y1 - 2013 SN - 9781624177415 SP - 501 EP - 523 PB - Nova Science Publ. CY - Hauppauge, NY ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Kluczka, Sven A1 - Vaeßen, Christiane A1 - Roeb, M. A1 - Neises, M. T1 - Scenario development for efficient methanol production using CO2 and solar energy T2 - Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012 Y1 - 2012 SP - ID 99 CY - Rijeka ER - TY - CHAP A1 - Anthrakidis, Anette A1 - Rusack, Markus A1 - Schwarzer, Klemens T1 - Low effort measurement method of PTC-efficiency T2 - SolarPACES 2010 : the CSP conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France Y1 - 2010 SP - 48 EP - 49 PB - Soc. OSC CY - Saint Maur ER - TY - JOUR A1 - Göttsche, Joachim A1 - Alexopoulos, Spiros A1 - Dümmler, Andreas A1 - Maddineni, S. K. T1 - Multi-Mirror Array Calculations With Optical Error N2 - The optical performance of a 2-axis solar concentrator was simulated with the COMSOL Multiphysics® software. The concentrator consists of a mirror array, which was created using the application builder. The mirror facets are preconfigured to form a focal point. During tracking all mirrors are moved simultaneously in a coupled mode by 2 motors in two axes, in order to keep the system in focus with the moving sun. Optical errors on each reflecting surface were implemented in combination with the solar angular cone of ± 4.65 mrad. As a result, the intercept factor of solar radiation that is available to the receiver was calculated as a function of the transversal and longitudinal angles of incidence. In addition, the intensity distribution on the receiver plane was calculated as a function of the incidence angles. KW - solar process heat KW - concentrating collector KW - raytracing KW - point-focussing system Y1 - 2019 SP - 1 EP - 6 ER - TY - CHAP A1 - Baumann, Torsten A1 - Teixeira Boura, Cristiano José A1 - Eckstein, Julian A1 - Dabrowski, Jan A1 - Göttsche, Joachim A1 - Hoffschmidt, Bernhard A1 - Schmitz, Stefan A1 - Zunft, Stefan T1 - Properties of bulk materials for high-temperature air-sand heat exchangers T2 - 30th ISES Biennial Solar World Congress 2011 : Kassel, Germany, 28 August - 2 September 2011. Vol. 2 Y1 - 2012 SN - 978-1-61839-364-7 SP - 1270 EP - 1278 PB - Curran CY - Red Hook, NY ER - TY - CHAP A1 - Hoffschmidt, Bernhard A1 - Alexopoulos, Spiros A1 - Göttsche, Joachim A1 - Sauerborn, Markus A1 - Kaufhold, O. T1 - High Concentration Solar Collectors T2 - Comprehensive Renewable Energy (Second Edition) / Volume 3: Solar Thermal Systems: Components and Applications N2 - Solar thermal concentrated power is an emerging technology that provides clean electricity for the growing energy market. To the solar thermal concentrated power plant systems belong the parabolic trough, the Fresnel collector, the solar dish, and the central receiver system. For high-concentration solar collector systems, optical and thermal analysis is essential. There exist a number of measurement techniques and systems for the optical and thermal characterization of the efficiency of solar thermal concentrated systems. For each system, structure, components, and specific characteristics types are described. The chapter presents additionally an outline for the calculation of system performance and operation and maintenance topics. One main focus is set to the models of components and their construction details as well as different types on the market. In the later part of this article, different criteria for the choice of technology are analyzed in detail. KW - Central receiver system KW - Concentrated solar collector KW - Solar dish KW - Solar concentration Y1 - 2022 SN - 978-0-12-819734-9 U6 - https://doi.org/10.1016/B978-0-12-819727-1.00058-3 SP - 198 EP - 245 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kluczka, Sven A1 - Eckstein, Julian A1 - Alexopoulos, Spiros A1 - Vaeßen, Christiane A1 - Roeb, Martin T1 - Process simulation for solar steam and dry reforming JF - Energy procedia : Proceedings of the SolarPACES 2013 International Conference N2 - In co-operation with the German Aerospace Center, the Solar-Institut Jülich has been analyzing the different technologies that are available for methanol production from CO2 using solar energy. The aim of the project is to extract CO2 from industrial exhaust gases or directly from the atmosphere to recycle it by use of solar energy. Part of the study was the modeling and simulating of a methane reformer for the production of synthesis gas, which can be operated by solar or hybrid heat sources. The reformer has been simplified in such a way that the model is accurate and enables fast calculations. The developed pseudo-homogeneous one- dimensional model can be regarded as a kind of counter-current heat exchanger and is able to incorporate a steam reforming reaction as well as a dry reforming reaction. Y1 - 2014 U6 - https://doi.org/10.1016/j.egypro.2014.03.092 SN - 1876-6102 (E-Journal) VL - 49 SP - 850 EP - 859 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Göttsche, Joachim A1 - Hinsch, Andreas A1 - Wittwer, Volker T1 - Electrochromic mixed WO3-TiO2 thin films produced by sputtering and the sol-gel technique : a comparison / J. Göttsche ; A. Hinsch ; V. Wittwer JF - Solar Energy Materials and Solar Cells. 31 (1993), H. 3 Y1 - 1993 SN - 0927-0248 SP - 415 EP - 428 ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Hoffschmidt, Bernhard A1 - Rau, Christoph A1 - Sattler, Johannes Christoph T1 - Choice of solar share of a hybrid power plant of a central receiver system and a biogas plant in dependency of the geographical latitude T2 - World Renewable Energy Congress-Sweden : 8 -13 May, 2011, Linköping, Sweden / ed.: Bahram Moshfegh Y1 - 2011 SN - 9789173930703 SP - 3710 EP - 3717 PB - Univ. Electronic Pr. CY - Linköping ER - TY - CHAP A1 - Achenbach, Timm A1 - Bosch, Timo A1 - Breitbach, Gerd A1 - Göttsche, Joachim A1 - Sauerborn, Markus T1 - Theoretical and experimental investigations regarding open volumetric receivers of CRS T2 - Energy procedia : proceedings of the SolarPACES 2013 International Conference Y1 - 2013 SN - 1876-6102 VL - Vol. 49 SP - 1259 EP - 1268 ER - TY - CHAP A1 - Hoffschmidt, Bernhard A1 - Alexopoulos, Spiros A1 - Rau, Christoph A1 - Sattler, Johannes Christoph A1 - Anthrakidis, Anette A1 - Teixeira Boura, Cristiano José A1 - O’Connor, B. A1 - Chico Caminos, Ricardo Alexander A1 - Rendón, C. A1 - Hilger, P. T1 - Concentrating Solar Power T2 - Earth systems and environmental sciences N2 - The focus of this chapter is the production of power and the use of the heat produced from concentrated solar thermal power (CSP) systems. The chapter starts with the general theoretical principles of concentrating systems including the description of the concentration ratio, the energy and mass balance. The power conversion systems is the main part where solar-only operation and the increase in operational hours. Solar-only operation include the use of steam turbines, gas turbines, organic Rankine cycles and solar dishes. The operational hours can be increased with hybridization and with storage. Another important topic is the cogeneration where solar cooling, desalination and of heat usage is described. Many examples of commercial CSP power plants as well as research facilities from the past as well as current installed and in operation are described in detail. The chapter closes with economic and environmental aspects and with the future potential of the development of CSP around the world. KW - Central receiver power plant KW - Concentrated systems KW - Concentrating solar power KW - Fresnel power plant KW - Gas turbine Y1 - 2021 SN - 978-0-12-409548-9 U6 - https://doi.org/10.1016/B978-0-12-819727-1.00089-3 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Alexopoulos, Spiros A1 - Hoffschmidt, Bernhard A1 - Rau, Christoph A1 - Schwarzbözl, Peter T1 - Simulation results for a hybridization concept of a small solar tower power plant T2 - SolarPACES 2009 : electricity, fuels and clean water powered by the sun ; 15 - 18 September 2009, Berlin, Germany ; the 15th SolarPACES conference ; proceedings Y1 - 2009 SN - 9783000287558 PB - Deutsches Zentrum f. Luft- u. Raumfahrt CY - Stuttgart ER - TY - CHAP A1 - Schulte, Jonas A1 - Schwager, Christian A1 - Noureldin, Kareem A1 - May, Martin A1 - Teixeira Boura, Cristiano José A1 - Herrmann, Ulf T1 - Gradient controlled startup procedure of a molten-salt power-to-heat energy storage plant based on dynamic process simulation T2 - SolarPACES: Solar Power & Chemical Energy Systems N2 - The integration of high temperature thermal energy storages into existing conventional power plants can help to reduce the CO2 emissions of those plants and lead to lower capital expenditures for building energy storage systems, due to the use of synergy effects [1]. One possibility to implement that, is a molten salt storage system with a powerful power-to-heat unit. This paper presents two possible control concepts for the startup of the charging system of such a facility. The procedures are implemented in a detailed dynamic process model. The performance and safety regarding the film temperatures at heat transmitting surfaces are investigated in the process simulations. To improve the accuracy in predicting the film temperatures, CFD simulations of the electrical heater are carried out and the results are merged with the dynamic model. The results show that both investigated control concepts are safe regarding the temperature limits. The gradient controlled startup performed better than the temperature-controlled startup. Nevertheless, there are several uncertainties that need to be investigated further. KW - Power plants KW - Energy storage KW - Associated liquids Y1 - 2023 SN - 978-0-7354-4623-6 U6 - https://doi.org/10.1063/5.0148741 SN - 1551-7616 (online) SN - 0094-243X (print) N1 - SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27 September–1 October 2021, Online IS - 2815 / 1 PB - AIP conference proceedings / American Institute of Physics CY - Melville, NY ER - TY - CHAP A1 - Rendon, Carlos A1 - Dieckmann, Simon A1 - Weidle, Mathias A1 - Dersch, Jürgen A1 - Teixeira Boura, Cristiano José A1 - Polklas, Thomas A1 - Kuschel, Marcus A1 - Herrmann, Ulf T1 - Retrofitting of existing parabolic trough collector power plants with molten salt tower systems T2 - AIP Conference Proceedings Y1 - 2018 U6 - https://doi.org/10.1063/1.5067030 VL - 2033 IS - 1 SP - 030014-1 EP - 030014-8 ER - TY - CHAP A1 - Achenbach, Timm A1 - Geimer, K. A1 - Göttsche, Joachim A1 - Hoffschmidt, Bernhard A1 - Lynen, A. A1 - Bauer, J. T1 - Simulation and flow measurements of volumetric high temperature absorbers for solar tower power plants T2 - SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain Y1 - 2011 CY - Granada ER -