@article{MeyerHaenelBeehetal.2020, author = {Meyer, S. and H{\"a}nel, Matthias and Beeh, B. and Dittmann-Gabriel, S{\"o}ren and Dluhosch, R. and May, Martin and Herrmann, Ulf and [und 5 weitere],}, title = {Multifunktionaler thermischer Stromspeicher f{\"u}r die Strom- und W{\"a}rmeversorgung der Industrie von morgen}, series = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)}, volume = {2020}, journal = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)}, number = {1}, issn = {2625-9907}, pages = {6 -- 9}, year = {2020}, language = {de} } @article{BlankeHagenkampDoeringetal.2021, author = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus}, title = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates}, series = {Geothermal Energy}, volume = {9}, journal = {Geothermal Energy}, number = {Article number: 19}, publisher = {Springer}, address = {Berlin}, issn = {2195-9706}, doi = {10.1186/s40517-021-00201-3}, pages = {23 Seiten}, year = {2021}, abstract = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.}, language = {en} } @article{GoettscheAlexopoulosDuemmleretal.2019, author = {G{\"o}ttsche, Joachim and Alexopoulos, Spiros and D{\"u}mmler, Andreas and Maddineni, S. K.}, title = {Multi-Mirror Array Calculations With Optical Error}, pages = {1 -- 6}, year = {2019}, abstract = {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.}, language = {en} } @article{ElMoussaouiTalbiAtmaneetal.2020, author = {El Moussaoui, Noureddine and Talbi, Sofian and Atmane, Ilyas and Kassmi, Khalil and Schwarzer, Klemens and Chayeb, Hamid and Bachiri, Najib}, title = {Feasibility of a new design of a Parabolic Trough Solar Thermal Cooker (PSTC)}, series = {Solar Energy}, volume = {201}, journal = {Solar Energy}, number = {Vol. 201 (May 2020)}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0038-092X}, doi = {10.1016/j.solener.2020.03.079}, pages = {866 -- 871}, year = {2020}, abstract = {In this article, we describe the structure, the functioning, and the tests of parabolic trough solar thermal cooker (PSTC). This oven is designed to meet the needs of rural residents, including Urban, which requires stable cooking temperatures above 200 °C. The cooking by this cooker is based on the concentration of the sun's rays on a glass vacuum tube and heating of the oil circulate in a big tube, located inside the glass tube. Through two small tubes, associated with large tube, the heated oil, rise and heats the pot of cooking pot containing the food to be cooked (capacity of 5 kg). This cooker is designed in Germany and extensively tested in Morocco for use by the inhabitants who use wood from forests. During a sunny day, having a maximum solar radiation around 720 W/m2 and temperature ambient around 26 °C, maximum temperatures recorded of the small tube, the large tube and the center of the pot are respectively: 370 °C, 270 °C and 260 °C. The cooking process with food at high (fries, ..), we show that the cooking oil temperature rises to 200 °C, after 1 h of heating, the cooking is done at a temperature of 120 °C for 20 min. These temperatures are practically stable following variations and decreases in the intensity of irradiance during the day. The comparison of these results with those of the literature shows an improvement of 30-50 \% on the maximum value of the temperature with a heat storage that could reach 60 min of autonomy. All the results obtained show the good functioning of the PSTC and the feasibility of cooking food at high temperature (>200 °C).}, language = {en} } @article{SattlerRoegerSchwarzboezletal.2020, author = {Sattler, Johannes, Christoph and R{\"o}ger, Marc and Schwarzb{\"o}zl, Peter and Buck, Reiner and Macke, Ansgar and Raeder, Christian and G{\"o}ttsche, Joachim}, title = {Review of heliostat calibration and tracking control methods}, series = {Solar Energy}, volume = {207}, journal = {Solar Energy}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.solener.2020.06.030}, pages = {110 -- 132}, year = {2020}, abstract = {Large scale central receiver systems typically deploy between thousands to more than a hundred thousand heliostats. During solar operation, each heliostat is aligned individually in such a way that the overall surface normal bisects the angle between the sun's position and the aim point coordinate on the receiver. Due to various tracking error sources, achieving accurate alignment ≤1 mrad for all the heliostats with respect to the aim points on the receiver without a calibration system can be regarded as unrealistic. Therefore, a calibration system is necessary not only to improve the aiming accuracy for achieving desired flux distributions but also to reduce or eliminate spillage. An overview of current larger-scale central receiver systems (CRS), tracking error sources and the basic requirements of an ideal calibration system is presented. Leading up to the main topic, a description of general and specific terms on the topics heliostat calibration and tracking control clarifies the terminology used in this work. Various figures illustrate the signal flows along various typical components as well as the corresponding monitoring or measuring devices that indicate or measure along the signal (or effect) chain. The numerous calibration systems are described in detail and classified in groups. Two tables allow the juxtaposition of the calibration methods for a better comparison. In an assessment, the advantages and disadvantages of individual calibration methods are presented.}, language = {en} } @article{RegerKuhnhenneEbbertetal.2020, author = {Reger, Vitali and Kuhnhenne, Markus and Ebbert, Thiemo and Hachul, Helmut and Blanke, Tobias and D{\"o}ring, Bernd}, title = {Nutzung erneuerbarer Energien durch thermische Aktivierung von Komponenten aus Stahl}, series = {Stahlbau}, volume = {2020}, journal = {Stahlbau}, number = {Volume 89, Issue 6512-519}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1049}, doi = {10.1002/stab.202000031}, pages = {512 -- 519}, year = {2020}, abstract = {Die Versorgung von Neubauten soll m{\"o}glichst weitgehend unabh{\"a}ngig von fossilen Energietr{\"a}gern erfolgen. Erneuerbare Energien spielen daf{\"u}r eine gewichtige Rolle. Eine gute M{\"o}glichkeit, erneuerbare Energien ohne viel zus{\"a}tzlichen Aufwand nutzbar zu machen, ist, bereits vorhandenen Komponenten im Geb{\"a}ude zus{\"a}tzliche Funktionen zu geben. Hier kann bspw. die Fassade oder das Dach solarthermisch aktiviert oder durch Fotovoltaikmodule erg{\"a}nzt werden. Auch Tiefgr{\"u}ndungen k{\"o}nnen neben der statischen Funktion noch eine geothermische Funktion zur Aufnahme oder Abgabe von W{\"a}rme erhalten. Neben der Erzeugung bietet sich auch f{\"u}r die Verteilung der W{\"a}rme oder K{\"a}lte im Geb{\"a}ude die Integration in Bauteile an. Hier kann bspw. der Boden durch eine Fußbodenheizung oder die Decke durch Deckenstrahlplatten aktiviert werden. Im Rahmen der Ver{\"o}ffentlichung wird auf die thermische Aktivierung von Stahlkomponenten eingegangen. Es wird eine L{\"o}sung vorgestellt, die vorgeh{\"a}ngte hinterl{\"u}ftete Stahlfassade (VHF) solarthermisch zu aktivieren. Außerdem werden zwei M{\"o}glichkeiten zur geothermischen Aktivierung von Tiefgr{\"u}ndungen mittels Stahlpf{\"a}hlen gezeigt. Zuletzt wird ein System zur thermischen Aktivierung von Stahltrapezprofilen an der Decke erl{\"a}utert, welches W{\"a}rme zuf{\"u}hren oder bei Bedarf abf{\"u}hren kann.}, language = {de} } @article{HerrmannSchwarzenbartDittmannGabriel2019, author = {Herrmann, Ulf and Schwarzenbart, Marc and Dittmann-Gabriel, S{\"o}ren}, title = {Speicher statt Kohle. Integration thermischer Stromspeicher in vorhandene Kraftwerksstandorte}, series = {BWK : Das Energie-Fachmagazin}, volume = {71}, journal = {BWK : Das Energie-Fachmagazin}, number = {4}, publisher = {Springer-VDI-Verl.}, address = {D{\"u}sseldorf}, issn = {1436-4883}, pages = {42 -- 45}, year = {2019}, language = {de} } @article{WoliszSchuetzBlankeetal.2017, author = {Wolisz, Henryk and Sch{\"u}tz, Thomas and Blanke, Tobias and Hagenkamp, Markus and Kohrn, Markus and Wesseling, Mark and M{\"u}ller, Dirk}, title = {Cost optimal sizing of smart buildings' energy system components considering changing end-consumer electricity markets}, series = {Energy}, volume = {137}, journal = {Energy}, publisher = {Elsevier}, address = {Amsterdam}, doi = {10.1016/j.energy.2017.06.025}, pages = {715 -- 728}, year = {2017}, language = {en} } @article{RegerKuhnhenneHachuletal.2019, author = {Reger, Vitali and Kuhnhenne, Markus and Hachul, Helmut and D{\"o}ring, Bernd and Blanke, Tobias and G{\"o}ttsche, Joachim}, title = {Plusenergiegeb{\"a}ude 2.0 in Stahlleichtbauweise}, series = {Stahlbau}, volume = {88}, journal = {Stahlbau}, number = {6}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1049 (E-journal), 0038-9145 (print)}, doi = {10.1002/stab.201900034}, pages = {522 -- 528}, year = {2019}, language = {de} } @article{PuppeGiulianoFrantzetal.2018, author = {Puppe, Michael and Giuliano, Stefano and Frantz, Cathy and Uhlig, Ralf and Schumacher, Ralph and Ibraheem, Wagdi and Schmalz, Stefan and Waldmann, Barbara and Guder, Christoph and Peter, Dennis and Schwager, Christian and Teixeira Boura, Cristiano Jos{\´e} and Alexopoulos, Spiros and Spiegel, Michael and Wortmann, J{\"u}rgen and Hinrichs, Matthias and Engelhard, Manfred and Aust, Michael}, title = {Techno-economic optimization of molten salt solar tower plants}, series = {AIP Conference Proceedings art.no. 040033}, volume = {2033}, journal = {AIP Conference Proceedings art.no. 040033}, number = {Issue 1}, publisher = {AIP Publishing}, address = {Melville, NY}, doi = {10.1063/1.5067069}, year = {2018}, abstract = {In this paper the results of a techno-economic analysis of improved and optimized molten salt solar tower plants (MSSTP plants) are presented. The potential improvements that were analyzed include different receiver designs, different designs of the HTF-system and plant control, increased molten salt temperatures (up to 640°C) and multi-tower systems. Detailed technological and economic models of the solar field, solar receiver and high temperature fluid system (HTF-system) were developed and used to find potential improvements compared to a reference plant based on Solar Two technology and up-to-date cost estimations. The annual yield model calculates the annual outputs and the LCOE of all variants. An improved external tubular receiver and improved HTF-system achieves a significant decrease of LCOE compared to the reference. This is caused by lower receiver cost as well as improvements of the HTF-system and plant operation strategy, significantly reducing the plant own consumption. A novel star receiver shows potential for further cost decrease. The cavity receiver concepts result in higher LCOE due to their high investment cost, despite achieving higher efficiencies. Increased molten salt temperatures seem possible with an adapted, closed loop HTF-system and achieve comparable results to the original improved system (with 565°C) under the given boundary conditions. In this analysis all multi tower systems show lower economic viability compared to single tower systems, caused by high additional cost for piping connections and higher cost of the receivers. REFERENCES}, language = {en} } @article{KearneyHerrmannNavaetal.2003, author = {Kearney, D. and Herrmann, Ulf and Nava, P. and Kelly, B. and Mahoney, R. and Pacheco, J. and Cable, R. and Potrovitza, N. and Blake, D. and Price, H.}, title = {Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field}, series = {Journal of Solar Energy Engineering}, volume = {125}, journal = {Journal of Solar Energy Engineering}, number = {2}, issn = {1528-8986}, doi = {10.1115/1.1565087}, pages = {170 -- 176}, year = {2003}, language = {en} } @article{DammSauerbornFendetal.2017, author = {Damm, Marc Andr{\´e} and Sauerborn, Markus and Fend, Thomas and Herrmann, Ulf}, title = {Optimisation of a urea selective catalytic reduction system with a coated ceramic mixing element}, series = {Journal of ceramic science and technology}, volume = {8}, journal = {Journal of ceramic science and technology}, number = {1}, publisher = {G{\"o}ller}, address = {Baden-Baden}, isbn = {2190-9385 (Print)}, issn = {2190-9385 (Online)}, doi = {10.4416/JCST2016-00056}, pages = {19 -- 24}, year = {2017}, language = {en} } @article{AlexopoulosHoffschmidt2017, author = {Alexopoulos, Spiros and Hoffschmidt, Bernhard}, title = {Advances in solar tower technology}, series = {Wiley interdisciplinary reviews : Energy and Environment : WIREs}, volume = {6}, journal = {Wiley interdisciplinary reviews : Energy and Environment : WIREs}, number = {1}, publisher = {Wiley}, address = {Weinheim}, issn = {2041-840X}, doi = {10.1002/wene.217}, pages = {1 -- 19}, year = {2017}, language = {en} } @article{HerrmannLippke1999, author = {Herrmann, Ulf and Lippke, F.}, title = {The influence of transients on the design of DSG solar fields}, series = {Journal de Physique IV : proceedings}, volume = {9}, journal = {Journal de Physique IV : proceedings}, number = {PR3}, isbn = {2-86883-402-7}, issn = {1764-7177 (Online)}, doi = {10.1051/jp4:1999377}, pages = {489 -- 494}, year = {1999}, language = {en} } @article{DerschGeyerHerrmannetal.2004, author = {Dersch, J{\"u}rgen and Geyer, Michael and Herrmann, Ulf and Jones, Scott A. and Kelly, Bruce and Kistner, Rainer and Ortmanns, Winfried and Pitz-Paal, Robert and Price, Henry}, title = {Trough integration into power plants—a study on the performance and economy of integrated solar combined cycle systems}, series = {Energy : the international journal}, volume = {29}, journal = {Energy : the international journal}, number = {5-6 (Special Issue SolarPaces)}, issn = {0360-5442}, doi = {10.1016/S0360-5442(03)00199-3}, pages = {947 -- 959}, year = {2004}, language = {en} } @article{KearneyKellyHerrmannetal.2002, author = {Kearney, David W. and Kelly, Bruce and Herrmann, Ulf and Cable, R. and Pacheco, J. and Mahoney, R. and Price, Henry and Blake, D. and Nava, P. and Potrovitza, N.}, title = {Engineering Aspects of a Molten Salt Heat Transfer Fluid in a Trough Solar Field}, series = {Energy : the international journal}, volume = {29}, journal = {Energy : the international journal}, number = {5-6 (Special Issue SolarPaces)}, issn = {0360-5442}, doi = {10.1016/S0360-5442(03)00191-9}, pages = {861 -- 870}, year = {2002}, language = {en} } @article{HerrmannKellyPrice2002, author = {Herrmann, Ulf and Kelly, Bruce and Price, Henry}, title = {Two Tank Molten Salt Storage for Parabolic Trough Solar Power Plants}, series = {Energy : the international journal}, volume = {29}, journal = {Energy : the international journal}, number = {5-6 (Special Issue SolarPaces)}, issn = {0360-5442}, doi = {10.1016/S0360-5442(03)00193-2}, pages = {883 -- 893}, year = {2002}, language = {en} } @article{HerrmannNava2005, author = {Herrmann, Ulf and Nava, P.}, title = {Die Strahlung der Sonne einfangen}, series = {DLR-Nachrichten / Deutsches Zentrum f{\"u}r Luft- und Raumfahrt}, volume = {109}, journal = {DLR-Nachrichten / Deutsches Zentrum f{\"u}r Luft- und Raumfahrt}, number = {Sonderheft Solarforschung}, issn = {0937-0420}, pages = {34 -- 37}, year = {2005}, language = {de} } @article{HerrmannKearney2002, author = {Herrmann, Ulf and Kearney, David W.}, title = {Survey of Thermal Energy Storage for Parabolic Trough Power Plants}, series = {Journal of Solar Energy Engineering}, volume = {124}, journal = {Journal of Solar Energy Engineering}, number = {2}, issn = {1528-8986 (Online)}, doi = {10.1115/1.1467601}, pages = {145 -- 152}, year = {2002}, language = {en} } @article{Alexopoulos2015, author = {Alexopoulos, Spiros}, title = {Simulation model for the transient process behaviour of solar aluminium recycling in a rotary kiln}, series = {Applied Thermal Engineering}, volume = {78}, journal = {Applied Thermal Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1359-4311}, doi = {10.1016/j.applthermaleng.2015.01.007}, pages = {387 -- 396}, year = {2015}, language = {en} }