@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{BlankeRegerDoeringetal.2021,
  author    = {Blanke, Tobias and Reger, Vitali and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Kuhnhenne, Markus},
  title     = {Koaxiale Stahlenergiepf{\"a}hle},
  series = {Stahlbau},
  volume    = {90. 2021},
  journal   = {Stahlbau},
  number    = {6},
  publisher = {Wiley},
  address   = {Weinheim},
  pages     = {417 -- 424},
  year      = {2021},
  abstract  = {Ein entscheidender Teil der Energiewende ist die W{\"a}rmewende im Geb{\"a}udesektor. Ein Schl{\"u}sselelement sind hier W{\"a}rmepumpen. Diese ben{\"o}tigen eine W{\"a}rmequelle, der sie Energie entziehen k{\"o}nnen, um sie auf ein h{\"o}heres Temperaturniveau zu transformieren. Diese W{\"a}rmequelle kann bspw. das Erdreich sein, dessen W{\"a}rme durch Erdsonden erschlossen werden kann. In diesem Beitrag werden in Stahlpf{\"a}hle integrierte Koaxialsonden mit dem Stand der Technik von Erdsonden gleichen Durchmessers bez{\"u}glich ihrer thermischen Leistungsmerkmale verglichen. Die Stahlenergiepf{\"a}hle bieten neben der W{\"a}rmegewinnung weitere Vorteile, da sie auch eine statische Funktion {\"u}bernehmen und r{\"u}ckstandsfrei zur{\"u}ckgebaut werden k{\"o}nnen. Es werden analytische und numerische Berechnungen vorgestellt, um die thermischen Potenziale beider Systeme zu vergleichen. Außerdem wird ein Testaufbau gezeigt, bei dem Stahlenergiepf{\"a}hle in zwei verschiedenen L{\"a}ngen mit vorhandenen g{\"a}ngigen Erdsonden verglichen werden k{\"o}nnen. Die Berechnungen zeigen einen deutlichen thermischen Mehrertrag zwischen 26 \% und 148 \% der Stahlenergiepf{\"a}hle gegen{\"u}ber dem Stand der Technik abh{\"a}ngig vom Erdreich. Die Messergebnisse zeigen einen thermischen Mehrertrag von {\"u}ber 100 \%. Es l{\"a}sst sich also signifikante Erdsondenl{\"a}nge einsparen. Dabei ist zu beachten, dass sich damit der thermisch genutzte Bereich des Erdreichs reduziert, wodurch die thermische Regeneration und/oder das Langzeitverhalten des Erdreichs an Bedeutung gewinnt.},
  language  = {de}
}
@article{Goettsche2005,
  author    = {G{\"o}ttsche, Joachim},
  title     = {Der vertikale Sonnenlichtquotient : Eine wichtige Kenngr{\"o}ße zur Charakterisierung von Lichtlenksystemen / G{\"o}ttsche, Joachim},
  series = {Elftes Symposium Innovative Lichttechnik in Geb{\"a}uden : 27./28. Januar 2005, [Kloster Banz] / OTTI-Kolleg Beratung, Projekte},
  journal   = {Elftes Symposium Innovative Lichttechnik in Geb{\"a}uden : 27./28. Januar 2005, [Kloster Banz] / OTTI-Kolleg Beratung, Projekte},
  publisher = {Ostbayerisches Technologie-Transfer-Inst., OTTI},
  address   = {Regensburg},
  isbn      = {3934681379},
  pages     = {79 -- 84},
  year      = {2005},
  language  = {de}
}
@article{Goettsche1994,
  author    = {G{\"o}ttsche, Joachim},
  title     = {Eldorado summer schools},
  series = {Progress in solar energy education. 3 (1994)},
  journal   = {Progress in solar energy education. 3 (1994)},
  isbn      = {1018-5607},
  pages     = {31 -- 33},
  year      = {1994},
  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{GoettscheBlumSchumacher1994,
  author    = {G{\"o}ttsche, Joachim and Blum, K. and Schumacher, J.},
  title     = {Simulationsprogramme in der Solarenergie-Ausbildung / Blum, K. ; G{\"o}ttsche, J. ; Schumacher, J.},
  series = {Energie f{\"u}r die Zukunft : : 28. Juni bis 1. Juli 1994; [Tagungsbericht] / 9. Internationales Sonnenforum '94. [Hrsg. Deutsche Gesellschaft f{\"u}r Sonnenenergie e.V. - DGS. Red. A. Hohmann ...] ; Bd. 2},
  journal   = {Energie f{\"u}r die Zukunft : : 28. Juni bis 1. Juli 1994; [Tagungsbericht] / 9. Internationales Sonnenforum '94. [Hrsg. Deutsche Gesellschaft f{\"u}r Sonnenenergie e.V. - DGS. Red. A. Hohmann ...] ; Bd. 2},
  publisher = {DGS-Sonnenenergie-Verl.},
  address   = {M{\"u}nchen},
  pages     = {1786 -- 1791},
  year      = {1994},
  language  = {de}
}
@article{GoettscheDelahayeGabryschetal.2003,
  author    = {G{\"o}ttsche, Joachim and Delahaye, A. and Gabrysch, K. and Schwarzer, Klemens},
  title     = {Solar-Campus J{\"u}lich - Nutzung solarer Gewinne in Geb{\"a}uden},
  series = {13. Symposium Thermische Solarenergie : 14. bis 16. Mai 2003, Kloster Banz / [Wiss. Gesamtleitung: Hans M{\"u}ller-Steinhagen]. Otti-Energie-Kolleg},
  journal   = {13. Symposium Thermische Solarenergie : 14. bis 16. Mai 2003, Kloster Banz / [Wiss. Gesamtleitung: Hans M{\"u}ller-Steinhagen]. Otti-Energie-Kolleg},
  publisher = {Ostbayerisches Technologie-Transfer-Inst., OTTI},
  address   = {Regensburg},
  isbn      = {3-934681-26-3},
  pages     = {362 -- 367},
  year      = {2003},
  language  = {de}
}
@article{GoettscheGabryschDelahayeetal.2002,
  author    = {G{\"o}ttsche, Joachim and Gabrysch, K. and Delahaye, A. and Schwarzer, Klemens},
  title     = {Solar-Campus Juelich - Energy performance and indoor climate},
  series = {AIVC 23rd conference - EPIC 2002 AIVC (in conjunction with 3rd European Conference on Energy Performance and Indoor Climate in Buildings) - 23-26 October 2002 - Lyon - France - vol 2},
  journal   = {AIVC 23rd conference - EPIC 2002 AIVC (in conjunction with 3rd European Conference on Energy Performance and Indoor Climate in Buildings) - 23-26 October 2002 - Lyon - France - vol 2},
  pages     = {381 -- 386},
  year      = {2002},
  language  = {en}
}
@article{GoettscheGabryschSchilleretal.2004,
  author    = {G{\"o}ttsche, Joachim and Gabrysch, K. and Schiller, H. and Kauert, B. and Schwarzer, Klemens},
  title     = {Energetic Effects of demand - controlled ventilation retrofitting in a biochemical laboratory building},
  series = {AIVC publications [Elektronische Ressource] / Air Infiltration and Ventilation Centre},
  journal   = {AIVC publications [Elektronische Ressource] / Air Infiltration and Ventilation Centre},
  publisher = {INIVE EEIG},
  address   = {Brussels},
  pages     = {50},
  year      = {2004},
  language  = {en}
}
@article{GoettscheGabryschSchilleretal.2006,
  author    = {G{\"o}ttsche, Joachim and Gabrysch, K. and Schiller, H. and Schwarzer, Klemens},
  title     = {Energetische Sanierung eines biochemischen Laborgeb{\"a}udes : Auswirkung bedarfsabh{\"a}ngiger L{\"u}ftung mit W{\"a}rmer{\"u}ckgewinnung auf den Prim{\"a}renergieverbrauch},
  series = {Heizungs- und Raumlufttechnik : 1. Fachtagung Leonberg, 31. Januar bis 1. Februar 2006 / VDI-Tage der Geb{\"a}udetechnik. VDI-Gesellschaft Technische Geb{\"a}udeausr{\"u}stung},
  journal   = {Heizungs- und Raumlufttechnik : 1. Fachtagung Leonberg, 31. Januar bis 1. Februar 2006 / VDI-Tage der Geb{\"a}udetechnik. VDI-Gesellschaft Technische Geb{\"a}udeausr{\"u}stung},
  publisher = {VDI-Verl.},
  address   = {D{\"u}sseldorf},
  isbn      = {3-18-091921-3},
  pages     = {221 -- 230},
  year      = {2006},
  language  = {de}
}