@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}
}
@techreport{ConanD'HaeyerBeguinetal.2006,
  author    = {Conan, Yulian and D'Haeyer, R. and B{\´e}guin, P. and D{\"o}ring, Bernd and Kuhnhenne, Markus and Bayo, E.},
  title     = {Steel in low-rise building : a symbiosis of cold formed sections and light rolled profiles : final report. Contract-No. 7215-PP/070. EUR 22080 en},
  publisher = {Office for Official Publications of the European Communities},
  address   = {Luxembourg},
  isbn      = {92-79-02082-X},
  pages     = {200 S.},
  year      = {2006},
  language  = {en}
}
@misc{DoeringFeldmannKuhnhenne2013,
  author    = {D{\"o}ring, Bernd and Feldmann, Markus and Kuhnhenne, Markus},
  title     = {Schallschutz-Wandaufbau f{\"u}r ein Bauwerk oder ein Bauteil in Metallleichtbauweise, das mit Solarzellen best{\"u}ckt ist : Offenlegungsschrift},
  publisher = {Deutsches Patent- und Markenamt},
  address   = {M{\"u}nchen},
  pages     = {14 S. : graph. Darst.},
  year      = {2013},
  language  = {de}
}
@article{DoeringFeldmannKuhnhenne2009,
  author    = {D{\"o}ring, Bernd and Feldmann, Markus and Kuhnhenne, Markus},
  title     = {Der Beitrag von Profilblechdecken zur passiven K{\"u}hlung},
  series = {Bauphysik},
  volume    = {Vol. 31},
  journal   = {Bauphysik},
  number    = {Iss. 2},
  publisher = {Wiley},
  address   = {Weinheim},
  isbn      = {1437-0980 (E-Journal); 0171-5445 (Print)},
  pages     = {65 -- 71},
  year      = {2009},
  language  = {de}
}
@inproceedings{DoeringFeldmannKuhnhenne2007,
  author    = {D{\"o}ring, Bernd and Feldmann, Markus and Kuhnhenne, Markus},
  title     = {An innovative thermally activated light-weight steel deck system - numerical investigations and practical tests},
  series = {Clima 2007 WellBeing Indoors: 9th Rehva World Congress, 10-14 June 2007, Helsinki, Finland : proceedings},
  booktitle = {Clima 2007 WellBeing Indoors: 9th Rehva World Congress, 10-14 June 2007, Helsinki, Finland : proceedings},
  address   = {Helsinki},
  isbn      = {978-952-99898-2-9},
  pages     = {1 -- 8},
  year      = {2007},
  language  = {en}
}
@inproceedings{DoeringFeldmannKuhnhenneetal.2008,
  author    = {D{\"o}ring, Bernd and Feldmann, Markus and Kuhnhenne, Markus and Hellberg, Jan},
  title     = {Implementing a thermal activation system into a light-weight steel deck element},
  series = {Eurosteel 2008 : 5th European Conference on Steel and Composite Structures ; research, practice, new materials ; 3rd to 5th September 2008, Graz, Austria / ed. by Robert Ofner ...},
  booktitle = {Eurosteel 2008 : 5th European Conference on Steel and Composite Structures ; research, practice, new materials ; 3rd to 5th September 2008, Graz, Austria / ed. by Robert Ofner ...},
  publisher = {ECCS, European Convention for Construction Steelwork},
  address   = {Brussels},
  organization    = {Eurosteel <5, 2008, Graz>},
  isbn      = {92-0147-000-90},
  pages     = {941 -- 946},
  year      = {2008},
  language  = {en}
}
@article{DoeringFeldmannKuhnhenneetal.2011,
  author    = {D{\"o}ring, Bernd and Feldmann, Markus and Kuhnhenne, Markus and M{\"u}ller, Dirk},
  title     = {Phasenwechselmaterial im Metallleichtbau zur Optimierung von Energieeffizienz und sommerlicher Raumtemperatur},
  series = {Stahlbau},
  volume    = {Vol. 80},
  journal   = {Stahlbau},
  number    = {Iss. 9},
  publisher = {Wiley},
  address   = {Weinheim},
  issn      = {1437-1049 (E-Journal); 0038-9145 (Print)},
  pages     = {666 -- 672},
  year      = {2011},
  language  = {de}
}
@inproceedings{DoeringKuhnhenneFeldmann2011,
  author    = {D{\"o}ring, Bernd and Kuhnhenne, Markus and Feldmann, Markus},
  title     = {Floor systems - key elements for sustainable multi-storey buildings},
  series = {SB11 Helsinki World Sustainable Building Conference : 18. - 21.10.2011},
  booktitle = {SB11 Helsinki World Sustainable Building Conference : 18. - 21.10.2011},
  organization    = {World Sustainable Building Conference <2011, Helsinki>},
  pages     = {1 -- 6},
  year      = {2011},
  language  = {en}
}
@article{DoeringKuhnhenneHellbergetal.2008,
  author    = {D{\"o}ring, Bernd and Kuhnhenne, Markus and Hellberg, Jan and Feldmann, Markus},
  title     = {Aktive und passive Temperierung eines Stahldeckensystems : thermische Bauteilaktivierung : numerische und messtechnische Untersuchungen. T. 2.},
  series = {HLH L{\"u}ftung/Klima, Heizung/Sanit{\"a}r, Geb{\"a}udetechnik},
  volume    = {Bd. 59},
  journal   = {HLH L{\"u}ftung/Klima, Heizung/Sanit{\"a}r, Geb{\"a}udetechnik},
  number    = {H. 11},
  issn      = {1436-5103},
  pages     = {37 -- 41},
  year      = {2008},
  language  = {de}
}