TY - JOUR A1 - Blanke, Tobias A1 - Hagenkamp, Markus A1 - Döring, Bernd A1 - Göttsche, Joachim A1 - Reger, Vitali A1 - Kuhnhenne, Markus T1 - Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates JF - Geothermal Energy N2 - 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 Hellström’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. Y1 - 2021 U6 - https://doi.org/10.1186/s40517-021-00201-3 SN - 2195-9706 N1 - Corresponding author: Tobias Blanke VL - 9 IS - Article number: 19 PB - Springer CY - Berlin ER - TY - JOUR A1 - Bitz, Andreas A1 - Zhou, Yi A1 - El Quardi, Abdessamad A1 - Streckert, Joachim T1 - Occupational Exposure at Mobile Communication Base Station Antenna Sites JF - Frequenz Y1 - 2009 U6 - https://doi.org/10.1515/FREQ.2009.63.7-8.123 SN - 2191-6349 VL - 63 IS - 7-8 SP - 123 EP - 128 ER - TY - JOUR A1 - Bitz, Andreas A1 - Felder, Jorg A1 - Wittig, Tilmann T1 - Designing MRI Coils with Aid of Simulation JF - Microwaves & RF Y1 - 2013 SN - 0745-2993 VL - 52 IS - 7 SP - 56 PB - Penton CY - Cleveland, Ohio ER - TY - JOUR A1 - Biselli, Manfred A1 - Zeng, Steffen A1 - Dinter, Andre A1 - Eisenkrätzer, Detlef T1 - Pilot Scale Expression and Purification of Soluble Protein A Tagged β1,6N-Acetylglucosaminyltransferase in CHO Cells / Zeng, Steffen ; Dinter, Andre ; Eisenkrätzer, Detlef ; Biselli, Manfred ; Wandrey, Christian ; Berger, Eric G. JF - Biochemical and Biophysical Research Communications. 237 (1997), H. 3 Y1 - 1997 SN - 0006-291X SP - 653 EP - 658 ER - TY - JOUR A1 - Biselli, Manfred A1 - Wandrey, Christian T1 - Reaction Mechanism of an Endoglucanase of Trichoderma Reesei QM 9414 using Cellodextrins as Substrate JF - Technology of biological processes, safety in biotechnology, applied genetic engineering : lectures held at the 5th DECHEMA Annual Meeting of Biotechnologists, May 12 - 13, 1987, [Frankfurt, Main] / [hrsg. von Dieter Behrens ...] Y1 - 1988 N1 - Jahrestagung der Biotechnologen ; <5, 1987, Frankfurt, Main> ; DECHEMA Biotechnology Conferences series ; 1 SP - 425 EP - 429 PB - VCH CY - Weinheim ER - TY - JOUR A1 - Biselli, Manfred A1 - Van der Pol, Jens J. A1 - Spohn, Uwe A1 - Eberhardt, Rolf T1 - On-line monitoring of an animal cell culture with multi-channel flow injection analysis / van der Pol, Jens J.; Spohn, Uwe ; Eberhardt, Rolf ; Gätgens, Jochen ; Biselli, Manfred ; Wandrey, Christian ; Tramper, Johannes JF - Journal of Biotechnology. 37 (1994), H. 3 Y1 - 1994 SN - 0168-1656 SP - 253 EP - 264 ER - TY - JOUR A1 - Biselli, Manfred A1 - Van der Pol, Jens J. A1 - Machnik, Marc A1 - Portela-Klein, Theresa T1 - On-line immunoanalysis of monoclonal antibodies during a continuous culture of hybridoma cells / Jens J. van der Pol, Marc Machnik, Manfred Biselli, Theresa Portela-Klein, Cornelis D. de Gooijer, Johannes Tramper und Christian Wandrey JF - Cytotechnology. 24 (1997), H. 1 Y1 - 1997 SN - 0920-9069 SP - 19 EP - 30 ER - TY - JOUR A1 - Biselli, Manfred A1 - Van der Pol, Jens J. A1 - Joksch, Burkhard A1 - Galgens, Jochem T1 - On-line control of an immobilized hybridoma culture with multi-channel flow injektion analysis / Jens J. van der Pol, Burkhard Joksch, Jochem Galgens, Manfred Biselli, Cornelis D. de Gooijer, Johannes Tramper and Christian Wandrey JF - Journal of Biotechnology. 43 (1995), H. 3 Y1 - 1995 SN - 0168-1656 N1 - 3. Autor vermutlich: Jochen Gätgens SP - 229 EP - 242 ER - TY - JOUR A1 - Biselli, Manfred A1 - Van der Pol, Jens J. A1 - Joksch, B. A1 - Spohn, U. T1 - On-line monitoring and control of glucose, glutamine, lactate and ammonium during a high-cell-density cultivation of hybridoma cells / van der Pol, Jens J. ; Joksch, B. ; Spohn, U. ; Biselli, M. ; Wandrey, C. JF - Proceedings of the sixth international meeting of the Japanese Association for Animal Cell Technology [JAACT 93]: Nagoya, Japan, November 9 - 12, 1993 / ed. by T. Kobayashi Y1 - 1994 SN - 0-7923-3156-7 N1 - International meeting of the Japanese Association for Animal Cell Technology, JAACT 93 ; (6 : ; 1993.11.09-12 : ; Nagoya, Japan) ; Animal cell technology, basic and applied aspects ; 6 SP - 167 EP - 170 PB - Springer Netherland CY - Berlin ER - TY - JOUR A1 - Biselli, Manfred A1 - Van der Pol, Jens J. A1 - Joksch, B. A1 - Eberhardt, R. T1 - Development of an enzymatic multichannel flow injection analysis system for monitoring mammalian cell fermentations / Van der Pol, J.J.; Joksch, B.; Eberhardt, R.; Biselli, M.; Wandrey, C., Tramper, J. JF - Biosensors : fundamentals, technologies and applications ; contributions to the BMFT status seminar with international participation May, 12 to 14, 1991, Internationales Bildungs-Centrum Bogensee/Brandenburg, Germany / org. by ZIM-Zentralinstitut für Molekularbiologie, Berlin-Buch and GBF, Braunschweig. Ed. by F. Scheller Y1 - 1992 SN - 3527284370 N1 - GBF Monographs ; 17 SP - 349 EP - 352 PB - VCH CY - Weinheim ER -