@article{VogtIwanowskiStrahserMarquartetal.2013, author = {Vogt, Christian and Iwanowski-Strahser, Katha and Marquart, Gabriele and Arnold, Juliane and Mottaghy, Darius and Pechnig, Renate and Gnjezda, Daniel and Clauser, Christoph}, title = {Modeling contribution to risk assessment of thermal production power for geothermal reservoirs}, series = {Renewable Energy}, volume = {53}, journal = {Renewable Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0960-1481}, doi = {10.1016/j.renene.2012.11.026}, pages = {230 -- 241}, year = {2013}, language = {en} } @article{MottaghySchwambornRath2013, author = {Mottaghy, Darius and Schwamborn, G. and Rath, V.}, title = {Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling}, series = {Climate of the Past}, volume = {9}, journal = {Climate of the Past}, number = {1}, publisher = {Copernicus}, address = {Katlenburg-Lindau}, issn = {1814-9332}, doi = {10.5194/cp-9-119-2013}, pages = {119 -- 133}, year = {2013}, language = {en} } @article{KuertenMottaghyZiegler2013, author = {K{\"u}rten, Sylvia and Mottaghy, Darius and Ziegler, Martin}, title = {W{\"a}rme{\"u}bergangswiderstand bei fl{\"a}chigen thermo-aktiven Bauteilen am Beispiel thermo-aktiver Abdichtungselemente}, series = {Bautechnik}, volume = {90}, journal = {Bautechnik}, number = {7}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-0999}, doi = {10.1002/bate.201300035}, pages = {387 -- 394}, year = {2013}, language = {de} } @article{MottaghyDijkshoorn2012, author = {Mottaghy, Darius and Dijkshoorn, Lydia}, title = {Implementing an effective finite difference formulation for borehole heat exchangers into a heat and mass transport code}, series = {Renewable Energy}, volume = {45}, journal = {Renewable Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0960-1481}, doi = {10.1016/j.renene.2012.02.013}, pages = {59 -- 71}, year = {2012}, abstract = {We present an effective finite difference formulation for implementing and modeling multiple borehole heat exchangers (BHE) in the general 3-D coupled heat and flow transport code SHEMAT. The BHE with arbitrary length can be either coaxial or double U-shaped. It is particularly suitable for modeling deep BHEs which contain varying pipe diameters and materials. Usually, in numerical simulations, a fine discretization of the BHE assemblage is required, due to the large geometric aspect ratios involved. This yields large models and long simulation times. The approach avoids this problem by considering heat transport between fluid and the soil through pipes and grout via thermal resistances. Therefore, the simulation time can be significantly reduced. The coupling with SHEMAT is realized by introducing an effective heat generation. Due to this connection, it is possible to consider heterogeneous geological models, as well as the influence of groundwater flow. This is particularly interesting when studying the long term behavior of a single BHE or a BHE field. Heating and cooling loads can enter the model with an arbitrary interval, e.g. from hourly to monthly values. When dealing with large BHE fields, computing times can be further significantly reduced by focusing on the temperature field around the BHEs, without explicitly modeling inlet and outlet temperatures. This allows to determine the possible migration of cold and warm plumes due to groundwater flow, which is of particular importance in urban areas with a high BHE installation density. The model is validated against the existing BHE modeling codes EWS and EED. A comparison with monitoring data from a deep BHE in Switzerland shows a good agreement. Synthetic examples demonstrate the field of application of this model.}, language = {en} } @article{MottaghyPechnigVogt2011, author = {Mottaghy, Darius and Pechnig, Renate and Vogt, Christian}, title = {The geothermal project Den Haag: 3D numerical models for temperature prediction and reservoir simulation}, series = {Geothermics}, volume = {40}, journal = {Geothermics}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0375-6505}, doi = {10.1016/j.geothermics.2011.07.001}, pages = {199 -- 210}, year = {2011}, abstract = {The proposed Den Haag Zuidwest district heating system of the city of The Hague consists of a deep doublet in a Jurassic sandstone layer that is designed for a production temperature of 75 °C and a reinjection temperature of 40 °C at a flow rate of 150 m3 h-1. The prediction of reservoir temperature and production behavior is crucial for success of the proposed geothermal doublet. This work presents the results of a study of the important geothermal and geohydrological issues for the doublet design. In the first phase of the study, the influences of the three-dimensional (3D) structures of anticlines and synclines on the temperature field were examined. A comprehensive petrophysical investigation was performed to build a large scale 3D-model of the reservoir. Several bottomhole temperatures (BHTs), as well as petrophysical logs were used to calibrate the model using thermal conductivity measurements on 50 samples from boreholes in different lithological units in the study area. Profiles and cross sections extracted from the calculated temperature field were used to study the temperature in the surrounding areas of the planned doublet. In the second phase of the project, a detailed 3D numerical reservoir model was set up, with the aim of predicting the evolution of the producer and injector temperatures, and the extent of the cooled area around the injector. The temperature model from the first phase provided the boundary conditions for the reservoir model. Hydraulic parameters for the target horizons, such as porosity and permeability, were taken from data available from the nearby exploration wells. The simulation results are encouraging as no significant thermal breakthrough is predicted. For the originally planned location of the producer, the extracted water temperature is predicted to be around 79 °C, with an almost negligible cooling in the first 50 years of production. When the producer is located shallower parts of the reservoir, the yield water temperatures is lower, starting at ≈76 °C and decreasing to ≈74 °C after 50 years of operation. This comparatively larger decrease in temperature with time is caused by the structural feature of the reservoir, namely a higher dip causes the cooler water to easily move downward. In view of the poor reservoir data, the reservoir simulation model is constructed to allow iterative updates using data assimilation during planned drilling, testing, and production phases. Measurements during an 8 h pumping test carried out in late 2010 suggest that a flow rate of 150 m3 h-1 is achievable. Fluid temperatures of 76.5 °C were measured, which is very close to the predicted value.}, language = {en} } @incollection{MottaghyMajorowiczRath2009, author = {Mottaghy, Darius and Majorowicz, Jacek and Rath, Volker}, title = {Ground Surface Temperature Histories Reconstructed from Boreholes in Poland: Implications for Spatial Variability}, series = {The Polish Climate in the European Context: An Historical Overview}, booktitle = {The Polish Climate in the European Context: An Historical Overview}, publisher = {Springer Science+Business Media}, address = {Dordrecht}, isbn = {978-90-481-3167-9}, doi = {10.1007/978-90-481-3167-9_17}, pages = {375 -- 387}, year = {2009}, language = {en} } @article{BergAngererMartinellietal.2013, author = {Berg, Milena and Angerer, Anita and Martinelli, Walter and Hammer, Stephan and Mottaghy, Darius}, title = {Erkundung des geothermischen Potenzials eines ehemaligen Untertagebergbaus}, series = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, volume = {64}, journal = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, number = {6}, pages = {46 -- 52}, year = {2013}, language = {de} } @article{MottaghyPechnigTaugsetal.2010, author = {Mottaghy, Darius and Pechnig, Renate and Taugs, Renate and Kr{\"o}ger, Jens and Thomsen, Claudia and Hesse, Fabian and Liebsch-Doerschner, Thomas}, title = {Erstellung eines geothermischen Modells f{\"u}r Teile Hamburgs und anliegende Gebiete}, series = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, volume = {61}, journal = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, number = {12}, publisher = {WVGW Wirtschafts- u. Verl.Ges. Gas und Wasser}, address = {Bonn}, issn = {1611-1478}, pages = {52 -- 59}, year = {2010}, language = {de} } @article{MottaghyPechnig2009, author = {Mottaghy, Darius and Pechnig, Renate}, title = {Numerische 3D Modelle zur Temperaturvorhersage und Reservoirsimulationen}, series = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, volume = {60}, journal = {BBR - Fachmagazin f{\"u}r Brunnen- und Leitungsbau}, number = {10}, pages = {44 -- 51}, year = {2009}, language = {de} } @article{MottaghyVosteenSchellschmidt2008, author = {Mottaghy, Darius and Vosteen, Hans-Dieter and Schellschmidt, R{\"u}diger}, title = {Temperature dependence of the relationship of thermal diffusivity versus thermal conductivity for crystalline rocks}, series = {International Journal of Earth Sciences}, volume = {97}, journal = {International Journal of Earth Sciences}, number = {2}, issn = {1437-3262}, doi = {10.1007/s00531-007-0238-3}, pages = {435 -- 442}, year = {2008}, language = {en} }