TY - CHAP A1 - Ziegler, M. A1 - Schüller, R. A1 - Mottaghy, Darius T1 - Numerical simulation of energy consumption of artificial ground freezing applications subject to water seepage T1 - Simulation numérique de la consummation d´énergie des applications pour la congélation artificielle du sol soumise au flux de l´eau souterraine T2 - Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013 Y1 - 2013 SP - 2985 EP - 2988 ER - TY - JOUR A1 - Vogt, Christian A1 - Iwanowski-Strahser, Katha A1 - Marquart, Gabriele A1 - Arnold, Juliane A1 - Mottaghy, Darius A1 - Pechnig, Renate A1 - Gnjezda, Daniel A1 - Clauser, Christoph T1 - Modeling contribution to risk assessment of thermal production power for geothermal reservoirs JF - Renewable Energy Y1 - 2013 U6 - http://dx.doi.org/10.1016/j.renene.2012.11.026 SN - 0960-1481 VL - 53 SP - 230 EP - 241 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vogt, C. A1 - Mottaghy, Darius A1 - Wolf, A. A1 - Rath, V. A1 - Pechnig, R. A1 - Clauser, C. T1 - Reducing temperature uncertainties by stochastic geothermal reservoir modelling JF - Geophysical Journal International N2 - Quantifying and minimizing uncertainty is vital for simulating technically and economically successful geothermal reservoirs. To this end, we apply a stochastic modelling sequence, a Monte Carlo study, based on (i) creating an ensemble of possible realizations of a reservoir model, (ii) forward simulation of fluid flow and heat transport, and (iii) constraining post-processing using observed state variables. To generate the ensemble, we use the stochastic algorithm of Sequential Gaussian Simulation and test its potential fitting rock properties, such as thermal conductivity and permeability, of a synthetic reference model and—performing a corresponding forward simulation—state variables such as temperature. The ensemble yields probability distributions of rock properties and state variables at any location inside the reservoir. In addition, we perform a constraining post-processing in order to minimize the uncertainty of the obtained distributions by conditioning the ensemble to observed state variables, in this case temperature. This constraining post-processing works particularly well on systems dominated by fluid flow. The stochastic modelling sequence is applied to a large, steady-state 3-D heat flow model of a reservoir in The Hague, Netherlands. The spatial thermal conductivity distribution is simulated stochastically based on available logging data. Errors of bottom-hole temperatures provide thresholds for the constraining technique performed afterwards. This reduce the temperature uncertainty for the proposed target location significantly from 25 to 12 K (full distribution width) in a depth of 2300 m. Assuming a Gaussian shape of the temperature distribution, the standard deviation is 1.8 K. To allow a more comprehensive approach to quantify uncertainty, we also implement the stochastic simulation of boundary conditions and demonstrate this for the basal specific heat flow in the reservoir of The Hague. As expected, this results in a larger distribution width and hence, a larger, but more realistic uncertainty estimate. However, applying the constraining post-processing the uncertainty is again reduced to the level of the post-processing without stochastic boundary simulation. Thus, constraining post-processing is a suitable tool for reducing uncertainty estimates by observed state variables. Y1 - 2010 U6 - http://dx.doi.org/10.1111/j.1365-246X.2009.04498.x SN - 1365-246X VL - 181 IS - 1 SP - 321 EP - 333 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Vogt, C. A1 - Mottaghy, Darius A1 - Rath, V. A1 - Marquart, G. A1 - Dijkshoorn, L. A1 - Wolf, A. A1 - Clauser, C. T1 - Vertical variation in heat flow on the Kola Peninsula: palaeoclimate or fluid flow? JF - Geophysical Journal International N2 - Following earlier studies, we present forward and inverse simulations of heat and fluid transport of the upper crust using a local 3-D model of the Kola area. We provide best estimates for palaeotemperatures and permeabilities, their errors and their dependencies. Our results allow discriminating between the two mentioned processes to a certain extent, partly resolving the non-uniqueness of the problem. We find clear indications for a significant contribution of advective heat transport, which, in turn, imply only slightly lower ground surface temperatures during the last glacial maximum relative to the present value. These findings are consistent with the general background knowledge of (i) the fracture zones and the corresponding fluid movements in the bedrock and (ii) the glacial history of the Kola area. Y1 - 2014 U6 - http://dx.doi.org/10.1093/gji/ggu282 SN - 1365-246X VL - 199 IS - 2 SP - 829 EP - 843 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Rath, V. A1 - Mottaghy, Darius T1 - Klimainformation aus dem Untergrund? JF - Geographische Rundschau Y1 - 2014 SN - 0016-7460 VL - 66 IS - 7-8 SP - 30 EP - 36 PB - Westermann CY - Braunschweig ER - TY - JOUR A1 - Rath, V. A1 - Mottaghy, Darius T1 - Smooth inversion for ground surface temperature histories: estimating the optimum regularization parameter by generalized cross-validation JF - Geophysical Journal International Y1 - 2007 U6 - http://dx.doi.org/10.1111/j.1365-246X.2007.03587.x SN - 1365-246X VL - 171 IS - 3 SP - 1440 EP - 1448 ER - TY - JOUR A1 - Mottaghy, Darius A1 - Vosteen, Hans-Dieter A1 - Schellschmidt, Rüdiger T1 - Temperature dependence of the relationship of thermal diffusivity versus thermal conductivity for crystalline rocks JF - International Journal of Earth Sciences Y1 - 2008 U6 - http://dx.doi.org/10.1007/s00531-007-0238-3 SN - 1437-3262 VL - 97 IS - 2 SP - 435 EP - 442 ER - TY - JOUR A1 - Mottaghy, Darius A1 - Schwamborn, G. A1 - Rath, V. T1 - Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling JF - Climate of the Past Y1 - 2013 U6 - http://dx.doi.org/10.5194/cp-9-119-2013 SN - 1814-9332 VL - 9 IS - 1 SP - 119 EP - 133 PB - Copernicus CY - Katlenburg-Lindau ER - TY - JOUR A1 - Mottaghy, Darius A1 - Schellschmidt, R. A1 - Popov, Y. A. A1 - Clauser, C. A1 - Kukkonen, I. T. A1 - Nover, G. A1 - Milanovsky, S. A1 - Romushkevich, R. A. T1 - New heat flow data from the immediate vicinity of the Kola super-deep borehole: Vertical variation in heat flow density confirmed and attributed to advection JF - Tectonophysics Y1 - 2005 U6 - http://dx.doi.org/10.1016/j.tecto.2005.03.005 SN - 1879-3266 VL - 401 IS - 1-2 SP - 119 EP - 142 ER - TY - JOUR A1 - Mottaghy, Darius A1 - Rath, Volker T1 - Latent heat effects in subsurface heat transport modelling and their impact on palaeotemperature reconstructions JF - Geophysical Journal International Y1 - 2006 U6 - http://dx.doi.org/10.1111/j.1365-246X.2005.02843.x SN - 1365-246X VL - 164 IS - 1 SP - 236 EP - 245 ER - TY - JOUR A1 - Mottaghy, Darius A1 - Pechnig, Renate A1 - Vogt, Christian T1 - The geothermal project Den Haag: 3D numerical models for temperature prediction and reservoir simulation JF - Geothermics N2 - 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. Y1 - 2011 U6 - http://dx.doi.org/10.1016/j.geothermics.2011.07.001 SN - 0375-6505 VL - 40 IS - 3 SP - 199 EP - 210 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mottaghy, Darius A1 - Pechnig, Renate A1 - Taugs, Renate A1 - Kröger, Jens A1 - Thomsen, Claudia A1 - Hesse, Fabian A1 - Liebsch-Doerschner, Thomas T1 - Erstellung eines geothermischen Modells für Teile Hamburgs und anliegende Gebiete JF - BBR - Fachmagazin für Brunnen- und Leitungsbau Y1 - 2010 SN - 1611-1478 VL - 61 IS - 12 SP - 52 EP - 59 PB - WVGW Wirtschafts- u. Verl.Ges. Gas und Wasser CY - Bonn ER - TY - JOUR A1 - Mottaghy, Darius A1 - Pechnig, Renate T1 - Numerische 3D Modelle zur Temperaturvorhersage und Reservoirsimulationen JF - BBR - Fachmagazin für Brunnen- und Leitungsbau Y1 - 2009 VL - 60 IS - 10 SP - 44 EP - 51 ER - TY - CHAP A1 - Mottaghy, Darius A1 - Majorowicz, Jacek A1 - Rath, Volker T1 - Ground Surface Temperature Histories Reconstructed from Boreholes in Poland: Implications for Spatial Variability T2 - The Polish Climate in the European Context: An Historical Overview Y1 - 2009 SN - 978-90-481-3167-9 U6 - http://dx.doi.org/10.1007/978-90-481-3167-9_17 SP - 375 EP - 387 PB - Springer Science+Business Media CY - Dordrecht ER - TY - JOUR A1 - Mottaghy, Darius A1 - Dijkshoorn, Lydia T1 - Implementing an effective finite difference formulation for borehole heat exchangers into a heat and mass transport code JF - Renewable Energy N2 - 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. KW - Borehole heat exchanger KW - Finite differences KW - Heat transport Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.renene.2012.02.013 SN - 0960-1481 VL - 45 SP - 59 EP - 71 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kürten, Sylvia A1 - Mottaghy, Darius A1 - Ziegler, Martin T1 - Wärmeübergangswiderstand bei flächigen thermo-aktiven Bauteilen am Beispiel thermo-aktiver Abdichtungselemente JF - Bautechnik Y1 - 2013 U6 - http://dx.doi.org/10.1002/bate.201300035 SN - 1437-0999 VL - 90 IS - 7 SP - 387 EP - 394 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Kürten, Sylvia A1 - Mottaghy, Darius A1 - Ziegler, Martin T1 - Planung, Auslegung und Dimensionierung von thermo-aktiven Bauteilen am Beispiel thermo-aktiver Abdichtungselemente JF - Geothermie, Bohr- und Brunnentechnik Y1 - 2014 SP - 18 EP - 20 PB - Ernst & Sohn CY - Berlin ER - TY - JOUR A1 - Kürten, Sylvia A1 - Mottaghy, Darius A1 - Ziegler, Martin T1 - A new model for the description of the heat transfer for plane thermo-active geotechnical systems based on thermal resistances JF - Acta Geotechnica Y1 - 2015 U6 - http://dx.doi.org/10.1007/s11440-014-0311-6 SN - 1861-1133 VL - 10 IS - 2 SP - 219 EP - 229 PB - Springer CY - Berlin ER - TY - JOUR A1 - Kürten, Sylvia A1 - Mottaghy, Darius A1 - Ziegler, Martin T1 - Design of plane energy geostructures based on laboratory tests and numerical modelling JF - Energy and Buildings Y1 - 2015 U6 - http://dx.doi.org/10.1016/j.enbuild.2015.08.039 SN - 0378-7788 VL - 107 SP - 434 EP - 444 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kürten, Sylvia A1 - Mottaghy, Darius A1 - Ziegler, Martin T1 - Besonderheiten bei der Planung und Berechnung von oberflächennahen thermo-aktiven Bauteilen JF - Geotechnik Y1 - 2015 U6 - http://dx.doi.org/10.1002/gete.201500002 SN - 2190-6653 VL - 38 IS - 2 SP - 107 EP - 119 PB - Wiley CY - Weinheim ER -