@article{HemmerleHaleDresseletal.2019, author = {Hemmerle, Hannes and Hale, Sina and Dressel, Ingo and Benz, Susanne and Attard, Guillaume and Blum, Philipp and Bayer, Peter}, title = {Estimation of Groundwater Temperatures in Paris, France}, volume = {2019}, pages = {5246307}, journal = {Geofluids}, publisher = {Hindawi}, address = {London}, issn = {1468-8123}, doi = {https://doi.org/10.1155/2019/5246307}, year = {2019}, abstract = {Subsurface temperature data is usually only accessible as point information with a very limited number of observations. To spatialize these isolated insights underground, we usually rely on interpolation methods. Unfortunately, these conventional tools are in many cases not suitable to be applied to areas with high local variability, like densely populated areas, and in addition are very vulnerable to uneven distributions of wells. Since thermal conditions of the surface and shallow subsurface are coupled, we can utilize this relationship to estimate shallow groundwater temperatures from satellite-derived land surface temperatures. Here, we propose an estimation approach that provides spatial groundwater temperature data and can be applied to natural, urban, and mixed environments. To achieve this, we combine land surface temperatures with anthropogenic and natural processes, such as downward heat transfer from buildings, insulation through snow coverage, and latent heat flux in the form of evapotranspiration. This is demonstrated for the city of Paris, where measurements from as early as 1977 reveal the existence of a substantial subsurface urban heat island (SUHI) with a maximum groundwater temperature anomaly of around 7 K. It is demonstrated that groundwater temperatures in Paris can be well predicted with a root mean squared error of below 1 K by means of satellite-derived land surface images. This combined approach is shown to improve existing estimation procedures that are focused either on rural or on urban conditions. While they do not detect local hotspots caused by small-scaled heat sources located underground (e.g., sewage systems and tunnels), the findings for the city of Paris for the estimation of large-scale thermal anomalies in the subsurface are promising. Thus, the new estimation procedure may also be suitable for other cities to obtain a more reliable insight into the spatial distribution of urban ground and groundwater temperatures.}, language = {en} } @article{TissenMenbergBayeretal.2019, author = {Tissen, Carolin and Menberg, Kathrin and Bayer, Peter and Blum, Philipp}, title = {Meeting the demand}, volume = {7}, pages = {9}, journal = {Geothermal Energy - Science, Society and Technology}, subtitle = {geothermal heat supply rates for an urban quarter in Germany}, publisher = {BioMed Central}, address = {London}, issn = {2195-9706}, doi = {https://doi.org/10.1186/s40517-019-0125-8}, year = {2019}, abstract = {Thermal energy for space heating and for domestic hot water use represents about a third of the overall energy demand in Germany. An alternative to non-renewable energy-based heat supply is the implementation of closed and open shallow geothermal systems, such as horizontal ground source heat pump systems, vertical ground source heat pump (vGSHP) systems and groundwater heat pump systems. Based on existing regulations and local hydrogeological conditions, the optimal site-specific system for heat supply has to be identified. In the presented technical feasibility study, various analytical solutions are tested for an urban quarter before and after building refurbishment. Geothermal heat supply rates are evaluated by providing information on the optimal system and the specific shortcomings. Our results show that standard vGSHP systems are even applicable in older and non-refurbished residential areas with a high heat demand using a borehole heat exchanger with a length of 100 m or in conjunction with multiple boreholes. After refurbishment, all studied shallow geothermal systems are able to cover the lowered heat demand. The presented analysis also demonstrates that ideally, various technological variants of geothermal systems should be evaluated for finding the optimal solution for existing, refurbished and newly developed residential areas.}, language = {en} } @article{RingelSomogyvariJalalietal.2019, author = {Ringel, Lisa Maria and Somogyv{\´a}ri, M{\´a}rk and Jalali, Mohammadreza and Bayer, Peter}, title = {Comparison of Hydraulic and Tracer Tomography for Discrete Fracture Network Inversion}, volume = {9}, pages = {274}, journal = {Geosciences}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2076-3263}, doi = {https://doi.org/10.3390/geosciences9060274}, year = {2019}, abstract = {Fractures serve as highly conductive preferential flow paths for fluids in rocks, which are difficult to exactly reconstruct in numerical models. Especially, in low-conductive rocks, fractures are often the only pathways for advection of solutes and heat. The presented study compares the results from hydraulic and tracer tomography applied to invert a theoretical discrete fracture network (DFN) that is based on data from synthetic cross-well testing. For hydraulic tomography, pressure pulses in various injection intervals are induced and the pressure responses in the monitoring intervals of a nearby observation well are recorded. For tracer tomography, a conservative tracer is injected in different well levels and the depth-dependent breakthrough of the tracer is monitored. A recently introduced transdimensional Bayesian inversion procedure is applied for both tomographical methods, which adjusts the fracture positions, orientations, and numbers based on given geometrical fracture statistics. The used Metropolis-Hastings-Green algorithm is refined by the simultaneous estimation of the measurement error's variance, that is, the measurement noise. Based on the presented application to invert the two-dimensional cross-section between source and the receiver well, the hydraulic tomography reveals itself to be more suitable for reconstructing the original DFN. This is based on a probabilistic representation of the inverted results by means of fracture probabilities.}, language = {en} } @article{SchweizerTutunaruHolzhammer2022, author = {Schweizer, Manuel and Tutunaru, Robin and Holzhammer, Uwe}, title = {Energie- und Leistungsbedarf des elektrischen Individualverkehrs}, volume = {74}, journal = {BWK ENERGIE.}, number = {7-8}, publisher = {VDI fachmedien}, address = {D{\"u}sseldorf}, issn = {1618-193X}, doi = {doi.org/10.37544/1618-193X-2022-7-8}, pages = {44 -- 48}, year = {2022}, language = {de} } @article{SchweizerStoecklTutunaruetal.2023, author = {Schweizer, Manuel and St{\"o}ckl, Martin and Tutunaru, Robin and Holzhammer, Uwe}, title = {Influence of heating, air conditioning and vehicle automation on the energy and power demand of electromobility}, volume = {2023}, pages = {100443}, journal = {Energy Conversion and Management: X}, number = {20}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2590-1745}, doi = {https://doi.org/10.1016/j.ecmx.2023.100443}, year = {2023}, abstract = {With the increasing number of electric vehicles in the transport sector, the relevance of accurate energy and power demand predictions of electromobility is growing. Thereby, different vehicle functions, especially heating and air conditioning and vehicle automation, have a significant influence. In accordance with the upcoming Euro-7 emissions standard, the energy consumption for heating even has to be contained in the manufacturer's consumption data in the future. To increase the accuracy of energy and power demand predictions of electromobility, the energy consumption of vehicle functions such as heating and air conditioning as well as the energy savings through vehicle automation must be considered. This paper presents approaches for modeling and simulation the energy consumption of heating, air conditioning and vehicle automation which can be used as an extension of electric vehicles WLTP (Worldwide Harmonized Light-Duty Vehicles Test Procedure) consumption simulation on the level of vehicle classes. The Germany-wide results of the electric vehicles energy demand for heating and air conditioning on the level of NUTS3-areas (Nomenclature of territorial units for statistics) and vehicle classes show regionally different results and confirm the relevance of the research approach. Vehicle automation results are described on the level of the five SAE automation levels (Society of Automotive Engineers automation levels) and the vehicle classes. The approaches and results can be used for single vehicles or assumed vehicle fleets.}, language = {en} } @article{SummEhrenwirthTrinkletal.2023, author = {Summ, Thorsten and Ehrenwirth, Mathias and Trinkl, Christoph and Z{\"o}rner, Wilfried and Pischow, Kaj and Greenough, Richard and Oyinlola, Muyiwa}, title = {Effect of argon concentration on thermal efficiency of gas-filled insulating glass flat-plate collectors}, volume = {2023}, pages = {120657}, journal = {Applied Thermal Engineering}, number = {230, Part A}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-5606}, doi = {https://doi.org/10.1016/j.applthermaleng.2023.120657}, year = {2023}, abstract = {Insulating glass flat-plate collectors can save cost by being produced quickly and automatically in insulated glass production facilities, and they can be filled with argon to reduce heat loss. During its lifetime, the collector is likely to lose argon because of gradual material degradation of the sealing. However, information on the influence of the argon concentration on the collector efficiency is limited. Therefore, the objective of this research work was to analyse this effect. A theoretical material property calculation of argon-air mixtures was carried out to determine the convective losses with variable argon concentrations. Thermal collector performance was measured experimentally using an outdoor solar tracker test rig. The results strongly suggest, that the influence of argon concentration on both the convective losses and the thermal efficiency is non-linear. The measurements revealed that an argon concentration of 90 \% can increase average thermal performance by 6.7 ± 4.8 percentage points. An increase in argon concentration from 0 \% to 50 \% has almost twice the effect on average thermal efficiency as an increase from 50 \% to 90 \%. Concluding from these results, an argon leakage threshold of 2.5 percentage points per year is proposed to avoid disproportionate loss of efficiency over time.}, language = {en} } @article{BesnerMehtaZoerner2023, author = {Besner, Rebekka and Mehta, Kedar and Z{\"o}rner, Wilfried}, title = {How to Enhance Energy Services in Informal Settlements?}, volume = {16}, pages = {4687}, journal = {Energies}, subtitle = {Qualitative Comparison of Renewable Energy Solutions}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {https://doi.org/10.3390/en16124687}, year = {2023}, abstract = {More than half of the urban population of Sub-Saharan Africa lives in informal housing conditions. While urban areas are, in general, characterized by a high electrification rate, residents of informal settlements are still affected by energy poverty, the use of traditional energy sources and unreliable electricity supply. The aim of the study is to give an overview of different renewable-energybased solutions which are able to improve local energy provision. These are Solar Home Systems, Mini-Grids, and Energy-Hubs. The technologies are compared to another option for improving energy supply, namely Grid Expansion. The analysis is based on 24 Key Performance Indicators, which can be classified into technical, economic, environmental, social, and political dimensions. The selection of indicators is based on the challenges prevalent in informal settlements that impede a comprehensive, sustainable energy supply. The literature-based indices are used to determine which of the four technologies is a suitable solution for minimizing the challenges prevailing in informal settlements. The resulting matrix provides a holistic comparison and serves as a decision aid in selecting the appropriate technology for future projects in informal settlements, depending on local conditions and the needs of the population. The results show that the Energy-Hub is a valid alternative for energy supply improvement in Informal Settlements.}, language = {en} } @article{PophillatAttardBayeretal.2018, author = {Pophillat, William and Attard, Guillaume and Bayer, Peter and Hecht-M{\´e}ndez, Jozsef and Blum, Philipp}, title = {Analytical solutions for predicting thermal plumes of groundwater heat pump systems}, volume = {2020}, journal = {Renewable Energy}, number = {147, Part 2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-0682}, doi = {https://doi.org/10.1016/j.renene.2018.07.148}, pages = {2696 -- 2707}, year = {2018}, language = {en} } @article{AttardBayerRossieretal.2019, author = {Attard, Guillaume and Bayer, Peter and Rossier, Yvan and Blum, Philipp and Eisenlohr, Laurent}, title = {A novel concept for managing thermal interference between geothermal systems in cities}, volume = {2020}, journal = {Renewable Energy}, number = {145}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-0682}, doi = {https://doi.org/10.1016/j.renene.2019.06.095}, pages = {914 -- 924}, year = {2019}, language = {en} } @article{PophillatBayerTeyssieretal.2019, author = {Pophillat, William and Bayer, Peter and Teyssier, Esther and Blum, Philipp and Attard, Guillaume}, title = {Impact of groundwater heat pump systems on subsurface temperature under variable advection, conduction and dispersion}, volume = {2020}, pages = {101721}, journal = {Geothermics}, number = {83}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-3576}, doi = {https://doi.org/10.1016/j.geothermics.2019.101721}, year = {2019}, language = {en} } @article{SelleneitMastHolzhammer2020, author = {Selleneit, Volker and Mast, Tanja and Holzhammer, Uwe}, title = {Method to describe and rate the ability to provide flexibility of residual power providers in electricity grids with a high share of variable renewable energies}, volume = {2020}, journal = {CIRED - Open Access Proceedings Journal}, number = {1}, publisher = {IET}, address = {Stevenage}, issn = {2515-0855}, doi = {https://doi.org/10.1049/oap-cired.2021.0294}, pages = {154 -- 157}, year = {2020}, abstract = {With an increasing ratio of variable renewable energies in Germany, power supply has to be ensured by providing flexibility from controllable supply and demand energy conversion units. For residual electricity supply, utilities in the industrial sector or flexible biogas plants may be suitable flexibility options. To describe and rate different technologies or utilities in terms of their ability to provide flexibility, a definition of flexibility and an innovative method to describe flexibility considering the grid requirements is elaborated. The method is based on a solid definition of flexibility indicators suitable for all technologies. For an increased flexibility, in many cases, it is reasonable to add supporting technologies like a storage to a utility or biogas combined heat and power (CHP). Such utility configurations can also be described with the elaborated method. The method can also make a valuable contribution to all distribution systems or utility system modellers as it can be taken as a basis for the modelling. In this study, the definition of flexibility indicators is described in detail and used on the example of a biogas CHP plant.}, language = {en} } @book{EltropNagelHolzhammeretal.2021, author = {Eltrop, Ludger and Nagel, Sylvio and Holzhammer, Uwe and Mast, Tanja and Selleneit, Volker and Tronnier, Annika and Wachinger, Gisela}, title = {Methodenhandbuch "Bioenergie als Flexibilit{\"a}tsoption im Energiesystem"}, series = {Schriftenreihe "Energetische Biomassenutzung", Band 21}, editor = {Eltrop, Ludger and Holzhammer, Uwe}, publisher = {Deutsches Biomasseforschungszentrum gemeinn{\"u}tzige GmbH}, address = {Leipzig}, issn = {2701-2719}, doi = {https://doi.org/10.48480/m6ak-zr53}, pages = {207}, year = {2021}, language = {de} } @inbook{DotzauerBuechnerEltropetal.2021, author = {Dotzauer, Martin and B{\"u}chner, Daniel and Eltrop, Ludger and H{\"a}rdtlein, Marlies and Henning, Christiane and Herrmann, Andr{\´e} and Holzhammer, Uwe and Kornatz, Peter and Mast, Tanja and Nagel, Sylvio and Oehmichen, Katja and Philipp, Matthias and Pohl, Marcel and Selleneit, Volker and Thr{\"a}n, Daniela}, title = {Flexible Bereitstellung von Bioenergie}, booktitle = {Methodenhandbuch: Stoffstromorientierte Bilanzierung der Klimagaseffekte: Methoden zur Bestimmung von Technologiekennwerten, Gestehungskosten und Klimagaseffekten von Vorhaben im Rahmen des BMWi-Forschungsnetzwerkes Bioenergie/ BMWi-F{\"o}rderbereich „Energetische Biomassenutzung"}, editor = {Thr{\"a}n, Daniela and Pfeiffer, Diana}, edition = {Version 5}, publisher = {Deutsches Biomasseforschungszentrum gemeinn{\"u}tzige GmbH}, address = {Leipzig}, isbn = {978-3-946629-58-0}, doi = {https://doi.org/10.48480/ddpt-ys74}, pages = {56 -- 108}, year = {2021}, language = {de} } @inproceedings{MastHolzhammerPhilipp2018, author = {Mast, Tanja and Holzhammer, Uwe and Philipp, Matthias}, title = {SmartBio : Biogasanlagen als Akteur in neuen intelligenten, regionalen M{\"a}rkten}, booktitle = {Tagungsband 12. Rostocker Bioenergieforum 2018}, editor = {Nelles, Michael}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009-473-0}, url = {https://www.openagrar.de/receive/dimport_mods_00001878}, pages = {143 -- 150}, year = {2018}, language = {de} } @inproceedings{MastNagelHolzhammeretal.2020, author = {Mast, Tanja and Nagel, Sylvio and Holzhammer, Uwe and Eltrop, Ludger}, title = {Biogasanlagen neu denken}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, subtitle = {technisch-{\"o}konomische Charakterisierung f{\"u}r die Einbindung in die modellgest{\"u}tzte Systemanalyse}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009-507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {123 -- 132}, year = {2020}, language = {de} } @inproceedings{NagelMastHolzhammeretal.2020, author = {Nagel, Sylvio and Mast, Tanja and Holzhammer, Uwe and Eltrop, Ludger}, title = {Die Rolle der Bioenergie im Energie- und Mobilit{\"a}tssystem in Deutschland}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, subtitle = {Ergebnisse einer modellgest{\"u}tzten Systemanalyse}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009- 507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {47 -- 56}, year = {2020}, language = {de} } @inproceedings{MastKollerHolzhammer2020, author = {Mast, Tanja and Koller, Maria and Holzhammer, Uwe}, title = {Verf{\"u}gbarkeit und Erl{\"o}sm{\"o}glichkeiten unterschiedlicher Biogasanlagenkonzepte im Smart-Market-Ansatz}, booktitle = {Tagungsband 14. Rostocker Bioenergieforum 2020, 19. Dialog Abfallwirtschaft MV}, publisher = {Universit{\"a}t Rostock}, address = {Rostock}, isbn = {978-3-86009- 507-2}, doi = {https://doi.org/10.18453/rosdok_id00002650}, pages = {391 -- 397}, year = {2020}, language = {de} }