TOPICS: Climate Envelopes / Berlin Geothermal / CityGML Decision Making Tools for the Berlin EnergyAtlas / Publications and Materials / Teams / Partners / Funding institution / Friends / Author
N-DEMO starts from the premise that to deliver sustainable cities requires large scale systemic innovation. In a set of real-world urban test-beds in London and Berlin, it demonstrates, evaluates and facilitates integrated pioneering ideas.
In Berlin, N-DEMO tackles three challenges in areas of planned investments. Firstly, N-DEMO proposes Climate Envelopes for sustainable housing in territories unavoidably affected by noise, such as in the vicinity of airports or high traffic infrastructures. Secondly, within the effort of providing the expanding city with reneawble energy sources, N-DEMO estimates the geothermal heat stored in its deepest underground and identifies the areas most suitable for a geothermal plant. Thirdly, to support the integrated planning of energy infrastructure and building retrofitting with help of the city owned 3D CityGML model, N-DEMO tests on the field and delivers IT-tools for decision making.

The N-DEMO Climate Envelopes are housing solutions characterized by a large transparent surface, allowing for sun light and its natural heat to penetrate abundantly. Humidity is generated naturally within a climate envelope by plants made grown within the transparent volume. Then, on the very base of these two natural resources, the technology of the StartUp Watergy provides renewable heating and air conditioning, by storing the heat and humidity exceeding our comfort window and releasing them – naturally filtered and cleaned up – in the colder and dryer months. The system responds also to the day-to-night oscillations, thus providing a high quality naturally stabilized living environment. It’s like a lung synchronized with our natural comfort window and the seasonal rhythm. As its transparent envelope isolates from noise disturbance, climate envelopes are attractive also in neighborhoods critically exposed to noise, such the surroundings of airports or communication ways with high traffic.
The N-DEMO climate envelope was presented to the public in Blankenfelde-Mahlow in the Summer 2013, was evaluated by the visitors and will be soon to visit as pavillon at the University Campus in Charlottenburg. Climate Envelopes are much more – they are being developed also for sustainable agriculture in green-houses, to naturally balance heat, water and humidity. An extensive description of concept, technology and application is to find in this BOOK.

Our underground is a second sun storing huge amounts of heat in its geological formations. This heat is called “heat-in-place”, stored in the fluids filling the rock pores and in the solid rock material itself. The possibility to extract the heat-in-place depends on the first hand on the combination between temperature and porosity at depth: temperature increases with depth (3°C/100 m in Berlin-Brandenburg), but porosity decreases more quickly. At large enough porosities, the heat can be pumped up to the surface with the pore fluid; at small porosities it can be extracted only through contact with a fluid made circulate in thermowells drilled into the rock. The fraction of the heat-in-place attaining the surface defines the productivity of a geothermal plant.

Our geothermal experts operate the experimental geothermal power plant in Größ Schönebeck, about 40 km north of Berlin, where they study and implement the specifics of geothermal energy for the so called “North-East German basin”, which Berlin is part of.
Gathering all data at disposal at present, they have modelled the whole Berlin geogological underground, and estimated its heat-in-place: this should me more than hundred times the 40 TWh heating demand from housing in the year 2005. The most interesting geological formations are for Berlin the “Middle Buntsandstein” and the “Sedimentary Rotliegend”, the former less deep – about 1500 m – and more pearmeable, the latter deeper – about 3000m -, significantly hotter but with reduced permeability.
As a next step, the researchers estimated the productivity of a basic double well system – combination of an injection and an extraction well – in suitable districts. Predicted trend figures in heating power of hydrothermal plants are in the range of 2 to 5 MW for the Middle Buntsandstein in the Berlin Region. These are to match with the local demand. However, concrete steps forward can be attained only with exploration boreholes, which would allow to solve the relevant uncertainties induced by the lack in geological data, to prove the local geology, assess feasibility and precisely quantify the investment risk.

The data and results from this study as well as the developed decision making tools have been stored in the Berlin EnergyAtlas – the 3D CityGML model of Berlin conceived for energy related challenges – where they are ready for retrieve, inspection, further development or export to analogous studies of geothermal sites. Indeed, the 3D model – which includes both underground and over-surface – is the other major focus of N-DEMO in Berlin and point of convergence of several of its activities. What is it? CityGML is a mark-up language conceived for the representation of cities. Cities are de-structured in their single elements (streets, bridges, buildings, utility networks, …) and these are given, in turn, attributes. Relevant attributes for a building are the years of construction and of retrofitting interventions, walls and their construction materials, its energy consumption.
The CityGML language is defined by a CityGML committee and has been largely adopted by the EU for the electronic representation of cities and the organisation of city reletd information by the public offices of the member states. The work executed in N-DEMO in Berlin builds upon and extends the CityGML model belonging to the city through the Berlin Partner GmbH. N-DEMO shows practical and effective ways to bring energy demand and offer to a synergic convergence with help of this IT-based tool-kit.

N-DEMO considers the heat and electricity demand from housing, which our researchers have estimated for a test neighborhood in Berlin-Moabit. To this purpose, they have brought databanks together and integrated in the calculations standards from legislation and the most recent research. Still, there have been gaps to fill, in both data avilability and methods for the calculations. For example, how to include the contribution from sun irradiation into the energy balance of a building, as its demand for heating might significantly vary with it. In those cases, research and the students at the involved Universities have been mobilized to solve these problems, thus securing an immediate impact of N-DEMO on the education of the upcoming generation of GIS and Energy experts.
The N-DEMO energy offer comes from geothermal heat. Within a nine minute MOVIE you are linked to, a sequence shows how the geothermal heat offer is compared with the heat demand from the buildings of the neighborhood beneath the candidate geothermal reservoir. As the approach is so strongly and flexibly location-oriented, it is possible to progressively incorporate in the design process all local features relevant to it, for example location and features of existing district-heating facilities in the neighborhood which could serve as vector for the geothermal heat offer, without having to build from skratch a new infrastructure.

Tools and plug-ins can be progressively added to the city model for the specific steps and necessities of design processes. In N-DEMO, we have developed a plug-in to automatically design the electricity network in a neighborhood, and applied it to a neighborhood in Berlin-Moabit. It works like this: as an input, we have the electricity demand from the neighborhood estates, from data or, when these are missing, from estimates. These data are associated with the estates on the 3D visual model. In addition to requiring electricity, estates might also produce it, for example through a local multi-property PV installationcan. On the other side, we have the engineering and security standards and norms ruling the design of electricity networks, translated into instructions for the plug-in. Once activated, the plug-in designs and draws on the model the electricity grid which best fulfills the neighborhood demand. In the video beside this text, the low (red) and medium (blue) voltage grid are drawn on the neighborhood map. The results inform, for example, neighborhood scaled energy production concepts in the perspective of negotiations with energy providers or authorities, but also the energy provider in the perspective of actualizing the grid for the upcoming scenarios of decentralized production. A second plug-in handles the topic “traffic and emissions”, as it maps the cause-effect relationships between urban space use, traffic flows, their emissions and energy impact and calculates the emissions.

Climate Envelopes
(2013) Bauen mit Klimahüllen / Building with Climate Envelopes, Karasu, A., Buchholz, M., Steffan, C., Universitätsverlag der TU Berlin
(2014) Lärmschutz durch Klimahüllen: Wissenschaftler der TU Berlin erforschen Nutzungsmöglichkeiten, In: BaustoffPraxis, 1195, ISSN: 1869-2206
Berlin Geothermal
(2012) Geothermische Wärmeversorgung von Metropolen aus dem Tiefgestein am Beispiel Berlins, Kastner O., Huenges, E., Bredel-Schürmann, S., Kolbe T.H., Kabus, F., Wärme- und Kälteerzeugung – Geothermische Wärmeversorgung, FVEE Themen 2012
(2013) Potential und thermische Eigenschaften der tiefen hydrothermalen Wärmreservoire in Berlin, Kastner O., Blöcher, G., Sippel, J., Fuchs, S., Erbas, K., Scheck-Wenderoth, M., In: Energie – Technologien und Energiewirtschaft, Workgroup “Energy” in the German Physical Society, Dresden, March 4-6
(2013) Deep 3D thermal modelling for the city of Berlin (Germany), Sippel J., Fuchs S., Cacace M., Braatz A., Kastner O., Huenges, E., Scheck-Wenderoth M., Environmental Earth Sciences, 70(8), 3545-3566
(2013) The deep geothermal potential of the Berlin area, Environmental Earth Sciences, 70(8), 3567-3584
CityGML Decision Making Tools for the Berlin EnergyAtlas
(2012) Integratives Entscheidungswerkzeug für die ganzheitliche Planung in Städten auf der Basis von semantischen 3D-Stadtmodellen am Beispiel des Energieatlas Berlin, Kaden, R., Krüger, A., Kolbe T.H., In: Deutsche Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation (DGPF), Wissenschaftlich-Technische Jahrestagung der DGPF 2012, Tagungsband 21, 2012–32
(2013) Kaden, R., Prytula, M., Krüger, A., Kolbe, T.H., Energieatlas Berlin: Vom Gebäude zur Stadt – Am Beispiel zur Abschätzung der Wärmeenergiebedarfe von Gebäuden. In: 18. Münchner Fortbildungsseminar Geoinformationssysteme –
Tagungsband, Wichmann Verlag

Author of this web-page: Ivana Agnolin @ TU-Berlin