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This paper statistically validates a novel methodology that quantifies, qualifies and spatially allocates the waste heat potential of sewage systems on an urban district level, in all cases in which real data from the sewage system does not exist or is not publicly available. The methodology is based on open data and open source technology and can be adapted to various types of cities. The results, from the application of the methodology for an example city, show that the methodology robustly calculated the paths and waste water volumetric flow from waste water sources to the waste water treatment plant. The modelled system maps the sewage system accurately within areas that have a population density close to the average. Despite small inaccuracies in the overall mapping, the methodology is able to present a good estimation of spatially distributed waste heat from water flows of the sewage system in the example city.

This paper presents the preliminary results of the District Heating Atlas, an online tool to collect and visualize key metrics of district heating systems in Germany. Since the scarce available public information on district heating systems is widely spread and not accessible via central data, the District Heating Atlas shall be the platform to enter and call up information centrally. With its online platform it provides a user interface where relevant information can be entered and system components of the currently recorded 82 district heating systems can be compared. So far, nearly 50 % of the thermal energy fed into district heating is covered by the District Heating Atlas. The analysis shows that the data availability is more than 60 % for five of the ten key metrics recorded. On the one hand, missing correlations between the key metrics show the diversity of the district heating systems and make it difficult to formulate general valid statements that could help to calculate missing data. On the other hand, this means that district heating systems are very diverse in their structure and thus offer versatile potential for sector coupling. In addition, district heating systems must be individually optimised in order to best utilize their potential for flexibility for the entire energy system. Finally, the first comparisons with information from the biggest district heating association in Germany show a high match with the currently collected data set.

Solar energy provides a minor percentage of the thermal demand of industrial processes globally. This paper proposes a new analytical energy model for the simulation of a solar thermal steam boiler system to be integrated into an industrial environment with steam parameters at 180 °C. The purposes of this study were to evaluate the influence of solar irradiation on the share of solar steam generation and to clarify how the levelised costs of energy are influenced by different technical and economic parameters. A solar steam boiler system with parabolic trough collectors is modelled and simulations for two scenarios of 1.5 and 2.0 MW thermal output at annual irradiation of 919 kWh/(m2a) were carried out. According to the results of the feasibility study a solar share of 17 – 23 % of total annual steam generation is feasible without the integration of a thermal storage. Levelised costs of solar steam generation of 55 – 60 EUR/MWh were determined under current market conditions at mid-latitude regions. The proposed concept can benefit the wider integration of solar process heat. Beyond a solution for the production process, the integration into a connected district heating network offers further potential to reduce its primary energy factor.

The integration of large solar heating systems in district heating (DH) networks with large combined heat and power (CHP) plants is rarely considered. This is often due to low costs for heat but also due to subsidies for the electricity by CHP plants. Possible changes in subsidies and requirements in the reduction of fossil fuel based CO2 emissions raise an awareness of improving the operational flexibility of fossil fuelled CHP plants. This paper provides a rather simple but detailed methodology of including large solar heating systems in an existing district heating system, where heat is supplied by a large CHP plant. It uses hourly data of load and temperature patterns as well as radiation data and collector efficiency data to determine collector field size and storage size. The possibility of largely independent operation of sub-networks is analysed, which allows different system temperatures. It is demonstrated that a sub-network can operate without a back-up boiler and that both network parts benefit from the interaction. (C) 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Meeting the heat demand of all customers attached, is the main objective for the operation of district heating (DH) systems combined with combined heat and power (CHP) plants. On the other hand, the economic ratification for the operation of CHP plants strongly depends on highly volatile electricity prices on the market. This trend will be reinforced in future, due to the additional integration and exploitation of renewable energies. Within this techno-economic field of most different operational objectives, DH systems and CHP plants must find a way for a cost-covering and efficient operation in future. Against this background, time shifts in producing and allocating heat supplied in parallel with electricity, are most attractive for DH system and CHP plant operators. Thus, margins on the electricity market could be maximized. On the other hand, heat amounts produced in parallel should be decoupled from the production of electricity as efficient as possible. Thus, thermal energy storages enter the limelight of interest for DH system operators. However, aspects concerning most different mechanisms for energetic and exergetic losses have to be considered for an optimized operation of these systems. Within this paper, the energetic and exergetic performance of sensible thermal storages will be examined. Underlying loss mechanisms of typical urban thermal storages are described qualitatively and quantified energetically and exergetically. For this purpose, existing models from literature are combined with practically relevant operational parameters for simulations.

This paper focuses on evaluating the technical, economic and ecological effects of the transition from the current high temperature charts to the lower temperature charts in the Moscow DHS by means of a developed spreadsheet-based model. A methodology suitable for assessing results of potential transition to lower temperatures in DHS of cities in Russia and worldwide is proposed and implemented in the model. The reference case of 2016 and three cases with decreased heat demand in buildings by 5, 10, and 20% were considered. The results show that fuel savings of 678–872 k t c e a can be achieved with respect to the current temperature charts in the Moscow DHS. The 110/50°С temperature chart is the most profitable option, with net present values varying from 4.64 to 10.74 bn RUB depending on the case. The 95/50°С chart, which leads to a reduction of 1.325–1.387 M t C O 2 / a , has the least impact on the environment. A more significant CO2 emissions reduction can be achieved by strong energy-saving measures and broad utilization of renewable and waste energy. The essential prerequisite for the transition is a reduction of the heat demand in buildings by at least 20%.

The paper presents some results of a recently completed research project funded by the German Science Foundation (DFG) dealing with the behavior of seismically excited granular material silos. A numerical model consisting of up to five components for describing the dynamic behavior of the silo is presented. The intergranular strain approach for hypoplasticity theory has been used for the granular material and soil–structure–interaction effects have also been taken into account. Results of numerical simulations obtained with this model are shown and compared to measurements carried out at a shaking table in Saclay, France. A squat and a slender silo have been simulated numerically in order to check the design loads specified by the European Code for silos subject to seismic loads. It follows that the Eurocode provisions for slender silos are quite good while for squat silos a reduction of the active mass assumed would be in order.

The paper presents a numerical model for the simulation of the bearing behaviour of textile-reinforced concrete structures under static load taking into account the specific bond characteristics. For the numerical simulation an assumed strain finite element based on the Reissner–Mindlin shell theory for finite rotations is used. The developed numerical model for textile-reinforced concrete allows cost efficient calculations and faster computer-aided analyses. The model verification is carried out by numerical simulations of experiments on textile-reinforced tension bars and also by simulating four-point-bending tests of textile-reinforced beams with thin-walled cross-sections under various loads. A comparison between the results of the simulations and the results of experiments is presented and discussed.

Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil–structure interaction effects are taken into account.

As a result of European energy and climate policy a growing share of renewable energy can be noted in European energy markets. Especially in the electricity market this leads to a higher volatility of the electricity price. In an open market this highly affects the share of cogeneration that is generally linked to local or district heating systems. The integration of thermal energy storage in district heating systems with cogeneration increases the flexibility of operation and thus maintains the profitability of combined heat and power units. In this paper a power-to-heat concept is proposed that offers additional benefits for thermal energy storage when electricity generation from renewable energy sources exceeds the current demand. The concept is analyzed from a technological and economic perspective.

Nadelstichverletzungen sind die Klassiker, wenn es um Unfalle in der Arztpraxis geht. Doch es gibt noch mehr Gefahrenquellen, gegen die sich Praxischefs wappnen mussen.