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Item type:Publication, Access status: without files , Status of the TransiEnt Library : transient simulation of complex integrated energy systems(Modelica Assoc., 2021-09-27); ; ; ; The open-source Modelica library TransiEnt Library was developed within the research project TransiEnt.EE. This paper presents two major extensions to this library which were developed in the follow-up research project ResiliEntEE. The modeling of the power sector on transmission grid level is possible due to the implementation of the complex bus voltage. In the gas sector, the efficiency of the computation of mass and energy balances was improved. Furthermore, an efficient physical pressure loss model was added that leads to more realistic results and faster simulations. The possible application of the library are presented in an exemplary simulation of an integrated energy system. It is shown that the dynamic simulation allows the depiction of disturbances and their possible consequences in coupled sectors. Thus, next to cost and CO2 emission, an integrated energy system can be assessed in terms of its resilience as well.Publicationtype: Conference Paper201 1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: Restricted , Influence of excess power utilization in power-to-heat units on an integrated energy system with 100 % renewables(2019-03); This paper presents the effect which the utilization of excess power in Power-to-Heat units has on an energy system which is fully supplied by renewables. For this, a possible future German integrated energy system consisting of the power, heat and gas sectors is modeled using the TransiEnt Library in Modelica R . The first system contains electric energy storage units, Power-to-Gas as well as Gas-to-Power plants and hot water storage units as energy storage technologies. The heat supply does not use excess power, and an option to curtail renewable power generation is added. The system costs are optimized by using simplified models in MATLAB R and designed in Modelica afterwards to include the dynamic effects. In a second system, excess power can also be used in existing electric heat pumps and in a third system as well in existing electric heating rods installed in the hot water storage tanks instead of curtailing renewable energy generation. This reduces the component sizes and thus the cost of the system because only control has to be added to enable this behavior.Publicationtype: Conference Paper375 74 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: Restricted , Modeling of the flow comparator prototype as new primary standard for high pressure natural gas flow meteringThe German national metrological institute, Physikalisch-Technische Bundesanstalt, is developing a new concept for volumetric primary standard to calibrate high pressure gas flow meters. The TUHH is supporting these R&D activities with its competence to elaborate computational models for detailed analysis of complex mechanical systems including fluid flow aspects. The new primary standard is based on a actively driven piston prover to measure the gas flow rate using the time the piston needs to displace a defined enclosed volume of gas in a cylinder. A computational model written in Modelica R is developeto investigate the Flow Comparator’s dynamic behavior. Validation of the model shows good compliance of the piston velocity and differential pressure at the piston in the model with measured data. With this model the control voltage trajectory can be optimized to increase the available measuring time and it allows to gather detailed information about pressure and temperature development at arbitrary chosen locations in the system with high time resolution.Publicationtype: Conference Paper198 79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Implementation of a non-discretized multiphysics PEM electrolyzer model in ModelicaIn this paper a multi-physics model of a proton exchange membrane electrolyzer with selectable physics submodels is developed in Modelica R . It will be included in the open-source TransiEnt Library for future studies on the efficiency of energy storage for intermittent renewable sources and the coupling of power, gas, and heat grids. The model is derived almost explicitly from a previous research paper by (Espinosa-López et al., 2018) but uses different models for cooling system power and anode/-cathode gas pressures. The model is then demonstrated in an application with wind speed records and corresponding power generation over the course of one year at a wind farm in northern Germany. It produces results similar to experimental results in other papers for use in general applications of further study.Publicationtype: Conference Paper252 641 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Optimizing the start-up process of post-combustion capture plants by varying the solvent flow rate(2017-07-04); This paper presents an optimization of the start-up process of a post-combustion carbon capture plant (PCC-plant) by varying the solvent flow rate. In a first optimization run the start-up time is minimized. In a second optimization run the overall carbon capture rate during the start-up process is maximized. The results show the great potential of the optimization, as the start-up time can be reduced from Dt = 4650s in the reference case to Dt = 2840s in the optimized scenario.Publicationtype: Conference Paper227 260 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Status of the TransiEnt Library : Transient Simulation of Coupled Energy Networks with High Share of Renewable Energy(Universität, 2015-09); ; ; ; The Modelica library TransiEnt is being developed within the research project TransiEnt.EE. After completion, the library will be freely available and will provide a framework to model coupled energy supply grids, i.e. electricity, district heating, and gas grids, including their corresponding producers, consumers and storage systems. This paper presents the current status of the library and outlines the library’s structure and the modeling concept. The application possibilities of the library are presented in an exemplary simulation where the city of Hamburg is selected as the reference system. The impact of a high share of fluctuating renewable energy generation in the electric grid and the integration of excess electricity in the district heating network is presented.Publicationtype: Conference Paper420 480 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Modeling of the German National Standard for High Pressure Natural Gas Flow Metering in Modelica(2015-09); ; The German national metrological institute Physikalisch-Technische Bundesanstalt uses a High Pressure Piston Prover as the primary standard for high pressure natural gas flow meters. The High Pressure Piston Prover measures the gas flow rate using the time a piston needs to displace a defined enclosed volume of gas in a cylinder. Fluctuating piston velocity during measurement can be a significant source of uncertainty if not considered in an appropriate way (Mickan et al., 2010). A computational model written in Modelica was developed to investigate measures for the reduction of this uncertainty. Validation of the model shows good compliance of the piston velocity in the model with measured data for certain volume flow rates. Reduction of the piston weight, variation of the start valve switching time and integration of a flow straightener were found to reduce the piston velocity fluctuations in the model significantly.Publicationtype: Conference Paper200 227 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Interfacing Models for Thermal Separation Processes with Fluid Property Data from External Sources(Linköping University Electronic Press, 2014-12); ; ; So far, when modelling processes that demand for multi-phase and multi-component fluid property data, the user has to implement the required media models in the Modelica language as these types of fluids are not supported by Modelica.Media. This paper presents a first approach on how to implement fluid property data in process models of an existing library from external sources and highlights which problems have to be overcome. Furthermore, it provides recommendations for the design of an efficient and user-friendly interface to external media packages.Publicationtype: Conference Paper192 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A Modelica library for scalable modelling of aircraft environmental control systemsIn this paper, the Modelica library developed in the Clean Sky project TEMPO is presented. The aim of the library is to support scalable system models for aircraft environmental control systems, which can be modified in detail and characteristic to be used during different phases of the design cycle without the need of rebuilding the system model or switching to another software tool. The design process of complex technical systems such as aircraft environmental control and cooling systems can be broken down into characteristic design phases. Depending on the design phase, models of the system under development may differ in structure and complexity, as they are designed to answer design phase specific questions. The library presented in this paper aims at using the object-oriented features of the Modelica language to integrate multiple layers of models. Each layer corresponds to a set of models designed for use in a particular design phase. The design phase-specific models are integrated such that a single system model that has been assembled from available library component models can be “scaled”, i.e. reused, for a simulation activity of a different phase of the system design cycle. The library structure and the chosen container model approach to integrate the different detail levels is outlined. The functionality of the library is then demonstrated at the example of a generic aircraft environmental control system architecture.Publicationtype: Conference Paper123