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Dr. Christoph Ummenhofer

School of Mechanical Engineering, University of Applied Sciences Landshut, Germany


Talk Title
System analysis of the dynamic behavior of micro combined heat and power units combined with thermal and electric energy storage

Talk Abstract

Micro-combined heat and power systems provide an efficient, decentralized means of power generation that can complement the composition of the electricity generation mix. However, intermittent load conditions, transient system behaviour and ensuring self-sufficiency represent challenges that micro-combined heat and power systems currently on the market need to address. System efficiency and run times can be increased by micro-combined heat and power units with thermal and electric energy storage systems, decoupling energy supply and demand. When local generation of energy is complemented with energy storage during times of high supply and with discharge of stored energy during periods of high demand, self-sufficiency can be increased. Reducing demand at peak times leads to a more resilient electricity grid and potentially lowers electricity costs for consumers. Here, we present an overview of advanced analysis tools suitable for system analysis of the dynamic behavior of micro-combined heat and power units in conjunction with thermal and electrical storage systems. Dynamic tools capable of handling transient system behaviour are required to assess micro-combined heat and power efficiency beyond a mere static analysis based on steady-state design parameters. A range of analysis tools are shown, such as exergy, degree of self-sufficiency, peak time coverage and load duration curves. The concept of exergy allows direct comparison of different forms of energy. Exergetic definitions for different operational system states can be combined to continuously quantify overall system efficiency. Sensitivity analysis allows an assessment of the effect on micro-combined heat and power performance under varying engine speed, thermal energy storage size and fluid storage temperature. Selecting specific thermal energy storage fluid temperatures can improve system efficiency. It is demonstrated how the micro-combined heat and power unit and electric energy storage system can complement each other to benefit the system performance. Supply composition characteristics that lead to higher load coverage by micro-combined heat and power -generated electricity are exemplarily identified: Incorporating an electric energy storage system has a significant impact on balancing supply and demand and also ensures longer micro-combined heat and power run times. Separating days according to their respective degree of electrical self-sufficiency assist in identifying supply composition characteristics that result in more of the required load being met by micro-combined heat and power-generated electricity.

Short Biography

Chris Ummenhofer obtained a Bachelor in Mechanical Engineering at the University of New South Wales in Sydney Australia in 2012. During several extended research visits to Germany, he worked at the Technology Centre Energy of the University of Applied Sciences in Landshut, Germany, on understanding and simulating MCHP system behaviour. He completed his PhD in 2017 in the School of Mechanical Engineering and Manufacturing working on “System analysis of the dynamic behaviour of MCHP units combined with thermal and electric energy storage”. Currently, he is working as a consultant engineer in the automotive industry in Germany.

Talk Keywords
Dynamic system behaviour, Micro Combined Heat and Power, MCHP, Thermal energy storage, TES, Electrical energy storage, EES, Exergy, Thermal transient analysis.
Target Audience
Anyone with a keen interest in energy modeling and energy storage, in particular within a micro-combined heat and power context
Speaker-intro video

The International Conference on Innovative Applied Energy (IAPE’18)