Master Thesis

In light of the conclusions presented in the Heat Roadmap Europe, it is evident that the collective heat demand across 27 European countries constitutes approximately 50% of the final energy consumption. Consequently, the heat sector takes a pivotal role influencing European CO2 emissions, underscoring the imperative for a renewable energy driven heat supply to effectively address the challenges posed by global warming.

In this context, district heating grids (DHGs) play a major role since they can realize fully decarbonized heat supply utilizing various distributed heat sources. The principle of operation of a DHG is the transport of water heated by the decentralized producers to the consumers, who extract heat from this water and thereby lower the water temperature across the grid.

A central component that couples a heat source or heat sink to the DHG is a heat exchanger. The applicable heat exchanger technology considered here enables heat transfer between two hydraulically separated mass flows. The heat transfer crucially depends on the mass flow rates and the mechanical design, resulting in complex (highly nonlinear) transfer properties. Precise control of such heat exchangers and the exhibited transfer processes is important for economical DHG operation. Therefore, the aim of this master thesis is to investigate the performance of state-of-the-art heat exchanger control methods on the basis of a physically compatible computational fluid dynamics (CFD) model of the heat exchanger. The CFD model may utilize different layers of fidelity and complexity from which a reduced-order representation of the operational parameter landscape is seeked (e.g. with machine learning tools).

The master thesis will be supervised by Fraunhofer IEG researchers on energy and control engineering topics and by researchers from the Chair of Numerical Fluid and Gas Dynamics from Brandenburg University of Technology Cottbus-Senftenberg regarding CFD-related topics.

**What you will do**
- Literature review on heat exchangers and internal transfer processes in district heating, mathematical modeling of heat exchangers based on CFD simulations of plate heat exchangers.
- Implementation of a CFD model with appropriate fidelity describing thermal and hydraulic dynamics of water-to-water plate heat exchangers, followed by CFD-data-based model reduction
- Design and software implementation of promising temperature control strategies for water-to-water plate heat exchangers
- Simulation case study to evaluate performance of designed temperature control strategies for heat exchangers when tested with the CFD-based reduced order model as Software-in-the-Loop approach
- Documentation of the results

**What you bring to the table**
- Student in Engineering, Mathematics, Energy technology, or other STEM programs
- Good knowledge of fluid dynamics or/and heat and mass transfer or/and mathematical modeling or/and simulation of dynamical systems
- User experience with CFD simulation tools, preferably ANSYS Fluent or OpenFOAM
- Good programming skills, e.g. Python, Julia, C++
- Additional skills in data analysis and/or machine learning, in particular multidimensional regression and interpolation, are desirable but not mandatory

**What you can expect**
- A practice-oriented Master's thesis in collaboration with the Fraunhofer IEG
- The opportunity to contribute your own ideas
- Our supervisors will make you strong so that you are successful
- Active participation in the success of your Master's thesis
- A well-equipped technical infrastructure at your workplace

With its focus on developing key technologies that are vital for the future and enabling the commercial utilization of this work by business and industry, Fraunhofer plays a central role in the innovation process. As a pioneer and catalyst for groundbreaking developments and scientific excellence, Fraunhofer helps shape society now and in the future.

**We will be happy to answer any questions you may have about this position**:
Mr. Max Rose
Phone: +49 355 35540 184

Mr. Philipp Steinborn
Phone +49 355 355 40 172

Fraunhofer Research Institution for Energy Infrastructures and Geothermal Systems IEG

Requisition Number: 72537 Application Deadline: 04/15/2024