Maximising the Performance of Complex Energy Systems

Lead Research Organisation: University of Cambridge
Department Name: Engineering


With increased interest in zero emission power and propulsion energy systems, there is a requirement for a method from which to choose the optimal system configuration and then maximise its performance for a specific application under given operating conditions. This is complicated further by rapid developments in specific component technology levels and sales market variation. A method is therefore required to quickly analyse and optimise the performance of these new, more complex cycles due to the inherent uncertainty of future technology levels and because current analysis methods, which use knowledge gained from previous experience to identify the best design parameters to optimise and improve system performance, cannot be used with these new complex cycles, due to the possible drastic changes in system architecture. Therefore, a new generalisable method is required to determine which parameter to optimise in each sub-system of a complex cycle, in order to maximise the performance of the cycle as a whole. Investigation into the limitations of current analysis methods has suggested a possible solution by including a consideration of the breakdown of individual exergy component performances in each component of the cycle in the analysis method. This will allow the real potential work of different cycles to be determined rather than the maximum potential work using perfect machines, as is determined in current total exergy calculations. This type of adjusted exergy analysis called 'Mechanical Work Potential' or 'Euergy' is outlined for a turbomachine in Miller 2013 [1], and has already been implemented successfully in Jardine 2019 [2] to explain the effect of turbine blade cooling on stage performance.
A set of key objectives that need to be met in order to reach the goal of the project are outlined as follows:
1. To expand current fuel cell low order models to include temperature and pressure effects, whilst also removing calibrated constants. Replacing them with non-dimensional groups to further the physical understanding of parameter changes on the performance characteristics. Also, to concentrate on improving the accuracy of models under varying operating conditions away from calibrated ranges.
2. To develop a combination of cycle analysis tools to allow rapid and accurate assessment of different power and propulsion cycles, with a focus on generalisable models for a wide range of user applications.
3. To understand and predict future technology levels to allow fair comparison of the future potential of different cycle performances through the developed cycle analysis tool.
4. To develop a generalisable method to find which parameter to optimise within each system component to maximise the performance of the cycle as a whole. This will be done by developing the current exergy and euergy analysis methods to include a consideration of the relative efficiencies of the energy systems at extracting different forms of exergy.
5. The overall goal is to be able to use the developed cycle tool, optimisation code and analysis method together to be able to answer questions such as, "Should I burn hydrogen in a gas turbine or react it in a fuel cell in order to provide best performance under a given set of operating conditions and criteria?"

[1] Miller, R. J. (2013) "Mechanical Work Potential." ASME Turbo Expo 2013: Power for Land, Sea and Air
[2] Jardine, J. L. and Miller, R. J. (2019) "The Effect of Heat Transfer on Turbine Performance." ASME Turbo Expo 2019: Power for Land, Sea and Air


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023003/1 30/09/2019 30/03/2028
2299852 Studentship EP/S023003/1 30/09/2019 29/09/2023 Nathan Clark