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Kyprianidis, KonstantinosORCID iD iconorcid.org/0000-0002-8466-356X
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Publications (10 of 182) Show all publications
Hashmi, M. B., Mansouri, M., Fentaye, A. D., Ahsan, S. & Kyprianidis, K. (2024). An Artificial Neural Network-Based Fault Diagnostics Approach for Hydrogen-Fueled Micro Gas Turbines. Energies, 17(3), Article ID 719.
Open this publication in new window or tab >>An Artificial Neural Network-Based Fault Diagnostics Approach for Hydrogen-Fueled Micro Gas Turbines
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2024 (English)In: Energies, E-ISSN 1996-1073, Vol. 17, no 3, article id 719Article in journal (Refereed) Published
Abstract [en]

The utilization of hydrogen fuel in gas turbines brings significant changes to the thermophysical properties of flue gas, including higher specific heat capacities and an enhanced steam content. Therefore, hydrogen-fueled gas turbines are susceptible to health degradation in the form of steam-induced corrosion and erosion in the hot gas path. In this context, the fault diagnosis of hydrogen-fueled gas turbines becomes indispensable. To the authors' knowledge, there is a scarcity of fault diagnosis studies for retrofitted gas turbines considering hydrogen as a potential fuel. The present study, however, develops an artificial neural network (ANN)-based fault diagnosis model using the MATLAB environment. Prior to the fault detection, isolation, and identification modules, physics-based performance data of a 100 kW micro gas turbine (MGT) were synthesized using the GasTurb tool. An ANN-based classification algorithm showed a 96.2% classification accuracy for the fault detection and isolation. Moreover, the feedforward neural network-based regression algorithm showed quite good training, testing, and validation accuracies in terms of the root mean square error (RMSE). The study revealed that the presence of hydrogen-induced corrosion faults (both as a single corrosion fault or as simultaneous fouling and corrosion) led to false alarms, thereby prompting other incorrect faults during the fault detection and isolation modules. Additionally, the performance of the fault identification module for the hydrogen fuel scenario was found to be marginally lower than that of the natural gas case due to assumption of small magnitudes of faults arising from hydrogen-induced corrosion.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
hydrogen fuel, micro gas turbines, health degradation, steam-induced corrosion, fault detection, diagnostics
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66085 (URN)10.3390/en17030719 (DOI)001160097200001 ()2-s2.0-85184656336 (Scopus ID)
Available from: 2024-02-20 Created: 2024-02-20 Last updated: 2024-02-20Bibliographically approved
Zhou, Y., Aslanidou, I., Karlsson, M. & Kyprianidis, K. (2024). An explainable AI model for power plant NOx emission control. Energy and AI, 15, Article ID 100326.
Open this publication in new window or tab >>An explainable AI model for power plant NOx emission control
2024 (English)In: Energy and AI, ISSN 2666-5468, Vol. 15, article id 100326Article in journal (Refereed) Published
Abstract [en]

In recent years, developing Artificial Intelligence (AI) models for complex system has become a popular research area. There have been several successful AI models for predicting the Selective Non-Catalytic Reduction (SNCR) system in power plants and large boilers. However, all these models are in essence black box models and lack of explainability, which are not able to give new knowledge. In this study, a novel explainable AI (XAI) model that combines the polynomial kernel method with Sparse Identification of Nonlinear Dynamics (SINDy) model is proposed to find the governing equation of SNCR system based on 5-year operation data from a power plant. This proposed model identifies the system's governing equation in a simple polynomial format with polynomial order of 1 and only 1 independent variable among original 68 input variables. In addition, the explainable AI model achieves a considerable accuracy with less than 21 % deviation from base-line models of partial least squares model and artificial neural network model.

National Category
Engineering and Technology Energy Engineering Chemical Process Engineering
Identifiers
urn:nbn:se:mdh:diva-65124 (URN)10.1016/j.egyai.2023.100326 (DOI)001132419000001 ()2-s2.0-85178644436 (Scopus ID)
Available from: 2023-12-20 Created: 2023-12-20 Last updated: 2024-01-17Bibliographically approved
Fentaye, A. D. & Kyprianidis, K. (2024). Gas turbine prognostics via Temporal Fusion Transformer. Aeronautical Journal
Open this publication in new window or tab >>Gas turbine prognostics via Temporal Fusion Transformer
2024 (English)In: Aeronautical Journal, ISSN 0001-9240Article in journal (Refereed) Epub ahead of print
Abstract [en]

Gas turbines play a vital role in various industries. Timely and accurately predicting their degradation is essential for efficient operation and optimal maintenance planning. Diagnostic and prognostic outcomes aid in determining the optimal compressor washing intervals. Diagnostics detects compressor fouling and estimates the trend up to the current time. If the forecast indicates fast progress in the fouling trend, scheduling offline washing during the next inspection event or earlier may be crucial to address the fouling deposit comprehensively. This approach ensures that compressor cleaning is performed based on its actual health status, leading to improved operation and maintenance costs. This paper presents a novel prognostic method for gas turbine degradation forecasting through a time-series analysis. The proposed approach uses the Temporal Fusion Transformer model capable of capturing time-series relationships at different scales. It combines encoder and decoder layers to capture temporal dependencies and temporal-attention layers to capture long-range dependencies across the encoded degradation trends. Temporal attention is a self-attention mechanism that enables the model to consider the importance of each time step degradation in the context of the entire degradation profile of the given health parameter. Performance data from multiple two-spool turbofan engines is employed to train and test the method. The test results show promising forecasting ability of the proposed method multiple flight cycles into the future. By leveraging the insights provided by the method, maintenance events and activities can be scheduled in a proactive manner. Future work is to extend the method to estimate remaining useful life.

Place, publisher, year, edition, pages
CAMBRIDGE UNIV PRESS, 2024
Keywords
gas turbines prognostics, remaining useful life, Temporal Fusion Transformer, compressor washing, predictive maintenance, maintenance optimisation
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66545 (URN)10.1017/aer.2024.40 (DOI)001207525400001 ()2-s2.0-85191409334 (Scopus ID)
Available from: 2024-05-08 Created: 2024-05-08 Last updated: 2024-05-08Bibliographically approved
Pettinari, M., Frate, G. F., Tran, A. P., Oehler, J., Stathopoulos, P., Kyprianidis, K. & Ferrari, L. (2024). Impact of the Regulation Strategy on the Transient Behavior of a Brayton Heat Pump. Energies, 17(5), Article ID 1020.
Open this publication in new window or tab >>Impact of the Regulation Strategy on the Transient Behavior of a Brayton Heat Pump
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2024 (English)In: Energies, E-ISSN 1996-1073, Vol. 17, no 5, article id 1020Article in journal (Refereed) Published
Abstract [en]

High-temperature heat pumps are a key technology for enabling the complete integration of renewables into the power grid. Although these systems may come with several variants, Brayton heat pumps are gaining more and more interest because of the higher heat sink temperatures and the potential to leverage already existing components in the industry. Because these systems utilize renewable electricity to supply high-temperature heat, they are particularly suited for industry or energy storage applications, thus prompting the development of various demonstration plants to evaluate their performance and flexibility. Adapting to varying load conditions and swiftly responding to load adjustments represent crucial aspects for advancing such systems. In this context, this study delves into assessing the transient capabilities of Brayton heat pumps during thermal load management. A transient model of an emerging prototype is presented, comprising thermal and volume dynamics of the components. Furthermore, two reference scenarios are examined to assess the transient performance of the system, namely a thermal load alteration due to an abrupt change in the desired heat sink temperature and, secondly, to a sudden variation in the sink mass flow rate. Finally, two control methodologies—motor/compressor speed variation and fluid inventory control—are analyzed in the latter scenario, and a comparative analysis of their effectiveness is discussed. Results indicate that varying the compressor speed allows for a response time in the 8–20 min range for heat sink temperature regulation (first scenario). However, the regulation time is conditioned by the maximum thermal stress sustained by the heat exchangers. In the latter scenario, regulating the compressor speed shows a faster response time than the inventory control (2–5 min vs. 15 min). However, the inventory approach provides higher COPs in part-load conditions and better stability during the transient phase.

Place, publisher, year, edition, pages
Multidisciplinary Digital Publishing Institute (MDPI), 2024
Keywords
Brayton heat pump, control system, dynamic modeling, high-temperature heat pump, transient simulation, Electric energy storage, Electric loads, Heat pump systems, High temperature applications, Inventory control, Pumps, Thermal load, Brayton, Dynamics models, Heat pumps, Heat sink temperature, High temperature heat pump, Integration of renewables, Key technologies, Transient behavior, Heat storage
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66281 (URN)10.3390/en17051020 (DOI)001182671500001 ()2-s2.0-85187468466 (Scopus ID)
Note

Article; Export Date: 20 March 2024; Cited By: 0; Correspondence Address: M. Pettinari; Department of Energy, Systems, Territory and Construction Engineering, University of Pisa, Pisa, 56122, Italy; email: matteo.pettinari@phd.unipi.it; L. Ferrari; Department of Energy, Systems, Territory and Construction Engineering, University of Pisa, Pisa, 56122, Italy; email: lorenzo.ferrari@unipi.it

Available from: 2024-03-20 Created: 2024-03-20 Last updated: 2024-03-27Bibliographically approved
Soibam, J., Aslanidou, I., Kyprianidis, K. & Bel Fdhila, R. (2024). Inverse flow prediction using ensemble PINNs and uncertainty quantification. International Journal of Heat and Mass Transfer, 226
Open this publication in new window or tab >>Inverse flow prediction using ensemble PINNs and uncertainty quantification
2024 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 226Article in journal (Refereed) Published
Abstract [en]

The thermal boundary conditions in a numerical simulation for heat transfer are often imprecise. This leads to poorly defined boundary conditions for the energy equation. The lack of accurate thermal boundary conditions in real-world applications makes it impossible to effectively solve the problem, regardless of the advancement of conventional numerical methods. 

This study utilises a physics-informed neural network to tackle ill-posed problems for unknown thermal boundaries with limited sensor data. The network approximates velocity and temperature fields while complying with the Navier-Stokes and energy equations, thereby revealing unknown thermal boundaries and reconstructing the flow field around a square cylinder. The method relies on optimal sensor placement determined by the QR pivoting technique, which ensures the effective capture of the dynamics, leading to enhanced model accuracy. In an effort to increase the robustness and generalisability, an ensemble physics-informed neural network is implemented. This approach mitigates the risks of overfitting and underfitting while providing a measure of model confidence. As a result, the ensemble model can identify regions of reliable prediction and potential inaccuracies. Therefore, broadening its applicability in tackling complex heat transfer problems with unknown boundary conditions.

Keywords
Heat transfer, mixed convection, physics informed neural network, optimal sensor placement, transient simulation, inverse method
National Category
Engineering and Technology Computational Mathematics
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-64897 (URN)10.1016/j.ijheatmasstransfer.2024.125480 (DOI)2-s2.0-85189514108 (Scopus ID)
Available from: 2023-11-29 Created: 2023-11-29 Last updated: 2024-04-17Bibliographically approved
Chen, H., Sandberg, A. H., Biancini, G., Dahlquist, E. & Kyprianidis, K. (2024). Profitability Analysis of Integrating Fast Pyrolysis into Existing Combined Heat and Power Plants for Biofuel Production. In: Energy Proceedings: . Paper presented at 15th International Conference on Applied Energy, ICAE 2023. Doha. 3 December 2023 through 7 December 2023. Scanditale AB, Article ID 310669.
Open this publication in new window or tab >>Profitability Analysis of Integrating Fast Pyrolysis into Existing Combined Heat and Power Plants for Biofuel Production
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2024 (English)In: Energy Proceedings, Scanditale AB , 2024, article id 310669Conference paper, Published paper (Refereed)
Abstract [en]

Existing combined heat and power plants are seeking additional heat sinks to address challenges arising from the declining district heating demand and the increasing share of renewable energy in primary energy use in the coming decades. In the meantime, the world’s demand for sustainable fuel production keeps increasing due to the need to reduce carbon emissions and mitigate the effects of climate change. Fast pyrolysis, as a thermochemical conversion process based on widely available feedstocks such as lignocellulosic biomass, is promising to provide a long‐term supply of sustainable fuels, and could be integrated into existing combined heat and power plants due to the scalability and maturity of this method. This work focuses on techno‐economic analysis of integrating fast pyrolysis into existing combined heat and power plants for biofuel production. A process model of fast pyrolysis and bio‐oil upgrading is established in Aspen Plus to simulate the integration process. In this work, particular attention is given to the profitability analysis based on different final fuel products(crude pyrolysis oil and upgraded bio‐oil). Different hydrogen generation solutions (electrolysis, and gasification) for onsite bio‐oil upgrading are also examined. This study also performs an analysis of several economic indicators, such as payback period, net present value, and internal rate of return to provide insights for the future business model development for such systems. Sensitivity analysis is also carried out to further reveal the impacts of key variables in the economic evaluation process on the system’s profitability.

Place, publisher, year, edition, pages
Scanditale AB, 2024
Keywords
biofuel production, combined heat and power, fast pyrolysis, profitability analysis, uncertainty quantification
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66576 (URN)10.46855/energy-proceedings-11014 (DOI)2-s2.0-85190879508 (Scopus ID)
Conference
15th International Conference on Applied Energy, ICAE 2023. Doha. 3 December 2023 through 7 December 2023
Available from: 2024-05-08 Created: 2024-05-08 Last updated: 2024-05-08Bibliographically approved
Chen, H., Dahlquist, E. & Kyprianidis, K. (2024). Retrofitting Biomass Combined Heat and Power Plant for Biofuel Production-A Detailed Techno-Economic Analysis. Energies, 17(2), Article ID 522.
Open this publication in new window or tab >>Retrofitting Biomass Combined Heat and Power Plant for Biofuel Production-A Detailed Techno-Economic Analysis
2024 (English)In: Energies, E-ISSN 1996-1073, Vol. 17, no 2, article id 522Article in journal (Refereed) Published
Abstract [en]

Existing combined heat and power plants usually operate on part-load conditions during low heating demand seasons. Similarly, there are boilers designated for winter use that remain inactive for much of the year. This brings a concern about the inefficiency of resource utilization. Retrofitting existing CHP plants (especially for those with spare boilers) for biofuel production could increase revenue and enhance resource efficiency. This study introduces a novel approach that combines biomass gasification and pyrolysis in a polygeneration process that is based on utilizing existing CHP facilities to produce biomethane, bio-oil, and hydrogen. In this work, a detailed analysis was undertaken of retrofitting an existing biomass combined heat and power plant for biofuel production. The biofuel production plant is designed to explore the polygeneration of hydrogen, biomethane, and bio-oil via the integration of gasification, pyrolysis, and renewable-powered electrolysis. An Aspen Plus model of the proposed biofuel production plant is established followed by a performance investigation of the biofuel production plant under various design conditions. An economic analysis is carried out to examine the profitability of the proposed polygeneration system. Results show that the proposed polygeneration system can achieve 40% carbon efficiency with a payback period of 9 years and an internal rate of return of 17.5%, without the integration of renewable hydrogen. When integrated with renewable-power electrolysis, the carbon efficiency could be significantly improved to approximately 90%; however, the high investment cost associated with the electrolyzer system makes this integration economically unfavorable.

Place, publisher, year, edition, pages
MDPI, 2024
Keywords
biofuel, biomass, existing CHP plants, process modeling, techno-economic analysis
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-65948 (URN)10.3390/en17020522 (DOI)001151936200001 ()2-s2.0-85183319309 (Scopus ID)
Available from: 2024-02-07 Created: 2024-02-07 Last updated: 2024-02-07Bibliographically approved
Bermperis, D., Ntouvelos, E., Kavvalos, M., Vouros, S., Kyprianidis, K. & Kalfas, A. I. (2024). Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling. Journal of engineering for gas turbines and power, 146(1), Article ID 011005.
Open this publication in new window or tab >>Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling
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2024 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 146, no 1, article id 011005Article in journal (Refereed) Published
Abstract [en]

Hybrid-electric propulsion is recognized as an enabling technology for reducing aviation’s environmental impact. In this work, a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modeling accuracy of propulsion systems is aimed for by development of an integrated framework. A multipoint synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modeling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses. A threshold system voltage of 1 kV, yielding 32% mass reduction of electrical branches and performance improvements of 1–2%, is identified. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2024
Keywords
Conceptual design, Economic and social effects, Efficiency, Electric loads, Electric power transmission, Electric propulsion, Engines, Environmental technology, Machine design, Efficiency improvement, Electric fans, Electrical components, Electrical power system, Fan designs, Integrated Power Systems, Mass reduction, Performance, Physics-based, Trade off, Environmental impact
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-64855 (URN)10.1115/1.4063381 (DOI)2-s2.0-85177224156 (Scopus ID)
Available from: 2023-11-29 Created: 2023-11-29 Last updated: 2023-11-29Bibliographically approved
Taha, M., Lundvall, N., Kyprianidis, K., Salman, A., Vouros, S. & Zaccaria, V. (2024). Techno-economic evaluation of hydrogen production for airport hubs. In: Energy Proceedings: . Paper presented at 15th International Conference on Applied Energy, ICAE 2023. Doha. 3 December 2023 through 7 December 2023. Scanditale AB, 45
Open this publication in new window or tab >>Techno-economic evaluation of hydrogen production for airport hubs
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2024 (English)In: Energy Proceedings, Scanditale AB , 2024, Vol. 45Conference paper, Published paper (Refereed)
Abstract [en]

Hydrogen is considered one of the most promising alternative fuels for aviation, which can be used to power aircraft and airport ground services. Onsite hydrogen production from renewables can be suitable for small- size airports, while the larger size airports can be supplied through transportation either from dedicated green hydrogen production plants or other sources of hydrogen. This paper presents a study of two hydrogen supply scenarios, one taking the small airport of Stockholm Skavsta as a case study for in-house hydrogen production. The second is evaluating offshore green hydrogen supply to the large size airport of Arlanda. The in-house hydrogen production evaluates 18 scenarios covering all possible scenarios for alkaline, PEM, and solid oxide electrolysis as production means and compressed, cryo- compressed, and liquid gas as storage, with power supply from grid and grid plus in-house solar system. The optimum production and storage facility size is determined in association with the levelized cost and carbon emissions for each scenario. For the large-size airport, the study evaluates the hydrogen supply from offshore production facilities transported as compressed, cryo-compressed, or liquid gas via offshore pipeline and onshore pipeline, Offshore pipeline and truck, Ship and onshore pipeline, or Ship and truck. The results showed the levelized cost to be between 2.93-2.44 Euro/kg H2 in the case of in-house production. Compressed hydrogen offshore and onshore pipeline is the least cost for Arlanda airport hydrogen supply. This paper demonstrates a direction for aviation sector decarbonization and establishes a pathway for airports' in-house hydrogen production and outsourced hydrogen supply.

Place, publisher, year, edition, pages
Scanditale AB, 2024
Keywords
Electrolysis systems, Hydrogen, Hydrogen for aviation, Hydrogen inhouse production
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66560 (URN)10.46855/energy-proceedings-11088 (DOI)2-s2.0-85190673122 (Scopus ID)
Conference
15th International Conference on Applied Energy, ICAE 2023. Doha. 3 December 2023 through 7 December 2023
Available from: 2024-05-14 Created: 2024-05-14 Last updated: 2024-05-14Bibliographically approved
Kavvalos, M., Kyprianidis, K. & Padulo, M. (2024). The Growth Engine Concept and Its Potential for an Electrified Aviation Future. Journal of engineering for gas turbines and power, 146(7), Article ID 070901.
Open this publication in new window or tab >>The Growth Engine Concept and Its Potential for an Electrified Aviation Future
2024 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 146, no 7, article id 070901Article in journal (Refereed) Published
Abstract [en]

The emerging need for cost- and energy-efficient propulsion systems have shifted the research interest to radical concepts, with several challenges to overcome in order to enter into service. However, revitalizing old yet provably successful engine designs-a practice followed by engine manufacturers over the years-can provide low-risk alternative solutions to move immediate market demands. The paper reviews this approach, known as concept of growth engines or core commonality, and investigates how a geometrically fixed or geometrically similar engine core can be utilized across a family of engines. The development programs of the highly successful CFM56 and PT6 engine families are analyzed, proving the success of this concept over the years. The idea is based on the engineering paradigm of product families and is briefly presented from a theoretical perspective. Implementation methods and simulation tools to initiate, conceptualize, design, and evaluate an engine family program are reviewed. The potential application of engine core commonality into electrified propulsion systems is investigated. Design challenges and opportunities that electrification imposes to the growth engine concept are discussed. Finally, the concept of growth electrified propulsion systems is introduced, conveying future research directions to achieve a successful family of engines for electrified applications.

Place, publisher, year, edition, pages
American Society of Mechanical Engineers (ASME), 2024
Keywords
CFM56, core commonality, electrification, engine family, engine variant, growth engines, PT6, Electric utilities, Energy efficiency, Cost-efficient, Energy efficient, Engine variants, Growth engine, Propulsion system, Engines
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-66335 (URN)10.1115/1.4063193 (DOI)2-s2.0-85187710513 (Scopus ID)
Note

Article; Export Date: 02 April 2024; Cited By: 0; Correspondence Address: M.D. Kavvalos; Future Energy Center, Mälardalen University (MDU), Västerås, 721 23, Sweden; email: mavroudis.kavvalos@mdu.se; CODEN: JETPE

Available from: 2024-04-02 Created: 2024-04-02 Last updated: 2024-04-02Bibliographically approved
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