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Performance analysis of deep borehole heat exchangers for decarbonization of heating systems

Deep Underground Science and engineering 2024年第3期3卷 349-357页

作者： Andreas E.D.Lund Department of Electrical Engineering and Automation Aalto UniversityEspooFinland

Meeting the climate change mitigation targets will require a substantial shift from fossil to clean fuels in the heating *** pumps with deep borehole exchangers are a promising solution to reduce *** the thermal behavior of deep borehole exchangers(DBHEs)ranging from 1 to 2 km was analyzed for various heat flow profiles.A strong correlation between thermal energy extraction and power output from DBHEs was found,also influenced by the heating profile *** operating time over the year typically resulted in higher energy production,while shorter one yielded higher average thermal power output,highlighting the importance of the choice of heating strategy and system design for optimal performance of *** breaks in operation for regenerating the borehole,for example,with waste heat,proved to be favorable for the performance yielding an overall heat output close to the same as with continuous extraction of *** results demonstrate the usefulness of deep boreholes for dense urban areas with less available *** the heat production from a single DBHE in Finnish conditions ranges from half up to even a few GWh a year,the technology is best suitable for larger heat loads.

关键词： clean energy deep borehole exchangers energy transition geothermal heat ground-coupled heat pump

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In-Plane AlN-Based Actuator: Toward a New Generation of Piezoelectric MEMS

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ADVANCED ELECTRONIC MATERIALS 2023年第12期9卷

作者： Bespalova, Kristina Nieminen, Tarmo Gabrelian, Artem Ross, Glenn Paulasto-Krockel, Mervi School of Electrical Engineering Department of Electrical Engineering and Automation Aalto University Tietotie 3 Espoo 02150 Finland

A novel design that utilizes aluminum nitride (AlN) piezoelectric thin films deposited on vertical surfaces for lateral motion and sensing is a step toward emerging multi-axial microelectromechanical systems (MEMS). This work demonstrates the fabrication process and potential applications of an in-plane moving piezoactuator. The actuator is excited using the inverse piezoelectric effect of the AlN thin film grown on the vertical surfaces of a Si cantilever. Lateral motion of the actuator is enabled when a voltage is applied between the top and bottom electrodes of the device, which are highly doped Si and titanium nitride thin film. The motion of the actuator is captured using scanning electron microscope.

关键词： aluminum nitride in-plane motion MEMS piezoelectric thin films

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A new technique for fault diagnosis in transformer insulating oil based on infrared spectroscopy measurements

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High Voltage 2024年第2期9卷 319-335页

作者： Mohamed M.F.Darwish Mohamed H.A.Hassan Nagat M.K.Abdel-Gawad Matti Lehtonen Diaa-Eldin A.Mansour Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland Department of Electrical Power Engineering Egypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityEgypt Department of Electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical *** gas analysis(DGA)is frequently used for this ***,DGA lacks the necessary level of accuracy to identify all equipment faults,particularly in their initial stages of ***,it does not have the capability for real-time monitoring and relies on manual sampling and laboratory testing,causing potential delays in fault ***,the interpretation of DGA data necessitates specialised expertise,which may pose difficulties for smaller entities that have limited access to ***,the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating *** inception faults that were considered in this study were the electrical fault(discharges of high energy)and the thermal fault(300°C

关键词： fault diagnosis spectroscopy

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Risk-Sensitive Filtering under False Data Injection Attacks

Risk-Sensitive Filtering under False Data Injection Attacks

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2024 IEEE International Conference on Multisensor Fusion and Integration for Intelligent Systems, MFI 2024

作者： Kumar, Kundan Iqbal, Muhammad Sarkka, Simo Aalto University Department of Electrical Engineering and Automation Finland

ISBN: (纸本)9798350368031

This paper addresses a risk-sensitive remote estimation problem for cyber-physical systems (CPSs) where the accurate model of a dynamic system is not completely known or may differ from the assumed model. In CPSs, sensors and the monitoring control center are remotely located. Sensors transmit the measurements via unreliable wireless communication channels that are vulnerable to cyber-attacks. Specifically, attackers can inject false data to alter the measurements in the communication channel or attack sensors. To tackle this, we design a risk-sensitive filtering algorithm to operate under false data injection attacks. The proposed estimator aims to minimize the risk-sensitive error criterion, defined as the expectation of the accumulated exponential quadratic error. Simulation results demonstrate the effectiveness of the proposed algorithm. © 2024 IEEE.

关键词： Cyber attacks

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Dynamic Response Analysis of Alkaline and PEM Electrolyzers in Low-Inertia Power Systems: A Comparative Study 24

Dynamic Response Analysis of Alkaline and PEM Electrolyzers ...

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24th EEEIC International Conference on Environment and electrical engineering and 8th I and CPS Industrial and Commercial Power Systems Europe, EEEIC/I and CPS Europe 2024

作者： Tofighi-Milani, Mahyar Fattaheian-Dehkordi, Sajjad Lehtonen, Matti Aalto University Department of Electrical Engineering and Automation Espoo Finland

ISBN: (纸本)9798350355185

In modern power systems, the increased integration of intermittent renewable energies has led to heightened uncertainty and low inertia challenges. Current investments in green hydrogen provides the opportunity of addressing these issues, which not only aid in smoothing renewable energy curves but also help manage low inertia issues in the power system. This paper focuses on modeling two similar plants for Alkaline (ALK) and Proton Exchange Membrane (PEM) electrolyzers, along with their respective power-electronics interfaces for grid connection. The dynamic responses of these plants are analyzed within a low-inertia power system, and a PID controller is implemented to control the frequency response in the presence of the electrolyzers. Simulation results conducted on the IEEE 30-bus test system demonstrate a superior dynamic response of PEM electrolyzers compared to ALK electrolyzers, observed from both power and frequency response perspectives. The results show that the fast response of PEM electrolyzers positions them as a more capable solution for Fast Frequency Response (FFR) services in power systems. © 2024 IEEE.

关键词： Power system analysis

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Printed Energy Harvesting Electrodes: Sustainable Power Solutions for Batteryless Smart Diapers

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SN Computer Science 2025年第4期6卷 1-10页

作者： Tanweer, Muhammad Sepponen, Raimo Tanzer, I. Oguz Halonen, Kari Department of Electronics and Nanoengineering Aalto University Espoo 02150 Finland Department of Automation and Electrical Engineering Aalto University Espoo 02150 Finland

Amid the rapid expansion of internet-of-things (IoT) devices, one of the most significant challenges is how to power these wireless sensor nodes adopting sustainable and environment-friendly solutions as the conventional batteries are inadequate to meet the power demands of the vast IoT ecosystem. Recent years have witnessed remarkable advancements in IoT sensor electronics, particularly in wearable biomedical devices. Innovative approaches have emerged to design energy-optimized electronic systems, opening the door to batteryless applications through energy harvesting techniques. In this study, a novel energy harvesting solution is proposed by designing sustainable energy harvesting electrodes, leveraging the capabilities of printed electronics technology. These electrodes are engineered directly on diaper back sheets to harvest green energy from urine with the ultimate goal of powering energy-efficient wearable IoT sensor nodes for batteryless smart diapers. The study encompasses a comprehensive characterization of these sustainable harvesting electrodes, involving experiments conducted within a controlled laboratory environment employing both in-jar and in-diaper deployment. The results demonstrate the great promise of continuously powering the IoT sensor nodes overnight to have batteryless smart diaper operations. This research highlights a significant stride towards addressing the power challenges of the ever-expanding IoT ecosystem. © The Author(s) 2025.

关键词： Batteryless IoT sensor nodes Energy harvesting Green electronics Printed electronics Smart diaper Wearable biomedical devices

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Seasonal Dynamics in Energy Cost Optimization of Commercial Buildings with Integrated Photovoltaic and Battery Storage Systems

Seasonal Dynamics in Energy Cost Optimization of Commercial ...

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2024 IEEE PES Innovative Smart Grid Technologies Europe Conference, ISGT EUROPE 2024

作者： Fatima, Samar Jokinen, Ilkka Puvi, Verner Lehtonen, Matti Pourakbari-Kasmaei, Mahdi Aalto University Department of Electrical Engineering and Automation Espoo Finland

ISBN: (纸本)9789531842976

This paper presents an energy management system (EMS) for commercial customers in southern Finland, equipped with photovoltaic (PV), battery energy storage systems (BESS), and electric vehicles (EVs). The model manages EV charging schedules and explores vehicle-to-grid (V2G) dynamics, effectively reducing energy procurement costs and accommodating seasonal variations. The energy management problem is implemented in GAMS as a mixed-integer linear programming model that utilizes real load, PV generation, EV driving patterns, and temperature variation across various seasons. Moreover, the customer's BESS is investigated to explore the export potential in an urban environment under a significantly high load demand. Results show percentage cost savings for three customers at 3.46%, 4.07%, and 9.26%, with export potential up to 878 kW, 757 kW, and 428 kW, respectively, highlighting the benefits of renewable sources and storage systems for energy management in similar large-scale facilities. © 2024 IEEE.

关键词： Sales

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Wind Farm Capacity Assessment for Hydrogen Production: A Case Study in Finland

Wind Farm Capacity Assessment for Hydrogen Production: A Cas...

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2024 IEEE PES Innovative Smart Grid Technologies Europe Conference, ISGT EUROPE 2024

作者： Salehi, Amin Pourakbari-Kasmaei, Mahdi Aalto University Department of Electrical Engineering and Automation Espoo Finland

ISBN: (纸本)9789531842976

Renewable energy-based generations are steadily playing a pivotal role in the global energy supply, and power-togas (P2G) technologies are recognized as a viable option for storing the excess power generated by renewable energy sources. In this context, hydrogen is one of the several potential alternative fuels produced by P2G equipment, and its favorable environmental effects make it a suitable option. Motivated by the aforementioned facts, this paper assesses wind farm capacity in Finland as a key driver for hydrogen production. To this end, an interconnected power and hydrogen network considering various scenarios in 2030 and 2040 is designed and implemented in SAInt. Subsequently, factors such as electrolyzer efficiency and geographical data are incorporated into the model to shed light on the critical role of wind farm infrastructure in facilitating Finland's transition, considering hydrogen as an extension of energy systems. Detailed simulations and assessments indicate a significant need in developing wind farm infrastructures in Finland. As a result of this development, Finland will be positioned as a major player in the emerging hydrogen market across Europe. Moreover, it can be traced that improving electrolyzer efficiency would be an imperative action for manufacturers, given that this enhancement could significantly reduce the investment costs associated with wind turbines' installation. © 2024 IEEE.

关键词： Capacity assessment Electrolyzer efficiency Hydrogen network Power grid Wind farm

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Evaluating transient behaviour of large-scale photovoltaic systems during lightning events using enhanced finite difference time domain method with variable cell size approach

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High Voltage 2024年第3期9卷 636-647页

作者： Ibrahim Hetita Diaa-Eldin A.Mansour Yang Han Ping Yang Congling Wang Mohamed M.F.Darwish Matti Lehtonen Amr S.Zalhaf School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China(UESTC)ChengduChina Electrical Power and Machines Engineering Department Faculty of EngineeringHelwan UniversityCairoEgypt Electrical Power and Machines Engineering Department Faculty of EngineeringTanta UniversityTantaEgypt Department of Electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and TechnologyAlexandriaEgypt Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland

Photovoltaic(PV)arrays are usually installed in open areas;hence,they are vulnerable to lightning strikes that can result in cell degradation,complete damage,service disruption,and increased maintenance *** a result,it is imperative to develop an effective and efficient lightning protection system by evaluating the transient behaviour of PV arrays during lightning *** aim is to evaluate the transient analysis of large-scale PV systems when subjected to lightning strikes using the finite difference time domain(FDTD)*** overvoltages are calculated at various points within the mounting *** optimise the FDTD method's execution time and make it more suitable for less powerful hardware,a variable cell size approach is ***,larger cell dimensions are used in the earthing system and smaller cell dimensions are used in the mounting *** FDTD method is utilised to calculate the temporal variation of transient overvoltages for large-scale PV systems under different scenarios,including variations in the striking point,soil resistivity,and the presence of a metal *** results indicate that the highest transient overvoltages occur at the striking point,and these values increase with the presence of a PV metal frame as well as with higher soil ***,a comparison is performed between the overvoltage results obtained from the FDTD approach and the partial element equivalent circuit(PEEC)method at the four corner points of the mounting systems to demonstrate the superior accuracy of the FDTD ***,a laboratory experiment is conducted on a small-scale PV system to validate the simulation *** calculated overvoltages obtained from the FDTD and PEEC methods are compared with the measured values,yielding a mean absolute error of 5%and 11%for the FDTD and PEEC methods,respectively,thereby confirming the accuracy of the FDTD simulation model.

关键词： transient behaviour finite

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Nash Equilibrium Seeking of Monotone N-Coalition Games

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Journal of Systems Science & Complexity 2025年第2期38卷 874-901页

作者： SUN Chao CHEN Bo WANG Jianzheng HU Guoqiang School of Electrical and Electronic Engineering Nanyang Technological University Department of Automation Zhejiang University of Technology

This study aims to solve the Nash equilibrium(NE) seeking problem for monotone N-coalition games. The authors assume that the gradient mapping of the game is monotone but not necessarily strictly or strongly monotone. Such a merely monotone assumption presents significant challenges to NE seeking, since the basic gradient descent method may fail to converge. The authors start with a regularization-based projected gradient dynamical system in a general non-cooperative game framework and analyze the convergence of the dynamics under different scenarios. Then, the authors develop NE seeking algorithms for monotone N-coalition games with undirected and connected inner-coalition communication graphs. Asymptotic convergence to the least-norm NE is proven. The convergence rate of the algorithm for an analytic mapping is provided. Furthermore, the authors propose a novel regularization-based dynamical system that allows different parameters among the coalitions. Rigorous analysis and a numerical example are provided to illustrate the effectiveness of the proposed method.

关键词： Cooperation and competition N-coalition game Nash equilibrium seeking regularization

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