Energy Engineering - Journal Articles
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Item A fully-coupled analysis of the spar-type floating offshore wind turbine with bionic fractal heave plate under wind-wave excitation conditions(Elsevier Ltd., 2024-08-05) Huang, Haoda; Liu, Qingsong; Iglesias, Gregorio; Yue, Minnan; Miao, Weipao; Ye, Qi; Li, Chun; Yang, Tingting; National Natural Science Foundation of ChinaAs shallow coastal areas for the installation of wind turbines approach saturation, wind turbines will need to be installed in deeper areas, requiring floating rather than seabed-fixed substructures. Considering factors such as economy and safety, floating offshore wind turbines (FOWTs) have become the major focus for offshore wind research and development. In the case of spar-type FOWTs, stability in the heave direction poses a challenge. With this in view, in this work a heave plate with bionic fractal structures is mounted on the bottom of the spar-type FOWT. The bionic fractal heave plates are innovatively proposed to further improve the dynamic response of the FOWT. In this study, the aero-hydro-mooring dynamic method of the FOWT is established to develop a reliable numerical solution model through the DFBI module using computational fluid dynamics software STAR-CCM+. The results of fully-coupled simulations of the original FOWT, the FOWT with heave plate (HP-FOWT) and FOWTs with 3∼5-layer bionic fractal heave plate (3∼5BFHP-FOWTs) are presented. Increases in average thrust and power of 0.44 % and 0.99 %, respectively, prove the optimal aerodynamic responses of the 5 BFHP-FOWT. As for the hydrodynamic responses, the average heave response amplitudes of the HP-FOWT and 3∼5BFHP-FOWTs are significantly lower than the original FOWT. The maximum reduction (25.03 %) is obtained by the 5BFHP-FOWT. The bionic fractal heave plate will slightly reduce the stability of the pitch response. For the standard deviation of the heave, surge, mooring lines 1 and 2 responses, the 5BFHP-FOWT decreases by 17.97 %, 11.44 %, 17.50 %, and 8.25 % respectively, showing the best stability improvement among the HP-FOWT and BFHP-FOWTs. Furthermore, the vortices in the bionic fractal heave plates are analyzed in detail at the Z = ±0.25 m section of the flow field. Only when the specific fractal layer number is 5, the number and curl of the vortices in the fractal structure increase significantly, showing excellent effect of the energy absorption.Item Integrating short term variations of the power system into integrated energy system models: A methodological review(Elsevier Ltd., 2017-03-27) Collins, Seán; Deane, John Paul; Poncelet, Kris; Panos, Evangelos; Pietzcker, Robert C.; Delarue, Erik; Ó Gallachóir, Brian Pádraig; SFI Research Centre for Energy, Climate and Marine; Vlaamse Instelling voor Technologisch OnderzoekIt is anticipated that the decarbonisation of the entire energy system will require the introduction of large shares of variable renewable electricity generation into the power system. Long term integrated energy systems models are useful in improving our understanding of decarbonisation but they struggle to take account of short term variations in the power system associated with increased variable renewable energy penetration. This can oversimplify the ability of power systems to accommodate variable renewables and result in mistaken signals regarding the levels of flexibility required in power systems. Capturing power system impacts of variability within integrated energy system models is challenging due to temporal and technical simplifying assumptions needed to make such models computationally manageable. This paper addresses a gap in the literature by reviewing prominent methodologies that have been applied to address this challenge and the advantages & limitations of each. The methods include soft linking between integrated energy systems models and power systems models and improving the temporal and technical representation of power systems within integrated energy systems models. Each methodology covered approaches the integration of short term variations and assesses the flexibility of the system differently. The strengths, limitations, and applicability of these different methodologies are analysed. This review allows users of integrated energy systems models to select a methodology (or combination of methodologies) to suit their needs. In addition, the analysis identifies remaining gaps and shortcomings.Item SmarTEG: An autonomous wireless sensor node for high accuracy accelerometer-based monitoring(MDPI, 2019-06-19) Magno, Michele; Sigrist, Lukas; Gomez, Andres; Cavigelli, Lukas; Libri, Antonio; Popovici, Emanuel M.; Benini, LucaWe report on a self-sustainable, wireless accelerometer-based system for wear detection in a band saw blade. Due to the combination of low power hardware design, thermal energy harvesting with a small thermoelectric generator (TEG), an ultra-low power wake-up radio, power management and the low complexity algorithm implemented, our solution works perpetually while also achieving high accuracy. The onboard algorithm processes sensor data, extracts features, performs the classification needed for the blade’s wear detection, and sends the report wirelessly. Experimental results in a real-world deployment scenario demonstrate that its accuracy is comparable to state-of-the-art algorithms executed on a PC and show the energy-neutrality of the solution using a small thermoelectric generator to harvest energy. The impact of various low-power techniques implemented on the node is analyzed, highlighting the benefits of onboard processing, the nano-power wake-up radio, and the combination of harvesting and low power design. Finally, accurate in-field energy intake measurements, coupled with simulations, demonstrate that the proposed approach is energy autonomous and can work perpetually.Item Zero carbon energy system pathways for Ireland consistent with the Paris Agreement(Taylor & Francis Group, 2018-04-26) Glynn, James; Gargiulo, Maurizio; Chiodi, Alessandro; Deane, Paul; Rogan, Fionn; Ó Gallachóir, Brian P.; Science Foundation Ireland; Environmental Protection Agency; Sustainable Energy Authority of Ireland; European Regional Development Fund; Higher Education AuthorityThe Paris Agreement is the last hope to keep global temperature rise below 2°C. The consensus agrees to holding the increase in global average temperature to well below 2°C above pre-industrial levels, and to aim for 1.5°C. Each Party’s successive nationally determined contribution (NDC) will represent a progression beyond the party’s then current NDC, and reflect its highest possible ambition. Using Ireland as a test case, we show that increased mitigation ambition is required to meet the Paris Agreement goals in contrast to current EU policy goals of an 80–95% reduction by 2050. For the 1.5°C consistent carbon budgets, the technically feasible scenarios' abatement costs rise to greater than €8,100/tCO2 by 2050. The greatest economic impact is in the short term. Annual GDP growth rates in the period to 2020 reduce from 4% to 2.2% in the 1.5°C scenario. While aiming for net zero emissions beyond 2050, investment decisions in the next 5–10 years are critical to prevent carbon lock-in.