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Thermo-economic analysis of a direct supercritical CO_(2) electric power generation system using geothermal heat

Frontiers in Energy 2022年第2期16卷 246-262页

作者： Xingchao WANG Chunjian PAN Carlos EROMERO Zongliang QIAO Arindam BANERJEE Carlos RUBIO-MAYA Lehua PAN Department of Mechanical Engineering Colorado School of MinesGoldenCO 80401USA National Renewable Energy Laboratory(NREL) GoldenCO 80401USA Energy Research Center Lehigh UniversityBethlehemPA 18015USA Key Laboratory of Energy Thermal Conversion and Control of the Ministry of Education Southeast UniversityNanjing 210096China Department of Mechanical Engineering and Mechanics Lehigh UniversityBethlehemPA 18015USA Mechanical Engineering Universidad Michoacán de San Nicolas de HidalgoMoreliaMichoacán C.P.58030Mexico Energy Geosciences Division Lawrence Berkeley National LaboratoryUniversity of CaliforniaBerkeleyCA 94720USA

A comprehensive thermo-economic model combining a geothermal heat mining system and a direct supercritical CO_(2) turbine expansion electric power generation system was proposed in this *** by this integrated model,thermo-economic and optimization analyses for the key design parameters of the whole system including the geothermal well pattern and operational conditions were performed to obtain a minimal levelized cost of electricity(LCOE).Specifically,in geothermal heat extraction simulation,an integrated wellbore-reservoir system model(T2Well/ECO_(2)N)was used to generate a database for creating a fast,predictive,and compatible geothermal heat mining model by employing a response surface methodology.A parametric study was conducted to demonstrate the impact of turbine discharge pressure,injection and production well distance,CO_(2) injection flowrate,CO_(2) injection temperature,and monitored production well bottom pressure on LCOE,system thermal efficiency,and capital *** was found that for a 100 MWe power plant,a minimal LCOE of$0.177/kWh was achieved for a 20-year steady operation without considering CO_(2) sequestration *** addition,when CO_(2) sequestration credit is$1.00/t,an LCOE breakeven point compared to a conventional geothermal power plant is achieved and a breakpoint for generating electric power generation at no cost was achieved for a sequestration credit of $2.05/t.

关键词： geothermal heat mining supercritical CO_(2) power generation thermo-economic analysis optimization

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Expert consensus for smoking cessation with metaverse in medicine

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Clinical eHealth 2024年 7卷 164-175页

作者： Wu, Lian Xiao, Dan Jiang, Weipen Jian, Zhihao Song, Katherine Yang, Dawei Chavannes, Niels H. Bai, Chunxue Medical Imaging Unitec Institute of Technology New Zealand Concurrent Professor of Fudan University China Chinese- Japanese Freidship Hospital Beijing China Department of Respiratory and Critical Care Medicine Zhongshan Hospital Fudan University China Management Science and Engineering Stanford University United States University of California Los Angeles United States Department of Public Health and Primary Care Leiden University Medical Center Leiden Netherlands Zhongshan Hospital Fudan University International Association for Metaverse in Medicine Chinese Alliance Against Lung Cancer Shanghai Association of Tobacco Control China

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Voltage control of Islanded DC Microgrid Using Hierarchical controllers Based on Kharitonov Theory

Voltage Control of Islanded DC Microgrid Using Hierarchical ...

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IEEE General Meeting Power& Energy Society

作者： Mohammad Javad Najafirad Nima Mahdian Dehkordi Hamidreza Nazaripouya Control Department of Electrical Engineering Faculty Shahid Rajaee Teacher Training University Tehran Iran Winston Chung Global Energy Center University of California Riverside CA USA

In this paper, a new hierarchical robust control approach based on decentralized and distributed schemes is proposed for voltage regulation and power sharing in islanded DC microgrids. In this method, using a decentralized robust PI control structure, the primary voltage control loop is designed based on Kharitonov’s theorem to be robust against uncertainties and disturbances. Then, using a distributed PI robust control, the voltage deviation caused by the droop control is compensated. The simulation results show the effectiveness of the proposed controller under different disturbances by using the MATLAB/SimPowerSystems toolbox. In addition, the proposed controller can increase microgrid reliability due to exchanging low data volume in communication channels.

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Time-Varying Convex Optimization: A Contraction and Equilibrium Tracking Approach

arXiv

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arXiv 2023年

作者： Davydov, Alexander Centorrino, Veronica Gokhale, Anand Russo, Giovanni Bullo, Francesco Center for Control Dynamical Systems and Computation UC Santa Barbara Santa BarbaraCA93106 United States Scuola Superiore Meridionale Naples Italy Department of Information and Electric Engineering and Applied Mathematics University of Salerno Italy

In this article, we provide a novel and broadly-applicable contraction-theoretic approach to continuous-time time-varying convex optimization. For any parameter-dependent contracting dynamics, we show that the tracking error is asymptotically proportional to the rate of change of the parameter and that the proportionality constant is upper bounded by Lipschitz constant in which the parameter appears divided by the contraction rate of the dynamics squared. We additionally establish that augmenting any parameter-dependent contracting dynamics with a feedforward prediction term ensures that the tracking error vanishes exponentially quickly. To apply these results to time-varying convex optimization, we establish the strong infinitesimal contractivity of dynamics solving three canonical problems: monotone inclusions, linear equality-constrained problems, and composite minimization problems. For each case, we derive the sharpest-known contraction rates and provide explicit bounds on the tracking error between solution trajectories and minimizing trajectories. We validate our theoretical results on two numerical examples and on an application to control barrier function-based controller design that involves real hardware. Copyright © 2023, The Authors. All rights reserved.

关键词： Continuous time systems

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Information Processing Factory 2.0 - Self-awareness for Autonomous Collaborative Systems

Information Processing Factory 2.0 - Self-awareness for Auto...

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Design, Automation and Test in Europe Conference and Exhibition

作者： Nora Sperling Alex Bendrick Dominik Stöhrmann Rolf Ernst Bryan Donyanavard Florian Maurer Oliver Lenke Anmol Surhonne Andreas Herkersdorf Walaa Amer Caio Batista de Melo Ping-Xiang Chen Quang Anh Hoang Rachid Karami Biswadip Maity Paul Nikolian Mariam Rakka Dongjoo Seo Saehanseul Yi Minjun Seo Nikil Dutt Fadi Kurdahi Institute of Computer and Network Engineering TU Braunschweig Germany Department of Computer Science San Diego State University School of Computation Information & Technology Technical University of Munich Germany Center for Embedded and Cyber-physical Systems (CECS) University of California Irvine

This paper summarizes the talks of a special session on the IPF 2.0 project, a collaborative German-US research project that leverages self-awareness principles for the self-management of distributed systems of autono...

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Extending the large molecule limit: The role of Fermi resonance in developing a quantum functional group

arXiv

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arXiv 2023年

作者： Zhu, Guo-Zhu Lao, Guanming Dickerson, Claire E. Caram, Justin R. Campbell, Wesley C. Alexandrova, Anastassia N. Hudson, Eric R. Department of Physics and Astronomy University of California Los AngelesCA90095 United States Department of Chemistry and Biochemistry University of California Los AngelesCA90095 United States Center for Quantum Science and Engineering University of California Los AngelesCA90095 United States Challenge Institute for Quantum Computation University of California Los AngelesCA90095 United States

Polyatomic molecules equipped with optical cycling centers (OCCs), enabling continuous photon scattering during optical excitation, are exciting candidates for advancing quantum information science. However, as these molecules grow in size and complexity the interplay of complex vibronic couplings on optical cycling becomes a critical, but relatively unexplored consideration. Here, we present an extensive exploration of Fermi resonances in large OCC-containing molecules, surpassing the constraints of harmonic approximation. High-resolution dispersed laser-induced fluorescence and excitation spectroscopy reveal Fermi resonances in calcium and strontium phenoxides and their derivatives. This resonance manifests as vibrational coupling leading to intensity borrowing by combination bands near optically active harmonic bands. The resulting additional vibration-changing decays require more repumping lasers for effective optical cycling. To mitigate these effects, we explore altering vibrational energy level spacing through substitutions on the phenyl ring or changes in the OCC itself. While the complete elimination of vibrational coupling in complex molecules remains challenging, our findings underscore the potential for significant mitigation, opening new avenues for optimizing optical cycling in large polyatomic molecules. Copyright © 2023, The Authors. All rights reserved.

关键词： Molecules

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Non-Euclidean Contraction Theory for Monotone and Positive Systems

arXiv

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arXiv 2021年

作者： Jafarpour, Saber Davydov, Alexander Bullo, Francesco The Center for Control Dynamical Systems and Computation University of California Santa Barbara93106-5070 United States

In this note we study contractivity of monotone systems and exponential convergence of positive systems using non-Euclidean norms. We first introduce the notion of conic matrix measure as a framework to study stability of monotone and positive systems. We study properties of the conic matrix measures and investigate their connection with weak pairings and standard matrix measures. Using conic matrix measures and weak pairings, we characterize contractivity and incremental stability of monotone systems with respect to non-Euclidean norms. Moreover, we use conic matrix measures to provide sufficient conditions for exponential convergence of positive systems to their equilibria. We show that our framework leads to novel results on (i) the contractivity of excitatory Hopfield neural networks, and (ii) the stability of interconnected systems using non-monotone positive comparison systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Hopfield neural networks

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From contraction theory to fixed point algorithms on Riemannian and non-Euclidean spaces

arXiv

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arXiv 2021年

作者： Bullo, Francesco Cisneros-Velarde, Pedro Davydov, Alexander Jafarpour, Saber Center of Control Dynamical Systems and Computation University of California Santa Barbara93106-5070 United States

The design of fixed point algorithms is at the heart of monotone operator theory, convex analysis, and of many modern optimization problems arising in machine learning and control. This tutorial reviews recent advances in understanding the relationship between Demidovich conditions, one-sided Lipschitz conditions, and contractivity theorems. We review the standard contraction theory on Euclidean spaces as well as little-known results for Riemannian manifolds. Special emphasis is placed on the setting of non-Euclidean norms and the recently introduced weak pairings for the 1 and ∞ norms. We highlight recent results on explicit and implicit fixed point schemes for non-Euclidean contracting systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Machine learning

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Distributionally Robust Optimization via Haar Wavelet Ambiguity Sets

Distributionally Robust Optimization via Haar Wavelet Ambigu...

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IEEE Conference on Decision and control

作者： Dimitris Boskos Jorge Cortés Sonia Martínez Department of Mechanical and Aerospace Engineering Delft Center for Systems and Control TU Delft University of California San Diego

ISBN: (数字)9781665467612

ISBN: (纸本)9781665467629

This paper introduces a spectral parameterization of ambiguity sets to hedge against distributional uncertainty in stochastic optimization problems. We build an ambiguity set of probability densities around a histogram estimator, which is constructed by independent samples from the unknown distribution. The densities in the ambiguity set are determined by bounding the distance between the coefficients of their Haar wavelet expansion and the expansion of the histogram estimator. This representation facilitates the computation of expectations, leading to tractable minimax problems that are linear in the parameters of the ambiguity set, and enables the inclusion of additional constraints that can capture valuable prior information about the unknown distribution.

关键词： Histograms Costs Uncertainty Probabilistic logic Optimization Wavelet coefficients

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ANISOTROPIC ANALYSIS OF VEM FOR TIME-HARMONIC MAXWELL EQUATIONS IN INHOMOGENEOUS MEDIA WITH LOW REGULARITY

arXiv

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arXiv 2023年

作者： Chen, Chunyu Guo, Ruchi Wei, Huayi School of Mathematics and Computational Science Xiangtan University National Center for Applied Mathematics in Hunan Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan411105 China Department of Mathematics University of California IrvineCA92697 United States

It has been extensively studied in the literature that solving Maxwell equations is very sensitive to the mesh structure, space conformity and solution regularity. Roughly speaking, for almost all the methods in the literature, optimal convergence for low-regularity solutions heavily relies on conforming spaces and highly-regular simplicial meshes. This can be a significant limitation for many popular methods based on polytopal meshes in the case of inhomogeneous media, as the discontinuity of electromagnetic parameters can lead to quite low regularity of solutions near media interfaces, and potentially worsened by geometric singularities, making many popular methods based on broken spaces, non-conforming or polytopal meshes particularly challenging to apply. In this article, we present a virtual element method for solving an indefinite time-harmonic Maxwell equation in 2D inhomogeneous media with quite arbitrary polytopal meshes, and the media interface is allowed to have geometric singularity to cause low regularity. There are two key novelties: (i) the proposed method is theoretically guaranteed to achieve robust optimal convergence for solutions with merely Hθ regularity, θ ∈ (1/2, 1];(ii) the polytopal element shape can be highly anisotropic and shrinking, and an explicit formula is established to describe the relationship between the shape regularity and solution regularity. Extensive numerical experiments will be given to demonstrate the effectiveness of the proposed method. Copyright © 2023, The Authors. All rights reserved.

关键词： Maxwell equations

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