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비만아 부모의 돌봄 경험: q 방법론

Overview of current development in electrical energy storage technologies and the application potential in power system operation

Hydrogen energy, economy and storage: Review and recommendation

Blockchains or distributed ledgers are an emerging technology that has drawn considerable interest from energy supply firms, startups, technology developers, financial institutions, national governments and the academic community. Numerous sources coming from these backgrounds identify blockchains as having the potential to bring significant benefits and innovation. Blockchains promise transparent, tamper-proof and secure systems that can enable novel business solutions, especially when combined with smart contracts. This work provides a comprehensive overview of fundamental principles that underpin blockchain technologies, such as system architectures and distributed consensus algorithms. Next, we focus on blockchain solutions for the energy industry and inform the state-of-the-art by thoroughly reviewing the literature and current business cases. To our knowledge, this is one of the first academic, peer-reviewed works to provide a systematic review of blockchain activities and initiatives in the energy sector. Our study reviews 140 blockchain research projects and startups from which we construct a map of the potential and relevance of blockchains for energy applications. These initiatives were systematically classified into different groups according to the field of activity, implementation platform and consensus strategy used. 1 Opportunities, potential challenges and limitations for a number of use cases are discussed, ranging from emerging peer-to-peer (P2P) energy trading and Internet of Things (IoT) applications, to decentralised marketplaces, electric vehicle charging and e-mobility. For each of these use cases, our contribution is twofold: first, in identifying the technical challenges that blockchain technology can solve for that application as well as its potential drawbacks, and second in briefly presenting the research and industrial projects and startups that are currently applying blockchain technology to that area. The paper ends with a discussion of challenges and market barriers the technology needs to overcome to get past the hype phase, prove its commercial viability and finally be adopted in the mainstream.

/pdf/blockchain-technology-in-the-energy-sector-a-systematic-24t1ywmkp0.pdf

Blockchain technology in the energy sector: A systematic review of challenges and opportunities

Maximum power point tracking (MPPT) control of pressure retarded osmosis (PRO) salinity power plant: Development and comparison of different techniques

To improve the wind power and photovoltaic power accommodation rate and reduce the power system operation costs, this paper considers thermal power units, price-based demand response (DR) and battery energy storage system (BESS) as scheduling resources and establishes an optimization scheduling model based on source, load and energy storage coordination. A two stages optimization method is proposed in order to minimize the system operational costs including thermal power units operation cost, wind power and photovoltaic power curtailment cost and price-based DR scheduling costs. The first stage optimization uses binary particle swarm optimization algorithm (BPSO) to minimize the sum of wind power and photovoltaic power curtailment cost and thermal power units start-up cost. Based on the optimization results at the first stage, the second stage optimization uses double layers' continuous particle swarm optimization (CPSO) algorithm to minimize the sum of price-based DR scheduling cost and fuel consumption cost. The simulation results verify the feasibility and effectiveness of this optimization scheduling model.

Optimization scheduling model based on source-load-energy storage coordination in power systems

A novel phase-locked loop (PLL) with simple structure is proposed in the present work for three-phase power converters under adverse grid conditions. Based on a synchronous rotating frame PLL (SRF-PLL), multi-resonant harmonic compensators with the ability of accommodating frequency deviations are employed in the feedback path of a pre-filter. As a result, the negative-sequence component and harmonic distortions of grid voltage can be attenuated. Different from existing methods, only classical regulators are used, avoiding complicated networks for the decoupling of unbalance and harmonics and thus greatly simplifying the control algorithm. The proposed method is analysed and designed in both the continuous s-domain and discrete z-domain, whereby stable, fast, accurate, and robust responses are achieved. Simulation results have been obtained to show the improved performance of the proposed PLL compared with two widely used methods.

Novel PLL for power converters under unbalanced and distorted grid conditions

The growing number of vehicles on the road has led to a rapid increase in fuel consumption and toxic gas emissions, so the challenges in fuel efficiency improvement and reduction of CO2 and NOx emissions have always been on the top agenda of the automotive industry. The paper presents a feasibility study of recovering the low-pressure exhaust gas energy via by-pass connection of a scroll expander to the engine system exhaust. The paper starts with the description of the proposed new exhaust energy recycling scheme and the mathematical modelling of the system. A feasibility study is carried out to investigate whether this new scheme can work with the engine operation conditions specified by the engine test data. The initial study indicated that the scroll expander structure needs to be modified; otherwise, it cannot be used for exhaust energy recovery. The experimental test and simulation results presented in this paper indicate that it is feasible to recover the low-pressure exhaust gas energy using a scroll expander with a modified structure. The proposed energy recovery system has the potential to produce over 400 W power output with over 90% of engine exhaust flow recycling.

https://www.mdpi.com/1996-1073/9/4/231/pdf

Feasibility Study of a Scroll Expander for Recycling Low-Pressure Exhaust Gas Energy from a Vehicle Gasoline Engine System

Energy efficiency and dynamic performance are key factors to drives, which, however, will be deteriorated by air leakage between the air pockets and friction distributions to the pneumatic drives. This paper presents a novel magnetic scroll expander, aiming at improving the typical scroll expander performance and energy efficiency especially when the expander operates at low compressed air pressures. The mathematical model of the proposed magnetic scroll expander is developed. ANSYS Maxwell software is employed to analyse the generalised magnetic field strength and magnetic forces/torque. The development of a prototype of magnetic scroll expander is described. From the initial study, it shows that the proposed magnetic scroll expander has potential in improving scroll expander's energy conversion efficiency.

Xing Luo

Papers

Maximum power point tracking (MPPT) control of pressure retarded osmosis (PRO) salinity power plant: Development and comparison of different techniques

Optimization scheduling model based on source-load-energy storage coordination in power systems

Novel PLL for power converters under unbalanced and distorted grid conditions

Feasibility Study of a Scroll Expander for Recycling Low-Pressure Exhaust Gas Energy from a Vehicle Gasoline Engine System

A novel magnetic scroll expander as a drive for electricity generation