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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.

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

Although pneumatic actuators are widely used in industry, they have two major weaknesses—nonlinearities associated with compressibility of air and low energy efficiency The former limits its applicability whenever accurate positioning is required, and the latter has a negative impact on users through increased energy costs This paper addresses these issues with the aim of developing a widely applicable servo control strategy, which combines improved tracking accuracy and energy efficiency A detailed actuator system model is linearized through nonlinear input–output feedback linearization, and the energy optimal velocity profile is derived Simulation and experimental studies indicate that energy efficiency improvements of 3–7% are possible, while tracking accuracy can be ensured The method is suitable for real-time implementation and is cost effective; it requires the implementation of an improved velocity profile, while hardware components do not need to be altered

Energy Optimal Control of Servo-Pneumatic Cylinders Through Nonlinear Static Feedback Linearization

Half of the global final energy consumption is related to heat, which accounts for 40% of global energy-related carbon emissions. Particularly in the UK, nearly 24 million end-users rely on gas boilers to provide heat, leading to 37% of the country’s carbon emissions. Quick and successful heat decarbonisation is critical if ambitious climate goals need to be met by the mid-21st century. Heat pumps have been recognised as a key solution to reduce carbon emissions. This would instead draw carbon-reduced electricity from the electrical grid to produce heat more efficiently. Reciprocatively, the potential flexibility offered by the growing adoption of heat pumps on a (gigawatt) scale could also potentially support the deep decarbonisation of power and reduce the costs involved in the power system balancing and upgrades. By reviewing the technical development and barriers to creating high-efficiency and high-flexibility heat pumps, this study discusses how heat pumps could support the decarbonisation of heat and power with a focus on the UK system and market, which is also useful to countries in which heating is currently relying on fossil fuels. The major hurdle that mitigates the use of heat pumps – the high cost involved – and the methods to improve the economics of the technology are also discussed. If these techno-economic challenges can be overcome, electrification of heat using heat pumps could provide a route towards decarbonising heat and power and give the two communities and industries a collaborative way of tackling climate change at the root.

Development of efficient, flexible and affordable heat pumps for supporting heat and power decarbonisation in the UK and beyond: Review and perspectives

The paper presents a mathematical model for vane-type air motors with arbitrary number of vanes. The paper starts from the working principles of the air motor and modeling approach. Then the mechanical geometry structure of air motors is analyzed in order to derive a generic mathematical description of the air motor. A complete dynamic process of the air motor system is derived based on the mechanical structure, orifice and other physics theory. The simulation results are presented with a typical set of air motor parameters. Due to the nature of the motor structure, the chamber volume changes are discontinuous which leads to discontinuous chamber pressure variations. The characteristics of the discontinuity present difficulties for applying advanced control theory to air motor control. Therefore, further approximations are carried out and the comparison of dynamic responses between the original model and the approximated model indicated that the approximation is accurate enough to be acceptable for control strategy development.

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Development of a mathematical model for vane-type air motors with arbitrary N vanes

Networked control system is a research area where the theory is behind practice. Closing the feedback loop through shared network induces time delay and some of the data could be lost. So the network induced time delay and data loss are inevitable in networked control Systems. The time delay may degrade the performance of control systems or even worse lead to system instability. Once the structure of a networked control system is confirmed, it is essential to identify the maximum time delay allowed for maintaining the system stability which, in turn, is also associated with the process of controller design. Some studies reported methods for estimating the maximum time delay allowed for maintaining system stability; however, most of the reported methods are normally overcomplicated for practical applications. A method based on the finite difference approximation is proposed in this paper for estimating the maximum time delay tolerance, which has a simple structure and is easy to apply.

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Stability and Time Delay Tolerance Analysis Approach for Networked Control Systems

For homogeneous charge compression ignition (HCCI) combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware-in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation (EGR) from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.

Jihong Wang

Papers

Energy Optimal Control of Servo-Pneumatic Cylinders Through Nonlinear Static Feedback Linearization

Development of efficient, flexible and affordable heat pumps for supporting heat and power decarbonisation in the UK and beyond: Review and perspectives

Development of a mathematical model for vane-type air motors with arbitrary N vanes

Stability and Time Delay Tolerance Analysis Approach for Networked Control Systems

Real-time control oriented HCCI engine cycle-to-cycle dynamic modelling