ALBERT

Beschreibung: The integration of renewable wind and pumped storage with thermal power generation allows for dispatch of wind energy by generation companies (GENCOs) interested in participation in energy and ancillary services markets. However, to realize the maximum economic profit, optimal coordination and accounting for reduction in cost for environmental emission are essential. The goal of this study is to develop a simulation model for maximizing economic profit from coordination of renewable wind and pumped storage with thermal power generation for a GENCO with the participation in energy and ancillary services markets with considerations for environmental emission and uncertainty associated with wind power based on a newly developed heuristic optimization algorithm. The simulation results for validation of the heuristic optimization algorithm, as compared with those reported in the literature, show profit improvements of 8.58%–14.53% for uncoordinated and coordinated wind-pumped storage systems. It is determined that for a GENCO with 13 MW wind farm capacity and 1662 MW thermal units, for meeting an average demand of 1129 MW, the utilization of 120 MW pumped storage in a coordinated wind-pumped storage-thermal system results in reduction of environmental emission by 13.54%, which leads to an increase in profit by 2.10%, as compared with operation with no pumped storage unit.

Beschreibung: With the economic integration of the world, the correlation between enterprises does not only include their cooperative and competitive relationships but also involves their mutual relationship in the market. In this paper, a new index, with considering cooperative, competitive as well as market relationships, is proposed to quantify the mutual influence between any two enterprises. Then, the influence index threshold network is built from a new perspective of complex network theory. Focusing on the empirical research by taking China's photovoltaic (PV) industry as an example, the leading enterprises are identified by their k -shell decomposition analysis in conjunction with their nodal degree. In addition, the reasons for some belong to the leading enterprises are explained using random matrix theory. The results show that leading enterprises with core technologies producing basic products, having complete industrial chain, and owning brand products are likely to have prominent positions during the fierce competition. Finally, some suggestions are made to promote the sustainable development of China's PV market.

Beschreibung: An experimental station for marine current power has been installed in a river. The station comprises a vertical axis turbine with a direct-driven permanent magnet synchronous generator. In measurements of steady-state operation in varying flow conditions, performance comparable to that of turbines designed for significantly higher flow speeds is achieved, demonstrating the viability of electricity generation in low speed (below 1.5 m/s) marine currents.

Beschreibung: The wastewater of a petroleum processing facility was used to grow the oleaginous bacterium Rhodococcus opacus PD630 to produce microbial oils. Undiluted wastewater supplemented with molasses (20 g/l) and ammonium chloride (1 g/l) provided a maximum dry biomass concentration of nearly 6 g/l in a 96 h batch culture. The lipid concentration in the bacterial broth exceeded 3 g/l and the lipid content in the dry biomass was nearly 52% by weight. Biomass and oil production were further improved using a 96-h fed-batch fermentation instead of a batch culture. The final biomass concentration exceeded 7.2 g/l and the lipid concentration was nearly 4 g/l. The lipid content of the dry biomass exceeded 54% and the lipid yield on sugars was 0.33 g/g. The lipids were similar to vegetable oils. They contained mainly long chain C16 and C18 fatty acids. Potentially such lipids may be used to replace vegetable oils in production of biodiesel.

Beschreibung: Hot-wire anemometry measurements have been performed in a 3 × 3 wind turbine array to study the multifractality of the turbulent kinetic energy dissipation. A multifractal spectrum and Hurst exponents are determined at nine locations downstream of the hub height, bottom and top tips. Higher multifractality is found at 0.5 D and 1 D downstream of the bottom tip and hub height. The second order of the Hurst exponent and combination factor shows the ability to predict the flow state in terms of its development. Snapshot proper orthogonal decomposition (POD) is used to identify the coherent and incoherent structures and to reconstruct the stochastic velocity signal using a specific number of the POD eigenfunctions. The accumulation of the turbulence kinetic energy in the top tip location exhibits fast convergence compared with the bottom tip and hub height. The dissipation of the large and small scales is determined using the reconstructed stochastic velocities. The higher multifractality is shown in the dissipation of the large scale compared with small scale dissipation showing consistency with the behavior of the original signals. Multifractality of turbulent kinetic energy dissipation in the wind farm is examined and the effect of the reconstructed flow field via proper orthogonal decomposition on the multifractality behavior is investigated. Findings are relevant in wind energy as multifractal parameters identify the variation between the near- and far-wake regions.

Beschreibung: A three-dimensional steady state model of internal reaction and mass transfer has been established for a better understanding of electrochemical performance of zinc-nickel single flow battery (ZNB). Combining with a global kinetic, the model is based on a comprehensive description of mass, momentum, charge for reactions considering the flow between anode and cathode, species transport, and electrochemical reaction between electrodes and electrolyte. This paper emphasizes an internal ion concentration and electrode current density distribution of the ZNB. The effect of channel width and electrolyte flow rate on the electrochemical performance is also studied in the simulation. In addition, the verification of the mathematical model is illustrated by the agreement between the numerical and experimental I–V curves.

Beschreibung: The main objective of this research is to investigate the degree to which variations in mechanical properties of constitutive composite materials can influence the aeroelastic behavior of a wind turbine blade. First, structural behavior of a full-scale wind turbine blade is evaluated from different aspects of bending, torsional and axial rigidities. For this purpose, simplified model of the blade is constructed and it is validated with experimental data of the full-scale blade. Then, a parametric study is performed to determine the most dominant mechanical properties which have a severe impact on the structural behavior of the blade. Identified dominant properties are varied randomly and independently. Thus, stochastic analysis is performed to investigate the variations in natural frequencies of the blade as the governing parameter in defining aeroelastic behavior. Finally, susceptibility of the blade to dynamics instability is also examined. Aeroelastic effects are found to have a stronger effect on the blade with lower material properties that lead to more power reduction.

Beschreibung: An exploration on the grounding characteristic of monopile foundation offshore wind turbines (WTs) is carried out in this paper by using the Grounding System Safe Analysis Software (GSSAS). A basic description is given for the structural feature of the monopile foundation. The discretization model is built for the monopile foundation by subdividing its continuous shell body into a discrete multiconductor system. The simulation computation is performed for analyzing the actual factors influencing the grounding resistance, including the seawater depth, thickness of clay layer, and resistivity of gravel layer. It is found from the simulation computation that the grounding resistance is mainly influenced by the seawater depth. Then, the result obtained from the software GSSAS is also compared with that from the software current distribution, electromagnetic fields, grounding and soil structure analysis for checking the validity of the GSSAS simulation in the exploration of grounding characteristic of offshore WTs.

Beschreibung: The annual average wind speed in more than 80% of the global area that can potentially be employed for onshore wind farm development is lower than 7 m/s. Onshore wind farm development has been accomplished in most regions with excellent wind resource. Based on the increasing need for onshore wind farm development in low-wind-speed sites owing to the effect of environmental factors, commercial demand of IEC-Class III wind turbine has significantly increased among the world's leading developers and wind turbine manufacturers of the wind power industry. Thus, aerodynamic design of a 3 MW wind turbine blade for low-wind-speed sites was performed in this study. The geometry was optimized to improve AEP (Annual Energy Production) and minimize the increasing rate of thrust. The performance analysis result by Blade Element Momentum method showed that the increase in thrust was limited to less than 5% and AEP was enhanced by 20% at annual average wind speed of 7 m/s compared to the reference blade. To verify the final aerodynamic design result, CFD simulation was performed. It was confirmed that AEP was increased by 15%, and the increasing rate of thrust was found to be 5.1% at the same annual average wind speed.

Beschreibung: In this paper, we report the fabrication of broadband antireflection porous nano-network on the glass substrate using the combination of candle soot and HF-based vapor phase etching method. Candle soot layer plays a key role to control the pore size during the etching process. Field emission electron microscopy results showed that the pores have the tapering profile, and the pores size was restricted to the sub-wavelength dimension. Therefore, an excellent broadband antireflection with an enhancement of ∼7% in the maximum total transmittance as compared to plain glass has been achieved. Moreover, reflectance from the etched surface remains quite low (