Efficiency and Optimal Loading of Contra-Rotating Marine Turbines

2011 ◽  
Author(s):  
Wei Xu ◽  
Spyros A. Kinnas
Keyword(s):  
Output Power ◽  
Maximum Output Power ◽  
Optimization Method ◽  
The Self ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Optimum Ratio ◽  
Line Model ◽  
Performance Effects ◽  
Lifting Line

In this paper, an optimization method is developed for determining the loading on each component, which leads to the maximum efficiency (i.e. maximum output power) of a contra-rotating turbine when subject to uniform inflow. The lifting line model is adopted and both the self-induced velocities and the interaction induced velocities between the front and the back components are included. The optimum ratio of rotational velocities for reducing the torque on support structures and the performance effects of the gap distance between two components are investigated. The optimum distance for two in-line turbines in a turbine farm is also analyzed.

Modeling and Simulation of MPPT-SEPIC Combined Bidirectional Control Inverse KY Converter Using ANFIS in Microgrid System

2016 ◽  
Vol 1 (2) ◽  
pp. 264 ◽  
Author(s):  
Soedibyo Soedibyo ◽  
Farid Dwi Murdianto ◽  
Suyanto Suyanto ◽  
Mochamad Ashari ◽  
Ontoseno Penangsang
Keyword(s):  
Energy Storage ◽  
Output Power ◽  
Distribution System ◽  
Maximum Output Power ◽  
Optimization Method ◽  
Photovoltaic System ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Pv System ◽  
Excess Power

<em>Photovoltaic system (PV) is widely used in various renewable energy application. The main problem of PV system is how to get the maximum output power which is integrated in microgrid system. Furthermore, the redundancy output power generated by on a distribution system should also be considered. This study utilizes the excess power for energy storage using bidirectional of KY inverse</em> <em>converter. Since the DC voltage which generated by PV and the energy storage will be converted into AC voltage using inverter toward load. This paper proposes ANFIS as search optimization method using SEPIC converter with a maximum efficiency of 99.95%</em> to impact to power generation performance  in microgrid system.

Computational Methods for the Design and Prediction of Performance of Tidal Turbines

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Spyros A. Kinnas ◽  
Wei Xu ◽  
Yi-Hsiang Yu ◽  
Lei He
Keyword(s):  
Output Power ◽  
Turbine Blade ◽  
Vortex Lattice ◽  
Design Method ◽  
Maximum Output Power ◽  
Optimization Method ◽  
Speed Ratio ◽  
Maximum Output ◽  
Lattice Method ◽  
Circulation Distribution

A design method based on a lifting line model is developed to determine the optimum radial circulation distribution on a turbine blade, which will produce the maximum output power for a given tip speed ratio and a given number of blades. The resulting optimum circulation distribution is used in order to determine the preliminary shape of the turbine blade. The blade shape is then refined by using an analysis method, based on a vortex-lattice scheme, in combination with a nonlinear optimization method, which determines the blade geometry that will produce the highest output power. Finally, the effect of nonuniform current inflow on the performance of a turbine is also addressed by coupling the vortex-lattice method with a viscous flow solver.

scholarly journals Design and simulate a doherty power amplifier using GaAs technology for telecommunication applications

2019 ◽  
Vol 15 (2) ◽  
pp. 845
Author(s):  
Ehsan Barmala
Keyword(s):  
Output Power ◽  
Power Amplifier ◽  
Power Amplifiers ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Input Power ◽  
Power Divider ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Doherty Power Amplifier

<span>In this paper, a Doherty power amplifier was designed and simulated at 2.4 GHz central frequency which has high efficiency. A Doherty power amplifier is a way to increase the efficiency in the power amplifiers. OMMIC ED02AH technology and PHEMT transistors, which is made of gallium arsenide, have been used in this simulation. The Doherty power amplifier unique feature is its simple structure which is consisting of two parallel power amplifiers and transmission lines. In order to integrate the circuit, the Doherty power transmission amplifier lines were implemented using an inductor and capacitive components. Also, the Wilkinson power divider is used on the chip input. To improve the efficiency, the auxiliary amplifier dimensions is selected enlarge and the further input power is allocated it by the power divider. A parallel R-C circuit has been used at the input of transistors to improve their stability. Simulation results show that the Doherty power amplifier has 17.2 dB output power gain, 23 dBm maximum output power, and its output power P<sub>1dB</sub> =22.6dBm at compression point -1 dB, also, its maximum efficiency is 55.5%.</span>

scholarly journals ANALYSES OF THE THERMAL EFFICIENCY AND THE OUTPUT POWER IN A JOULE-BRAYTON CYCLE

2009 ◽  
Vol 12 (4) ◽  
pp. 39-46
Author(s):  
Kien Chi Le
Keyword(s):  
Output Power ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Pressure Ratio ◽  
Maximum Output Power ◽  
Maximum Temperature ◽  
Maximum Efficiency ◽  
Maximum Output ◽  
Brayton Cycle ◽  
Compressor Inlet

The analyses on Joule-Brayton cycle, which could be used for a high efficiency power generation system, using the temperature and the pressure of compressor have been carried out. As a result, when the ratio of maximum temperature to the minimum temperature in the cycle increased, the thermal efficiency increased. By analyzing the efficiency and the output power, it is understood that the ratio of compressor outlet pressure to the compressor inlet pressure, as well as the pressure ratio across the compressor for maximum thermal efficiency and maximum output power are different. The maximum thermal efficiency could be an important technical parameter; however, the maximum output power is significant in the cost and the size of system. For that reason, depending on the required system for maximum efficiency or for maximum power, the ratio of temperature and pressure are designed

scholarly journals One-Step Preparation of Biochar Electrodes and Their Applications in Sediment Microbial Electrochemical Systems

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 508
Author(s):  
Kui You ◽  
Zihan Zhou ◽  
Chao Gao ◽  
Qiao Yang
Keyword(s):  
Output Power ◽  
Electrode Materials ◽  
Maximum Output Power ◽  
Composite Cathode ◽  
Maximum Output ◽  
Electrochemical Systems ◽  
Composite Cathodes ◽  
One Step ◽  
Microbial Electrochemical Systems ◽  
Hot Melt

Biochar is a kind of carbon-rich material formed by pyrolysis of biomass at high temperature in the absence or limitation of oxygen. It has abundant pore structure and a large surface area, which could be considered the beneficial characteristics for electrodes of microbial electrochemical systems. In this study, reed was used as the raw material of biochar and six biochar-based electrode materials were obtained by three methods, including one-step biochar cathodes (BC 800 and BC 700), biochar/polyethylene composite cathodes (BP 5:5 and BP 6:4), and biochar/polyaniline/hot-melt adhesive composite cathode (BPP 5:1:4 and BPP 4:1:5). The basic physical properties and electrochemical properties of the self-made biochar electrode materials were characterized. Selected biochar-based electrode materials were used as the cathode of sediment microbial electrochemical reactors. The reactor with pure biochar electrode (BC 800) achieves a maximum output power density of 9.15 ± 0.02 mW/m2, which increases the output power by nearly 80% compared with carbon felt. When using a biochar/polyaniline/hot-melt adhesive (BPP 5:1:4) composite cathode, the output power was increased by 2.33 times. Under the premise of ensuring the molding of the material, the higher the content of biochar, the better the electrochemical performance of the electrodes. The treatment of reed powder before pyrolysis is an important factor for the molding of biochar. The one-step molding biochar cathode had satisfactory performance in sediment microbial electrochemical systems. By exploring the biochar-based electrode, waste biomass could be reused, which is beneficial for the environment.

scholarly journals Study of the Properties of a Hybrid Piezoelectric and Electromagnetic Energy Harvester for a Civil Engineering Low-Frequency Sloshing Environment

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Nan Wu ◽  
Yuncheng He ◽  
Jiyang Fu ◽  
Peng Liao
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Civil Engineering ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
Maximum Output ◽  
Piezoelectric Film ◽  
Hybrid Energy ◽  
Level Height

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring.

LD-pumped high-power continuous-wave Pr3+:YLF deep red lasers at 718.5 and 720.8 nm

Laser Physics ◽  
2021 ◽  
Vol 32 (2) ◽  
pp. 025801
Author(s):  
Xiangrui Liu ◽  
Zhuang Li ◽  
Chengkun Shi ◽  
Bo Xiao ◽  
Run Fang ◽  
...  
Keyword(s):  
Output Power ◽  
High Power ◽  
Slope Efficiency ◽  
Laser Emission ◽  
Continuous Wave ◽  
Optical Glass ◽  
Maximum Output Power ◽  
Glass Plate ◽  
Maximum Output ◽  
First Time

Abstract We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF lasers.

Design and Analysis of a High Power Density, Low Temperature Waste Heat Recovery System Using an Oil-Free Turboalternator

2010 ◽  
Author(s):  
James F. Walton ◽  
Andrew Hunsberger ◽  
Hooshang Heshmat
Keyword(s):  
Output Power ◽  
Waste Heat ◽  
Maximum Output Power ◽  
Output Power Level ◽  
Working Fluid ◽  
Prototype System ◽  
Low Grade ◽  
Maximum Output ◽  
Test Results ◽  
Study Results

In this paper the authors will present the design and preliminary test results for a distributed electric generating system that uses renewable energy source for economical load-following and peak-shaving capability in an oil-free, high-speed micro-turboalternator system using compliant foil bearings and a permanent magnet alternator. Test results achieved with the prototype system operating to full speed and under power generating mode will be presented. A comparison between predicted and measured electrical output will also be presented up to a power generating level of 25 kWe at approximately 55,000 rpm. The excellent correlation between design and test provides the basis for scale up to larger power levels. Based upon the turboalternator test results a thermodynamic cycle analysis of a system using low grade waste heat water at approximately 100 C will be reviewed. The tradeoff study results for a series of environmentally friendly refrigerant working fluids will also be presented including sensitivity to vaporization and condensing temperatures. Based on the cycle and pinch point analyses predicted maximum output power was determined. Finally a preliminary turbine design for the selected R134a working fluid was completed. The results of this study show that a net output power level of greater than 40 kW is possible for approximately 240 l/m flow of water at 100C is possible.

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