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 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>

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.

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.

scholarly journals Thermo-economic optimization of supercritical CO2 Brayton cycle on the design point for application in solar power tower system

2021 ◽  
Vol 242 ◽  
pp. 01002
Author(s):  
Tianye Liu ◽  
Jingze Yang ◽  
Zhen Yang ◽  
Yuanyuan Duan
Keyword(s):  
Ambient Temperature ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Solar Power ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Economic Optimization ◽  
Compressor Inlet ◽  
Solar Power Tower ◽  
Tower System

The supercritical CO2 Brayton cycle integrated with a solar power tower system has the advantages of high efficiency, compact cycle structure, strong scalability, and great power generation potential, which can positively deal with the energy crisis and global warming. The selection and optimization of design points are very important for actual operating situations. In this paper, the thermodynamic and economic models of the 10 MWe supercritical CO2 Brayton cycle for application in solar power tower system are established. Multi-objective optimizations of the simple recuperative cycle, reheating cycle, and recompression cycle at different compressor inlet temperature are completed. The thermal efficiency and the levelized energy cost are selected as the fitness functions. The ranges of the optimal compressor inlet pressure and reheating pressure on the Pareto frontier are analyzed. Finally, multiobjective optimizations and analysis of the supercritical CO2 Brayton cycle at different ambient temperature are carried out. This paper investigates the influence of the compressor inlet temperature and ambient temperature on the thermal efficiency and economic performance of the supercritical CO2 Brayton cycle.

scholarly journals Tandem Solar Cells Based on Cu2O and c-Si Subcells in Parallel Configuration: Numerical Simulation

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Mihai Răzvan Mitroi ◽  
Valerică Ninulescu ◽  
Laurenţiu Fara
Keyword(s):  
Numerical Simulation ◽  
Solar Cells ◽  
Solar Cell ◽  
Output Power ◽  
High Efficiency ◽  
Low Cost ◽  
Maximum Output Power ◽  
Model Parameters ◽  
Maximum Output ◽  
Parallel Configuration

A tandem solar cell consisting of a bottom c-Si high-efficiency subcell and a top low-cost Cu2O subcell in parallel configuration is evaluated for the first time by a use of an electrical model. A numerical simulation based on the single-diode model of the solar cell is performed. The numerical method determines both the model parameters and the parameters of the subcells and tandem from the maximization of output power. The simulations indicate a theoretical limit value of the tandem power conversion efficiency of 31.23% at 298 K. The influence of temperature on the maximum output power is analyzed. This tandem configuration allows a great potential for the development of a new generation of low-cost high-efficiency solar cells.

scholarly journals Modeling, control, and implementation of the soft switching dc-dc converter for battery charging/discharging applications

2017 ◽  
Vol 7 (1.3) ◽  
pp. 104
Author(s):  
J Barsana Banu ◽  
M Balasingh Moses
Keyword(s):  
Output Power ◽  
High Efficiency ◽  
Maximum Output Power ◽  
Power Converter ◽  
Soft Switching ◽  
Maximum Output ◽  
Battery Charging ◽  
Power Semiconductor ◽  
Operating Modes ◽  
Bidirectional Converters

This paper presents a soft switching bidirectional buck-boost converter for battery charging and discharging systems. The proposed method comprises of Inductance Capacitance Diode combination of the bidirectional dc-dc converter with one more electric switch is presented to accomplish high efficiency, high conversion ratio and maximum output power compared to the other bidirectional converters. It works in both steps up and steps down conversions. The proposed converter has alleviated the switching stress problems in the conventional bidirectional dc-dc converter. It suppresses the switching losses by zero voltage and zeroes current turn ON and OFF all switches. The complete steady-state analysis of the proposed bi-directional converter has described with its operating modes. Design consideration of parameters also presented to realize the converter characteristics. The switching stress on the power semiconductor devices is given, and the comparisons between the proposed technique and other bidirectional converters are illustrated with some results. Finally, the experimental prototype of 20 kHz, 315 W output power converter developed, and its feasibility verified through computer simulation results.

Preliminary Experimental Study of Precooler in Supercritical CO2 Brayton Cycle

2015 ◽  
Author(s):  
Seungjoon Baik ◽  
Seong Gu Kim ◽  
Seong Jun Bae ◽  
Yoonhan Ahn ◽  
Jekyoung Lee ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Thermal Efficiency ◽  
High Efficiency ◽  
Power Conversion ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Test Results ◽  
Power Cycle ◽  
Compressor Inlet ◽  
House Design

The supercritical carbon dioxide (S-CO2) Brayton power conversion cycle has been receiving worldwide attention because of high thermal efficiency due to relatively low compression work near the critical point (30.98°C, 7.38MPa) of CO2. The S-CO2 Brayton cycle can achieve high efficiency with simple cycle configuration at moderate turbine inlet temperature (450∼650°C) and relatively high density of S-CO2 makes possible to design compact power conversion cycle. In order to achieve compact cycle layout, a highly compact heat exchanger such as printed circuit heat exchanger (PCHE) is widely used. Since, the cycle thermal efficiency is a strong function of the compressor inlet temperature in the S-CO2 power cycle, the research team at KAIST is focusing on the thermal hydraulic performance of the PCHE as a precooler. The investigation was performed by first developing a PCHE in-house design code named KAIST-HXD. This was followed by constructing the designed PCHE and testing it in the KAIST experimental facility, S-CO2PE. The test results of the PCHE were compared to the test results of a shell and tube type heat exchanger as well.

scholarly journals A Transformer Class E Amplifier

2014 ◽  
Vol 63 (4) ◽  
pp. 621-633 ◽  
Author(s):  
Miroslaw Mikolajewski
Keyword(s):  
Output Power ◽  
High Efficiency ◽  
Supply Voltage ◽  
Maximum Output Power ◽  
Switching Frequency ◽  
Maximum Output ◽  
Theoretical Predictions ◽  
Inductive Component ◽  
Isolation Transformer ◽  
Class E

Abstract In a high-efficiency Class E ZVS resonant amplifier a matching and isolation transformer can replace some or even all inductive components of the amplifier thus simplifying the circuit and reducing its cost. In the paper a theoretical analysis, a design example and its experimental verification for a transformer Class E amplifier are presented. In the experimental amplifier with a transformer as the only inductive component in the circuit high efficiency ηMAX = 0.95 was achieved for supply voltage VI = 36 V, maximum output power POMAX = 100 W and the switching frequency f = 300 kHz. Measured parameters and waveforms showed a good agreement with theoretical predictions. Moreover, the relative bandwidth of the switching frequency was only 19% to obtain output power control from 4.8 W to POMAX with efficiency not less than 0.9 in the regulation range.

scholarly journals Spark ignition engine performance and emissions in a high compression engine using biogas and methane mixtures without knock occurrence

2015 ◽  
Vol 19 (6) ◽  
pp. 1919-1930 ◽  
Author(s):  
Montoya Gómez ◽  
Arrieta Amell ◽  
Lopez Zapata
Keyword(s):  
Output Power ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Combustion Engine ◽  
Maximum Output Power ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Maximum Output ◽  
Engine Operation ◽  
High Compression

With the purpose to use biogas in an internal combustion engine with high compression ratio and in order to get a high output thermal efficiency, this investigation used a diesel engine with a maximum output power 8.5 kW, which was converted to spark ignition mode to use it with gaseous fuels. Three fuels were used: Simulated biogas, biogas enriched with 25% and 50% methane by volume. After conversion, the output power of the engine decreased by 17.64% when using only biogas, where 7 kW was the new maximum output power of the engine. The compression ratio was kept at 15.5:1, and knocking did not occur during engine operation. Output thermal efficiency operating the engine in SI mode with biogas enriched with 50% methane was almost the same compared with the engine running in diesel-biogas dual mode at full load and was greater at part loads. The dependence of the diesel pilot was eliminated when biogas was used in the engine converted in SI mode. The optimum condition of experiment for the engine without knocking was using biogas enriched with 50% methane, with 12 degrees of spark timing advance and equivalence ratio of 0.95, larger output powers and higher values of methane concentration lead the engine to knock operation. The presence of CO2 allows operating engines at high compression ratios with normal combustion conditions. Emissions of nitrogen oxides, carbon monoxide and unburnt methane all in g/kWh decreased when the biogas was enriched with 50% methane.

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