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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean society for New and Renewable Energy
Journal Basic Information
Journal DOI :
The Korean Society for New and Renewable Energy
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Volume & Issues
Volume 7, Issue 4 - Dec 2011
Volume 7, Issue 3 - Sep 2011
Volume 7, Issue 2 - Jun 2011
Volume 7, Issue 1 - Mar 2011
Selecting the target year
Optimization of Fermentation Conditions for the Ethanol Production from Sweet Sorghum Juice by Saccharomyces cerevisiae using Response Surface Methodolgy
Cha, Young-Lok ; Park, Yu-Ri ; Kim, Jung-Kon ; Choi, Yong-Hwan ; Moon, Youn-Ho ; Bark, Surn-Teh ; An, Gi-Hong ; Koo, Bon-Cheol ; Park, Kwang-Geun ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 3~9
DOI : 10.7849/ksnre.2011.7.4.003
Optimization of initial total sugar concentration of sweet sorghum juice, aeration time and aeration rate on ethanol production was performed by response surface methodology (RSM). The optimum conditions for ethanol production from concentrated sweet sorghum juice were determined as follows: initial total sugar concentration, 21.2 Brix; aeration time, 7.66h; aeration rate, 1.22 vvm. At the optimum conditions, the maximum ethanol yield was predicted to be 91.65% by model prediction. Similarly, 92.98% of ethanol yield was obtained by verification experiment using optimum conditions after 48 h of fermentation. This result was in agreement with the model prediction.
The Sensitivity Comparison of Each Risk Factors Analysis on Renewable Energy and Other Generating Technologies
Koh, Kyung-Ho ; Park, Se-Ik ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 10~17
DOI : 10.7849/ksnre.2011.7.4.010
Recently, electricity industry is facing high market uncertainty which has ever had and which increase risks in power market. In this study, we analyze risk factors such as discount rates, initial investment (overnight cost), plant factor, fuel cost, carbon price, etc, for the perspective of investor. For the analysis of risk factors, we used LCOE method. The results of this study show that renewable energy is more affected by plant factor and overnight cost than other risk factors. First, Renewable energy has higher proportion of overnight cost in the total investment than that of other technologies. Second, renewable energy is free of fuel cost and carbon price so plant factor is the most important factor, in other words, competitiveness of renewable energy depends on plant factor. Furthermore, we conducted economic feasibility of wind power and PV in domestic case study. The minimum requirement condition to get profitability is that plant factor 15% and overnight cost \6,000,000/kW and 26%, \2,200,000/kW for PV and Wind Power, respectively.
Study on Comparison of Global Biofuels Mandates Policy in Transport Sector
Kim, Jae-Kon ; Yim, Eui-Soon ; Jung, Choong-Sub ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 18~29
DOI : 10.7849/ksnre.2011.7.4.018
Biofuls are considered as an option to reduce greenhouse gases emission, increase energy supply diversity and security of supply, as well as an opportunity for job creation and rural development. First of all, biofuls technologies have been promoted as a means for reducing the carbon intensity of the transport sector. Hence, in the last decade biofuels production has been driven by governmental policies. The key instruments widely adopted to foster production and increase consumption have been mandatory blending targets, tax exemptions and sibsidies. As one of the most powerful instruments, biofuel mandates require fuel producers to produce a pre-defined amount (or share) of biofuels and blend them with petroleum fuel. National biofuels mandates are in place 35 countries and partially in place in 6 countries. In this study, we reviewed status of global biofuels policies to reduce greenhouse gases in the European Union, United States and other countires worldwide. Especially, we discussed representative biofuels mandates policies same as Renewable Fuel Standard (RFS, US), Renewable Transport Fules Obligation (RTFO, UK) in transport sector.
Influence of Refrigerant Charge Amount on the Performance of a Water-to-Water Type Ground Source Heat Pump with a Variation of Compressor Speed and Water Flow Rate
Cho, Chan-Yong ; Choi, Jong-Min ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 30~36
DOI : 10.7849/ksnre.2011.7.4.030
The objective of this study is to investigate the effects of the refrigerant charge amount on the performance of a water-to-water ground source heat pump with a variation of compressor speed and the secondary fluid flow rate. The water-to-water ground source heat pump was tested by varying refrigerant charge amount from -40% to 20% of full charge. Compressor speed was changed from 30 Hz to 75 Hz and the secondary fluid flow rate was adjusted from 6 LPM to 14 LPM. For all test conditions, EWTs of an indoor heat exchanger and an outdoor heat exchanger were maintained at standard conditions of ISO 13256-2. The slope of the COP with the variation of charge amount is much steeper at undercharged conditions than that at overcharged conditions. For all compressor speed, the variation of the system performance according to charge amounts showed the similar trends. However, the optimum charge amount of the system increased a little with an increment of compressor speed. When the secondary fluid flow rate decreased, the system was optimized at higher refrigerant charge amount conditions.
A Buoyant Combined Solar-Wave Power Generation and Its Application for Emergency Power Supply of Nuclear Power Plant
Cha, Kyung-Ho ; Kim, Jung-Taek ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 37~41
DOI : 10.7849/ksnre.2011.7.4.037
This paper presents a Combined solar-wave Power Generation (CPG) concept that the CPG unit is maintained as buoyant at the level of sea water and it is also supported by a submerged tunnel, with the aim of supplying emergency electric power during the station blackout events of nuclear power plants. The CPG concept has been motivated from the 2011 Fukushima-Daiichi Accidents due to the loss of both offsite AC power and emergency diesel power caused by natural hazards such as earthquake and tsunami. The CPG is conceptualized by applying different types and different sites for emergency power generation, in order to reduce common cause failures of emergency power suppliers due to natural hazards. Thus, the CPG can provide a new mean for supplying emergency electric power during station blackout events of nuclear power plants. For this application, the CPG requirements are described with a typical configuration at the ocean side of a submerged tunnel.
A Comparative Performance Test for Turbine in Wind Tunnel and Towing Tank
Kang, Jung-Min ; Lee, Yeong-Ho ; Lee, Kyu-Chan ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 42~49
DOI : 10.7849/ksnre.2011.7.4.042
The objective of this paper is to suggest a new method of a wind turbine performance test. The performance test of a wind turbine is generally carried out in a wind tunnel. The test needs not only a high-accuracy measuring system but also durable structure to withstand high speed turbine rotation and wind flow. Therefore, we tried turbine performance test using a towing tank to improve stability and reliability. Because a turbine rotates more slowly and generates more torque in the water than in the wind tunnel under similarity conditions. In this study, we developed turbine performance test systems and verified the turbine test method using a towing tank through comparing results of the wind tunnel and the towing tank test.
Wind Turbine Simulation Program Development using an Aerodynamics Code and a Multi-Body Dynamics Code
Song, Jin-Seop ; Rim, Chae-Whan ; Nam, Yong-Yun ; Bae, Dae-Sung ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 50~57
DOI : 10.7849/ksnre.2011.7.4.050
A wind turbine simulation program for the coupled dynamics of aerodynamics, elasticity, multi-body dynamics and controls of turbine is newly developed by combining an aero-elastic code and a multi-body dynamics code. The aero-elastic code, based on the blade momentum theory and generalized dynamic wake theory, is developed by NREL(National Renewable Energy Laboratory, USA). The multi-body dynamics code is commercial one which is capable of accounting for geometric nonlinearity and twist deflection. A turbulent wind load case is simulated for the NREL 5-MW baseline wind turbine model by the developed program and FAST. As a result, the two results agree well enough to verify the reliability of the developed program.
Characteristics of Filters for Signal Processing Applied to Wind Turbine Controllers
Moon, Seok-Jun ; Shin, Yun-Ho ; Chung, Tae-Young ; Rim, Chae-Whan ; Ryu, Ji-Yune ;
Journal of the Korean society for New and Renewable Energy, volume 7, issue 4, 2011, Pages 58~65
DOI : 10.7849/ksnre.2011.7.4.058
In variable-speed variable-pitch wind turbines, the conventional approach for controlling power-production operation relies on a generator-torque controller and a rotor-collective blade-pitch controller. Both controllers use the generator speed measurement as the sole feedback input. In order to mitigate unwanted excitation of the control system, many filters are adopted. In this study, the characteristics of some filters for signal processing are investigated based on frequency response function. They include low-pass filters, band-pass filters, and notch filters. Especially, this study focuses on design parameters of their filters.