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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 8, Issue 4 - Dec 2012
Volume 8, Issue 3 - Sep 2012
Volume 8, Issue 2 - Jun 2012
Volume 8, Issue 1 - Mar 2012
Selecting the target year
Unsteady Internal Flow Analysis of a Cathode Air Blower Used for Fuel Cell System
Jang, Choon-Man ; Lee, Jong-Sung ;
Journal of the Korean society for New and Renewable Energy, volume 8, issue 3, 2012, Pages 6~13
DOI : 10.7849/ksnre.2012.8.3.006
This paper describes unsteady internal flow characteristics of a cathode air blower, used for the 1 kW fuel cell system. The cathode air blower considered in the present study is a diaphragm type blower. To analyze the flow field inside the diaphragm cavity, compressible unsteady numerical simulation is performed. Moving mesh system is applied to the numerical analysis for describing the volume change of the diaphragm cavity in time. Throughout a numerical simulation by modeling the inlet and outlet valves in a diaphragm cavity, unsteady nature of an internal flow is successfully analyzed. Variations of mass flow rate, force and pressure on the lower moving plate of a diaphragm cavity are evaluated in time. The computed mass flow rate at the same pressure and rotating frequency of a motor has a maximum of 5 percent error with the experimental data. It is found that flow pattern at the suction process is more complex compared to that at the discharge process. Unsteady nature of internal flow in the cathode air blower is analyzed in detail.
Neural PID Based MPPT Algorithm for Photovoltaic Generator System
Park, Ji-Ho ; Cho, Hyun-Cheol ; Kim, Dong-Wan ;
Journal of the Korean society for New and Renewable Energy, volume 8, issue 3, 2012, Pages 14~22
DOI : 10.7849/ksnre.2012.8.3.014
Performance of photovoltaic (PV) generator systems relies on its operating conditions. Maximum power extracted from PV generators depends strongly on solar irradiation, load impedance, and ambient temperature. A most maximum power point tracking (MPPT) algorithm is based on a perturb and observe method and an incremental conductance method. It is well known the latter is better in terms of dynamics and tracking characteristics under condition of rapidly changing solar irradiation. However, in case of digital implementation, the latter has some error for determining a maximum power point. This paper presents a PID based MPPT algorithm for such PV systems. We use neural network technique for determining PID parameters by online learning approach. And we construct a boost converter to regulate the output voltage from PV generator system. Computer simulation is carried out to evaluate the proposed MPPT method and we accomplish comparative study with a perturb and observe based MPPT method to prove its superiority.
Estimation of LCOE for Korean PV Projects : For the Ones that Financial Investors Participated in
Kim, Young-Kyung ; Chang, Byung-Man ;
Journal of the Korean society for New and Renewable Energy, volume 8, issue 3, 2012, Pages 23~29
DOI : 10.7849/ksnre.2012.8.3.023
LCOE of 11 Korean PV projects, total capacity of 44 MW, were calculated for each project being larger than 1 MW respectively. 9 out of 11 projects were constructed in 2008 under FIT scheme revealed that average LCOE is 600 Korean Won per kilowatt-hour and it becomes reduced to 348 Korean Won per kilowatt-hour for 2 projects that are constructed under RPS scheme in 2012. During the period between 2008 and 2012, installation cost per megawatt became 55% of 2008 value with operation and maintenance cost lowered to 80% while LCOE became only 58% due to reduced project size and lower irradiation for later projects. However, it is found that the ratio of LCOE / unit installation cost looks relatively constant, so that it can be used as an auxiliary parameter to gauge learning effect of BOS portion of a PV project.
An Analysis of the Competitiveness of Renewable Energy Technologies
Koo, Ki-Kwan ; Lee, Deok-Ki ; Hong, Jong-Chul ; Park, Soo-Uk ;
Journal of the Korean society for New and Renewable Energy, volume 8, issue 3, 2012, Pages 30~37
DOI : 10.7849/ksnre.2012.8.3.030
In this study, we studied solar cell and fuel cell. To estimate the technology competitiveness, we used patent analysis using patent information and delphi method. For patent analysis, PII indicating the impact of patent was used. Also to analysis PII, citations data of registered and published patent were used from 2001 through 2010 in the United States, Japan, South Korea and the European Patent Office. And the delphi method results of the 'International trend analysis on the Green Energy Technology and the establishment of international cooperation models(2009)' were cited to estimate the technology level. According to the analysis results, Korea's patent registration growth rate was fairly high, but the patent impact and technology levels were significantly lower than in the United States, Japan and Germany. Especially in the solar cell, United States's PII is 1.8, but Korea's PII is 0.2. And the technology level of United States is 7 to 8, but Korea's is 5 to 6. Therefore, to improve technology competitiveness, Korea need to enhance the core technology R&D, and set up the consumer-oriented R&D strategy for commercialization from R&D planning phase. In this study, we analysed competitiveness of renewable energy which is not actively discussed. But there are limitations of the study because we used the result of past research and patent data in the past 10 years. Therefore to accurate research the period of patent data should be extended. Finally diverse indicators for measuring the technology competitiveness should be researched and developed.
Development of Project Management System for Geothermal Well Construction
Kim, Kwang-Yeom ; Lee, Seung-Soo ;
Journal of the Korean society for New and Renewable Energy, volume 8, issue 3, 2012, Pages 38~46
DOI : 10.7849/ksnre.2012.8.3.038
Enhanced Geothermal System (EGS) among geothermal system types enables to produce sustainable energy even in non-volcanic region while conventional geothermal energy has been restricted to obtain only from hot and permeable formation such as in volcanic regions. Successful EGS project in terms of economy, however, can be expected only when the project is managed effectively considering most of influencing factors (e.g., tangible and intangible resources, cost, time, risks, etc.). In particular, well construction is of the utmost importance in geothermal project as it dominantly influences on time and cost in the whole project. Therefore, when it comes to viable geothermal project without abundant experience, managing drilling economically and efficiently is inevitable. In this study, a project management system for well construction in geothermal project based on project control system including work breakdown structure and cost account was developed to predict and assess the performance of drilling and to visualize the progress.