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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Solar Energy Society
Journal Basic Information
Journal DOI :
The Korean Solar Energy Society
Editor in Chief :
Volume & Issues
Volume 32, Issue 6 - Dec 2012
Volume 32, Issue 5 - Oct 2012
Volume 32, Issue 4 - Aug 2012
Volume 32, Issue spc3 - Jun 2012
Volume 32, Issue 3 - Jun 2012
Volume 32, Issue 2 - Apr 2012
Volume 32, Issue 1 - Feb 2012
Selecting the target year
An Experimental Study on Relationship Between Temperature Change and Generation Performance of a-Si BIPV Window System
Kim, Bit-Na ; Yoon, Jong-Ho ; Shin, U-Cheul ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 179~184
DOI : 10.7836/kses.2012.32.spc3.179
This research on building Integrated Photovoltaic System replacing windows and doors with amorphous silicon thin film PV windows and doors installing same exact mount on Mock-up. The windows and doors should be installed in different angle and bearing so that we can analyse the amount of electricity from them. The objective of the research is to evaluate and investigate the relationship between factors(intensity of solar radiation, PV window surface temperature, incidence angle, and sky conditions) that affects performance of PV window and performance. The range and method of this research is to establish monitoring system and analysis the data from the monitoring system to evaluate the performance of PV windows that have thin film of solar battery. We should evaluate the insolation according to the position of PV window, output, and surface temperature according to months and seasons so that we can figure out the relationship between these. And we should investigate the relationship between performance and efficiency according to incidence angle and sky condition so that we can figure out the correlation between factors and performance.
Modification of CFD results for Wind Environment in Urban area with Tree Canopy Model
Jung, Su-Hyeon ; Hong, In-Pyo ; Choi, Jong-Kyu ; Song, Doo-Sam ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 185~193
DOI : 10.7836/kses.2012.32.spc3.185
Recently rapid urbanization facilitates development of high-rise building complex including apartment and office building in urban area. Many problems related with high -rise building are reported. Especially, unpleasant strong winds in pedestrian area are frequently encountered around the high-rise building. CFD simulation methods are used to analyze the wind environment of pedestrian level in high-rise building block. However, the results show differences between CFD and measurement. This difference is attributed to improper use of CFD. Conventional CFD simulation for wind environment around high-rise building does not describe the effect of trees, shrubs and plants near ground which affect the wind environment of pedestrian level. Canopy model can be used to reproduce the aerodynamic effects of trees, shrubs and plants near ground. In this paper, CFD simulation methods coupled with the tree canopy model to predict wind environment of pedestrian level in high-rise residential building block were suggested and the validity was analyzed by comparison between measurement and CFD results.
Bow Reduction in Thin Crystalline Silicon Solar Cell with Control of Rear Aluminum Layer Thickness
Baek, Tae-Hyeon ; Hong, Ji-Hwa ; Lim, Kee-Joe ; Kang, Gi-Hwan ; Kang, Min-Gu ; Song, Hee-Eun ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 194~198
DOI : 10.7836/kses.2012.32.spc3.194
Crystalline silicon solar cell remains the major player in the photovoltaic marketplace with 80% of the market, despite the development of various thin film technologies. Silicon's excellent efficiency, stability, material abundance and low toxicity have helped to maintain its position of dominance. However, the cost of silicon materials remains a major barrier to reducing the cost of silicon photovoltaics. Using the crystalline silicon wafer with thinner thickness is the promising way for cost and material reduction in the solar cell production. However, the thinner the silicon wafer is, the worse bow phenomenon is induced. The bow phenomenon is observed when two or more layers of materials with different temperature expansion coefficiencies are in contact, in this case silicon and aluminum. In this paper, the solar cells were fabricated with different thicknesses of Al layer in order to reduce the bow phenomenon. With less amount of paste applications, we observed that the bow could be reduced by up to 40% of the largest value with 120 micron thickness of the wafer even though the conversion efficiency decrease by 0.5% occurred. Since the bowed wafers lead to unacceptable yield losses during the module construction, the reduction of bow is indispensable on thin crystalline silicon solar cell. In this work, we have studied on the counterbalance between the bow and conversion efficiency and also suggest the formation of enough back surface field (BSF) with thinner Al layer application.
A Study on Visual Comfort for Compound Lighting Control Method of Applied Daylighting
Han, Sang-Pil ; Jeon, Yong-Han ; Han, Sang-Chul ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 199~206
DOI : 10.7836/kses.2012.32.spc3.199
The purpose of this study is to understand the change of impression by comparing the uniformity lighting with the compound lighting. In previous study, we proposed a light controlling method to harmonize daylight from a window and artificial lights from a ceiling and obtained the results to support our method. We referred this method as the Adjusted Compound-Lighting Model (AC Model). The experiment is carried out with the scaled-models and mock-up spaces that were supposed to be an office space. One is lit by the uniform lighting and the other by the compound lighting in each experimental space. In order to present varying illuminance distributions, the two variables were used in this study. Subjects were asked to evaluate the point of difference by semantic differential rating on their overall impression after comparing with two rooms. The results showed that the impressions of compound lighting were more positive score than that of uniformity lighting on the items of 'dim-bright', 'dislike-like', 'artificial-natural' and 'closed-open', and that there was no significant difference in impressions between two spaces on other items.
Design and Performance Evaluation of Solar Air Receivers
Cho, Hyun-Seok ; Lee, Hyun-Jin ; Kim, Jong-Kyu ; Lee, Sang-Nam ; Kang, Yong-Heack ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 207~212
DOI : 10.7836/kses.2012.32.spc3.207
It is important to produce the high-temperature and high-pressure air for the concentrated solar power system using the combined cycle. In this paper, we designed two types of tubular receivers to heat up the compressed air and provided their preliminary experimental results for performance evaluation and further improvements. The developed receivers are in a square cavity shape surrounded by flow conduits for easy scale-up and radiation loss reduction. The two receivers were tested with 5 bar air in the KIER solar furnace and evaluated in terms of the outlet temperature and the efficiency.
A Comparative Study on the Thermal Conductivities and Viscosities of the Pure Water and Ethanol Carbon Nanofluids
An, Eoung-Jiw ; Park, Sung-Seek ; Chun, Won-Gee ; Park, Yoon-Chul ; Jeon, Youn-Han ; Kim, Nam-Jin ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 213~219
DOI : 10.7836/kses.2012.32.spc3.213
Nanofluids are advanced concept fluid that solid particles of nanometer size are stably dispersed in fluid likes water, ethylene glycol and others. They have higher thermal conductivities than base fluids. If using this characteristic, efficiencies of heat exchangers can be increased. Therefore in this study, we measured thermal conductivity and viscosity of carbon nanofluids. They were made to ultra sonic dispersed oxidized multi-walled carbon nanotubes(OMWCNTs) in distilled water and ethanol, respectively. The mixture ratios of OMWCNTs were from 0.0005 vol% ~ 0.1 vol%. Thermal conductivity and viscosity was measured by transient hot-wire method and rotational viscometer. The results of an experiment are as in the following: thermal conductivity of the 0.1 vol% pure-water nanofluid improved 7.98% (
), 8.34% (
), and 9.14% (
), and its viscosity increased by 37.08% (
), 33.96% (
) and 21.64% (
) than the base fluids. Thermal conductivity of the 0.1 vol% ethanol nanofluids improved 33.72% (
), 33.14% (
), and 32.25% (
), and its viscosity increased by 35.12% (
), 32.01% (
) and 19.12% (
) than the base fluids.
A Novel Maximum Power Point Tracking Algorithm Considering the partially shaded in PV generating system
Shim, Jae-Hwe ; Choi, Ju-Yeop ; Choy, Ick ; Lee, Sang-Cheol ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 220~227
DOI : 10.7836/kses.2012.32.spc3.220
The maximum power point tracking(MPPT) is important part pf PV generating system, because of nonlinear characteristic of PV array. Many MPPT algorithms have been developed and proposed, but partially shaded in PV generating system, these algorithms can not track maximum power point. This paper explains the partially shaded conditions in the PV generating system and describes a novel new MPPT algorithm. To verify the proposed novel algorithm, PSIM simulation tool is used in this paper, and proper 3kW PV module modeling is made. As a result, the right maximum power point(11PP) of PV PCS can be tracked directly under shading effect for any mismatched condition in solar array.
The Compensation of the Grid Current Distortion caused by the Grid Voltage Unbalance and Distortion for 3-Phase Bi-Directional DC to AC Inverter
Yang, Seung-Dae ; Kim, Seung-Min ; Choi, Ju-Yeop ; Choy, Ick ; Song, Seung-Ho ; Lee, Sang-Cheol ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 228~234
DOI : 10.7836/kses.2012.32.spc3.228
This paper presents the algorithm of the compensation of the grid current distortion caused by the grid voltage unbalance and distortion in 3-phase bi-directional DC to AC inverter. Usually 3-phase grid system has unbalance and distortion because of connecting 1-phase and non-linear load with 3-phase load using same input node. Controlling 3-phase inverter by general method under the unbalanced and distorted grid voltage, the grid current has distortion. This distortion of the grid current cause the grid voltage distortion again. So, it need to control the grid current balanced and non-distorted, even the grid voltage gets unbalanced and distorted. There are some complex method to compensate the gird current distortion. it sugest simple method to solve the problem. PSIM simulation is used to validate the proposed algorithm.
The Design of Controller and Modeling for Bi-directional DC-DC Converter including an Energy Storage System
Kim, Seung-Min ; Yang, Seung-Dae ; Choi, Ju-Yeop ; Choy, Ick ; An, Jin-Woong ; Lee, Sang-Chul ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 235~244
DOI : 10.7836/kses.2012.32.spc3.235
This paper presents a design and simulation of bi-directional DC/DC boost converter for a fuel cell system. In this paper, we analyze the equivalent model of both a boost converter and a buck converter. Also we propose the controller of bi-directional DC-DC converter, which has buck mode of charging a capacitor and boost mode of discharging a capacitor. In order to design a controller, we draw bode plots of the control-to-output transfer function using specific parameters and incorporate proper compensator in a closed loop. As a result, it has increased PM(Phase Margin) for better dynamic performance. The proposed bi-directional DC-DC converter's 3pole-2zero compensation method has been verified with computer simulation and simulation results obtained demonstrates the validity of the proposed control scheme.
Comparative Study between Two-loop and Single-loop Control of DC/DC Converter for PVPCS
Kim, Dong-Hwan ; Jung, Seung-Hwan ; Song, Seung-Ho ; Choi, Ju-Yeop ; Choi, Ick ; An, Jin-Ung ; Lee, Sang-Chul ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 245~254
DOI : 10.7836/kses.2012.32.spc3.245
In photovoltaic system, the characteristics of photovoltaic module such as open circuit voltage and short circuit current will be changed because of cell temperature and solar radiation. Therefore, the boost converter of a PV system connects between the output of photovoltaic system and DC link capacitor of grid connected inverter as controlling duty ratio for maximum power point tracking(MPPT). This paper shows the dynamic characteristics of the boost converter by comparing single-loop and two-loop control algorithm using both analog and digital control. Both proposed compensation methods have been verified with computer simulation to demonstrate the validity of the proposed control schemes.
Output Current DC offset Removal Method for Trans-less PV Inverter
Hong, Ki-Nam ; Choy, Ick ; Choi, Ju-Yeop ; Lee, Sang-Chul ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 255~261
DOI : 10.7836/kses.2012.32.spc3.255
Since PV PCS uses output current sensor for ac output current control, the sensor's sensing value includes unnecessary offset inevitably. If PV inverter is controlled by the included offset value, it's output current will generate DC offset. The DC offset of output current for trans-less PV inverter is fatal to grid, which results in saturating grid side transformer. Usually DSP controller of PV inverter reads several times sensing value during initial operation and, finally, it's average value is used for offset calibration. However, if temperature changes, the offset changes, too. And also, the switch device is not ideal, both each switching element of the voltage drop difference and on & off time delay difference generate DC offset. Thus, to compensate for deadtime and the switch voltage drop, feedback control by output current DC offset should be provided to compensate additional distortion of the output current. The validity of the proposed method is confirmed through PSIM simulation.
Development of an Energy Efficient Tri-Rotor Vertical Take Off and Landing Unmanned Aerial Vehicle
Park, Hee-Jin ; Kong, Dong-Uck ; Son, Byung-Rak ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 262~268
DOI : 10.7836/kses.2012.32.spc3.262
In the recent research technical solutions have been studied to integrate renewable energy into unmanned aerial vehicles to use it as the main power source. As the weight of the aerial vehicle body is essential for its performance, we consider to use light-weight solar cell technology. Furthermore fuel cells are also integrated create a highly energy-efficient aerial robot. In this paper, construction concept and software design of the tilt-rotor aerial vehicle GAORI is introduced which uses solar cells and fuel cells as power source. The future work direction and prognosis are discussed.
The wing structure modeling of the bioinspired aerial robot
Choi, Youn-Ho ; Cho, Nae-Soo ; Joung, Jung-Eun ; Kwon, Woo-Hyen ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 269~274
DOI : 10.7836/kses.2012.32.spc3.269
The research of the biological mimics robot which utilizes the operation of the organism is progressed on the ground, aerial, and underwater robot sector. In the field of flying robot, the research for implementing the wing movement structure of the bird and insect is progressed. The joint structure for the wing movement of the bird is implemented. The operation of the wing is simulated. For this purpose, by using the Matlab/Simulink, the joint structure of the wing is modelled. The joint movement of the wing is tested through the simulation.
Design Optimization of a 500W Fuel Cell Stack Weight for Small Robot Applications
Hwang, S.W. ; Choi, G.H. ; Park, Sam. ; Ench, R. Michael ; Bates, Alex M. ; Lee, S.C. ; Kwon, O.S. ; Lee, D.H. ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 275~281
DOI : 10.7836/kses.2012.32.spc3.275
Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate for energy source of small robot applications. PEMFC has superior in power density and thermodynamic efficiency as compared with the Direct Methaol Fuel Cell (DMFC). Furthermore, PEMFC has lighter weight and smaller size than DMFC which are very important factors as small robot power system. The most significant factor of mobile robots is weight which relates closely with energy consumption and robot operation. This research tried to find optimum specifications in terms of type, number of cell, active area, cooling method, weight, and size. In order to find optimum 500W PEMFC, six options are designed in this paper and studied to reduce total stack weight by applying new materials and design innovations. However, still remaining problems are thermal management, robot space for energy sources, and soon. For a thermal management, design options need to analysis of Computational Fluid Dynamics (CFD) for determining which option has the improved performance and durability.
The study of proton exchange membrane fuel cell and Li-poly battery hybrid system
Kwon, O-Sung ; Lee, Sang-Cheol ; Lee, Sang-Woo ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 282~288
DOI : 10.7836/kses.2012.32.spc3.282
Proton exchange membrane fuel cell (PEMFC) is the most promising energy source for the robot applications because it has unique advantages such as high energy density, no power drop during operating, and easy to make compact size. However, PEMFC has intrinsic disadvantages which are delay to start up and difficulty to correspond drastic load changes. These disadvantages can be compensated by hybrid operating with a Li-poly battery. This study is focus to build and understand the hybrid system for the robot system. In this study, we build the PEMFC hybrid system using EOS-320 PEMFC stack, Li-poly battery and G-Philos FDX1-250BU dc-dc converter. The hybrid system is accurately monitored by CAN and RS485. The system was studied under two conditions such as non-loaded and loaded operating conditions. The results show that the system has delay to start up without hybrid operating and it can be compensated with the hybrid operating.
Load Characteristics of the DC GRID Connected to Small Fuel Cells
Lee, Sang-Woo ; Lee, Sang-Cheol ; Kwon, O-Sung ; Bae, Jun-Hyung ; Park, Tae-Joon ; Kang, Jin-Kyu ; Lee, Dong-Ha ;
Journal of the Korean Solar Energy Society, volume 32, issue spc3, 2012, Pages 289~294
DOI : 10.7836/kses.2012.32.spc3.289
In recent years, understanding the dynamics of DC distribution system has become critically important due mainly to the increasing needs for the interconnection of DC distributed generators and the (DC-based) electric vehicle (EV) charging systems. In this paper, the characteristics of the DC grid system connected to the compact proton exchange membrane fuel cell (PEMFC) has been studied. In particular, the voltage and current transient phenomena were measured by varying the load of the DC grid system. Also, the voltage and current ripple were measured at the different load conditions. Our experimental results clearly manifested that the study contributes to the establishment of fundamental method to characterize the small DC grid system including distributed generation.