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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
Power Quality Control of Wind/Diesel Hybrid Power Systems Using Fuzzy PI Controller
Yang, Su-Hyung ; Ko, Jung-Min ; Boo, Chang-Jin ; Kang, Min-Jae ; Kim, Jeong-Uk ; Kim, Ho-Chan ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 1~10
DOI : 10.7836/kses.2012.32.5.001
This paper proposes a modeling and controller design approach for a wind-diesel hybrid system including dump load. Wind turbine depends on nature such as wind speed. It causes power fluctuations of wind turbine. Excessive power fluctuation at stand-alone power grid is even worse than large-scale power grid. The proposed control scheme for power quality is fuzzy PI controller. This controller has advantages of PI and fuzzy controller. The proposed model is carried out by using Matlab/Simulink simulation program. In the simulation study, the proposed controller is compared with a conventional PI controller. Simulation results show that the proposed controller is more effective against disturbances caused by wind speed and load variation than the PI controller, and thus it contributes to a better quality wind-diesel hybrid power system.
Performance Prediction of a Hot Water Supply and Panel Heating System with Solar Energy
Han, Yuri ; Park, Youn Cheol ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 11~17
DOI : 10.7836/kses.2012.32.5.011
In this study, a simulation program was developed with heat transfer model in the thermal storage tank for a solar collector and burner combined heating and hot water supply system. Analysis was conducted with variation of operating condition and schedule to analyze performance of a hot water supply and panel heating system with a solar collector and burner combined thermal storage tank. The simulation program is divided two sections. One part is calculation of temperature variation of water which flows through the panel in the floor for heating of the residential house during 24 hours, and the other part is heat transfer calculation for the reaction time to get desired water temperature in the thermal storage tank. As results, light oil consumption and system performance during operation period were analyzed with variation of climate condition and with or without solar collector. Most of the case, oil could be saved about from 24 to 41% with installing the solar collector. The performance of the system is more dependent on radiation time of the solar collector rather than the intensity of the solar radiation which was adopted for the climate analysis.
The Basic Study on the Ripple Effect of Industrial & Technological Policy for New & Renewable Energy
Kim, Jeongbae ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 18~24
DOI : 10.7836/kses.2012.32.5.018
This study is to propose the quantitative methods instead of total results on New & Renewable energy R&D investments. To do that, this study used KETEP R&D investment profile, National R&D investment profile, and ISTANS industrial census results. From the analysis, this study firstly showed that the R&D investment on New&Renewable energy is higher than that of other industrial parts. And the investment increase ratio on New&Renewable energy is also very higher during past 10 years. And finally showed that the ripple effects(relatively the employee number, the amount of sales, and the amount of export) of the focus energy group including feul cell, photovoltaic, and wind power was higher than those of general manufacturing industry. This approach was firstly conducted using the poor census results, so other analysis methods will be developed and performed to exact;y show the investment ripple effect.
Heating Performance Analysis of Building Integrated Geothermal System With Radiant Floor Heating
Jin, Shangzhen ; Lee, Jin-Uk ; Kim, Taeyeon ; Leigh, Seung-Bok ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 25~30
DOI : 10.7836/kses.2012.32.5.025
Ground source heat pumps(GSHPs) are among the most efficient and comfortable heating and cooling technologies currently available, because they use the earth's natural heat to provide heating, cooling, and often, water heating. And Building Integrated Geothermal System(BIGS) is one of GSHPs which install ground heat exchanger(GHE) in energy pile without borehole to save the investment cost. Therefore, the experiment is to evaluate the heating performance of BIGS in Korea. The experimental results indicate that the average heat pump COP and overall system's COP values are approximately 4.4 and 3.0 in one week. This study shows that the BIGS could be used for heating in Korea.
Control System Design of NREL 5MW Wind Turbine
Nam, Yoonsu ; Im, Changhee ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 31~40
DOI : 10.7836/kses.2012.32.5.031
This paper introduces a methodology for NREL 5MW wind turbine, which is the variable speed and variable pitch(VSVP) control system. This control strategy maximizes the power extraction capability from the wind in the low wind speed region and regulates the wind turbine power as the rated one for the high wind speed region. Also, pitch control efficiency is raised by using pitch scheduling.Torque schedule is made of torque table depending on the rotor speed. Torque control is used for vertical region in a torque-rotor speed chart. In addition to these, mechanical loads reduction using a drive train damper and exclusion zone on a torque schedule is tried. The NREL 5MW wind turbine control strategy is comprised by the generator torque and blade pitch control. Finally, proposed control system is verified through GH Bladed simulation.
Design of Heliostat Field for 200kW Tower Type Solar Thermal Power Plant
Park, Young Chil ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 41~51
DOI : 10.7836/kses.2012.32.5.041
Heliostat field is the most important subsystem in the tower type solar thermal power plant since its optical performance affects the total system efficiency most significantly while the construction cost of it is the major part of total construction cost in such a power plant. Thus a well designed heliostat field to maximize the optical efficiency as well as to minimize the land usage is very important. This work presents methodology, procedures and result of heliostat filed design for 200kW solar thermal power plant built recently in Daegu, Korea. A
rectangular shaped receiver located at 43(m) high and tilted
toward heliostat field, 450 of heliostats of which the reflective surface is formed by 4 of
flat plate mirror facet, and the land area having about
size are used to form the heliostat field. A procedure to deploy 450 heliostats in radial staggered nonblocking formation is developed. Also the procedures to compute the cosine effect, intercept ratio, blocking and shading ratio in the field are developed. Finally the heliostat filed is designed by finding the optimal radial distance and azimuthal spacing in radial staggered nonblocking formation such that the designed heliostat field optical efficiency could be maximized. The designed heliostat field has 77% of annual average optical efficiency, which is obtained by annually averaging the optical efficiencies computed between the time of where sun elevation angle becomes
after sunrise and the time of where sun elevation angle becomes
before sunset in each day.
A Feasibility Study for the Application of the Cold-heat Storage System Considering the Real Operation Status of the Showcase
Lee, Dong-Won ; Kim, Jeongbae ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 52~58
DOI : 10.7836/kses.2012.32.5.052
Experimental study was performed to understand the real operation conditions of a showcase working usually in a convenient store and discount store. The purpose of this study was to show the possibility for practical use of cold-heat storage systems being operated for the showcase. To do that, evaporator and condenser temperatures were measured and the compressor electric power consumption were measured simultaneously. To use the ice storage system, the ice making process was typically operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was subcooled using the stored cold-heat after being discharged from the condenser during daytime. So, the cooling performance was increased with the sub-cooling of refrigerant during daytime,hence the actual running time of the compressor could be effectively decreased. Through the experiments, this study showed that the compressor electric power consumption during daytime could be transferred to nighttime for applying the refrigerant sub-cooling. So, for the convenient store, the maximum load transfer rates for each working cooler and showcase were estimated about 31.1% and 19.9% respectively. And for the discount store, the maximum load transfer rates for each refrigeration and freezing showcase were estimated about 34.1% and 49.0% respectively.
The Development and Performance Analysis of Compact Type Solar Thermal/Ground Coupled Heat Pump Hybrid System for Heating, Cooling and Hot water
Baek, Nam-Choon ; Jeong, Seon-Yeong ; Yoon, Eung-Sang ; Lee, Kyoung-Ho ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 59~67
DOI : 10.7836/kses.2012.32.5.059
In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.
Analysis of Soil Thermal Conductivities, Borehole Thermal Resistances and Initial Soil Temperature with In-Situ Testing in South Korea
Ro, Jeong-Geun ; Yon, Kwangseok ; Song, Heon ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 68~74
DOI : 10.7836/kses.2012.32.5.068
Investigation of the effective soil thermal conductivity(
) is the first step in designing the ground loop heat exchanger(borehole) of a geothermal heat pump system. Another important factor is the borehole thermal resistance(
). Thermal response tests offer a good method to determine the ground thermal properties for the total heat transport in the ground. The first step is measured for initial soil temperature. This is done by supplying a only pump power into a borehole heat exchanger. They need to supply into water unload heat power more than 30 minutes. In this study, the initial soil temperature was found to analysis
,the ratio was 68.7% represented. In this case of
, was 2.1~3.0
. In this work, it is also shown that the distribution of a soil thermal conductivity and borehole thermal resistance were on the influence of initial soil temperature. And soil thermal conductivity was related with factors of equation by linear least square method, borehole thermal resistance was on the influence of composite factors.
An Analysis of Problems and the Current Status of Renewable Energy System in Buildings
Jang, Hyang-In ; Seong, Yoon-Bok ; Cho, Young-Hum ; Kim, Yong-Shik ; Jo, Jae-Hun ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 75~82
DOI : 10.7836/kses.2012.32.5.075
This study aims to investigate the usage of the renewable energy systems installed in buildings and make suggestions for the effective management. In this regard, a questionnaire survey was conducted on 1)design and construction, 2) operation and management, 3) user satisfaction and improvements about the renewable energy systems in buildings. Findings from this study can be summarized as follows; a lack of the basic information about systems, non-use of energy management systems, the differences in the features by energy source, and a lack of expertise of managers. The requirements to resolved these problems include the integrated management of various electric heat sources including a renewable energy source, an operation schedule based on the prediction of production and consumption, and so on. Furthermore the necessity of multiplex energy sources management system was confirmed and the basic data needed to establish the targets of this system were obtained.
Comparison Study on Thermal Environment Characteristics in Each Region and the Seasons of Summer and Winter Through Air Temperature Analysis in Urban Areas
Choi, Dong-Ho ; Lee, Bu-Yong ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 83~93
DOI : 10.7836/kses.2012.32.5.083
This study is to perform the effect of urbanization in urban and suburban districts, and to identify regional characters of climate according to the analysis of slope at rise, and descent of temperature and globe temperature, correlation between seasonal temperature analysis, and calculation of degree hour. According to this study, the result is summarized as follows. (1) The average temperature, rated from high to low, consists of residential area, Daegu weather station, intracity, green belt, water-front green belt, and suburban. (2) At the rise and descent of temperature, the result of the slope change of in each point may be one of the useful indexes to be able to perform the regional unique thermal characteristic, including the seasonal urbanization. (3) Although there is a difference between the surface of the earth and ambient environment. The result of the correlation of temperature between summer and winter is that temperature slope in urban districts was higher than in suburban districts, and the difference of slope was unvaried among the four observations in the same city region. (4) To show objectively, regional thermal characteristics in urban and suburban districts, the exponentiation of winter degree hour and summer degree hours were checked. The result of the exponentiation is that the more artificial a region, the lower index.
Wind Resource Assessment for Green Island - Dokdo
Kim, Hyun-Goo ; Kim, Keon-Hoon ; Kang, Young-Heaok ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 94~101
DOI : 10.7836/kses.2012.32.5.094
A Dokdo wind resource map has been drawn up for the Green Island Energy Master Plan according to Korea's national vision for 'Low Carbon Green Growth'. The micro-siting software WindSim v5.1,which is based on Computational Flow Analysis, is used with MERRA reanalysis data as synoptic climatology input data, and sensitivity analysis on turbulence model is accompanied. A wind resource assessment has been conducted for the Dokdo wind power dissemination plan, which consists of two 10kW wind turbines to be installed at the Dongdo dock and Dokdo guard building. It is evaluated that the capacity factors at Dongdo dock and Dokdo guard building are about 20% and 30% respectively, and annual and hourly variations of wind power generation have been analyzed, but summertime energy production is predicted to be only 40% of wintertime energy production.
Equipment Manufacturing of Lamp Heating to Fabricate Selective Emitter Silicon Solar Cell
Han, Kyu-Min ; Choi, Sung Jin ; Lee, Hi-Deok ; Song, Hee-Eun ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 102~107
DOI : 10.7836/kses.2012.32.5.102
Halogen lamp was applied to fabricate the selective emitter crystalline silicon solar cell. In selective emitter structure, the recombination of minority carriers is reduced with heavily doped emitter under metal grid, consequently improving the conversion efficiency. Laser selective emitter process which is recently used the most generally induces the damage on the silicon surface. However the lamp has enough heat to form heavily doped emitter layer by diffusing phosphorus from PSG without surface damage. In this work, we have studied to find the design and the suitable condition for halogen lamp such as power, time, temperature and figured out the possibility to fabricate the selective emitter silicon solar cell by lamp heating. The sheet resistance with
was lower to
after halogen lamp treatment. Heat transfer to lightly doped emitter region was blocked by using the shadow mask.
A Study on the Improvement of Scoring System by Issues as well as Criteria in the Green Building Certification System for Office Building
Mo, Hye-Ran ; Moon, Mi-Seon ; Haan, Chan-Hoon ; Tae, Choon-Seob ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 108~117
DOI : 10.7836/kses.2012.32.5.108
The purpose of Green Building Certification System is to promote the environment-friendly building construction as the life-cycle environmental performance of a certain building is assessed and certified nationally(domestically). By the way, a building can get the green building certificate just with the minimum standard in prerequisite assessment criteria and with the designated scores in totals. GBCS consists of 9 assessment issues and it has 4 grades. Nevertheless the 1st. grade green building has uneven scores in each issue. In other words, it has even 0 point in a special issue. Due to the above problem, the discrimination and reliability in the GBCS grading and scoring has to be secured. This study aims at a new grading and scoring system equipped with the discrimination and reliability through analysing the scores of prerequisite assessment criteria and the scores by issues in the actually certified green office buildings.
Analysis on a Dynamic Model with One Dimension in Water Transportation of PEM Fuel Cell
Bakhtiar, Agung ; Hong, Boo-Pyo ; You, Jin-Kwang ; Kim, Young-Bok ; Yoon, Jung-In ; Choi, Kwang-Hwan ;
Journal of the Korean Solar Energy Society, volume 32, issue 5, 2012, Pages 118~123
DOI : 10.7836/kses.2012.32.5.118
Water balance has a significant impact on the overall fuel cell performance. Maintenance of proper water management should provide an adequate membrane hydration and avoidance of water flooding in the catalyst layer and gas diffusion layer. Considering the important of advanced water management in PEM fuel cell, this study proposes a simple one dimensional water transportation model of PEM fuel cell for use in a dynamic condition. The model has been created by assumption that the output is the water liquid saturation difference. The liquid saturation change is the total difference between the additional water and the removal water on the system. The water addition is obtained from fuel cell reaction and the electro osmotic drag. The water removal is obtained from capillary transport and evaporation process. The result shows that the capillary water transport of low temperature fuel cell is high because the evaporation rate is low.