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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Solar Energy Society
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Journal DOI :
The Korean Solar Energy Society
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Volume & Issues
Volume 33, Issue 6 - Dec 2013
Volume 33, Issue 5 - Oct 2013
Volume 33, Issue 4 - Aug 2013
Volume 33, Issue 3 - Jun 2013
Volume 33, Issue 2 - Apr 2013
Volume 33, Issue 1 - Feb 2013
Selecting the target year
Three-Dimensional Computational Flow Analysis on Meteorological-Tower Shading Effect
Rhee, Hui-Nam ; Kim, Tae-Sung ; Jeon, Wan-Ho ; Kim, Hyun-Goo ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 1~6
DOI : 10.7836/kses.2013.33.1.001
It is difficult to avoid measurement errors caused by the shading effect of the meteorological tower, which is used for wind resource assessment according to the IEC Standard. This paper presents a validation of the computational flow analysis results by comparing the results with the wind tunnel experiment conducted for Reynolds numbers in the
range, for the preparation of a database for use in an automatic method of correcting met-tower shading errors. A three-dimensional simulation employing the MP (Modified Production)
turbulence model predicted a wind speed deficit in the wake region according to minimum wind speed ratio, within an MAE (Mean Absolute Error) of 2.4%.
A Study on the Effects of Turbulence to Ultimate Loads Acting on the Blade of Wind Turbine
Hyun, Seung-Gun ; Kim, Keon-Hoon ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 7~14
DOI : 10.7836/kses.2013.33.1.007
This study has analysed the ultimate loads acting on a wind turbine which is operating in a high turbulent flow condition because the ultimate loads are critical factors on the safe design of wind turbine. Since wind flow on the most parts of Korean mountainous are strongly influenced by complex configurations of the topography, turbulence intensity on somewhere is so stronger than an international design standard. For this reason, the characteristics of turbulent wind data collected from actual sites were analyzed and used for the ultimate load evaluation of the wind turbine. With the 270 design load cases on the international standards, the differences of ultimate loads on the wind turbine operating in the standard or high turbulent wind condition are calculated and compared for the an enhanced knowledge of the safe design basis. As are result, it is revealed the specific ultimate loads are strongly affected by the high turbulent wind conditions, thus the characteristics of turbulent flow must be considered during the design of wind turbine.
Performance Evaluation of R435A on Refrigeration System of Water Purifiers
Lee, Yo-Han ; Kang, Dong-Gyu ; Choi, Hyun-Joo ; Jung, Dong-Soo ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 15~23
DOI : 10.7836/kses.2013.33.1.015
In this study, thermodynamic performance of R435A is examined both numerically and experimentally in an effort to replace HFC134a used in the refrigeration system of domestic water purifiers. Even though HFC134a is used predominantly in such a system these days, it needs to be phased out in the near future in Europe and most of the developed countries due to its high global warming potential. To solve this problem, cycle simulation and experimental measurements are carried out with a new refrigerant mixture of 20%R152a/80%RE170 using actual domestic water purifiers. This mixture is numbered and listed as R435A by ASHRAE recently. Test results show that the system performance with R435A is greatly influenced by the amount of charge due to the small internal volume of the refrigeration system of the domestic water purifiers. With the optimum amount of charge of 21 to 22 grams, about 50% of HFC134a, the energy consumption of R435A is 11.8% lower than that of HFC134a. The compressor discharge temperature of R435A
lower than that of HFC134a at the optimum charge. Overall, R435A, a new long term environmentally safe refrigerant, is a good alternative for HFC134a requiring little change in the refrigeration system of the domestic water purifiers.
A Study on Building Energy Demand for Design of Energy System on Green Home Apartment
Park, Jae-Wan ; Yoon, Jong-Ho ; Kwak, Hee-Youl ; Lee, Jae-Bum ; Shin, U-Cheul ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 24~31
DOI : 10.7836/kses.2013.33.1.024
More than 23% of total nation's energy is consumed by residential building and 57.2% of Korean people are living in apartment. This study was carried out to two kind of process. First, after selecting one standard apartment, our research team investigate realistic energy consumption. Second, using 3-dimension heat transfer tool(TRISCO RADICON) and building energy simulation tool(Visual DOE) As a result, amount of heating and hot-water energy is composed of above 80 percent in standard apartment. And, after applying high performance technologies to standard apartment, namely, after being green home apartment, total energy consumption is reduced by54.6 percent. Also, because of energy consumption characteristics of green home apartment, for making more high performance green home apartment, especially, we have to figure out effective method to reduce electric and hot water energy.
Variation of Capacity Factors by Weibull Shape Parameters
Kwon, Il-Han ; Kim, Jin-Han ; Paek, In-Su ; Yoo, Neung-Soo ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 32~39
DOI : 10.7836/kses.2013.33.1.032
Effects of Weibull shape parameter, k, on capacity factors of wind turbines were investigated. Wind distributions with mean wind speeds of 5 m/s, 6 m/s, 7 m/s and 8 m/s were simulated and used to estimate the annual energy productions and capacity factors of a 2MW wind turbine for various Weibull shape parameters. It was found from the study that the capacity factors of wind turbines are much affected by Weibull shape parameters. When the annual mean wind speed at the hub height of a wind turbine was about 7 m/s, and the air density was assumed to be 1.225
, the maximum capacity factor of a 2 MW wind turbine having a rated wind speed of 13 m/s was found to occur with the shape parameter of 2. It was also found that as the mean wind speed increased, the Weibull k parameter which yielded the maximum capacity factor increased. The simulated results were also validated by predictions of capacity factors of wind turbines using wind data measured in complex terrain.
Development of an aerodynamic design program for a small wind turbine blade
Yoon, Jin-Yong ; Paek, In-Su ; Yoo, Neung-Soo ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 40~47
DOI : 10.7836/kses.2013.33.1.040
An aerodynamic design tool was developed for small wind turbine blades based on the blade element momentum theory. The lift and drag coefficients of blades that are needed for aerodynamic blade design were obtained in real time from the Xfoil program developed at University of Illinois. While running, the developed tool automatically accesses the Xfoil program, runs it with proper aerodynamic and airfoil properties, and finally obtains lift and drag coefficients. The obtained aerodynamic coefficients are then used to find out optimal twist angles and chord lengths of the airfoils. The developed tool was used to design a wind turbine blade using low Reynolds number airfoils, SG6040 and SG6043 to have its maximum power coefficient at a specified tip speed ratio. The performance of the blade was verified by a commercial code well known for its prediction accuracies.
A Comparative Study on Heating Energy Consumption of Multi-Family Apartment using EnergyPlus and eQUEST
Park, Doo-Yong ; Yoon, Kap-Chun ; Kim, Kang-So ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 48~56
DOI : 10.7836/kses.2013.33.1.048
Energy consumption analysis of multi-family apartment is an important area of research for the design of energy-saving housing. In this study, we selected a universal type of Flat-type apartments and analyzed the heating energy consumption of variables such as U-value, G-value, infiltration rate, heating setpoint and boiler efficiency with EnergyPlus and eQUEST. With these results, we identify the characteristics of EnergyPlus and eQUEST and provided base data for the design of energy-saving housing. The results indicate that infiltration rate is the most important factors to consider. And eQUEST heating energy consumption is approximately 10% higher compared to the EnergyPlus under same condition.
The Characteristics of Thermal Diffusion With the Vertical-Closed Loop Type Geothermal Heat Exchanger
Sun, Jong-Cheol ; Kim, Byung-Chul ; Koh, Young-Ha ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 57~65
DOI : 10.7836/kses.2013.33.1.057
The temperatures with the ground depth, the positions of circulation water in ground heat exchanger were measured and thermal diffusion characteristics with the distances of the direction normal to the borehole was analysed. The deeper the depth of ground, the less the influences of outdoor temperature, but below 10m of ground, there was no influences of ground temperature. When the depth of trench pipe was below the depth of 2m, there was no influence. In the ground of 10m when the distances between the pipe and the other places were above 0.5m, the variations of temperature were less than
and above 2.5m they were less than
. When the distances of bore hole were above 5m, there were no. influences of the nearest ground heat exchanger.
Thermal Conductive Characteristics and Basic Properties of Bentonite Grouts for the Ground Heat Exchanger of Geo-source Heat Pump
Bai, Kang ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 66~72
DOI : 10.7836/kses.2013.33.1.066
In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.
Preparation and Thermal Characteristics of Hexadecane/xGnP Shape-stabilized Phase Change Material for Thermal Storage Building Materials
Kim, Sug-Hwan ; Jeong, Su-Gwang ; Lim, Jae-Han ; Kim, Su-Min ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 73~78
DOI : 10.7836/kses.2013.33.1.073
Hexadecane and exfoliated graphite nanoplate (xGnP)composite was prepared as a shape-stabilized phase change material (SSPCM) in a vacuum to develope thermal energy storage. The Hexadecane as an organic phase change material (PCM) is very stable against phase separation of PCM and has a melting point at
that is under the thermally comfortable temperature range in buildings. The xGnP is a porous carbon nanotube material with high thermal conductivity. Scanning electron microscope (SEM) and Fourier transformation infrared spectrophotometer (FT-IR)were used to confirm the chemical and physical stability of Hexadecane/xGnP SSPCM. In addition, thermal properties were determined by Deferential scanning calorimeter(DSC) and Thermogravimetric analysis (TGA). The specific heat of Hexadecane/xGnPSSPCM was
. The melting temperature range of melting and freezing were found to be
. At this time, the laten heats of melting and freezing were 96.4J/g and 94.8J/g. The Hexadecane was impregnated into xGnP as much about 48.8% of Hexadecane/xGnP SSPCM's mass fraction.
A Study on the Optimization of a Renewable Energy System in Fire Station Buildings
Lee, Yong-Ho ; Hong, Jun-Ho ; Cho, Young-Hum ; Hwang, Jung-Ha ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 79~88
DOI : 10.7836/kses.2013.33.1.079
This study set out to evaluate the economy, environmentality, and complexity (economy+environmentality) of fire station buildings of public service facilities and propose ways to apply the optimization of renewable energy system to fire station buildings. As for economy according to life cycle costs, economy increased when the application percentage of the geothermal and solar heat system increased over the three renewable energy system types (geothermal, solar heat, and solar photovoltaic). On the other hand, economy decreased when the application percentage of the solar photovoltaic system increased. As for environmentality according to tons of carbon dioxide, environmentality decreased when the application percentage of the geothermal and solar heat system increased. Environmentality increased when the application percentage of the solar photovoltaic system increased. As for complexity (economy+environmentality) according to the weighted coefficient method, complexity increased when the application percentage of the geothermal system increased. It was highest at the combination of the solar heat system (20%) and geothermal system (80%). On the other hand, complexity decreased when the application percentage of the solar photovoltaic system increased. It was lowest at the combination of the solar photovoltaic system (80%) and geothermal system (20%).
Evaluation Study of a Double Blind Light Pipe Daylighting System Efficiency and an Illumination Energy Reduction
Kang, Eun-Chul ; Yoo, Seong-Yeon ; Lee, Euy-Joon ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 89~95
DOI : 10.7836/kses.2013.33.1.089
A DBLP(Double blind light pipe) daylight system can be installed at a building exterior wall or roof to replace artificial light during the day time. This system was consisted of a double blind light collector, a mirror duct type light transformer and a prism light pipe distributor. The double blinds were used to track the sun's altitude and azimuth movements to collect the sunlight throughout the day. The sunlight collected by the light collector was reflected on the first mirror and the second mirror and sent to the light pipe through the light transformer. The transformer was designed to deliver the sunlight into the light pipe efficiently. The light distributor plays a role in diffusing the sunlight coming in through the light collector to be used for indoor lighting. In this paper, a DBLP system has been designed, installed and tested at a KIER daylighting twin test cell. The DBLP daylighting system was applied to the experimental test cell which has an indoor area of 2.0 m wide
2.4 m height
3.8 m length. The experiment was conducted from January 30 to February 27, 2012, under clear skies and partially cloudy skies. Data was collected from 10:00 am to 16:00 pm every 2 minute and the average was calculated for every 30 minute of the data collection to obtain the system efficiency. The results indicated that the DBLP system efficiency was evaluated as 11.67%. The DBLP system indoor illumination energy reduction was predicted as 0.822 kWh/day. This could replace 4 sets of a 32W fluorescent lamp operating 6.4 hours per a day.
An Analysis of Heating and Cooling Energy Cost according to Building Type of Apartment Complex
Roh, Ji-Woon ;
Journal of the Korean Solar Energy Society, volume 33, issue 1, 2013, Pages 96~105
DOI : 10.7836/kses.2013.33.1.096
This study aims to investigate the energy performance of apartment in respect of complex design, building type and generation house layout and finally to produce the guide line for energy saving design. To grasp the present condition and problem about this subject, apartment building types were examined and representative types were extracted. Considering azimuth angle, private area, and generation number, building type of the subject apartment was classified in detail, energy simulation was conducted, and the effect to energy cost was compared. In the research, using VE energy simulation program, the heating and cooling load were calculated and converted to energy cost. It is expected that this analysed results will be basic data for the more integrated study. Research consequence can be summarized as follow: 1) Energy cost is compared according to several azimuth in plank '一' type apartment. As the results, calculated gas cost is the best in
, but total cost is in
. 2) Apartment buildings of tower types are compared, it is resulted that 'Y' type (azimuth
) is the best in gas cost, but the total cost is worst because of high cooling load.