• Research Article

    A Study on the Development Direction of the Renewable Energy Carbon Certification System: Focused on Analysis of International Trade Policy and the Dispute Cases Related to Environmental Labeling

    재생에너지 탄소인증제도의 개발 방향성에 관한 연구 : 국제무역규범 및 환경라벨링 관련 무역 분쟁사례분석을 중심으로

    Sang Min-Kyung, Han Sung-Ae , Park Sun-Hyo

    상민경, 한성애, 박선효

    With the adoption of the Paris Agreement, a new climate regime is intensifying the global interest in reducing greenhouse gas emissions. In ... + READ MORE
    With the adoption of the Paris Agreement, a new climate regime is intensifying the global interest in reducing greenhouse gas emissions. In the meantime, Korea is preparing to introduce a new renewable energy carbon certification system in order to activate the use of renewable energy and to reduce carbon emissions in the entire life cycle of manufacturing and disposal of renewable energy facilities. Therefore, this study aims to identify the implications for the introduction of the carbon certification system and to establish a theoretical basis for the system design by examining the status of overseas carbon certification, international trade norms and trade disputes. As a result, carbon emissions certification is being implemented in developed countries such as EU, UK, France, USA and Japan, but only France, Germany and EU have adopted carbon certification for renewable energy sector. The analysis of the WTO TBT Agreement and GATT also confirmed the possibility of a violation of the international trade rules of the carbon certification system and derived nine international technical standards related to carbon certification. Finally, by examining the case of trade disputes related to environmental labeling, the minimum requirements to be considered at the institutional design stage were drawn to eliminate the possibility of trade disputes. - COLLAPSE
    December 2019
  • Research Article

    Electric Circuit Analysis for PV Array on Short-Circuit Failure of Bypass Diode in PV Module

    PV모듈의 바이패스 다이오드 단락 고장 시 태양광어레이 회로 특성분석

    Lee Chung-Geun, Shin Woo-Gyun, Lim Jong Rok, Hwang Hye-Mi, Ju Young-Chul, Jung Young-Seok, Kang Gi-Hwan, Chang Hyo-Sik, Ko Suk-Whan

    이충근, 신우균, 임종록, 황혜미, 주영철, 정영석, 강기환, 장효식, 고석환

    As the installation of photovoltaic systems increases, fire accidents of PV system grow every year. Most of PV system fires have been ... + READ MORE
    As the installation of photovoltaic systems increases, fire accidents of PV system grow every year. Most of PV system fires have been reported to be caused by electrical components. The majority of fire accidents occurred in combiner box, which is presumed to be short-circuit accidents due to dustproof and waterproof failures or heat deterioration of blocking diode. For this reason, the blocking diode installation became optional by revised PV combiner regulation. In this paper, according to the revised regulation, reverse current that generated by voltage mismatch was measured and analyzed in PV array without a blocking diode. The factors that cause voltage mismatch in array are assumed to be shaded PV module and short circuit failure of bypass diode. As the result of experiment, there is no reverse current to flow under shading condition in module, but reverse current flows on the failure of bypass diode in module. According to the module’s I-V characteristic curve analysis, open voltage was slightly reduced due to operation of bypass diode in shading. However, it showed that open circuit voltage has decreased significantly in the failure of bypass diode. This indicates that the difference in open voltage reduction of voltage mismatch factor causes reverse current to flow. - COLLAPSE
    December 2019
  • Research Article

    Study on Development of Inducing Airflow Duct System for Kitchen Hood Using Ejector Method

    이젝터 기술을 활용한 주방후드용 기류유인 덕트 시스템의 개발에 관한 연구

    Son,Yu-Ra, Hong,Seong-Gyu, Yang,Jeong-Hoon

    손유라, 홍성규, 양정훈

    Kitchen hoods are limited in discharging all contaminants produced during cooking. Contaminants that have not been discharged can rise to the upper ... + READ MORE
    Kitchen hoods are limited in discharging all contaminants produced during cooking. Contaminants that have not been discharged can rise to the upper part of the kitchen and become stacked. To solve this problem, there is a way to increase the air volume of the kitchen hood, but there are limits, so a new system is required. This study proposes the Duct System (IADK : Inducing Airflow Duct system for Kitchen hood )through 3D printers and experiments. To do this, the pressure is measured to verify the three levels of air volume provided by the kitchen hood. To check the degree of loss of flow in the existing kitchen hood system, install flexible ducts alone to measure the pressure. Change the internal diameter and type of connection of the IADK and measure the pressure. The air pressure, static pressure difference, and loss factor are calculated and analyzed using the pressure measured through the experiment. - COLLAPSE
    December 2019
  • Research Article

    A Study on Performance of Solar Thermal System for Domestic Hot Water According to the Weather Conditions and Feedwater Temperatures at Different Locations in Korea

    지역별 기상조건과 급수온도에 따른 태양열 온수공급 시스템 성능에 관한 연구

    Sohn Jin Gug

    손진국

    The purpose of this study is to analyze the performance of solar thermal system according to regional weather conditions and feedwater temperature ... + READ MORE
    The purpose of this study is to analyze the performance of solar thermal system according to regional weather conditions and feedwater temperature. The performance analysis of the system was carried out for the annual and winter periods in terms of solar fraction, collector efficiency and it’s optimal degree. The system is simulated using TRNSYS program for 6 cities, Seoul, Incheon, Gangneung, Mokpo, Gwangju, and Ulsan. Simulation results prove that the solar fraction of the system varies greatly from region to region, depending on weather conditions and feedwater temperatures. Monthly average solar fraction for winter season from November to February, a time when heat energy is most required, indicated that the highest is 73.6% in Gangnueng and the lowest is 56.9% in Seoul. This is about 30% relative difference between the two cities. On the other hand, the collector efficiency of the system for all six cities was analyzed in the range between 40% and 42%, indicating small difference compare to the solar fraction. The annual average solar fraction is rated the highest at 40 collector degree, while monthly average solar fraction during winter season is rated at 60 degree. - COLLAPSE
    December 2019
  • Research Article

    The Development of Infrared Thermal Imaging Safety Diagnosis System Using Pearson’s Correlation Coefficient

    피어슨 상관계수를 이용한 적외선 열화상 안전 진단 시스템 개발

    Jung Jong-Moon, Park Sung-Hun, Lee Yong-Sik, Gim Jae-Hyeon

    정종문, 박성훈, 이용식, 김재현

    With the rapid development of the national industry, the importance of electrical safety was recognized because of a lot of new electrical ... + READ MORE
    With the rapid development of the national industry, the importance of electrical safety was recognized because of a lot of new electrical equipment are installing and the electrical accidents have been occurring annually. Today, the electrical equipments is inspect by using the portable Infrared thermal imaging camera. but the most negative element of using the camera is inspected for only state of heating, the reliable diagnosis is depended with inspector’s knowledge, and real-time monitoring is impossible. This paper present the infrared thermal imaging safety diagnosis system. This system is able to monitor in real time, predict the state of fault, and diagnose the state with analysis of thermal and power data. The system consists of a main processor, an infrared camera module, the power data acquisition board, and a server. The diagnostic algorithm is based on a mathematical model designed by analyzing the Pearson’s Correlation Coefficient between temperature and power data. To test the prediction algorithm, the simulations were performed by damaging the terminals or cables on the switchboard to generate a large amount of heat. Utilizing these simulations, the developed prediction algorithm was verified. - COLLAPSE
    December 2019
  • Research Article

    The Impacts of Built Environmental Features on the Land Surface Temperatures for the Heat Wave Seasons in Gwangju, South Korea

    도시화에 따른 건조환경이 하절기 광주시 외부공간의 열환경에 미치는 영향에 대한 연구

    Hong, Sung-Woon, Yang, Dongwoo, Oh, Byoung-Chull

    홍성운, 양동우, 오병철

    This study aims to examine the impacts of built environmental features on the nocturnal and diurnal temperatures during the heat wave season ... + READ MORE
    This study aims to examine the impacts of built environmental features on the nocturnal and diurnal temperatures during the heat wave season in Gwangju, Korea. Built environmental measures are summarized at micro-scale level, such as 50 meters and 100 meters from temperature monitoring spots. Regressing the built environment on nocturnal and diurnal temperatures, we estimate how the artificial constructs contribute to temperature either day and night times. We found that impervious surface ratio is positively and negatively associated with nocturnal and diurnal temperatures, respectively. Buildings and structures tend to construct high thermal mass and absorb heat during day time and emit it for the night time. This property contributes to the nocturnal temperature model. On the other hand, urban areas with more vertical structure tend to block sun radiation more than rural, and it is more likely to find the negative relationship between impervious surface ratio and the diurnal temperatures. - COLLAPSE
    December 2019
  • Research Article

    A Study for Improving Thermal Performance According to Variables of Perforated Baffle in Air-type PVT Collector

    공기식 PVT 컬렉터에 적용된 타공 베플의 변수에 따른 열 성능 향상을 위한 연구

    Yu Ji-Suk, Kim Jin-Hee, Kim Jun-Tae

    유지숙, 김진희, 김준태

    Photovoltaic thermal (PVT) collectors are devices that simultaneously produce electricity and heat. Research on conventional air-type PVT collector focuses on installing baffles ... + READ MORE
    Photovoltaic thermal (PVT) collectors are devices that simultaneously produce electricity and heat. Research on conventional air-type PVT collector focuses on installing baffles to enhance the collector's thermal performance. However, the baffles have pressure drop inside the collector which degrades the thermal performance. Thus, it is necessary to design baffles to smoothen the flow inside the air-type PVT collector. Alternatively, installing perforated baffles in air-type PVT collectors can reduce the collector weight, but parameters such as the diameter of the perforated holes and the height of the perforated plates should be considered. Therefore, the main aim of this study was to analyze thermal characteristics of each variable of perforated baffles installed inside air-type PVT collector. For this purpose, the uniformity of air flow in the collector was compared through NX program, and the resultant heat gain and thermal efficiency of the air-type PVT collector were compared and analyzed. Therefore, the main aim of this study was to analyze thermal characteristics of each variable (Baffle angle, length, height, pitch, perforated ratio) of perforated baffles installed inside air-type PVT collector. For this purpose, the uniformity of air flow in the collector was compared through CFD program, and the resultant heat gain and thermal efficiency of the air-type PVT collector were compared and analyzed. As a result, the maximum outlet temperature was increased by 1.45 times and the heat gain was increased by 193.8 Wth, depending on the perforated baffle plate, compared to the collector without the baffle. The heat transfer performance showed that the maximum internal velocity was 1.61 times higher and the Reynolds number was 1.06 times higher depending on the parameters of the baffle plate. - COLLAPSE
    December 2019
  • Research Article

    Development of Economic Evaluation Solution and Power Prediction of Renewable Energy System

    신재생에너지 발전 출력 예측과 경제성 종합평가 기술개발

    Jeoune Dae-Seong, Kim Jin-Young, Kim Hyun-Goo, Kim Jonghyun, Youm Carl, Shin Ki-Yeol

    전대성, 김진영, 김현구, 김종현, 염기웅, 신기열

    In this paper, a very new web-based software for renewable energy system (RES) design and economic evaluation was introduced. This solution would ... + READ MORE
    In this paper, a very new web-based software for renewable energy system (RES) design and economic evaluation was introduced. This solution would provide the precise RES estimation service including not only photovoltaic (PV), wind turbine (WT) and fuel cell (FC) individually but also energy storage system (ESS) as combined forms with PV or WT. The three reasons why we ought to develop it are: First, the standardized tool suitable to the domestic environment for estimating power generation from RES facilities and economic evaluation is required. Secondly, the standardized tool is needed to spread domestic RES supply policy and to promote the new industry in the micro-grid field. The last, the reliability of economic evaluation should be enhanced more for new facilities. To achieve those aims, the weather database of one hundred locations have established and the RES facility database has also constructed. For the energy management, mathematical models for PV, WT, ESS and FC were developed. As a final phase, the analytical process to evaluate economics has performed with field data verification. - COLLAPSE
    December 2019
  • Research Article

    Non-linear Regression Model Between Solar Irradiation and PV Power Generation by Using Gompertz Curve

    Gompertz 곡선을 이용한 비선형 일사량-태양광 발전량 회귀 모델

    Kim Boyoung, Alba Vilanova Cortezon, Kim Chang Kim, Kang Yong-Heack, Yun Chang-Yeol, Kim Hyung-Goo

    김보영, 알바빌라노바 코르테존, 김창기, 강용혁, 윤창열, 김현구

    With the opening of the small power brokerage business market in December 2018, the small power trading market has started in Korea ... + READ MORE
    With the opening of the small power brokerage business market in December 2018, the small power trading market has started in Korea. Operators must submit the day-ahead estimates of power output and receive incentives based on its accuracy. Therefore, the accuracy of power generation forecasts is directly affects profits of the operators. The forecasting process for power generation can be divided into two procedure. The first is to forecast solar irradiation and the second is to transform forecasted solar irradiation into power generation. There are two methods for transformation. One is to simulate with physical model, and another is to use regression model. In this study, we found the best-fit regression model by analyzing hourly data of PV output and solar irradiation data during three years for 242 PV plants in Korea. The best model was not a linear model, but a sigmoidal model and specifically a Gompertz model. The combined linear regression and Gompertz curve was proposed because a the curve has non-zero y-intercept. As the result, R2 and RMSE between observed data and the curve was significantly reduced. - COLLAPSE
    December 2019
  • Research Article

    Observation and Analysis of Long and Short-wave Radiation According to Types of Summer Shelters

    하계 그늘쉼터 유형별 장· 단파복사 관측과 해석

    Baek Chang-Hyeon, Choi Dong-Ho, Lee Bu-Yong, Lee In-Gyu

    백창현, 최동호, 이부용, 이인규

    In this study, we analyzed the relationship between five factors: long-wave radiation, short-wave radiation, cloudiness, SVF and summer shelters. In the previous ... + READ MORE
    In this study, we analyzed the relationship between five factors: long-wave radiation, short-wave radiation, cloudiness, SVF and summer shelters. In the previous study, we recognized the correlation between single building SVF and long-wave radiation. Furthermore, this study attempted to confirm the relationship at the summer shelter with high solar radiation blocking rate. The observations are as follows. ① Cooling in summer shelters was not the effect of temperature but the effect of radiation reduction due to short-wave radiation shielding. ② In the case of the canopy tent with low heat capacity, the long-wave radiation was observed to be 16.7% higher per hour than the comparison control point due to the increase in surface temperature. ③ The long-wave radiation increase rate was different according to SVF, but showed very similar pattern according to the material characteristics of the summer shelters. ④ Passive Cooling effect on the type of summer shelters are determined by the size of the total long and short-wave radiation at that point. - COLLAPSE
    December 2019
  • Research Article

    Assessment of Energy Self-sufficiency Ratio Based on Renewable Market Potentials for Unit of Local Government

    기초지방자치단체별 보급 가능한 재생에너지 시장잠재량을 이용한 에너지 자립률 평가

    Kim Jin-Young, Kang Yong-Heack, Cho Sangmin, Yun Changyeol, Kim Chang Ki, Kim Ha-Yang, Lee Seung Moon, Kim Hyun-Goo

    김진영, 강용혁, 조상민, 윤창열, 김창기, 김하양, 이승문, 김현구

    This study estimated the available renewable market potential based on Levelized Cost Of Electricity and then assessed the renewable derived energy self-sufficiency ... + READ MORE
    This study estimated the available renewable market potential based on Levelized Cost Of Electricity and then assessed the renewable derived energy self-sufficiency for the unit of local government in South Korea. To calculate energy self-sufficiency, 1 km gridded market renewable generation and local government scale of final energy consumption data were used based on the market costs and statistics for the recent three years. The results showed that the estimated renewable market potentials were 689 TWh (Install capacity 829 GW, 128 Mtoe), which can cover 120% of power consumption. 55% of municipalities can fully replace the existing energy consumption with renewable energy generation and the surplus generation can compensate for the rest area through electricity trade. However, it was confirmed that, currently, 47% of the local governments do not fully consider all renewable energy sources such as wind, hydro and geothermal in establishing 100% renewable energy. The results of this study suggest that energy planning is decentralized, and this will greatly contribute to the establishment of power planning of local governments and close the information gap between the central government, the local governments, and the public. - COLLAPSE
    December 2019