• Research Article

    A Study on the Optimization of Photovoltaic System for the ZEB Certification in Detached Housing

    단독 주택의 제로에너지건축물 인증을 위한 태양광시스템 최적화에 관한 연구

    Shin Jee-Woong, Yun Jae-Hyun, Ko Jeong-Lim

    신지웅, 윤재현, 고정림

    As part of the government’s energy policy, Zero Energy Building certification was launched on January of 2017. However, the three passive-housing ... + READ MORE
    As part of the government’s energy policy, Zero Energy Building certification was launched on January of 2017. However, the three passive-housing rental housing projects are the only ZEB-certified detached housing since the certification’s launch. The reason is that, in order for a detached housing to earn ZEB certification, it has to secure self-reliance in energy, and a photovoltaic system is the only viable renewable energy system. Therefore, conducting an analysis to optimize the photovoltaic system in an early design stage is strongly recommended. This study aimed to propose an optimal photovoltaic system design for a detached housing after analyzing through the ECO2 energy simulation of 44 cases, varying in a module type and efficiency, inclination and azimuth. As a result, 15 cases out of 44 cases were analyzed to satisfy ZEB evaluation criteria, and it is thought that these data could contribute greatly to the expansion of ZEB certification dissemination. - COLLAPSE
    June 2019
  • Research Article

    Fabrication and Chracteristics of Cutting Cell with Various Laser Conditions

    다양한 레이저 조건에 따른 컷팅셀 제작 및 특성 분석

    Park Jeong Eun, Kim Dong Sik, Choi Won Seok, Jang Jae Joon, Lim Dong gun

    박정은, 김동식, 최원석, 장재준, 임동건

    Laser cutting cell of solar cells can achieve high voltage and efficiency through more array than conventional 6 inch cell compared to ... + READ MORE
    Laser cutting cell of solar cells can achieve high voltage and efficiency through more array than conventional 6 inch cell compared to same area. In this study, we fabricated c-Si cutting cell with various lasers and laser conditions such as power, speed, and number of times. In the case of picosecond laser, excellent surface characteristics were obtained due to small surface defects and low thermal damage at the output of 20W and the speed of 100 mm/s. However, it is not possible to fabricate a cutting cell having good characteristics due to nonuniform cutting inside the wafer when the processing for forming a cutting cell is not sufficiently performed. For nanosecond lasers, the best wafer characteristics were obtained for fabrication of excellent cutting cells at a frequency of 500 kHz and a laser speed of 100 mm/s. However, the nanosecond laser has not been processed sufficiently in the condition of a number of times. As a result, it was confirmed that the wafer thickness was cut by 63 μm of the cell thickness of 170 μm in the condition of five times of laser process. It was found that more than 30% of the wafer thickness had to be processed to fabricate the cutting cell. After cutting the 6-inch cell having the voltage of 0.65 V, we obtained the voltage of about 0.63 V. - COLLAPSE
    June 2019
  • Research Article

    Thermal Environment Around the Outdoor Unit Installed in the Space between Buildings in the Commercial Area

    상업지역내 건물 사이 공간에 설치된 실외기 주변 열 환경 분석

    Shin Hak-Jong, Kwak In-Kyu, Mun Sun-Hye, Huh Jung-Ho

    신학종, 곽인규, 문선혜, 허정호

    In commercial areas, outdoor units are typically installed close to one another in the narrow space between buildings due to insufficient regulations ... + READ MORE
    In commercial areas, outdoor units are typically installed close to one another in the narrow space between buildings due to insufficient regulations. This makes it difficult to ventilate the discharge airflow, which may lead to deterioration of the performance of outdoor units. This study conducted CFD simulation to analyze the thermal environment according to the installation distance of the outdoor unit. The outdoor unit was installed in the space between buildings, and the thermal environment was analyzed by changing installation distance and wind speed. The performance of the outdoor unit was evaluated by measuring the on-coil temperature. The results show that the closer the distance between outdoor units, the higher the condenser on-coil temperature. Also, the on-coil temperature appeared to rise dramatically at lower wind speed. - COLLAPSE
    June 2019
  • Research Article

    A Study on the Installation Potential of Photovoltaic System Based on Regional Architectural Data

    지역별 건축물 데이터를 활용한 태양광발전시스템 설치 잠재량 산정에 관한 연구

    Shin Min-Su, Lee Kyung-Soo

    신민수, 이경수

    As the solar energy market grows, the need to investigate the potential of photovoltaic system is being highlighted. However, due to the ... + READ MORE
    As the solar energy market grows, the need to investigate the potential of photovoltaic system is being highlighted. However, due to the lack of plain field, the system on top of buildings is being exploited. This paper analyzes the potential to install PV systems on the rooftops. First of all, with the aid of a photovoltaic system simulation software, buildings were designed in a specific area based on the architectural data. And then, with the same software, the potential to install photovoltaic system was explored by placing PV modules on the buildings’ rooftops. The installation potential was calculated and simulated with consideration for obstacles on the rooftops. The parameters are composed of available area for system installation, area utilization rate, PV system power capacity, operation yield hour per day and performance ratio. In the simulation, 5 sites were analyzed based on their architectural data. In the end, reliable data that can be utilized were collected for the potential to install the system with the photovoltaic system simulation software. - COLLAPSE
    June 2019
  • Research Article

    Analysis of Clear Sky Index Defined by Various Ways Using Solar Resource Map Based on Chollian Satellite Imagery

    천리안 위성 영상 기반 태양자원지도를 활용한 다양한 정의에서의 청천지수 특성 분석

    Kim Chang Ki, Kim Hyun-Goo, Kang Yong-Heack, Yun Chang-Yeol

    김창기, 김현구, 강용혁, 윤창열

    Clear sky indices were estimated by various ways based on in-situ observation and satellite-derived solar irradiance. In principle, clear sky index defined ... + READ MORE
    Clear sky indices were estimated by various ways based on in-situ observation and satellite-derived solar irradiance. In principle, clear sky index defined by clear sky solar irradiance indicates the impacts of cloud on the incoming solar irradiance. However, clear sky index widely used in energy sciences is formulated by extraterrestrial irradiance, which implies the extinction of solar irradiance due to mainly aerosol, water vapor and clouds drops. This study examined the relative difference of clear sky indices and then major characteristics of clear sky irradiance when sky is clear are investigated. Clear sky is defined when clear sky index based on clear sky irradiance is higher than 0.9. In contrast, clear sky index defined by extraterrestrial irradiance is distributed between 0.4 and 0.8. When aerosol optical depth and air mass coefficient are relative larger, solar irradiance is lower due to enhanced extinction, which leads to the lower value of clear sky index defined by extraterrestrial irradiance. - COLLAPSE
    June 2019
  • Research Article

    Solar Power Generation Forecast Model Using Seasonal ARIMA

    SARIMA 모형을 이용한 태양광 발전량 예보 모형 구축

    Lee Dong-Hyun, Jung Ahyun, Kim Jin-Young, Kim Chang Ki, Kim Hyun-Goo, Lee Yung-Seop

    이동현, 정아현, 김진영, 김창기, 김현구, 이영섭

    New and renewable energy forecasts are key technology to reduce the annual operating cost of new and renewable facilities, and accuracy of ... + READ MORE
    New and renewable energy forecasts are key technology to reduce the annual operating cost of new and renewable facilities, and accuracy of forecasts is paramount. In this study, we intend to build a model for the prediction of short-term solar power generation for 1 hour to 3 hours. To this end, this study applied two time series technique, ARIMA model without considering seasonality and SARIMA model with considering seasonality, comparing which technique has better predictive accuracy. Comparing predicted errors by MAE measures of solar power generation for 1 hour to 3 hours at four locations, the solar power forecast model using ARIMA was better in terms of predictive accuracy than the solar power forecast model using SARIMA. On the other hand, a comparison of predicted error by RMSE measures resulted in a solar power forecast model using SARIMA being better in terms of predictive accuracy than a solar power forecast model using ARIMA. - COLLAPSE
    June 2019
  • Research Article

    Comparative Analysis on the Characteristic of Typical Meteorological Year Applying Principal Component Analysis

    주성분분석에 의한 TMY 특성 비교분석

    Kim Shin Young, Kim Chang Ki, Kang Yong Heack, Yun Chang Yeol, Jang Gil Soo, Kim Hyun-Goo

    김신영, 김창기, 강용혁, 윤창열, 장길수, 김현구

    The reliable Typical Meteorological Year (TMY) data, sometimes called Test Reference Year (TRY) data, are necessary in the feasibility study of renewable ... + READ MORE
    The reliable Typical Meteorological Year (TMY) data, sometimes called Test Reference Year (TRY) data, are necessary in the feasibility study of renewable energy installation as well as zero energy building. In Korea, there are available TMY data; TMY from Korea Institute of Energy Research (KIER), TRY from the Korean Solar Energy Society (KSES) and TRY from Passive House Institute Korea (PHIKO). This study aims at examining their characteristics by using Principle Component Analysis (PCA) at six ground observing stations. First step is to investigate the annual averages of meteorological elements from TMY data and their standard deviations. Then, PCA is done to find which principle components are derived from different TMY data. Temperature and solar irradiance are determined as the main principle component of TMY data produced by KIER and KSES at all stations whereas TRY data from PHIKO does not show similar result from those by KIER and KSES. - COLLAPSE
    June 2019
  • Research Article

    Variation of Solar Photovoltaic Power Estimation due to Solar Irradiance Decomposition Models

    일사량 직산분리 모델에 따른 표준기상연도 데이터와 태양광 발전 예측량의 불확실성

    Jo Eul-Hyo, Lee Hyun-Jin

    조을효, 이현진

    Long-term solar irradiance data are required for reliable performance evaluation and feasibility analysis of solar photovoltaic systems. However, measurement data of the ... + READ MORE
    Long-term solar irradiance data are required for reliable performance evaluation and feasibility analysis of solar photovoltaic systems. However, measurement data of the global horizontal irradiance (GHI) are only available for major cities in Korea. Neither the direct normal irradiance (DNI) nor the diffuse horizontal irradiance (DHI) are available, which are also needed to calculate the irradiance on the tilted surface of PV array. It is a simple approach to take advantage of the decomposition model that extracts DNI and DHI from GHI. In this study, we investigate variations of solar PV power estimation due to the choice of decomposition model. The GHI data from Korea Meteorological Administration (KMA) were used and different sets of typical meteorological year (TMY) data using some well-known decomposition models were generated. Then, power outputs with the different TMY data were calculated, and a variation of 3.7% was estimated due to the choice of decomposition model. - COLLAPSE
    June 2019
  • Research Article

    Comparative Analysis of Decomposition Models with Site-fitted Coefficients for Seoul

    서울지역 지역계수가 적용된 직산분리 모델의 성능 비교

    Seo Dong-Hyun, Kim Hye-Jin

    서동현, 김혜진

    Decomposition models are essential in TMY development and solar energy system design. Up until recently, only a few decomposition model related researches ... + READ MORE
    Decomposition models are essential in TMY development and solar energy system design. Up until recently, only a few decomposition model related researches are implemented in Korea due to lack of measured direct normal solar irradiance. In contrast, numerous researches have been conducted in various countries, and some quasi-universal composition models have been recommended by several papers. In this research, three decomposition models – Watanabe model, Reindl-2 model and Engerer1 model - are selected and their site-fitted coefficients are developed using measured direct normal solar irradiance in Seoul. R-squared, RMSE, MBE of the site-fitted models are compared with the case of original coefficients and then each other. The comparison result shows that the Reindl-2 model with site-fitted coefficients is best suitable for Seoul. Further researches will be conducted to find the best model using more various measured data of Korean cities and site-fitting methods. - COLLAPSE
    June 2019