• The Assessments of Operational Performance for North-facing PV System based on Measured Data

    실측을 통한 북향 설치 PV 시스템의 발전성능 평가

    Lee Hyomun, Bae SangSoon, Choi Minjoo, Kim Dongsu, Yoon Jongho

    이효문, 배상순, 최민주, 김동수, 윤종호

    Photovoltaic (PV) systems are commonly used as on-site electric power generators for ZEBs in the Republic of Korea. To enhance the performance … + READ MORE
    Photovoltaic (PV) systems are commonly used as on-site electric power generators for ZEBs in the Republic of Korea. To enhance the performance of PV systems, considering efficient installation conditions, such as the optimal azimuth and tilt angles, is critical. Under domestic PV application guidelines, the azimuth of installation for building-applied PV systems is stipulated within a maximum of ±90° based on the south-facing direction. In general, the north-facing direction is known as a weak position for PV systems. However, several studies have shown that the north-facing direction can be a good option for building PV installations, typically when the installation areas are limited within a building site. Even if the PV panel faces north, the system can operate effectively with proper performance when installed at a suitable inclination angle. In existing studies, system behavior has been verified based on simulation-based analysis, but actual operational data analysis remains insufficient. This study aims to evaluate the feasibility of north-facing PV systems based on a performance evaluation of the measured data of a roof PV system. The roof PV system analyzed in this study was composed of modules, module-level power electronics (MLPE), and one inverter. The PV modules and MLPEs were installed on both the southern (SIR) and northern (NIR) inclined roofs. Based on the annual cumulative DC power, the energy yields of the MLPE connected to modules of the SIR and NIR are 1,445.0 and 1,068.7 kWh/kWp, respectively. Our study found that the ratio of the performance of MLPE on the NIR to MLPE on the SIR was 74.0%. This ratio was similar to the energy yield of the PV system on the south vertical plane as compared to that on the south slope plane. The analyzed results revealed that an acceptable performance of the PV system installed on a northern slope at a suitable inclination angle could be expected as compared with other PV installations such as the southern vertical. - COLLAPSE
    30 October 2022
  • A Study on Deriving a Model for Predicting Energy Performance of a 1 kW Polymer Electrolyte Membrane Fuel Cell

    1 kW 고분자 전해질형 연료전지의 에너지성능 예측 모델 도출 연구

    Mun Sun Hye, Cho Su Hyun, Jeong Young Sun, Hwang Seung Tae

    문선혜, 조수현, 정영선, 황승태

    The dissemination of green architecture is one of the representative strategies of the architectural sector for the preemptive implementation of government-backed goals … + READ MORE
    The dissemination of green architecture is one of the representative strategies of the architectural sector for the preemptive implementation of government-backed goals of increased greenhouse gas reductions. One implementation method is to realize zero-energy buildings through the convergence of passive houses and new and renewable energy. Energy self-sufficiency in residential buildings can be accomplished by the fusion of fuel cells with other renewable energy sources. To apply a fuel cell to a building, predictions of a building’s energy consumption and fuel-cell energy production should be conducted simultaneously. Although many existing studies and tools have been developed for predicting building energy consumption, research on the application of fuel cells to buildings remains insignificant. This study aims to derive an energy performance prediction equation for a 1-kW polymer electrolyte membrane fuel cell. To this end, operational data based on the partial load ratio were collected and analyzed, and the heat and power energy production and fuel consumption prediction equations of the corresponding fuel cell were derived. - COLLAPSE
    30 October 2022
  • A Methodology for Calculating Representative Regional Photovoltaic Power Generation in 24 Hours of the Year for Expanding Renewable Energy Cloud Platform Functionality

    재생에너지 클라우드 플랫폼 기능 확장을 위한 지역별 연중 대표 24시간대 태양광 발전량 산정 방법론

    Kim Yong-Ha, Kim Yu-ri, Han Sang-Hwa, Lee Hye-Seon, Park Jong-Min, Han Gyu-Rim

    김용하, 김유리, 한상화, 이혜선, 박종민, 한규림

    In this study, a methodology for calculating representative regional photovoltaic power generation in 24 hours of the year was developed to expand … + READ MORE
    In this study, a methodology for calculating representative regional photovoltaic power generation in 24 hours of the year was developed to expand renewable energy cloud platform functionality of Korea Energy Agency. To compute regional photovoltaic power generation in 24 hours of the year, the monthly regional representative insolation in 24 hours was calculated, as well as their probability distributions. Accordingly, the monthly regional photovoltaic power generation in 24 hours was calculated, and the expected value of regional photovoltaic power generation in 24 hours of the year was derived. Subsequently, the representative regional photovoltaic power generation in 24 hours of the year was calculated. Representative regional photovoltaic power generation in 24 hours of the year calculated in this study can be applied to distributed energy resources to resolve the output variability of renewable energy. The obtained result can be used for distributed resource operation planning, such as estimating the regional Energy Storage System capacity. Currently, the Korea Energy Agency's renewable energy cloud platform provides users only with information about solar installation. However, the function of the renewable energy cloud platform can be expanded by applying the results obtained in this study to the distributed resource operation planning. - COLLAPSE
    30 October 2022
  • Conventional Polymer Solar Cell using Low Temperature Sol-gel ZnO Thin Film

    저온 졸젤 공정 ZnO 박막을 적용한 정구조 고분자 태양전지 연구

    Kim Jun Young, An Kunsik

    김준영, 안건식

    The performance of conventional polymer solar cells with low-temperature-processed zinc oxide (ZnO) as an electron extraction layer is investigated in this study. … + READ MORE
    The performance of conventional polymer solar cells with low-temperature-processed zinc oxide (ZnO) as an electron extraction layer is investigated in this study. Conventional polymer solar cells consist of molybdenum oxide (MoO3) as a hole extraction layer, a poly (3-hexylthiopene): phenyl-C60-butyric acid methyl ester (P3HT:PCBM) bulk heterojunction as a photo-active layer, and ZnO as an electron extraction layer. The ZnO layer is formed from a precursor solution on the P3HT:PCBM film through sol–gel spin-coating and annealed at a low temperature (~150°C). We first investigated various solvents of the ZnO precursor solution to identify the best solvent for coating the ZnO layer on the P3HT:PCBM film. Using the best ZnO precursor solution, we fabricated polymer solar cells under various ZnO thicknesses and analyzed their photovoltaic performance to obtain the optimal thickness of the ZnO layer. The device with the optimal thickness of the ZnO film showed a ~10% higher short-circuit current density and power conversion efficiency than the devices without the ZnO film. - COLLAPSE
    30 October 2022
  • A Study on Improving the Properties of Wide Bandgap Perovskite Through Triple Halide Composition

    삼중 할라이드(triple halide) 조성을 통한 와이드 밴드갭 페로브스카이트 특성 향상 연구

    Moon Chan Su, Jeon Nam Joong

    문찬수, 전남중

    The bandgap of halide perovskite materials can be easily adjusted through compositional variation. Perovskite solar cells (PSCs) have attracted attention as promising … + READ MORE
    The bandgap of halide perovskite materials can be easily adjusted through compositional variation. Perovskite solar cells (PSCs) have attracted attention as promising materials for tandem solar cells because of their tunable bandgaps. Nevertheless, the photoinduced halide segregation phenomenon, which is related to photostability and device performance, remains a problem. Herein, we confirmed that the perovskite composition was controlled by the triple halide composition through the addition of lead chloride (PbCl2). The triple halide composition not only controlled the perovskite bandgap but also suppressed the photoinduced halide segregation in the perovskite film. In addition, the device performance was improved by the enhanced crystallinity of the perovskite thin film with the triple halide composition. - COLLAPSE
    30 October 2022
  • Characteristics of PV Short Circuit Faults Through Experiment with Line-Line Faults in PV Arrays

    태양광 직류 전로 사고 실증실험을 통한 태양광 단락사고 특성

    Cho Sung-Koo, Jung Do-Yun, Kim Jae-Hyun, Kim Ji-Yeon, Kim Jun-Tae

    조성구, 정도연, 김재현, 김지연, 김준태

    The rapid development of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. Fault analysis … + READ MORE
    The rapid development of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. Fault analysis in photovoltaic arrays is a fundamental task to increase reliability, efficiency, and safety in PV systems. If no fault is detected, it may reduce power generation, accelerate system aging, and increase the risks of fire hazards. In this study, we considered the line–line fault through verification experiments in PV arrays for fire hazard analysis and analyzed accident characteristics to improve electrical safety in PV systems. This paper presents a comparison and analysis of accident characteristics regarding the location of the accident, use of blocking diodes, and PV inverter operation. String line–line fault protection in systems without blocking diodes should be designed considering the current acceptable ratings of all facilities in the path, from the combiner box to the PV module. In addition, the array line-line fault characteristics include short-circuit current from the solar array and back feed current from the inverter based on the accident point. These accident currents contribute to fire accidents with strong arcs from the short-circuit point. - COLLAPSE
    30 October 2022
  • Analysis of Building Energy Reduction by Building Energy Package Regarding Vietnam Environmental Condition and Economic

    베트남 기후 및 경제적 여건을 고려한 건물에너지 패키지 적용에 따른 건물에너지 절감효과 분석

    Yun Tae Gyun, Shin Jae Yoon, Kang Seok-pyo

    윤태균, 신재윤, 강석표

    Due to the construction industry, the increase in energy demands from the population, and economic growth in Vietnam, the need for energy … + READ MORE
    Due to the construction industry, the increase in energy demands from the population, and economic growth in Vietnam, the need for energy efficient buildings has increased. An analysis of Vietnam’s regulations and standards related to building energy shows that Vietnam’s current technology level is similar to Korea in the 1980s, so it needs to upgrade its technology. Using Korea’s advanced energy efficient building technology, it will be possible to satisfy Vietnam’s need for energy efficient buildings. In a prior study, the baseline data were calculated using a building energy simulation program with Vietnam’s weather data and input values provided by the most recent Vietnam building energy standards (QCVN 09:2017:BXD). Then, the optimized input combination of building energy packages was derived to achieve energy savings of 60% by integrating the building energy simulation program (Energyplus) with a programming language (Python). Vietnam’s climate characteristics vary by region, so simulations were run with three sets of weather data (Northern: Hanoi, Central: Da Nang, Southern: Ho Chi Minh). As a result, the optimized input combination could reduce building energy usage by about 55% compared to the baseline model. In this study, building energy savings were analyzed using simulated data by modeling a real example building in Vietnam before the building energy package was installed. - COLLAPSE
    30 October 2022
  • Data-Driven Sensor Calibration Method of VAV Terminal Unit

    VAV 터미널 유닛 시스템의 데이터 기반 센서 보정 방법

    Kim Hyo-Jun, Cho Young-Hum

    김효준, 조영흠

    The objective of this study is to develop a data-driven prediction model and sensor calibration method in variable air volume (VAV) terminal … + READ MORE
    The objective of this study is to develop a data-driven prediction model and sensor calibration method in variable air volume (VAV) terminal unit systems. Based on the operational data of VAV terminal unit systems, indoor loads and carbon dioxide (CO2) concentrations were predicted, and a Bayesian markov chain monte carlo (MCMC)-based sensor calibration method was used. The operational data of a VAV terminal unit used for data-driven model analysis and development were collected using the dynamic energy simulation tool, TRNSYS 17. Data analysis and Bayesian MCMC algorithms were analyzed and developed using R Studio. The indoor comfort and energy consumption were analyzed for the offset error effect of supply air flow rate in VAV terminal units. A sensor error distance function was developed using a prediction model. The sensor calibration method was developed using the Bayesian MCMC algorithm. The performance evaluation of sensor calibration methods utilized simulations data. It is confirmed that sensor calibration was confirmed to be possible in case of supply air flow rate sensor errors. - COLLAPSE
    30 October 2022