• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.727-730
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• 2023

The operation of electric automatic windows is used in harsh environments, and the energy density decreases as charging and discharging are repeated, and as soundness deteriorates due to damage to the internal separator, the vehicle's mileage decreases and the charging speed slows down, so about 5 to 10 Batteries that have been used for about a year are classified as waste batteries, and for this reason, as the risk of battery fire and explosion increases, it is essential to diagnose batteries and estimate SOH. Estimation of current battery SOH is a very important content, and it evaluates the state of the battery by measuring the time, temperature, and voltage required while repeatedly charging and discharging the battery. There are disadvantages. In this paper, measurement of discharge capacity (C-rate) using a waste battery of a Tesla car in order to predict SOH estimation of a lithium-ion battery. A Support Vector Machine (SVM), one of the machine models, was applied using the data measured from the waste battery.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.457-457
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• 2022

최근 기후변화로 인한 위기가 인류의 생존을 위협하면서 전 지구적으로 기후변화에 대응하기 위한 탄소 중립 대책을 모색하고 있으며, 지속가능한 신재생에너지에 대해 주목하고 있다. 산업통상자원부는 2034년까지 총 발전량 중 신재생에너지의 비율을 25.8%까지 증가시키는 것을 목표로 신재생에너지의 발전 비율을 증가시키기 위한 다양한 노력을 기울이고 있다. 특히, 신재생에너지 중 가장 많은 비중을 차지하고 있는 태양광 발전은 비교적 광범위한 부지를 필요로 하고 있으며, 환경 및 지형적 영향이 크게 작용하는 만큼 발전 시설 부지 선정 및 운용 계획을 위한 면밀한 분석이 필수적이다. 그러나, 태양광 발전 활용 계획을 수립하기 위해 고려할 수 있는 지상 관측 일사량 및 일조량 데이터는 상당히 제한적이며 관측 밀도가 조밀하지 않다는 한계점이 있다. 본 연구에서는 천리안위성의 후속으로 발사된 천리안2위성의 산출물인 일사량 데이터를 활용하여 한반도 영역에서의 일사량에 대한 시·공간적 분석을 수행하였으며, 이를 기반으로 각 지역적 특성을 파악하고, 토지 피복 유형에 따른 태양광 발전의 효율 정도를 분석·평가하였다. 본 연구의 결과는 계측 지역 및 미계측 지역에서의 시공간적인 태양광 에너지의 효율성에 대한 정보를 제공함에 따라 태양광 발전을 위한 관련 시설물들의 최적 설치 위치 및 규모 등에 대한 설계 기준 마련에 활용될 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.108-108
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• 2022

기후변화는 전 지구 수문순환과 수자원 분포에 커다란 영향을 준다. 하지만 지금까지 관측되어온 지구상의 건조도 변화에 있어서 기후의 자연변동성의 영향과 인간활동에 의한 온난화의 영향을 명시적으로 밝힌 연구는 존재하지 않는다. 본 연구에서는 데이터 구동형 모델과 물리 모델을 이용해 관측 기반의 전구 수자원 분포를 1902년부터 2014년까지 재구축함으로써 지구의 평균온도가 약 1도 상승해온 지난 세기에 걸쳐 건기의 수자원 분포가 어떻게 변해왔는지 보인다. 재구축된 전구 변화 패턴은 인간활동에 의한 온실가스 증가등을 고려한 기후 모델 시뮬레이션과 흡사함을 알 수 있었으며 기후의 자연변동성만을 고려한 기후 모델 시뮬레이션에서는 발견되지 않았다. 주로 북아시아, 북미, 유럽 등 중위도 온대지방에서 더욱더 건조한 건기가 뚜렷하게 나타났으며 이는 강수량의 감소보다는 증발산의 증가에 기인하는 것으로 나타난다. 이와 같은 건조도의 변화는 미래 있어서 또한 인류에 대한 커다란 위협으로 자리한다. 미래 기후에서의 가뭄의 변화에 대해 다양한 연구들이 존재하지만 대부분 높은 수준의 온난화 (예를들어 RCP-SSP 585)에서의 영향에 국한된다. 다시 말해 인류가 21세기 중반에 달성을 목표로 하는 탄소중립이 가뭄의 측면에서 어떤 영향을 주게 될지에 대한 연구는 아직 충분하지 않다고 할 수 있다. 본 연구에서는 약한 혹은 중간 수준의 기후변화 시나리오를 이용해 파리협약에서 목표로 하는 1.5℃와 2℃ 상승에 따라 전 지구의 건조도 분포가 어떻게 변하고 그 변화에 있어서 어떠한 수문기후학적 메커니즘이 작용하는지 밝힌다. 지중해 연안 지역에서는 건조도의 가속이 +1.5℃와 +2℃사이에 존재하였으나 동아시아에서는 +1.5℃와 +2℃ 모두에서 습윤해짐을 알 수 있었으며 이러한 지역적 불균일성은 기후변화 대응 노력에 있어서 과거 온실가스 배출에 대한 책임뿐만 아니라 다양한 부문에 걸친 미래의 잠재 적응 노력 또한 고려해야만 함을 시사한다. 본 연구는 제6차 Coupled Model Intercomparison Project의 Land Surface, Snow, Soil-moisture Model Intercomparison Project (CMIP6/LS3MIP)와 Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI)의 다중 모델 앙상블 시뮬레이션 결과를 이용했다.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.56-63
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• 2023

The development of renewable energy technologies, such as solar, wave, and wind power, has led to the diversification of water electrolysis technologies, which can be easily coupled with renewable energy sources in terms of economics and scale. Water electrolysis technologies can be classified into three types based on operating temperature: low-temperature (<100 ℃), medium-temperature (300-700 ℃), and high-temperature (>700 ℃). It can also be classified by the type of electrolyte membrane used in the system. However, the concepts of thermodynamic and thermo-neutral voltages calculations and are very important factors in the evaluation of energy consumption and efficiency of water electrolysis technologies, are often confused. This review aims to contribute to a better understanding of the calculation of operating voltage and efficiency of PEM water electrolysis technologies and to clarify the differences between thermodynamic voltage and thermo-neutral voltage.

• Journal of Powder Materials
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• v.30 no.6
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• pp.509-515
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• 2023

Lead-free perovskite ceramics, which have excellent energy storage capabilities, are attracting attention owing to their high power density and rapid charge-discharge speed. Given that the energy-storage properties of perovskite ceramic capacitors are significantly improved by doping with various elements, modifying their chemical compositions is a fundamental strategy. This study investigated the effect of Zn doping on the microstructure and energy storage performance of potassium sodium niobate (KNN)-based ceramics. Two types of powders and their corresponding ceramics with compositions of (1-x)(K,Na)NbO₃-xBi(Ni_2/3Ta_1/3)O₃ (KNN-BNT) and (1-x)(K,Na)NbO₃-xBi(Ni_1/3Zn_1/3Ta_1/3)O₃ (KNN-BNZT) were prepared via solid-state reactions. The results indicate that Zn doping retards grain growth, resulting in smaller grain sizes in Zn-doped KNN-BNZT than in KNN-BNT ceramics. Moreover, the Zn-doped KNN-BNZT ceramics exhibited superior energy storage density and efficiency across all x values. Notably, 0.9KNN-0.1BNZT ceramics demonstrate an energy storage density and efficiency of 0.24 J/cm³ and 96%, respectively. These ceramics also exhibited excellent temperature and frequency stability. This study provides valuable insights into the design of KNN-based ceramic capacitors with enhanced energy storage capabilities through doping strategies.

• Resources Recycling
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• v.32 no.6
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• pp.79-89
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• 2023

One of the foremost environmental challenges, alongside the contemporary focus on achieving carbon neutrality, pertains to the pervasive issue of plastic waste. Thermochemical recycling technology, operating under high-temperature conditions to covert organic matter and recycle it into raw materials and energy, represents a transformative approach surpassing the conventional bounds of material recycling predominantly applied in plastic waste management. The thermochemical recycling paradigm is emerging as a pivotal technology within the circular economy, capable of transforming waste plastics into raw materials for producing original plastics. Its significance extends beyond national borders, garnering global attention due to its versatility as a chemical or energy recycling method, contingent upon the subsequent processes and final products. This study aims to scrutinize three quintessential thermochemical recycling technologies: combustion, gasification, and pyrolysis. Furthermore, the study discusses the recent major technology trends of these technologies.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.17-31
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• 2023

Amidst escalating global warming fueled by indiscriminate fossil fuel consumption, concerted efforts are underway worldwide to mitigate atmospheric carbon dioxide (CO₂) levels. Electrochemical CO₂ reduction technology is recognized as a promising and environmentally friendly approach to convert CO₂ into valuable hydrocarbon compounds, deemed essential for achieving carbon neutrality. Copper, among the various materials used as CO₂ reduction electrodes, is known as the sole metal capable of generating C₂₊ compounds. However, low conversion efficiency and selectivity have hindered its widespread commercialization. This review highlights diverse research endeavors to address these challenges. It explores various studies focused on utilizing copper-based electrodes for CO₂ reduction, offering insights into potential solutions for advancing this crucial technology.

• Clean Technology
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• v.29 no.4
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• pp.321-326
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• 2023

Recently, there has been a growing interest in clean hydrogen energy that does not emit carbon dioxide during combustion due to the increasing focus on carbon neutral. Research related to hydrogen production continues, and in this study, we applied waste-derived synthesis gas to the water-gas shift reaction to simultaneously treat waste and produce high-purity hydrogen. To enhance catalytic activity in the high-temperature water-gas shift (HT-WGS) reaction, magnesium was used as a support material alongside cerium. Cu-CeO₂-MgO catalysts were synthesized, with copper acting as the active component for the HT-WGS reaction. A study on the catalytic activity based on the preparation method was conducted, and the Cu-CeO₂-MgO catalyst prepared by impregnation method exhibited the highest activity in the HT-WGS reaction. The observed superior performance of the Cu-CeO₂-MgO catalyst prepared through the impregnation method can be attributed to its significantly higher oxygen storage capacity and amount of active Cu species.

• Journal of Advanced Technology Convergence
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• v.2 no.4
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• pp.43-48
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• 2023

Globally, there is a collaborative effort to achieve global carbon neutrality in response to climate change. In the case of South Korea, greenhouse gas emissions are rapidly increasing, presenting an urgent situation that requires resolution. In this context, this study developed a thermal energy collection device named a 'steam trap' and created an AI model capable of predicting future electricity usage by collecting energy usage data through steam traps. The average accuracy of electricity usage prediction with this AI model was 96.7%, demonstrating high precision. Consequently, the AI model enables the prediction and management of days with high electricity consumption and identifies which facilities contribute to elevated power usage. Future research aims to optimize energy consumption efficiency through efficient equipment operation using anomaly detection in steam traps and standardizing energy management systems, with the ultimate goal of reducing greenhouse gas emissions.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.841-852
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• 2023

Gas turbines, which are used as generators for frequency regulation of the domestic power system, are increasing in use due to the carbon-neutral policy, quick startup and shutdown, and high thermal efficiency. Since the gas turbine rotates the turbine using high-temperature flame, the turbine inlet temperature is acting as a key factor determining the performance and lifespan of the device. However, since the inlet temperature cannot be directly measured, the temperature calculated by the manufacturer is used or the temperature predicted based on field experience is applied, which makes it difficult to operate and maintain the gas turbine in a stable manner. In this study, we present a model that can predict the inlet temperature of a reheat gas turbine based on Deep Neural Network (DNN), which is widely used in artificial neural networks, and verify the performance of the proposed DNN based on actual data.