• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.51.2-51.2
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• 2010

Efficient and durable electrical energy storage is one of the major factors limiting the wide-spread adoption of renewable energy. Since lithium-ion batteries (LIBs) were first commercialized in the early 1990s, LIBs have emerged as an important energy storage device for portable electronics. LIBs are very desirable because of their high energy storage per volume and per mass. However, LIBs with high energy and power as well as higher stability are needed for their use in a variety of energy storage applications such as MEMS devices, PDA, plug-in hybrids, all-electric vehicles and large scale utility systems. In this talk, I will discuss present energy perspective, especially energy storage and its role in renewable energy. After that I will discuss the recent advances in nanostructured materials and interface engineering that have led to the achievement of improved Li-ion batteries. Finally I will talk aboutcritical issues that need to be addressed to obtain further improvements in Li-ion batteries.

• Journal of the Korean Society of Combustion
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• v.21 no.1
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• pp.18-30
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• 2016

Pyro-process of solids is the way to heat solid materials under high temperature. In this processing, energy efficient use is one of the main concerns due to its high energy consumption of bulk materials. To calculate the energy use of processes, heat & mass balance in simplified 0-dimensional model was performed. Energy calculation by this simplified model can lead to confusion due to simplification. Thus, it is necessary to understand considerations of energy analysis. In this study, cement manufacturing as a very common example of pyro-processing of solids, was introduced for explaining considerations of energy analysis for energy efficient use.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.129-134
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• 2001

• Advances in Energy Research
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• v.5 no.3
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• pp.239-254
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• 2017

The world began to search for new energy sources with increasing energy demand. Renewable energy sources are as hydropower important for alternative energy. Countries with high hydroelectric potentials continue to work to utilize hydroelectric power plants in the most efficient way. Pumped storage hydropower plants are an important investment to meet the growing energy needs at peak times and to store energy. Although it produces energy in many countries, pumped storage hydropower plants have not begun to be built in Turkey which has high hydroelectric potential. A new era will be opened for energy production in Turkey where a large number of pumped storage hydropower plants projects are in study phase with the construction of pumped storage hydropower plants and first nuclear power plant.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.121-126
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• 2009

This study analyzed the standard school's energy usage and patterns as the zero-energy goal of primary school building, and proposed the energy reduction process of school building using energy analysis computing simulation tool. As a analysis simulation tool, Visual DOE 4.0 is used. For analysis of actual energy usage, selected primary school that is standard in the nation's energy consumption. Standard of the school's energy consumption analysis were devided into electric and gas energy. Input parameters of the simulation program based on the literature material and field survey material. after, but it was calibrated to comparison with the standard school's energy consumption. Finally, its energy usage analyzed by component and made the priority order of energy saving. Applied energy saving technologies are envelopment insulation, high efficiency lighting, high performance HAVC system and used active equipment system of solar collector and photovoltaic generation for additional savings.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.235-236
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• 2017

• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.97-97
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• 2007

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.129-131
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• 2006

This paper presents a new ZVS-PWM high frequency inverter. The ZVS operation is achieved in the whole load range by using a simple auxiliary reverse blocking switch in parallel with series resonant capacitor. The operating principle and the operating characteristics of the new high frequency circuit treated here are illustrated and evaluated on the basis of simulation results. It was examined that the complete soft switching operation can be achieved even for low power setting ranges by introducing the high frequency dual duty cycle control scheme. In the proposed high frequency inverter treated here, the dual mode pulse modulation control strategy of the asymmetrical PWM in the higher power setting ranges and the lower power setting ones, the output power of this high frequency inverter could introduce in order to extend soft switching operation ranges. Dual duty cycle is used to provide a wide range of output power regulation that is important in many high frequency inverter applications. It is more suitable for induction heating applications the operation and control principle of the proposed high frequency inverter are described and verified through simulated results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.391-394
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• 2006

This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

• Korean Journal of Materials Research
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• v.33 no.4
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• pp.159-163
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• 2023

Zinc-ion Batteries (ZIBs) are currently considered to be effective energy storage devices for wearable electronics because of their low cost and high safety. Indeed, ZIBs show high power density and safety compared with conventional lithium ion batteries (LIBs) and exhibit high energy density in comparison with supercapacitors (SCs). However, in spite of their advantages, further current collector development is needed to enhance the electrochemical performance of ZIBs. To design the optimized current collector for high performance ZIBs, a high quality graphene film is suggested here, with improved electrical conductivity by controlling the defects in the graphene film. The graphene film showed improved electrical conductivity and good electron transfer between the current collector and active material, which led to a high specific capacity of 346.3 mAh g^-1 at a current density of 100 mA g^-1, a high-rate performance with 116.3 mAh g^-1 at a current density of 2,000 mA g^-1, and good cycling stability (68.0 % after 100 cycles at a current density of 1,000 mA g^-1). The improved electrochemical performance is firmly because of the defects-controlled graphene film, leading to improved electrical conductivity and thus more efficient electron transfer between the current collector and active material.