• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.740-746
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• 2009

Two step serial load induction superheater has been proposed using resonance type induction heat method in this paper. Heat method is a type of flowing the electron induction and current to special alloy heater in body from external heat coil with non-contact method. Inverter was a full bridge serial load resonance type and inductor was used as load in LC resonance design to maximize the efficiency. The developed system is a new heat exchanging method combined with electromagnetic induction heater and fluid movement, ana very accurate to control of heating the gas, liquid and evaporated mass, so on without combustion process.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.3
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• pp.329-335
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• 2008

Volatile organic compounds emitted to the atmosphere can cause adverse effects on human health and participate in photochemical smog formation reactions. The destruction of a series of VOCs has been carried out by non-thermal plasma in other researches. And the characteristic of non-thermal plasma was operated at atmospheric pressure and low temperature. A new type non-thermal plasma reactor was investigated combined Glidarc plasma with water jet in this research. Also, it was found that the water-jet had an significant effect on the toluene removal efficiency. But too much water content does not favor toluene decomposition by decreasing of reaction temperature. The input toluene concentration, gas flow rate, water flow rate and specific energy input were used as experiment variables. The toluene removal efficiency, energy efficiency and specific energy input were 75.3%, 146.6 g/kWh and $1.12kWh/m^3$ at a water flow rate of 100 mL/min.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.187-190
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• 2007

A combined hydrogen generator of plasma and catalytic reformers has been developed, and has been applied to stabilize unstable flame of 200,000 Kcal/hr LPG combustor. The role of the plasma reformer is to generate hydrogen in a short period and to heat-up the catalytic reformer during the start-up time. After the start-up period, the catalytic reformer generates hydrogen through steam reforming with oxygen (SRO) reactions. The maximum capacity of the hydrogen generator is 100 lpm that is sufficient to be used to stabilize the flame of the present combustor. In order to reduce NOx and CO emissions simultaneously, 1) FGR (Flue Gas Recirculation) technique has been adopted and 2) the hydrogen has been added into the fuel supplied to the combustor. Test results shows that 25 % addition of hydrogen and 30 % FGR rate lead to simultaneous decrease of CO and NOx emissions. The technique proposed in the present study shows good potential to replace $NH_3$ SCR technique, especially in the case of small-scale combustor applications.

• Environmental Engineering Research
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• v.19 no.4
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• pp.387-393
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• 2014

The purpose of this study is to evaluate integrated anaerobic hydrogen fermentation and membrane bioreactor (MBR) for on-site domestic wastewater treatment and resource recovery. A synthetic wastewater (COD 17,000 mg/L) was used as artificial brown water which will be discharged from urine diversion toilet and fed into a continuous stirred tank reactor (CSTR) type anaerobic reactor with inclined plate. The effluent of anaerobic reactor mixed with real household grey water (COD 700 mg/L) was further treated by MBR for reuse. An optimum condition maintained in anaerobic reactor was HRT of 8 hrs, pH 5.5, SRT of 5 days and temperature of $37^{\circ}C$. COD removal of 98% was achieved from the overall system. Total gas production rate and hydrogen content was 4.6 L/day and 52.4% respectively. COD mass balance described the COD distribution in the system via reactor byproducts and effluent COD concentration. The results of this study asserts that, anaerobic hydrogen fermentation combined with MBR is a potent system in stabilizing waste strength and clean hydrogen recovery which could be implemented for onsite domestic wastewater treatment and reuse.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.250-253
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• 2007

Gas Discharge Tubes (GDTs) are widely used as surge protectors for commnuication applications due to their small internal capacitance. In these days, however, they are mostly used in combined configurations, because the activation voltage required to initiate the discharge process in the GDTs for sufficient amount of time can be large enough to damage surge-sensitive protected circuits. For GDTs with a considerably high initial over-voltage value, we should limit the peak voltage using a TVS or filter. As for ZnO varistors, even though their performance for voltage restriction is excellent, their applications in high-frequency commnuication circuits have been limited because of higher internal capacitance when compared to the GDTs. In order to develop a surge protector for commnuication applications by taking advantages of these two devices, we built a combination circuit that connects a GDT and a ZnO varistor along with a choke coil in common and differential modes. We describe how the applied SPDs operate in protection process steps with the actual data obtained from the residual voltage measurements at each step. The experiment results show that the surge voltage restriction with the choke coil is more effective in 100 [kHz] RingWave voltage than in lightning impulse voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.901-904
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• 2001

For the c-axis oriented epitaxial YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin film on r-cut sapphire substrate it is necessary to deposit buffer layers. The CeO$_2$buffer layer was deposited on sapphire substrate using RF magnetron sputtering system. We investigated XRD pattern of CeO$_2$thin films at various sputtering conditions such as sputtering gas ratio, sputtering power, target to substrate distance, sputtering pressure and substrate temperature. The optimum condition was 15 mTorr with deposition pressure, 1:1.2 with $O_2$and Ar ratio and 9cm with target to substrate distance. The CeO$_2$(200) peak was notable for a deposition temperature above 75$0^{\circ}C$. The YBa$_2$Cu$_3$O$_{7-{\delta}}$ was deposited on CeO$_2$buffered r-cut sapphire substrate using pulsed laser ablation. The YBa$_2$Cu$_3$O$_{7-{\delta}}$CeO$_2$(200)/A1$_2$O$_3$thin film was exhibited a critical temperature of 89K.xhibited a critical temperature of 89K.

• Proceedings of the KIEE Conference
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• 2000.11d
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• pp.700-702
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• 2000

The new design methodology of a hybrid fuzzy controller by means of the genetic algorithms is presented. In fuzzy controller which has been widely applied and used. in order to construct the best fuzzy rules that include adjustment of fuzzy sets, a highly skilled techniques using trial and error are required. To deal with such a problem, first, a hybrid fuzzy controller(HFC) related to the optimal estimation of control parameters is proposed. The HFC combined a PID controller with a fuzzy controller concurrently produces the better output performance than any other controller from each control output in steady state and transient state. Second, a auto-tuning algorithms is presented to automatically improve the performance of hybrid fuzzy controller, utilizing the simplified reasoning method and genetic algorithms. In addition, to obtain scaling factors and PID Parameters of HFC using GA, three kinds of estimation modes such as basic, contraction, and expansion mode are effectively utilized. The HFCs are applied to the first-order second-order process with time-delay and DC motor Computer simulations are conducted at step input and the performances of systems are evaluated and also discussed from performance indices.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.539-540
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• 2006

소형 열병합 (CHP, Combined Heat & Power)은 발전 용량이 1MW 이하인 발전 시스템을 지칭하는 용어로, 전기와 더불어 원동기에서 발생한 폐열을 회수하여 사용한 수 있는 발전 시스템을 말한다. 대표적인 원동기로서는 가스 엔진, 터빈, 마이크로 터빈, 연료 전지 등이 있다. 소형 열병합 시스템은 폐열 회수의 특징으로 기존 시스템에 비해 50% 이상의 에너지 이용 효율이 높으며, 기존의 대형 발전 시스템에서 필연적으로 존재하는 송전 및 배전 손실이 존재하지 않는 수요지 발전의 특징도 갖고 있어서 연료 절약형 에너지 생산 시스템으로서의 높은 가치를 가지고 있다. 또 다른 장점으로 열병합 발전 시스템은 여름철의 최대 전력 부하를 제거하는 역할을 할 수 있음으로 국가 전력 수요 공급의 안정화에 기여하는 바가 크다. 본 논문에서는 최근에 개발된 325kW급 열병합 가스엔진 발전 시스템의 주제어를 담당하는 통합 제어 장치의 개발과 소형 열병합 시스템의 시험 결과에 대해서 소개한다.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.294-299
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• 2008

Steam reforming of methane is the most wide spread method for hydrogen production. It has heed studied more than 60 years. methane reforming has advantages in technological maturity and economical production cost. Using a high-temperature solar thermal energy is an advanced technology in Steam reforming process. The synthesis gas, the product of the reforming process, can be applied directly for a combined cycle or separated for a hydrogen. In this paper, hydrogen conversion rate of a solar chemical reactor is calculated using commercial CFD program. 2 models are considered. Model-1 is original model which is designed from the former researches. And model-2 is ring-disk set of baffle is inserted to enhance the performance. The solar chemical reactor has 3 inlet nozzle at the bottom of the side wall near quartz glass and an exit is located at the top. Methane and steam is premixed with 50:50 mole fraction and goes into the inside. Passing through the porous media, the reactants are conversed into hydrogen and carbon monoxide.

• Journal of Hydrogen and New Energy
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• v.20 no.4
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• pp.265-273
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• 2009

Proton Exchange Membrane Fuel Cell (PEMFC) has low operating temperature and high efficiency. And PEMFC consists of many components as bipolar plate, gas diffusion layer, membrane etc.. Flow-field in bipolar plate roles path for transporting reactants to membrane. Therefore a design of flow-field has an effect on PEMFC's performance. In this study, Computational Fluid Dynamics (CFD) simulations were performed for comparing mixed multiple serpentine (MMS) flow-field and multiple serpentine (MS) flow-field. And we studied an effect according to change mixing region design in MMS flow-field. Finally the applicability of results is verified by performing CFD simulation about fixed MMS flow-field which is combined good designs.