• Applied Chemistry for Engineering
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• v.30 no.1
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• pp.62-67
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• 2019

This study was focused on the design and the performance analysis of integral Hot BoP for recovering waste heat from high-temperature exhaust gas in 2 kW class solid oxide fuel cell (SOFC). The hot BoP system was consisted of a catalytic combustor, air preheater and steam generator for burning the stack exhaust gas and for recovering waste heat. In the design of the system, the maximum possible heat transfer was calculated to analyze the heat distribution processes. The detail design of the air preheater and steam generator was carried out by solving the heat transfer equation. The hot BoP was fabricated as a single unit to reduce the heat loss. The simulated stack exhaust gas which considered SOFC operation was used to the performance test. In the hot BoP performance test, the heat transfer rate and system efficiency were measured under various heat loads. The combustibility with the equivalent ratio was analyzed by measuring CO emission of the exhaust gas. As a result, the thermal efficiency of the hot BoP was about 60% based on the standard heat load of 2 kW SOFC. CO emission of the exhaust gas rapidly decreased at an equivalent ratio of 0.25 or more.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.695-701
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• 2018

Research into exhaust heat recovery has been actively carried out to improve the thermal efficiency of internal combustion engines. In this study, the performance of thermoelectric generation from exhaust heat recovery for motorcycle engines was analyzed by 1-D thermo-fluid simulation. GT-SUITE, which was developed by Gamma Tech., was used for the simulation of the internal combustion engine and thermoelectric generation system. The basic performance of the engine was analyzed in the range of engine speed of 1000~7000 rpm and engine load of 0~100%. The ratio of exhaust heat energy to fuel chemical energy was found to be about 40~60%. A combined simulation of the engine model and thermoelectric generation model was carried out to analyze the voltage, current and power generated by the thermoelectric material. The generation characteristics of the thermoelectric material was dominantly affected by the exhaust gas temperature. The maximum generated power of the current thermoelectric generation system was found to be about 2.2% of the total exhaust heat energy. The design optimization of the thermoelectric generation system will be carried out to maximize its power generation and economic feasibility.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.11a
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• pp.13-17
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• 2000

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.171-177
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• 2000

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.60-67
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• 2021

This study presented techno-economic analysis of a 500 MWe oxy-coal power plant with CO2 capture. The power plant included a circulating fluidized-bed (CFB), ultra-supercritical steam turbine, flue gas conditioning (FGC), air separation unit (ASU), and CO2 processing unit (CPU). The dry flue gas recirculation (FGR) was used to control the combustion temperature of CFB. One FGR heat exchanger, one heat exchanger for N2 stream exiting ASU, and a heat recovery from CPU compressor were considered to enhance heat efficiency. The decrease in the temperature difference (ΔT) of the FGR heat exchanger that means the increase in heat recovery from flue gas enhanced the electricity and exergy efficiencies. The annual cost including the FGR heat exchanger and FGC cooling water was minimized at ΔT = 10 ℃, where the electricity efficiency, total capital cost, total production cost, and return on investment were 39%, 1371 M$, 90 M$, and 7%/y, respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.153-158
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• 2013

The purpose of this study is to investigate the performance characteristics of the counterflow exhaust heat recovery device for the applied gasoline engines. The EHRS device is installed behind the catalyst. This study investigates the engine warm-up characteristic, the exhaust noise characteristic, the back-pressure characteristic. The engine warm-up characteristics is (load 0%, load 10%, load 20%) in (idle, 1000rpm, 1500rpm, 2000rpm, 2500rpm) conditions by measuring the time it warmed up, coolant temperature ($25^{\circ}C{\sim}80^{\circ}C$) until the performance evaluation is performed. The wide open throttle and the coast down the exhaust noise and the back-pressure characteristic experiment repeated twice. The test conditions is 950rpm~6,050rpm proceed experiment repeated 3-5 times. Load 0% idle conditions except the results improved engine warm-up characteristics. The exhaust noise obtain similar results the BASE+EHRS W/O_FRT_MUFF with BASE and back-pressure to obtain similar results BASE+EHRS W/O_FRT_ MUFF with BASE+EHRS.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.595-602
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• 2012

In this study, for the purpose of reduction of $CO_2$ gas emission and to increase recovery of waste heat from ships, the ORC (Organic Rankine Cycle) is investigated and offered for the conversion of temperature heat to electricity from waste heat energy from ships. Simulation was performed with waste heat from the exhaust gasse which is relatively high temperature and cooling sea water which is relatively low temperature from ships. Various fluid is used for simulation of the ORC system with variable temperature and flow condition and efficiency of system and output power is compared. Finally, 2,400kW output power is obtained by system optimization of the preheater and reheater utilizing waste heat form sea water cooling system.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.44-44
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• 2010

대부분의 산업분야에서 사용되는 공업로는 연소 시 $1000^{\circ}C$이상의 고온 배기가스가 배출되고 있기 때문에, 이들 배기가스로부터 폐열을 회수하여 에너지를 절감하고자 열교환기를 사용하고 있다. 하지만 현재 사용되고 있는 금속 소재의 열교환기의 경우 사용온도가 $800^{\circ}C$로 제한되어 있으며, 산화, 부식, creep등의 문제가 대두되고 있다. 본 연구에서는 세라믹 소재의 열교환기를 제작하여 열전달율, 공기누설율등을 평가하는 성능실험을 하였다. 실험방법은 연소시작 후 정상상태에 도달하기까지의 경향을 알아보고 공기유량과 가스유량에 변화를 주었을 때, 열전달율과 공기누설율등을 평가하고 이론적인 데이터와 비교하였다. 실험 결과, $1300^{\circ}C$이상의 환경에서도 정상적으로 작동하였으며, 외부환경조건을 고려하였을 때, 이론적인 데이터와 근접한 데이터를 얻을 수 있었다. 그러나 대류열전달에 의한 열손실과 공기누설등이 문제점으로 지적되었다. 향후 연구에서는 대류열전달에 의한 열손실을 고려한 연구와 효과적인 씰링으로 누설을 줄일 수 있는 실험장치를 개발할 필요가 있다.

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.212-222
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas flue connected to combustion chamber of greenhouse heating system. The experimental heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas flue, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amounts by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air tubes and exhaust air passages crossing the tubes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through flue.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.11
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• pp.14-20
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• 2003

가스엔진의 열병합 발전은 가스엔진으로 구동하는 발전기에서 전기를 얻고, 가스엔진 작동 시에 발생하는 배기가스와 냉각수에서 열에너지를 회수하여, 전기와 열을 동시에 생산하는 고효율 에너지 절약 시스템으로서 지금까지 개발된 기술의 동향과 보급사례 등을 살펴보고자 한다.