• The Magazine for Energy Service Companies
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• s.1
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• pp.40-43
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• 1999

이 자료는 지난 11월 15일부터 18일까지 서울 이마빌딩에서 개최되었던 한$\cdot$ 에너지 효율향상을 위한 워크샵에서 발표된 내용중 하나이다. 에너지관리공단과 US-AEP가 공동주관한 이 행사에서는 에너지 관리 진단 및 이익, 폐열회수기술 및 방법, 사례등에 관한 내용들이 주로 소개되었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.839-845
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• 2021

In this study, it shows the efficiency of each refrigerant through simulation method for ORC (Organic Rankine Cycle) power generation that converts waste heat discarded by ship exhaust into electricity for the purpose of reducing CO₂ emission and increasing ship waste heat recovery. by Simulation was performed with waste heat from the exhaust gas which is relatively high temperature and cooling sea water which is relatively low temperature from ships. As a result of the sea water cooling ORC power generating system, efficiency of the working fluid with R717 is highest as a 2.86 % and the next working fluid is R152a, R134a, R143a and R125a.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.371-372
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• 2020

최근 차량에 적용 가능한 에너지 하베스팅 연구가 활발히 이루어지고 있다. 차량 폐열을 활용하는 열전 소자의 경우 급격한 온도 변화 특성이 있는 내연기관, 배기관 등의 전장 부품에 적용될 수 있다. 이러한 전장 부품에서 가능한 많은 열에너지를 회수하기 위해 빠르고, 정확한 최대 발전전력 추종 기법이 필수적이다. 본 논문은 이러한 열전 소자 발전의 차량 적용을 위한 최대 전력 추종 기법을 살펴보고 비교 조사 분석한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.171-179
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• 2013

The thermodynamic characteristics of a combined cycle applied with a topping cycle such as a trilateral cycle at relatively high temperatures and a bottoming cycle such as an organic Rankine cycle at relatively low temperatures have been theoretically investigated. This is an electric generation system used to recover the waste heat of the exhaust gas from a diesel engine used for the propulsion of a large ship. As a result, when the boundary temperature between the topping and the bottoming cycles increased, the system efficiencies of energy and exergy were simultaneously maximized because the total exergy destruction rate (${\sum}\dot{E}_d$) and exergy loss ($\dot{E}_{out2}$) decreased, respectively. In the case of a marine diesel engine, the waste heat recovery electric generation system can be utilized for additional propulsion power, and the propulsion efficiency was found to be improved by an average of 9.17 % according to the engine load variation, as compared to the case with only the base engine. In this case, the specific fuel consumption and specific $CO_2$ emission of the diesel engine were reduced by an average of 8.4% and 8.37%, respectively.

• The KSFM Journal of Fluid Machinery
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• v.12 no.1
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• pp.43-50
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• 2009

Waste heat recovery process designs and performance analyses are conducted on the IGCC(Integrated Gasification Combined Cycle) power plants integrated with two different coal gasification and gas cleanup processes by Shell and GE/Texaco. Through the analysis results, the present study provides the steam integration concept between the HRSG and the chemical processes of IGCC power plant, and investigates the effect of steam integration on the power generation of IGCC power plant. The present simulation results show less steam power output and higher overall IGCC efficiency of the Shell-based power plant than the GE/Texaco.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.99-105
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• 2002

About 70% of energy input to internal combustion engine is rejected to atmosphere by heat. By utilizing this waste heat, a plenty of energy can be conserved in nationwide. One of possible ways is the thermoelectric generation to utilize engine's waste heat to provide auxiliary electric power. Under th is concept, we have been developing the thermoelectric generation system to replace the alternator by converting the waste heat in the engine's exhaust directly to electricity This system may reduce the shaft horse power of the engine, then improves the vehicle fuel economy and the exhaust emissions. In the present study, the characteristics of the electric energy and exhaust heal energy in city and highway mode driving conditions are analysed by using a gasoline passenger car. These results would be used to determine the optimum design parameters of the thermoelectric generation system.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.8-14
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• 2014

This research designed Waste Heat Recovery System(WHRS) generation system of 250kW whose working fluid is R-245fa and studied on cycle characteristics by superheater organization. It simulated two conditions; series connection and parallel connection between superheater and evaporator. In simulation of series connection of superheater and evaporator, output of 4.7% could be improved because of the increase of enthalpy by overheating of working fluid. When setting 250kW for target output, cycle flux could be reduced by 4.1%. When setting 250kW as a target output of cycle In parallel connection simulation of superheater and evaporator, cycle flux was reduced as flux of heat source fluid for superheater was increased. So, the maximum 7.9% of working fluid pump's electric power was reduced and there was no big change in cycle efficiency and net efficiency by flux ratio.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.6
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• pp.403-410
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• 2009

This paper proposes a new approach to find the optimum ratios between sizes of the heat exchangers of the heat recovery steam generator (HRSG) system with limited size to maximize the efficiency of the steam turbine (bottom) cycle of combined cycle power plants (CCPP), but without performing the bottom cycle analysis. This could be achieved by minimizing the unavailable exergy (the sum of the destroyed and the lost exergies) resulted from the heat transfer process of the HRSG system. The present approach is relatively simple and straightforward because the process of the trial-and-error method, typical in performing the bottom cycle analysis for the system optimization, could be avoided. To demonstrate the usefulness of the present method, a single-stage HRSG system was chosen and the optimum evaporation temperature was obtained corresponding to the condition of the maximum useful work. The results show that the optimum evaporation temperature based on the present exergy analysis appears similar to that based on the bottom cycle analysis. Also shown is the dependency of size (NTU) ratios between the heat exchangers on the inlet gas temperature, which is another important factor in determining the optimum condition once overall size of the heat recovery steam generator is given. The present approach turned out to be a useful tool for optimization of the singlestage HRSG systems and can easily be extended to multi-stage systems.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.175-181
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• 2011

The purpose of this study is to secure the design data for the optimization of the radial turbine and heat cycle system, by using the CFD analysis technique and the design of 100kW class radial turbine applicable to waste heat recovery generation system for ship. Radial turbine was comprised of scroll casing, vane nozzle with 18 blades and rotor with 13 blades, and analysis grid was used to about 2.3 million. Mass flow rate and rotational speed was 0.5kg/s, 75,0000rpm, respectively. Eight kinds of inlet pressure was set between 195 and 620kPa. As the flow accelerated through the nozzle passage to the throat, the pressure level at the pressure and suction sides becomed similar to about Mach number of 0.35. When the inlet temperature and pressure was $250^{\circ}C$, 352kPa respectively, the isentropic efficiency and mechanical power showed the analysis results of 74% and 108kW.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.294-301
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• 2022

In this study, a multi-layer cascade (MLC) electrical array configuration method for thermoelectric generator consisting of plural number of thermoelectric modules (TEMs) was proposed to reduce mismatch loss caused by temperature maldistribution on the surfaces of the TEMs. To validate the effect of MLC on the mismatch loss reduction, a numerical model capable of reflecting multi-physics phenomena occuring in the TEMs was developed. MLC can be employed by placing a group of TEMs experiencing relatively low temperature differences in an electric layer with more electrical branches while locating a group of TEMs experiencing relatively high temperature differences in an electric layer with less electrical branches. The TEMs were classified using the temperature distribution obtained by the numerical model. A MLC with an optimal electrical branch ratio showed a 96.5% of electric power generation compared to an ideal case.