Taehong Sung

LNG Cold Energy Utilization Technology

A large amount of cold energy is discarded without being utilized during natural gas transmission process. In this chapter, available cold energy in LNG and LNG cold energy application areas are analyzed. LNG cold energy can be used for power generation, air separation, liquefaction of CO2, production of dry ice, cold storage and rapid cooling, district cooling and other applications. The schematics and characteristics for those application systems are described in detail. As for the case study, an organic Rankine cycle based power system which is attached with natural gas fueled LNG carrier is designed and an analysis of proper working fluid selection is conducted.

Design and Thermodynamic Analysis of Hybrid Tri-generation Gas Engine-Organic Rankine Cycle

Abstract >> In a gas engine, the exhaust and the engine cooling water are generated. The engine cooling water temperature is 100 ℃ and the exhaust temperature is 500 ℃. The amount of heat of engine cooling water is43 kW and the amount of heat of exhaust is 21 kW. Eight different hybrid organic Rankine cycle (ORC) systemconfigurations which considering different amount and temperature of waste heat are proposed for two gas enginetri-generation system and are thermodynamically analyzed. Simple system which concentrating two different wasteheat on relatively low temperature engine cooling water shows highest thermal efficiency of 7.84% with pressureratio of 3.67 and shaft power of 5.17 kW. Key words : Gas engine(가스 엔진), Engine exhaust(엔진 배기), Organic Rankine cycle(유기랭킨사이클), Hybridsystem(하이브리드 시스템), Thermodynamic analysis(열역학적 분석) † Corresponding author : kckim@pusan.ac.kr Received : 2015.01.02 in revised form 2015.01.24 Accepted: 2015.02.28Copyright ⓒ 2015 KHNES Nomenclature h : enthalpy (kJ/kg)η : efficiency

Dynamic Simulation of Molten Carbonate Fuel Cell and Mechanical Balance of Plant

Key Words: Molten Carbonate Fuel Cell Modeling(용융탄산염연료전지 모델링), Machanical Balance of Plant(기계적 주변기기), Dynamic Simulation(동적 시뮬레이션)초록: 본 연구의 목적은 용융탄산염연료전지와 같은 고온연료전지에 동반하는 기계적 주변기기의 타당성을 검토할 수 있는 동적 시뮬레이션 모델을 개발하는 것이다. 연료전지를 운송수단과 같은 독립적인 동력기관에서 사용하기 위해서는 동반하는 기계적 주변기기를 최적화 및 소형화할 필요가 있다. 본 연구에서는 유입가스의 조성, 압력, 유량 및 스택의 온도에 따른 용융탄산염연료전지 내부의 화학반응의 동적 모델링을 구현하고 정상상태 시뮬레이션을 수행하여 실험결과와 비교 분석하였다. 또 연료전지의 전류밀도 제어에 따른 on/off 시뮬레이션을 수행하여 동적 시뮬레이션 모델의 타당성을 분석하였다.Abstract: This study aims to develop a simulation bed for the mechanical balance of plants of high temperature fuel cells such as molten carbonate fuel cells. For using fuel cells in transportation, the optimization of the balance of plants should be considered. In this study, the dynamic model of a molten carbonate fuel cell and the models responses to inlet gas composition, pressure, flow rate, and stack temperature were analyzed. On/off simulation was performed for testing the dynamic models feasibility. The simulation results are in reasonable agreement with the experimental results from published literatures.논문은대한기 계학 회