폐열회수시스템의 열교환기 최적설계조건

성규식(Gyu-Sik Sung),황은빛(Eunbit Hwang),박주헌(Juheon Park),최종성(Jongseong Choi),신기열(Ki-Yeol Shin),배상수(Sang-Su Bae),조경철(Kyung-Chul Cho),권오대(Oh-Dae Kwon) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

In this study, optimum capacity design of heat exchangers in a waste heat recovery system(WHRS) that recovers a large amount of heat energy from high-temperature exhaust gas which was supplied from a power generation gas engine using biogas produced from organic waste in an industrial complex were performed. The type and size of waste heat recovery system components suitable for engine power capacity according to biogas production volume were designed, and energy recovery efficiency was analyzed. The waste heat recovery system consists of a smoke tube boiler that produces 5 bar pressure and 161°C superheated steam from exhaust gas as heat source, and two economizers that produce preheating of supply water and hot water. Two different gas engine capacities as 100kW and 250kW were analyzed to product a target amount of superheated steam and hot water to maximize efficiency of waste heat recovery system. From the result of heat exchanger performance analysis, the optimum value of heat exchanger capacity ratio was founded as similar range as 0.43 ~ 0.46 even two different capacity of engines.

배기열 회수 시스템을 적용한 엔진의 웜업 특성 해석

이헌균(Heonkyun Lee),허형석(Hyungseok Heo),황재순(Jaesoon Hwang),배석정(Sukjung Bae),정재우(Jaewoo Chung) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Recently, improvement of vehicle economy at low temperature operating condition has become an issue. Utilizing waste heat of exhaust gas is effective to improve the overall vehicle economy. The exhaust heat recovery system transfers the thermal energy from “hot” exhaust gas to “cold” engine coolant, and heated coolant reduces engine warm-up time. Therefore, it is possible that vehicle economy is enhanced by reduced engine fiction loss. The current work evaluated the effect of the exhaust heat recovery system applied to the PHEV engine. Results showed an improvement of warm-up time for the engine thermal management system by use of the heat recovery system. Moreover, the warm-up characteristics were analyzed according to the variation of the thermal management system layout.

초대형 트럭 배기열 회수 시스템 개발에 관한 연구

김우석(Wooseok Kim),서정민(Jungmin Seo),손유상(Yousang Son) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5

Waste heat recovery (WHR) has been recognized as a promising technology to achieve the fuel economy and greenhouse gas reduction goals for future heavy-duty (HD) truck diesel engines. A Rankine cycle system with ethanol as the working fluid was developed with HMC & VOITH, to investigate the fuel economy benefit from recovering waste heat from a 12.7L HD truck diesel engine. Thermodynamic analysis on this WHR system demonstrated that 6.5% fuel saving could be achievable. Finally, test bench measurements of the applied engine coupled with a heat recovery device are carried out. It can be demonstrated that waste heat recovery can produce an additional power output of about 3.2~4.5% at partial load and 1.2 ~ 2.8% at full load condition. Also as a result of vehicle testing, fuel economy can be achieved to increase 3.3% at chassisdynamometer mode test.

Waste heat recovery of the turbocharged engine employing vortex tube for improving transient cold start

S. Entezari,I. Chitsaz,S. Kazemzadeh Hanani,M. Monemi 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

Most of the vehicle pollutants during emission tests are raised from catalyst inefficiency during cold start. Catalysts usually convert harmful emissions only when their temperature reaches around 250 °C to 350 °C. In this research, the vortex tube is implemented to recover the waste heat energy of exhaust gas during the cold start to improve catalyst heating. The experiments are conducted on the turbocharged direct-injection gasoline engine to extract the boundary conditions of numerical simulations. Numerical simulations are performed to evaluate the effects of different hot exhaust mass fractions on the flow regime and waste heat recovery. The results reveal that the level of turbulence inside the vortex tube increases for higher hot mass fractions that lead to lower exhaust temperature on the hot side. By implementing the vortex tube, the maximum temperature at the hot exhaust is related to 20 % of the hot mass fraction and after that, the hot exhaust temperature decreases. By implementing the vortex tube, gas temperature before the catalyst is reached to 658 K at 52.3 % hot mass fraction which shows 48 K increase in exhaust temperature before the catalyst. At this point, 300 W heat is transferred to the exhaust gas that improves transient cold start time.

대형 가솔린 엔진의 폐열 회수 장치인 슈퍼히터의 최적 위치선정을 위한 시뮬레이션 연구

김세린(Se Lin Kim),최경욱(Kyung Wook Choi),이기형(Ki Hyung Lee),김기범(Ki Bum Kim) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.2

최근 자동차 엔지니어들은 자동차 엔진의 열효율을 향상시키기 위한 수단으로 폐열 회수 기술에 많은 관심을 기울이고 있다. 배기량이 큰 가솔린 엔진은 대체로 V형인데, 열 회수를 위해 두 개의 슈퍼히터를 각각의 배기 다기관 가까이에 설치하는 것은 비용 면에서 효율적이지 않다. 하나의 슈퍼히터를 한쪽 배기 다기관에 최대한 가깝게 부착하면 좀 더 높은 열교환 효율을 얻을 수 있으나 폐열회수를 위한 배기가스의 유량은 절반이 된다. 반면에, 배기가스의 유량을 전부 이용하기 위하여 두 배기관이 합류된 지점에 슈퍼히터를 설치하면 배기가스의 온도는 많이 감소된다. 이 사실을 바탕으로 슈퍼히터의 최적 위치를 조사하기 위하여 상용프로그램인 AMESim을 이용해 해석을 수행하였다. 이 때, 배기가스 유량 중 절반만을 사용하더라도 슈퍼히터를 배기 다기관과 최대한 가까이 부착하는 것이 엔진의 배기가스로부터 3.8 kW의 열을 더 회수할 수 있는 것으로 나타났다. 이 결과를 바탕으로 최적의 폐열 회수 모델을 도출하고 제안하였다. Recently, automotive engineers have paid much attention to waste heat recovery technology as a possible means to improve the thermal efficiency of an automotive engine. A large displacement gasoline engine is generally a V-type engine. It is not cost effective to install two superheaters at each exhaust manifold for the heat recovery purposes. A single superheater could be installed as close to the exhaust manifold as possible for the higher recovery efficiency; however, only half of exhaust gas can be used for heat recovery. On the contrary, the exhaust temperature is decreased for the case where the superheater is installed at a junction of two exhaust tail pipes. With the fact in mind, the optimum position of a single superheater was investigated using simulation models developed from a commercial software package (i.e. AMESim). It was found that installing the superheater near the exhaust manifold could recover 3.8 kW more from the engine exhaust despite utilizing only half of the exhaust mass flow. Based on this result, the optimum layout of an automotive waste heat recovery system was developed and proposed in this paper.

AMESim software를 이용한 엔진 폐열 회수율 조사 및 최적 시스템 개발

김세린(Se-lin Kim),최경욱(Kyung-wook Choi),이기형(Ki-hyung Lee),김기범(Ki-bum Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

In recent, automobile engineers have paid much attention on the waste heat recovery technologies, one of possible means to improve thermal efficiency of automotive engine. Two superheaters for the heat recovery in V-type gasoline engine is not cost effective. Therefore, finding the optimum position for one superheater is always tricky decision. The superheaterd better be installed as near exhaust manifold as possible for higher effectiveness; however, only half of exhaust mass flow could be utilized for heat recovery. With the fact in mind, the optimum position of one superheater was investigated with simulation models developed using a commercial software (i.e. AMESim). It was found that installing the superheater near the exhaust manifold regardless of utilizing only half of exhaust mass flow, could recover 3.8 kW more energy from the engine exhaust. Based on this result, the optimum layout of an automotive waste heat recovery system was developed and proposed in this paper.

Experimental study on oscillating flow steam engine in a single micro tube

Kanno, Hiroshi,Han, Youngbae,Shikazono, Naoki Elsevier 2017 Experimental thermal and fluid science Vol.81 No.-

<P><B>Abstract</B></P> <P>Oscillating flow steam engine can be a cost-effective solution for recovering work from waste heat due to its structural simplicity. In the present study, the effects of design parameters and operating conditions of oscillating flow steam engine such as tube diameter, heating section temperature, cooling section length ratio and compression ratio are experimentally investigated. The pressure variation due to boiling and condensation induces a continuous oscillating flow in a single micro tube, which can generate work using crank-piston system. The indicated work and cycle efficiency both increase as the heating section temperature and compression ratio are increased. The investigated oscillating flow steam engine achieved indicated work of 1W with the cycle efficiency of <I>η</I> =5% at <I>T</I> <SUB>heat</SUB> =230°C and <I>T</I> <SUB>cool</SUB> =80°C in a <I>D</I> =1.0mm tube.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oscillating flow steam engine is investigated for waste heat recovery. </LI> <LI> Experimental setup for oscillating flow steam engine in a single micro tube is made. </LI> <LI> Effects of several parameters on heat engine are investigated experimentally. </LI> <LI> Current heat engine achieved 1W work and 5% efficiency between 230°C and 80°C. </LI> </UL> </P>

내연기관에 적용하기 위한 10 kW급유기랭킨사이클의 구심 터빈에 관한 실험적 연구

신동길,김영민,류영현 한국마린엔지니어링학회 2018 한국마린엔지니어링학회지 Vol.42 No.4

Internal combustion engines are used as the main power source in various fields. They emit carbon dioxide during the combustion process. Among the various ways to reduce carbon dioxide, one would be to reduce fuel consumption. In this study, we compare and analyze the performance of the radial turbine applied to the expander of the 10 kW class ORC system. Waste heat of the engine is recovered to reduce the fuel consumption of the internal combustion engine. The ORC system was constructed using R134a as the working fluid, and the experiment was conducted. The expander is a permanent magnet synchronous type generator with two poles and an integral radial turbine. The maximum number of revolutions is 100,000 rpm. The expander is the most important core component to improve the efficiency of the ORC system. The heat source of the ORC system can be divided into exhaust heat and cooling water heat. The authors have constructed and tested a high temperature oil boiler to simulate the heat of the individual hot exhaust and a low temperature steam boiler, to simulate the engine coolant heat of the low temperature boiler. 내연기관은 다양한 분야에서 주 동력원으로 사용되고 있는데, 연소과정에서 이산화탄소를 배출한다. 이산화탄소를줄이기 위한 여러 가지 방법 중에서 연료소모량을 줄이는 방법이 있다. 본 연구에서는 내연기관의 연료 소모량을 줄이기 위해서 엔진 폐열 회수를 위한 10 kW급 ORC 시스템의 팽창기로 적용된 구심 터빈 성능을 비교, 분석하였다. R134a 를 작동유체로 사용하여 ORC시스템을 구성하여 실험을 수행하였다. 팽창기는 2극을 가진 영구자석동기 발전기와 일체형 구심 터빈으로서, 최대 회전수는 100,000 rpm 이다. 팽창기는 ORC 시스템의 효율향상을 위해서 가장 중요한 부품이라고 할 수 있다. ORC 시스템의 열원은 배기열과 냉각수열로 구분할 수 있다. 고온 열매체인 배기열을 모사할 수 있는고온 가스 보일러와 저온 열매체인 엔진 냉각수열을 모사할 수 있는 저온 스팀 보일러를 각각 구성하여 실험 하였다.

선박 주기관 폐열 회수를 위한 유기 랭킨 사이클 시스템 최적화

이동길(Dongkil Lee),이호기(Hoki Lee),박건일(Gunil Park),최재웅(Jaewoong Choi) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

Addition of evaporator and preheater were studied to maximize output power of organic rankine cycle as a waste heat recovery system of the marine diesel engine. Exhaust gas, scavenge air and jacket cooling water were considered as possible heat sources to be recovered. Dual loop system which has multiple heat transfer loops for each waste heat source shows better performance than the single loop system which has only one heat transfer loop. By changing ORC evaporator and preheater, the output of ORC increased by 6~27%.

유기 랜킨 사이클을 이용한 선박 주기관 폐열 회수 시스템의 열역학적 분석

진정근(Jungkun Jin),이호기(Hoki Lee),박건일(Gunil Park),최재웅(Jaewoong Choi) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

A thermodynamic analysis and feasibility study of Organic Rankine Cycle (ORC) were carried out as a waste heat recovery system for a marine diesel engine. ORC and its combined cycle with the engine were simulated and its performance was estimated theoretically under the various engine operation conditions and cooling water conditions using R245fa as working fluid. According to the thermodynamic analysis, ~10% of thermodynamic efficiency of the cycle was able to be realized with the low temperature heat source below 250℃. The electric power output of the ORC was estimated to be about 4% of the mechanical power output of the engine considering additional pumps for cooling water and circulation of the heat transfer medium.