• 동력기계공학회지
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• 제20권2호
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• pp.73-78
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• 2016

In this study, the performance characteristics of a high temperature heat pump dryer that is able to raise the air temperature up to $80^{\circ}C$ by using waste heat as heat source were investigated numerically. The main components of the heat pump dryer were modeling as a compressor, condenser, evaporator and expansion device, and R245fa was selected as refrigerant. Experiments were also conducted to validate the numerical data. As a result, when the evaporator air inlet temperature increased from $50^{\circ}C$ to $65^{\circ}C$, the numerical results of the hot air temperature at outlet and heat pump COP were about 8~11% and 5~8% higher than that of experimental ones, respectively.

• 에너지공학
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• 제27권4호
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• pp.50-63
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• 2018

화석연료의 무분별한 사용으로 인해 지구 온난화 및 환경오염 문제가 대두되고 있으며, 이에 따라 효율적인 에너지 활용을 위해 기존에 버려지는 폐열을 회수하는 기술에 대한 필요성이 커지고 있다. 산업폐열 발전 시장은 발전효율을 높일 수 있다는 장점으로 인해 연평균 5% 성장하고 있다. 고효율 폐열발전시스템 설계를 위해 열원별 조건에 따른 발전 기술별 경제성을 평가할 수 있는 프로그램 개발이 필요하다. 따라서 본 연구에서는 산업폐열 발전시스템에 최적화된 경제성분석 모듈 개발을 위해 균등화 전력원가를 산출하는 모듈을 개발하고 NETL의 경제성분석 사례를 바탕으로 시스템의 신뢰도를 검증하였다. 검증 결과, 오차율은 약 6~7%로 사업 타당성 평가를 위한 정확도를 만족하였으나, 신뢰성 향상을 위해 NETL에서 사용하는 균등화 방법론을 적용하여 알고리즘을 개선하였고 이에 따라 오차율은 1% 미만으로 신뢰도가 향상되었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2021년도 추계학술대회
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• pp.132-133
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• 2021

In recent years, energy harvesting from natural sources and waste heat has been attracting more attention from researchers in response to ever-growing energy demands, high energy prices, and climate-change-mitigation purposes. It is also an important step towards future sustainable energy usages. In thermal dynamic cycles, expanders are playing as the most important equipment for waste heat recovery and energy harvesting as well. As a kind of expander, the bladeless turbine has a promising future and more widely using owning its advantages on relatively long life, good off-design performance, easy operation cleaning and maintenance, a simple structure, no blade corrosion, and low manufacturing costs. There are numerous studies about using the Tesla Turbine as a key technology for energy harvesting in a wide range of applications and conditions. They are presented to help identify technologies that have sufficient potential for applicating to our life and marine industrial engineering. This review paper, initially, presents an overview of current studies both theoretical and experimental of Tesla Turbine usage for waste heat recovery alongside its challenges and investigation on the effect of its configuration, working fluid selection as well. To conclude, future perspectives besides possible ways of transforming waste heat energy to electricity or work, which leads to circular energy, are discussed. The ambition of this paper is to act as a first-hand reference, through the well-defined possible directions, to the young researchers and senior scientists.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.460-463
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• 2008

A large part of the overall industrial energy is dissipated as waste heat despite of much development in the utilization of thermal energy. A mean efficiency is reported to be only around 30 to 35%. The existing waste heat recovery technology has reached its limit and consequently, the development of a new technology is necessary. Improving efficiency using thermoelectric technology has recently come into the spotlight because of its unique way to recover thermal energy. In fact, thermoelectric generator directly converts thermal energy into electric energy by a solid state without any moving parts. Futhermore remarkable improvement in the thermoelectric energy conversion efficiency has been achieved. In this study, a thermoelectric generator was made using commercialized thermoelectric modules. With thermoelectric modules attached on a duct surface, hot air was blown into the duct using a hot air blower. On the other side of the module, a water jacket was attached to cool the module. With different air inlet temperatures and water flowrates, the electrical power of the thermoelectric generator was measured.

• 시멘트
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• 통권164호
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• pp.15-18
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• 2004

• 한국자동차공학회논문집
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• 제21권6호
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• pp.81-91
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• 2013

A novel design process of a parallel multi-flow type air-cooled condenser of a dual-loop waste heat recovery system with Rankine steam cycles for improving the fuel efficiency of gasoline automobiles has been investigated focusing on reduction of the pressure drop inside the micro-tubes. The low temperature condenser plays a role to dissipate heat from the system by condensing the low temperature loop working fluid sufficiently. However, the refrigerant has low evaporation temperature enough to recover the waste from engine coolant of about $100^{\circ}C$ but has small saturation enthalpy so that excessive mass flow rate of the LT working fluid, e.g., over 150 g/s, causes enormously large pressure drop of the working fluid to maintain the heat dissipation performance of more than 20 kW. This paper has dealt with the scheme to design the low temperature condenser that has reduced pressure drop while ensuring the required thermal performance. The number of pass, the arrangement of the tubes of each pass, and the positions of the inlet and outlet ports on the header are most critical parameters affecting the flow uniformity through all the tubes of the condenser. For the purpose of the performance predictions and the parametric study for the LT condenser, we have developed a 1-dimensional user-friendly performance prediction program that calculates feasibly the phase change of the working fluid in the tubes. An example is presented through the proposed design process and compared with an experiment.

• 한국자동차공학회논문집
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• 제10권1호
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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.

• 에너지공학
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• 제15권4호
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• pp.284-290
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• 2006

냉 난방 수요에서 일어나는 환경오염의 최소화와 화석연료 소비를 감소시키기 위해서 에너지 회수를 개선시키는 것은 필수적이다. 이러한 점에서 흡수식 열펌프기술은 에너지 절약을 위해서 많은 가능성을 가지고 있다. 흡수식 열펌프는 에너지를 주입하지 않고 폐열의 이용을 높일 수 있는 방법이다. 본 연구에서는 에너지 회수를 위한 재흡수 열펌프 연군를 메탄올-글리세린을 이용하여 수행하였다. 이 물질의 열역학 데이터를 이용하여 재흡수 열펌프의 이론적 열효율 값을 각 기관의 조업 조건에 따라서 계산하였다. $70{\sim}80^{\circ}C$의 산업 폐열 온도를 가지고 $40{\sim}50^{\circ}C$ 승온 시킬 때 열효율 값 0.4 이상을 얻을 수 있었다.

• 한국지반환경공학회 논문집
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• 제8권3호
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• pp.11-18
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• 2007

본 연구에서는 파급효과가 큰 공동주택에서 지열 냉난방 시스템의 경제성을 아파트 분양평형, 운전시간, 냉난방 및 급탕 설치형태별로 구분하여 초기 공사비 증가, 운전비 절감액, 초기 투자비 회수기간등을 산정하였다. 냉난방 및 급탕 운전시간이 많을수록 초기 공사비 증가액에 비해 운전비용 절감액이 커 초기 투자비 회수기간이 단축되었다. 전용면적이 클수록 투자회수 기간이 길었으며 냉난방 및 급탕 설치형태에서는 냉난방을 지열원, 급탕을 폐열회수한 경우가 초기 투자 회수기간이 가장 짧았다. 기존 시스템(패키지 에어콘, LNG 난방 및 급탕)에 비해 냉난방, 급탕을 모두 지열로 이용하는 경우, 냉난방은 지열, 급탕은 폐열을 이용하는 경우, 냉난방은 지열, 급탕은 LNG인 경우에 공사비가 $m^2$당 각각 약 72,000원, 66,900원, 62,300원 정도 증가하였다.

• 시스템엔지니어링학술지
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• 제14권1호
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• pp.1-12
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• 2018

In the energy-guzzling industries such as steel making and cement, power plants utilizing waste heat have been attracting attention to increase energy efficiency. However, the existing economic analysis system doesn't consider the special working fluids and the cost models of the main equipment used in the waste heat recovery power plant. So it is difficult to estimate the plant economics accurately. Therefore, It is required to develop a economic analysis module that can more accurately evaluate for the power plant. In this study, the systems engineering approach was used to design and develop the module that systematically reflects the characteristics of the power plant and various requirements. Specifically, first, the special working fluids and main equipment applied to the power plant were investigated. Next, the cost models for each equipment were developed. Finally, the economic analysis module based on this was developed.