• Clean Technology
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• v.12 no.2
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• pp.95-100
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• 2006

Fractionation and hydrodealkylation (HDA) units, subparts of BTX plant, were thermodynamically analyzed using the notion of exergy. Exergy values were calculated as the sum of physical and chemical exergies due to the existence of chemical reactions. The analysis was based on the simulation results with the aid of real operating data. Driving and material exergy losses were separately defined and quantified. Locations and the reason of major exergy losses were identified and improvement strategies were suggested. It was noted that the exergy analysis could provide a sound base for adopting the concept of industrial ecology and developing loss prevention schemes.

• Clean Technology
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• v.6 no.2
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• pp.129-137
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• 2000

A methanol synthesis process via reverse-water-gas-shift and methanol formation reactions has been analyzed using the notion of exergy. The analysis has been based on the simulation results with the aid of real operating data. Driving and material exergy losses have been defined and quantified, respectively. Locations and the reason of major exergy losses have been pinpointed and improvement strategies have been suggested. It had been noted that the exergy analysis can provide a sound scientific base for adopting the concept of industrial ecology and developing loss prevention schemes.

• The Magazine for Energy Service Companies
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• s.62
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• pp.44-47
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• 2010

엑서지 진단기법을 개발해 그 수준을 한 차원 높이면서 새로운 에너지진단의 지평을 열고 있는 (주)엑서지엔지니어링. 우수한 에너지관리 및 환경문제에 대한 끊임없는 연구, 기술 전문 인력 확보, 고효율 에너지절약기기로 교체사업을 주도하는 등 분주하게 경영성과를 올리고 있는 엑서지엔지니어링 박명호 대표를 만나 ESCO 사업에 대한 기술력과 노하우를 들어보았다.

• Journal of Energy Engineering
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• v.18 no.2
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• pp.93-100
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• 2009

An exergy analysis is carried out for the regenerative wet-compression Brayton cycle which has a potential of enhanced thermal efficiency owing to the reduced compression power consumption and the recuperation of exhaust energy. Using the analysis model, the effects of pressure ratio and water injection ratio are investigated on the exergy efficiency of system, exergy destruction ratio for each component of the system, and exergy loss ratio due to exhaust gas. The results of computation for the typical cases show that the regenerative wet-compression gas turbine cycle can make a notable enhancement of exergy efficiency. The injection of water results in a decrease of exergy loss of exhaust gas and an increase of net power output.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.4
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• pp.45-54
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• 2009

An exergy analysis is carried out for the regenerative steam-injection gas turbine systems which has a potential of enhanced thermal efficiency and specific power. Using the analysis model in the view of the second law of thermodynamics, the effects of pressure ratio, steam injection ratio, ambient temperature and turbine inlet temperature are investigated on the performance of the system such as exergetic efficiency, heat recovery ratio of heat exchangers, exergy destruction, loss ratios, and on the optimal conditions for maximum exergy efficiency. The results of computation show that the regenerative steam-injection gas turbine system can make a notable enhancement of exergy efficiency and reduce irreversibilities of the system.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.1
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• pp.9-14
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• 2011

The expansion work that is wasted through the irreversible expansion through the PC valve of decompression process of the natural gas governor station can be recovered by replacing the process by an isentropic expansion. The energy and exergy analyses for the two decompression process models of power producing and current decompression process model are presented. Analysis results showed that the exergy by gas supply is 56.29%, the exergy by producing power is 32.12 % in case of preheating system and 22.52% in case of non-preheating system. The dead exergy at the PCV is generated much more network. As these results, the usefulness of exergy analysis is verified.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.83-94
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• 1993

In this paper, the performance of an energy conversion system is analyzed using two efficiency concepts, one of conventional and the other of energetic efficiently. The objective of this analysis was to improve and optimize the energy conversion system in point, namely, and LNG-fired Combined Heat and Power Plant (CHP). To this end, energies which represent the true efficiency figures were evaluated for various flows of the system with a set of system configurations given. Then the economic values of the energies were assigned to respective flows and subsystems. With these economic data locations of inefficiencies and opportunities for improvement are identified.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.593-600
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• 2012

The exergy characteristics for R245fa and water working fluids have been analyzed for an electric generation system utilizing the Rankine cycle to recover heat from the wasted exhaust gas from a diesel engine used for the propulsion of a large ship. The theoretical calculation results showed that the efficiencies of exergy and system exergy improved as the turbine inlet pressure increased for R245fa at a fixed mass flow rate. Furthermore, the exergy destruction rates of the condenser and evaporator were relatively larger than those in other components. The exergy efficiency of the system increased with increasing mass flow rate. For a water working fluid, although the exergy destruction rate of the evaporator was similar to that for R245fa, the exergy loss rate varied significantly in response to variations in the pressure and mass flow rates at the turbine inlet.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.6
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• pp.542-549
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• 1987

중요한 기본을 요약하고 엑서지를 에너지 변환에서 가장 중요한 기본 과정에 응용하는 열전달 문제를 제시한다. 열전달로 인한 엑서지 손실과 고온체, 저온체의 단열, 열교환기의 설계와 관련된 결과를 논의한다. 또한 비아제오트로픽(non-azeotropic) 혼합물을 응용한 열펌프 열교환기에서의 엑서지 절약에 대한 연구를 설명한다. 열전달과 압력강하로 인한 손실의 합인 총엑서지 손실이 최소로 되는 최적의 Reymolds 수가 존재함을 보여준다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.751-758
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• 2001

Exergy concept is applied to the analysis of part-load performance of gas turbine engine. Exergy is a useful tool to find the source of irreversibility in thermal system. In this study, details of the performance characteristics of a heavy-duty gas turbine, l50MW-class GE 7FA model, are described by theoretical investigations with exergy analysis. Result shows that exergy destruction rate of gas turbine increases with decreased load, which means increase of irreversibility. Also, it is found that variations of IGV angle and amount of cooling air for turbine blades are closely related to the inefficiencies of compressor and turbine, respectively.