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Byun J.-K.,Korea University | Jeong D.-H.,KEPCO Engineering and Construction Company Inc. | Choi Y.-D.,Korea University | Shin J.-K.,Hanzhong University
Energies | Year: 2013

In the present study, a fuel cell driven ground source heat pump (GSHP) system is applied in a community building and heat pump system performance is analyzed by computational methods. Conduction heat transfer between the brine pipe and ground is analyzed by TEACH code in order to predict the performance of the heat pump system. The predicted coefficient of performance (COP) of the heat pump system and the energy cost were compared with the variation of the location of the objective building, the water saturation rate of the soil, and the driven powers of the heat pump system. Compared to the late-night electricity driven system, a significant reduction of energy cost can be accomplished by employing the fuel cell driven heat pump system. This is due to the low cost of electricity production of the fuel cell system and to the application of the recovered waste heat generated during the electricity production process to the heating of the community building. © 2013 by the authors.

Jung J.,Seoul National University | Jeong Y.S.,Seoul National University | Lim Y.,Seoul National University | Lee C.S.,KEPCO Engineering and Construction Company Inc. | Han C.,Seoul National University
Energy Procedia | Year: 2013

CO2 capture process using aqueous Monoethanolamine (MEA) scrubbing is a well-proven and commercially-ready technology for reducing CO2 emission to the atmosphere. Although the MEA scrubbing is the one of the most suitable technologies for post-combustion CO2 capture, the MEA process has a critical problem which is high consumption of reboiler heat energy for solvent regeneration. In order to reduce the reboiler heat requirement, this paper suggests an advanced configuration of MEA process which consists of split flow and a phase separation heat exchanger. The split flow permits to reduce the reflux ratio in the stripper and the phase separation heat exchanger permits to alleviate preheating duty loss. As a result, the regeneration energy of the advanced process is reduced by 2.84GJ/ton CO 2, which is lower than one of the reference process by 27%. © 2013 The Author.

Lee Y.I.,Seoul National University | Yi J.,Seoul National University | Yi J.,KEPCO Engineering and Construction Company Inc. | Choi T.,Chosun University
Journal of Sedimentary Research | Year: 2015

The Sindong Group (Aptian-Albian) in southeastern Korea is a 2-3-km-thick fluvio-lacustrine sedimentary package deposited in an elongated basin (the Nakdong Trough), which was formed by extension in an active-continental-margin setting. The provenance of the Sindong Group was studied to understand spatial and temporal variation in composition in three different parts of the basin by using integrated data on petrography, quartz SEM-cathodoluminescence (CL) analysis, and zircon Zr/Hf analysis. Although Sindong Group sandstones display wide variation in the composition of framework grains, they generally have increasing amounts of feldspar and decreasing amounts of quartz up sequence. Significant amounts of volcanic rock fragments and volcanic quartz are observed in the late-stage sediments. Metamorphic quartz is predominant in all Sindong Group sandstones, indicative of the exposure of metamorphic rocks in the source terrane, mostly from Precambrian basement and Triassic granites. The occurrence of significant amounts of plutonic quartz from early-stage sediments suggests that Jurassic granites were widely exposed in the source terranes. In addition, the episodic increase in volume of plutonic quartz content in the sequence, especially in the northern part of the basin, suggests that episodic tectonic activity occurred in the catchment. The increasing feldspar content up sequence could support the occurrence of tectonic activity in the catchments. The Zr/Hf analysis of detrital zircons revealed that the majority of zircons are of continental-crust origin formed in orogenic settings, but zircons in the lowest strata in the northern part of the basin were derived largely from anorogenic magmatic rocks of mantle origin. Our results demonstrate that source terranes for the Sindong Group have heterogeneous spatial and temporal distribution and were composed mainly of Precambrian basement and Triassic to Jurassic granitic rocks, with minor (meta)sedimentary rocks and syndepositional volcanic rocks. The detritus derived from syndepositional volcanic rocks became significant in the late stage of basin filling, representing the transition from extensional tectonism to continental-arc magmatism. The differences in characteristics of quartz SEM-CL and zircon Zr/Hf ratios in different parts of the basin are best explained by deposition on different alluvial fans and river systems. Copyright © 2015, SEPM (Society for Sedimentary Geology).

Yang B.J.,Korea Advanced Institute of Science and Technology | Kim B.R.,KEPCO Engineering and Construction Company Inc. | Lee H.K.,Korea Advanced Institute of Science and Technology
Acta Mechanica | Year: 2012

The objective of this study is to develop a micromechanics-based viscoelastic damage model that can predict the overall viscoelastic behavior of particle-reinforced polymeric composites undergoing damage. The emphasis here is that the present model successfully combines a rate-dependent viscoelastic constitutive model and a damage model. The Laplace transform based on the Boltzmann superposition principle and the ensemble-volume averaged method suggested by Ju and Chen (Acta Mech 103:103-121, 1994a; Acta Mech 103:123-144, 1994b) are extended toward effective viscoelastic properties. Further, the probability of the distribution function of Weibull (J Appl Mech 18:293-297, 1951) is adopted to describe a damage model that is dependent on damage parameters. A series of numerical simulations including parametric studies, and experimental comparisons are carried out to give insight into the potential capacity of the present micromechanics-based viscoelastic damage framework. © 2012 Springer-Verlag.

Oh Y.G.,KEPCO Engineering and Construction Company Inc. | Lee S.J.,Chungnam National University
IEEE Transactions on Nuclear Science | Year: 2010

The advanced design features of NSSS (Nuclear Steam Supply System) Integrity Monitoring System for Shin-Kori Nuclear Units 3 and 4 are summarized herein. During the overall system design and detailed component design processes, many design improvements have been made for the system. The major design changes are: 1) the application of a common software platform for all subsystems, 2) the implementation of remote access, control and monitoring capabilities, and 3) the equipment redesign and rearrangement that has simplified the system architecture. Changes give an effect on cabinet size, number of cables, cyber-security, graphic user interfaces, and interfaces with other monitoring systems. The system installation and operation for Shin-Kori Nuclear Units 3 and 4 will be more convenient than those for previous Korean nuclear units in view of its remote control capability, automated test functions, improved user interface functions, and much less cabling. © 2010 IEEE.

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