Experiments were conducted to evaluate the performance factors such as type of working fluid, flow direction, arrangement and stage of loop thermosyphon heat exchanger for ESS battery container cooling. Pentane showed slightly better performance of the heat exchanger than R-134a as a working fluid. Driving the fan in the suction direction showed improved performance compared to the blowing direction. The two-stage heat exchanger increased the heat transfer rate by more than 30% at the same temperature difference compared to the single-stage heat exchanger. Also, the counterflow flow showed better performance than the parallel flow in the two-stage heat exchanger.

Experiments were conducted on the operating characteristics and performance of various types of working fluid, filling amount and heat flow rate of a loop thermosyphon for cooling ESS battery container. As results of performance test on various working fluids, HFE-7100 and R-134a as a working fluids showed unstable operating and low performance due to vapor pressure drop, and performance was improved by increasing the number of vapor lines for reducing a pressure drop. In this study, n-pentane was more stable and showed better thermal performance among various working fluids.

Urban planning and engineering undergraduate students need to understand the earth physical systems and that how human beings interact with the earth systems to planning and engineering urban area. The eco-friendly or geofriendly design and planning of an urban area is a critical issue not only for economic benefits but more importantly for the sustainable future of urban life. However, little study has been done dealing with the urban engineering students’ understanding of the earth as a system and what pedagogical approach is appropriate to improve their understanding of the earth as a system. This study is to investigate the impact of a purposely designed ESS course on urban engineering students’ understanding of the earth as a system and their perceptions about the instructional approaches of the course on their learning competency. This study utilized a mixed-methodology with three main data sources: concept maps, student’s perception survey about their learning competency, and course contents. Both the survey and concept maps were analyzed quantitatively as well as qualitatively. The result of this study showed that the urban engineering students’ experience of team-based research about the topic they chose based on their own interest had a positive impact on their understanding of the earth as a system and their learning competency. The results of this study suggest that structuring and presenting the earth system contents in the context of engineering students’ understanding and their future career be effective not only for the improvement of students’ content knowledge but also for the enhancement of their learning competency such as creativity and problem-solving skills in everyday life situation

This paper discusses the grammatical categories of tense-aspect expressions at a discourse level and how discourse dimensions should be connected with discourse functions. Among many tense-aspect expressions, the paper focuses on the forms ‘-ess-’ and ‘-essess-’, which are complex in a sense that they depict both tense and aspect. The results show that ‘-ess-’ has a total of five discourse functions: ‘statement of past situation,’ ‘reminiscence of past situation,’ ‘objectification of present situation,’ ‘present validation of default result’ and ‘realization of hypothetical result.’ Moreover, ‘-essess-’ represents ‘order of past situations’ and ‘present invalidation of default results.’ Also these discourse functions are related to the discourse elements of ‘topic, information, and speaker.’ The findings of this study explain the characteristics of the discourse function relevant to discourse elements. Ultimately, discourse research on tense-aspect expressions in Korean language education enables understanding of the utterance intention of Korean speakers using tense-aspect grammar. And it provides learners with the basis of using Korean correctly and appropriately.

In this paper, we have studied about the Energy Storage System (ESS) for renewable energy such as wind and solar energy by using Battery Energy Storage System (BESS). The BESS, by using Li-Ion battery, takes the advantage of high energy density. The ESS is composed of a large number of the battery. It is necessary to stabilize the temperature of the battery in order to improve the performance of the ESS. To improve the performance of ESS, Using as a program to analysis the container internal flow and heat distribution. The use of the battery to the stable and suggest in the initial battery array design of the heat concentration phenomenon in the battery array

최근 폐자원에너지를 이용한 신재생에너지의 활용에 대한 관심이 늘고 있는 추세이다. 유기성 폐자원의 경우 생성되는 메탄가스 및 가연성 가스를 이용한 가스발전이 가장 대표적인 활용 예이다. 그러나 폐자원으로부터 생성되는 가스는 생산량 조절이 어려움이 있다. 또한 가스 발전은 계속적으로 가동되어야 하기 때문에 전기사용량이 적은 심야에는 버려지는 가스가 존재한다. Energy Storage System (ESS)은 낭비되는 전기를 저장하였다가 필요한 요구가 있을 때 사용하는 장치로서 폐자원 에너지와 같은 신재생에너지 산업에 없어서는 안될 부분이다. 또한 에너지를 저장하는데 있어 어떠한 환경오염이나 CO2가 발생되지 않는 청정의 에너지 저가 요구된다. 이러한 ESS 중의 하나로, 바나듐 레독스 흐름 전지(Vanadium Redox Flow Batter)는 차세대 에너지 저장장치로서 기존의 리튬전지를 이용한 저장보다 에너지 수명이 10배 이상 길고, 환경에 무해한 물질을 사용하는 친환경적이 물질이다. 그러나 VRFB의 경우 낮은 에너지 밀도와 값비싼 분리막등 보완해야할 점들이 있다. 현재 사용되고 있는 Nafion 계열의 분리막의 경우 값비싼 가격과 활물질의 Crossover 현상을 막아주지 못하는 단점을 가지고 있는데 이를 polybenzimidazole로 구성된 분리막을 사용함으로서 분리막의 표면에 positively charged functional groups을 달아주어 Crossover를 막아주어 에너지효율과 밀도 모두 향상시킬 수 있었다.

It is well‐known in the literature of Korean linguistics that the difficulty with the semantic treatment of –ess lies in the fact that it can be used to refer to a past eventuality or a perfect eventuality, depending on the context of use. For this reason, after pointing out that it is of no use to posit that –ess is a past tense marker, a perfect marker, or both, this paper argues that –ess itself is neither a past tense marker nor a perfect marker, which completely departs from the previous treatments of –ess . To put it differently, -ess is indeterminate between a past tense marker and a perfect marker across the sentences in which it occurs. The context of use serves to resolve its indeterminacy by presenting the most salient semantic interpretation that may arise from –ess .