• 대한건축학회논문집:구조계
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• 제34권9호
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• pp.27-34
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• 2018

The purpose of this study is to demonstrate and analyze the function of a Smart Plug before and after it is applied on the electrical appliances by controlling standby power usage. The research measures and analyzes the amount of electrical energy used while activating the Smart Plug with two types of appliances in a university facilities. The smart plugs were applied into a Group 1 appliances (Multi-function device, computer, laptop, Air con) which completely hinder the standby power, and a Group 2 appliances (Refrigerator, cold and hot water dispenser) which does not completely hinder the standby powers due to the characteristics of the function. First, the total standby power saving of all electrical appliances (Group 1 and Group 2) using the Smart plug was measured as 4.59%. Second, the energy saving of the Group 1 products was analyzed as 26.43%. Third, the standby power saving of the air conditioners from mid October to early December was measured as 31.06%, during the seasons when air conditioning was not actively in use. The research indicates that all specified appliances did have better energy efficiency with the Smart plug regardless of the amount of energy usage.

• Architectural research
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• 제19권4호
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• pp.89-94
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• 2017

In Korea, it is necessary to improve the performance of buildings with respect to the energy efficiency while improving the quality of occupants' lives through a sustainable built environment. During the design and development process, building projects must have a comprehensive, integrated perspective that seeks to reduce heating, cooling and lighting loads through climate-responsive designs. The aim of this study is to assess the optimal window-to-wall ratio of multi-rise residential units in the early design phase in Korea. The study analyzed the variation of annual heating and cooling energy load in two apartment prototype units located in Seoul city using different WWRs. The analysis was conducted using Autodesk Ecotect Analysis 2011 tool. The study found for total annual building load reductions WWR on the south and north face should be studied independently based on the room function. It also found reducing the WWR for bedrooms and windows on the northern façade resulted in reduced total annual building load.

• 한국수산과학회지
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• 제30권6호
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• pp.929-935
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• 1997

The total energy of fish movement and the maximum burst swimming speed were estimated and formulated in accordance with body length and water temperature for several species in fisheries by empirical methods and also by using published results. Under the assumption of swimming energy reserve of a fish at the initial rest state, the swimming endurance of fish with different body lengths, swimming speeds and angular velocity was calculated using the relevant equations under similar conditions in tank experiments as well as natural conditions in field. Relative swimming energy efficiency or the transition swimming speed between red and white muscle for energy consumption was represented as a trigonometric function of swimming speed ratio. Therefore, this model does closely approach the actual swimming abilities and their limits especially in relation to the fishing gear operation and allow for the greater vitality of the wild fish in the fields.

• 설비공학논문집
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• 제27권3호
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• pp.146-151
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• 2015

The heat transfer performance of heating medium oil fluidized bed heat exchanger was measured. The operation variables were air flow rate, air inlet temperature, moisture content, water flow rate and water inlet temperature. The outside heat transfer coefficient was determined from the heat exchanger experiment and its experimental correlation was determined as a function of air velocity and viscosity of heating medium oil. Effect of viscosity was well agreed with the previous studies. Errors of the correlation equation was less than about 10% for outside heat transfer coefficient developed in this study when compared with the measured value. Hot water with the temperature greater than $77^{\circ}C$ could be produced by using the heating medium oil fluidized bed heat exchanger.

• 태양에너지
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• 제18권4호
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• pp.1-10
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• 1998

Polymer induced turbulent drag reduction in a rotating disk apparatus was investigated using four different molecular weights of poly(ethylene oxide)(PEO) in a synthetic seawater solution for the purpose of potential application to the cold water piping in the Ocean Thermal Energy Conversion(OTEC) system. To apply drag reduction to the OTEC we measured the temperature dependence on the drag reduction efficiency. From this study, it was found that the drag reduction efficiency increases with the temperature and the concentration. To measure the drag reduction efficiency during the operation period, the drag reduction behavior was detected as a function of time and the results obtained from the experiment was compared to the Brostow's model equation.

• Korean Chemical Engineering Research
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• 제45권3호
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• pp.264-268
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• 2007

마이크론 금속섬유 필터 표면상에 탄소나노튜브를 직접 합성 성장함으로써 마이크론 필터의 성능을 향상할 수 있었다. 탄소나노튜브는 합성조건에 따라 마이크론 섬유 주위를 덮는 덤불 나노구조체 또는 섬유 사이를 연결하는 망 형상의 나노구조체로 성장하였다. 탄소나노튜브가 성장한 금속필터와 탄소나노튜브가 성장하지 않은 금속필터의 여과성능을 측정하여 비교한 결과, 차압의 변화는 미미하나 여과효율은 더욱 향상되었고, 이는 탄소나노튜브가 오염 나노입자를 잡는 트랩으로 작용하였기 때문이다.

• 한국태양에너지학회 논문집
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• 제29권6호
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• pp.39-44
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• 2009

Entering in the time of high oil price, seriousness of an energy effect sector has given a huge impact and the importance of energy is growing. Especially, building energy occupying 24% of total demand of energy is expected to be possible to reduce energy demand more than other section. To reduce the building energy consumption, this study analyzes function and thermal performance of Super window by heat experimental apparatus. Super window is a 2-track low-e glazing window for high insulation efficiency. By applying the results of this experiment to building energy efficience rating tool, this study compares energy efficiency rates depending on a region.-Jeju, South, Central. And it shows how much does Super window reduce Building energy consumption.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.185-194
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• 2020

Designing of a hierarchical clustering algorithm is one of the numerous approaches to minimize the energy consumption of the Wireless Sensor Networks (WSNs). In this paper, a homogeneous and randomly deployed sensor nodes is considered. These sensors are energy constrained elements. The nominal selection of the Cluster Head (CH) which falls under the clustering part of the network protocol is studied and compared to Low Energy Adaptive Clustering Hierarchy (LEACH) protocol. CHs in this proposed process is the function of total remaining energy of each node as well as total average energy of the whole arrangement. The algorithm considers initial energy, optimum value of cluster heads to elect the next group of cluster heads for the network as well as residual energy. Total remaining energy of each node is compared to total average energy of the system and if the result is positive, these nodes are eligible to become CH in the very next round. Analysis and numerical simulations quantify the efficiency and Average Energy Ratio (AER) of the proposed system.

• 한국식품과학회지
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• 제24권5호
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• pp.428-439
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• 1992

고추건조에 대한 에너지사용의 효율성을 표현할 수 있는 건조효율 지표를 유도하고 정의하였으며 건조효율에 미치는 공정변수의 영향을 분석하고 carotenoids 보존의 제한조건하에서 건조효율을 최대화시키는 최적건조조건을 찾았다. 전체 사용에너지에 대한 증발에너지의 비로 단순화시켜서 열풍의 건구 및 습구온도의 함수로 표현된 건조효율이 건조공정중 실제의 에너지 사용의 효율성을 표현할 수 있는 것으로 확인되었고, 이를 이용하여 주어진 조건에서의 최적화가 가능하였다. 최적화 결과 1단계 건조에 비해서 2단계 건조가 같은 품질제한 조건하에서 건조효율을 증가시킬 수 있었다. 한편 배기공기 온도를 포함하는 간단한 변환변수와 건조되는 고추의 수분함량 사이의 관계에 의하여 건조시간 종료를 제어할 수 있는 가능성도 검토되었다. 전체적으로 본 연구에서 고추 건조시 좋은 품질을 유지하면서 건조효율을 향상시키고 에너지소비를 절감할 수 있는 건조기 운전의 방향을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.5928-5947
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• 2019

Multicast Mesh based Mobile Ad-hoc NETworks (MANETs) provide efficient data transmission in energy restraint areas without a fixed infrastructure. In this paper, the authors present an improved version of protocol SLIMMER developed by them earlier, and name it SLIMMER-SN. Most mesh-based protocols suffer from redundancy; however, the proposed protocol controls redundancy through the concept of forwarding nodes. The proposed protocol uses remaining energy of a node to decide its energy efficiency. For measuring stability, a new metric called Stability of Node (SN) has been introduced which depends on transmission range, node density and node velocity. For data transfer, a weighted cost function selects the most energy efficient nodes / most stable nodes or a weighted combination of both. This makes the node selection criteria more dynamic. The protocol works in two steps: (1) calculating SN and (2) using SN value in the weighted cost function for selection of nodes. The study compared the proposed protocol, with other mesh-based protocols PUMA and SLIMMER, based on packet delivery ratio (PDR), throughput, end-to-end delay and average energy consumption under different simulation conditions. Results clearly demonstrate that SLIMMER-SN outperformed both PUMA and SLIMMER.