• 상하수도학회지
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• 제30권4호
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• pp.459-469
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• 2016

Gas hydrate desalination process is based on a liquid to solid (Gas Hydrate, GH) phase change followed by a physical process to separate the GH from the remaining salty water. The GH based desalination process show 60.5-90% of salt rejection, post treatment like reverse osmosis (RO) process is needed to finally meet the product water quality. In this study, the energy consumption of the GH and RO hybrid system was investigated. The energy consumption of the GH process is based on the cooling and heating of seawater and the heat of GH formation reaction while RO energy consumption is calculated using the product of pressure and flow rate of high pressure pumps used in the process. The relation between minimum energy consumption of RO process and RO recovery depending on GH salt rejection, and (2) energy consumption of electric based GH process can be calculated from the simulation. As a result, energy consumption of GH-RO hybrid system and conventional seawater RO process (with/without enregy recovery device) is compared. Since the energy consumption of GH process is too high, other solution used seawater heat and heat exchanger instead of electric energy is suggested.

• 재활복지공학회논문지
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• 제11권2호
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• pp.165-171
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• 2017

고령자 및 장애인의 삶의 질을 높이기 위하여 일상생활동작을 보조하는 경량의 재활보조 시스템이 필요하다. 본 논문에서는 수소저장합금 모듈 3가지를 설계하였고, 열전달 해석을 통하여 수소저장합금 엑츄에이터의 성능을 높일 수 있는 수소저장합금 모듈을 선정하였다. 수소저장합금 엑츄에이터는 열전소자의 열전달을 통하여 수소저장합금 모듈 안에 담겨 있는 수소의 흡수/방출을 통하여 공압 엑츄에이터의 기계적인 동작을 구동시킨다. 수소저장합금 모듈의 열전달의 효과를 검증하기 위하여, 열전소자와 수소저장합금 모듈의 접촉 방식을 선접촉과 면접촉 방식의 3가지 타입으로 3D 모델을 설계하였고, 열전달 해석을 통하여 열전달에 대한 특성을 비교하였다. 그 결과, 열전소자와의 열전달 방식이 선접촉 방식과 비교하여 면접촉 방식의 수소저장합금 모듈이 열전달 특성이 4.4배 좋아지는 것을 확인하였다. 면접촉 방식의 수소저장합금 모듈은 재활보조 시스템의 착용성을 높일 수 있는 수소저장합금 엑츄에이터 개발에 적용될 수 있을 거라 판단된다.

• 한국융합학회논문지
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• 제10권7호
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• pp.281-287
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• 2019

최적의 환기시스템 활용과 에너지 절약을 위한 급 배기공기 간의 열교환을 적용시킨 열회수시스템의 활용과 보급은 에너지관리시스템에서 필수적이다. 이러한 기술은 특히, 겨울철과 여름철의 냉난방에너지를 절약할 수 있어 고효율에너지 빌딩의 기반기술의 주요 요소이다. 본 논문에서는 균일한 형상과 동일한 유동조건에서 열교환기 성능을 비교하기 위해 종이, 플라스틱, 알루미늄을 재질로 시뮬레이션을 통한 열전달효율을 검토하였다. 또한 평판형과 굴절형 구조를 갖는 열교환기의 형상에 따른 열전달 효율을 시험하였고, 그 결과를 토대로 열전달 성능과 압력손실에 대해 고성능의 열교환기를 제작하는데 기여를 할 수 있을 것으로 기대된다.

• Architectural research
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• 제19권2호
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• pp.45-52
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• 2017

Recently, as a new perspective to view the architecture in relation to global environmental problems, interest in environmental architecture that conforms to the surrounding environment and nature with nature has been expanded as a part of the natural ecosystem, rather than seeing the building as an independent entity. Traditional Korean architecture creates a comfortable indoor environment by appropriately using the natural energy around, ranging from the arrangement of the building and the space composition to the use of detailed materials and to harmonize the artificial architectural environment without harming the natural ecosystem. The purpose of this study is to propose a method to apply the environmental control techniques of traditional buildings to modern buildings. As a research method, the characteristics of Korean traditional buildings according to the climatic characteristics of Korea were recognized through existing literature data and when applied to methods of traditional buildings, ventilation systems, control through eaves, and humidity control using Hanji the effect of energy load control on traditional buildings was analyzed and identified through existing literature. After analyzing the problems of modern architecture, we analyzed the effect of the environmental control system of traditional architecture on modern architecture. Simulation results show that the application of the environmental control system of traditional buildings to modern buildings reduces the cooling and heating load of modern buildings and has an effect on humidity control. This study suggests that quantitative energy saving will be possible if the environmental control techniques of traditional buildings are appropriately applied to modern buildings.

• 한국인터넷방송통신학회논문지
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• 제18권1호
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• pp.1-8
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• 2018

도시철도의 이용량이 매년 증가하고 있으며 승객들의 불편한 사항들 또한 이에 비례하여 증가하고 있다. 하지만 철도 관계자들은 해당 민원사항들에 대해 신속하게 조치하지 못하고 있다. 이러한 문제를 해결하기 위하여 본 논문에서는 철도 관계자들과 승객들 간의 소통을 원활하게 하고 이로 인한 신속한 처리를 수행하기 위한 사물인터넷 기반의 IOS 어플리케이션을 제안한다. 본 제안 시스템에서는 전동차량 내에 온습도 센서를 적합한 장소에 설치하고 이렇게 측정된 측정치를 실시간으로 원격 서버에 전송함과 동시에 승객들은 자신의 희망온도를 IOS 기기 어플리케이션을 통하여 요청하도록 하였다. 이렇게 수집된 데이터들을 기반으로 실시간 도시철도 관계자들이 전동차량의 온습도를 조절할 수 있는 시스템을 제안한다. 제안 시스템은 광주광역시 도시철도 1호선에 구현을 통하여 그 효율성을 검증하였다.

• 한국세라믹학회지
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• 제22권3호
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• pp.35-40
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• 1985

The composition of the base glass was determined to be $Na_2O$ 15, $Fe_2O_3$ 35, $B_2O_3$ 0~20, $P_2O_5$ 30~50 by mole percent. The heating temperature for nucleation was determined by means of thermal expansion curve. Crystalline phases were investigated by X-ray diffraction method and I.R Spectra. Electrical conductivities of glass spec-imens were observed in the temperature range 25~20$0^{\circ}C$ The activation energies of these specimens were caculated. The results obtained were as follows : 1) The limit composition of the melts 15mol% $Na_2O$ 35mole% $Fe_2O_5$ 20mole% $B_2O_3$ 30mole% $P_2O_5$ was able to be formed into desired shapes during cooling, . 2) In the measurement of d. c conductivity($\delta$) on the glasses in the system $15Na_2O-35Fe_2O_3$-$B_2O_3$-(50-x) $P_2O_5$ the values decreased by replacing 5 mole% $P_2O_5$ with $B_2O_3$ 3) The d. c conducties of heat treated samples were increased by replacing $P_2O_5$ with $B_2O_3$ 4) $B_2O_3$ contributed to precipitate crystals such as${\gamma}$-$Fe_2O_3$ $Fe_3O_4$ which had the advantage of electronic conduction in heat treated samples. 5) The slope plotted Log($\delta$) versus 1/T in this glass system was linear in the measured temperature range.

• Architectural research
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• 제17권3호
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• pp.109-115
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• 2015

The dynamic pricing of electricity, where the electricity rate increases in a time zone with a high demand for electricity is typically applied to a building whose power reception capacity is greater than a certain size. This includes the time of use(TOU) electricity pricing in Korea which can induce the effect of reducing the power demand of a building. Meanwhile, a VRF (Variable Refrigerant Flow) system that uses electricity is regarded as one of the typical heating and cooling systems along with central air conditioning (central HVAC) for its easy operation and application to the building. Thus, to reduce power energy and operating costs of a building in which the TOU and VRF systems are applied simultaneously, we suggested a control for changing the indoor temperature setting within the thermal comfort range or limiting the rotational speed of an inverter compressor. In this study, to describe the features of the above-mentioned control and verify its effects, we evaluated the results obtained from the analysis of its operation data. Through the actual measurements in winter operations for 73 days since mid- December 2014, we confirmed a reduction of 10.9% in power energy consumption and 12.2% in operating costs by the new control. Also, a reduction of 13.3% in power energy consumption was identified through a regression analysis.

• 인터넷정보학회논문지
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• 제9권6호
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• pp.117-125
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• 2008

유비쿼터스 응용 시스템에 대한 관심의 증대와 함께 소형화된 임베디드 컴퓨팅 시스템의 필요성은 커지고 있다. 이러한 가운데 ARM 임베디드 프로세서는 기능의 우수성과 높은 활용도로 인해 임베디드 시스템 시장에서 높은 점유율을 보여주고 있다. 본 논문에서는 ARM 마이크로컨트롤러를 이용해 RTD-1000 컨트롤러 구성과 개발을 위한 최적의 방법을 제안하였다. 기존 RTD-1000은 케이블의 단선, 단락, 파손 등의 진단이 가능한 TDR를 탑재하여 구리선을 삽입한 감지관의 누수 및 누유, 파괴 등을 원격으로 감지할 수 있는 기기이다. 실제로 시공되어 현장에서 운영되고 있는 RTD-1000은 시스템 운영에 필요한 범위에 비해 리소스 낭비가 크고 그에 따라 구축비용이 높다는 단점을 가지고 있다. 또한, 발열이 심해 별도의 냉각장치가 요구되며, 하드 디스크와 같은 보조저장장치의 사용으로 고장 발생율과 전류의 소비가 커지는 등의 문제점을 야기하였다. 본 논문에서는 도출된 문제점의 해결 방법으로 ARM 마이크로컨트롤러 기반의 RTD-1000A 임베디드 시스템을 제안하고 시뮬레이션 하였다.

• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.73-80
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• 2014

This study introduces and analyzes the geothermal energy availability in Non-active volcanic region. Jeju island in Korea is situated in non-active volcanic region. The island is composed of rock with high pore and clinker, scoria geological layer formed by volcanic activity about two million ago. Volcanic geological layers with porous characteristics have air, vapor, water and a underground structure through which air or water can move easily. For this reason, it is probable that the mechanism of energy acquisition is by convective heat transfer. For this presumption, the availability of underground air as energy source has been studied here through theoretical analysis and experimental data. The energy output of our system ranged from 2,485,076 kJ/day to 4,060,978 kJ/day monitored using variable velocity air flow controller. Our system has capability to be a reliable energy source irrespective of environmental changes. Consequently, underground air can be utilized for energy source and provide the optimal design of heating/cooling system.

• 동아시아식생활학회지
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• 제26권6호
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• pp.517-530
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• 2016

This research was conducted on Seoul region elementary, middle, and high school nutritionists to analyze execution conditions of HACCP control standards, focusing on PHF and CCP 3~CCP 7, in order to determine more efficient methods for school meals' sanitation system settlement. All surveys were distributed and collected via email. A total of 305 survey papers were collected, and 300 school results were analyzed. The following percentage of nutritionists perceived the following foods as potentially hazardous foods(PHF): raw or cooked animal foods (94.7%), blossomed seed products (93.7%), packed pickled radish (36.7%), unopened mayonnaise (30.2%), and unopened snails & corn cans 54.8%. Exactly 51.2% of nutritionists believed that foods were properly supplied via CCP 3's food quality standard. Exactly 33.9% of nutritionists answered that they had never corrected the digital thermometer since there were no issues with the CCP 4's digital thermometer correction frequency level. As for CCP 5's chroline disinfection of green vegetables, 57.1% of nutritionists answered that vegetables were slightly softened while 36.2% said there were no changes at all. According to the nutritionists, the most difficult execution level of CCP levels (excluding CCP 3, CCP 4) was CCP 7 (37.1%), CCP 6 (16.4%), and CCP 2 (16.4%). For the above results, proper training/education must be enforced so that nutritionists can have a clear notion of the PHF. A solution must be developed enhancing the execution of CCP 4's digital thermometer correction frequency level. For CP 5's chroline disinfection of green vegetables, food characteristics must be considered to suggest an appropriate number and method of cleansing. Furthermore, cooking employees are needed that properly use and manage cooling & heating equipments to maintain heated foods above $57^{\circ}C$ under the CCP 7 standard.