• International Journal of Air-Conditioning and Refrigeration
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• 제11권4호
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• pp.209-217
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• 2003

The term “energy saving is economical” is appropriate for the national view point and for design and assessment of one system, but not appropriate when choosing the system by comparing alternative systems in the early design step. Sometimes, non-energy saving system is more economical than energy saving system because of the price of electricity, gas or oil, which are used for operating the air conditioning system. Therefore, when designing a system, we should consider the efficient alternatives through economic assessment of energy saving method. However, research on non-operating number control of the system is not sufficient because it is more common to use operating number control of the system for most economic assessment of air conditioning systems. For this reason, this research can provide the economic operating number control method as basic design data. The data obtained through analysis of life cycle cost based on amount of yearly energy use, are produced by system simulation of HASP/ACLD/8501 and HASP/ACSS/8502 for six alternative heating$.$cooling systems based on seasonal air conditioning system, which is widely used for medium and large size office buildings in Busan.

• KIEAE Journal
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• 제7권6호
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• pp.3-8
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• 2007

Recently, because of the continuous rise of international oil price, energy saving is strongly demanding. So, Ecological technics of architecture such as use of natural energy have been actively explored in the field of building. In the method of utilizing natural energy, the key point is to saving energy effectively as not lowering the comfort of indoor environment, various systems investigated. Many papers about double skin facade system have been reported, it is announced broadly that the system is very effective in improvement of natural ventilation and indoor thermal environment, and also protecting outdoor sound. The shaft box facade is a special form of box window construction. It consists of a system of box windows with continuous vertical shafts that extend over a number of stories to create a stack effect. The facade layout consists of an alternation of box windows and vertical shaft segments. This research investigated the natural ventilation performance of shaft box type balcony which conform the shaft box type double skin to the exiting balcony construction. First, analyzed various types of exiting apartments, proto-type was decided. By using virtual environment Program, modeling the proto-type, compared the contribution of air temperature and the effect of outdoor air cooling. by this research, we confirmed that shaft box type balcony had many possibility for improvement of indoor environment.

• 한국안전학회지
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• 제8권1호
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• pp.29-34
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• 1993

Two major hazardous gases. SOx and NOx. are emissioned from fossile fuels. SOx has been removed when oil is refined but NOx hasn't. So NOx is very serious problem in air pollution now There are several technologies to remove NOx. e.g. cooling method. scrubbers method. combustion method, polymer membrane method and adsorbent methods. Polymer membrane and adsorbent methods have good economic merit in removal systems of low content hazard gases. Traditional absorbents are porous silicas, aluminas. active carbon and zeolites. But these absorbents act only physisorption which has less removal performance than chemisorption. In this study. polymeric absorbent which has chemisorption as well as physisorption was analyzed about chemical structure and experimented about optimum operation conditions. The results showed that the chemical structure of the polymeric absorbent was expected as polystyrene having -N-CH$_2$COOH absorbent was revealed about 310$m^2$/g. The molar ratio of absored NO to charged NO in absorption experiments was shown 60% of the polymeric absorbent and 45% of zeolite absorbent at 3$0^{\circ}C$.

• 에너지공학
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• 제23권2호
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• pp.57-61
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• 2014

자동차산업이 해결해야 할 과제로서 석유에너지의 소비증가와, $CO_2$ 배출에의한 지구온난화, 배기가스 배출에 의한 도시부 대기오염 등에 대한 대처가 필요한 시점이다. 이들의 해법으로 시장에서 높은 평가를 받고 있는 전기자동차의 필요성이 대두되고 있다. 본 연구에서는 전기자동차 모터, 배터 리 및 구동모터를 포함한 고전압 핵심부품들의 효율적인 열관리 기술, 배터리 및 구동모터의 열관리 기술 및 개발동향을 알아보고자 한다.

• 동력기계공학회지
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• 제10권4호
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• pp.25-30
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• 2006

This paper represents the numerical analysis in unsteady state on the variation of diameter and environmental velocity of carbon heating source. In general heating system, the oil and sheath heater is widely used, but these systems have many problems. So, the heating source with carbon ingredient has been researched in many country about manufacture, thermal and electrical properties. In this research, the carbon heating source was studied through numerical analysis on several conditions of unsteady state, heat generation, diameter and environmental velocity. The temperature distributions at steady state are appeared as a non-proportional linear pattern with variations of environmental velocity due to the Nesselt number with convective heat flux is proportioned to 0.805 of Reynolds number. As the radius is increasing, the temperature distributions is appeared the minus tilt because of the environmental condition is cooling by constant temperature. So, the correlation equation between temperature at steady state and environmental velocity was obtained.

• 한국기계가공학회지
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• 제18권8호
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• pp.60-66
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• 2019

This study aims to develop and manufacture a device for inspecting impurities in a sealed aluminum container using an X-ray technique. Two X-ray oscillators and detectors are used to detect the entire sample. The stage for sample movement was fabricated using two high-voltage generators and X-ray detectors arranged diagonally. In addition, the high-voltage generator is composed of a vacuum tube, a high-voltage generator, and circulating oil for cooling. It includes a control unit for controlling other equipment, a power supply unit, and a video output unit; the most important part of the X-ray is the X-ray generation part. In this study, a flat panel was used along with the aim of developing the detector part. In particular, the development of the scintillator introduced in this study is a primary focus. The developed scintillator can be combined with a lens and can then be assembled with a charge coupled device (CCD) sensor.

• 드라이브 ㆍ 컨트롤
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• 제21권2호
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• pp.15-22
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• 2024

The objective of this study was to examine whether a gerotor pump used in a transmission could be converted into an electric vehicle thermal management system pump using a virtual design environment. To achieve this objective, we first built an environment that could analyze the performance of a gerotor pump in heat transfer fluid. Flow rate, pressure, and volumetric efficiency were then analyzed when using heat transfer fluid in a gerotor pump. Finally, how large the displacement volume of the pump should be designed when using a heat transfer fluid other than oil was determined. Based on results of this study, it is expected that gerotor pumps will be applied to new business fields such as electric vehicle cooling systems.

• 한국식품과학회지
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• 제24권5호
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• pp.440-446
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• 1992

쌀을 원료로 한 우리나라 전통주인 삼일주를 제조하고 이를 증류한 증류주의 성분변화를 압력, 환류비 및 충전물의 유무에 따라 분획별로 분석하여 다음과 같은 결과를 얻었다. 삼일주의 성분중 에탄올 함량은 14%, 총산 16.2g/100 ml, 환원당 7.9 mg/ml, 전당 84 mg/ml였다. 향기성분은 아세트알데히드 6 ppm, 휴젤유 161 ppm, 에틸아세테이트 6 ppm이었다. 증류가 진행됨에 따라 에탄올, 메탄올, 휴젤유, 아세트알데히드, 에틸아세테이트는 감소하였으며 총산은 증가하였다. 대체적으로 총산을 제외하고는 상압보다는 감압에서 향기성분들은 감소하였다. 증류초기 1, 2, 3분액에서는 에탄올의 농도가 70%이상이었지만 5분액부터는 에탄올 함량이 급격히 감소하였는데 이때의 에탄을 함량은 50% 이하였다. 관능검사 결과 증류주의 특성은 총 16가지가 밝혀졌으며 그 중에서 항기성분이 4가지, 맛성분이 7가지, 그리고 후미가 5가지였다. 이들 특성중 증류주의 품질에 크게 영향을 미치는 특성은 누룩향과 시원한감 등이며 전체적인 품질은 충전상태, 260 mmHg의 2, 3, 4분액이 가장 높은 품질을 보였다. 이 분액의 성분은 메탄올 $24{\sim}36\;ppm$, 총산 $0.21{\sim}0.29\;g/100\;ml$, 휴젤유 $657{\sim}1340\;ppm$, 아세트알데히드 $12{\sim}41\;ppm$ 그리고 에틸아세테이트가 $22{\sim}311\;ppm$ 범위에 있었다.

• 한국식품과학회지
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• 제34권5호
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• pp.931-934
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• 2002

폐기화 되고 있는 포도씨를 대체 식용유지 자원으로 개발하고자 포도씨에 함유되어 있는 기름의 최적 추출 방법을 확립하고자 실시하였다. Campbell early 포도씨의 일반 성분 분석 결과 압착 법으로 추출한 기름의 수율은 분쇄 후 볶아 증숙한 처리구, 분쇄 후 볶음 처리구, 분쇄 후 증숙 처리구순이었고 볶음 후 분쇄 처리구에서 가장 낮은 수율을 나타내었다. 용매 추출에 의한 수율은 정치 추출하였을 때 ether 처리구가 24시간 77.4%, 48시간 80.9%로 가장 높았고, 그 다음이 methanol과 n-hexane으로 나타났다. 포도씨 기름의 추출수율을 높이기 위한 방법으로 여러 가지 처리를 조합하여 실시한 결과 다음과 같은 순으로 방법이 확립되었다. (1) 수분 $10{\sim}12%$의 포도씨를 $95{\sim}100^{\circ}C$에서 20분 정도 볶음 처리하고 30분간 실온으로 방냉한다. (2) 분쇄기로 1차 $1{\sim}2\;mm$ 정도 입자로 하여 2차 분쇄로 0.5 mm 이하 입자크기로 분쇄한다. (3) 분쇄된 씨를 steam boiler에서 $0.8{\sim}0.9\;kg{\cdot}f/cm^2$의 압력으로 10분 정도 증숙 시킨 후 열 교환 장치가 부착된 압착 추출기에 $6{\sim}\;8kg$ 정도 넣어 추출한다. (4) 이때의 압착력은 $400\;kg/cm^2$에서 $2{\sim}3$분, $550{\sim}600\;kg/cm^2$에서 10분 그리고 $700\;kg/cm^2$에서 기름 흔적이 없어 질 때까지 추출한다. 추출 방법을 달리하여 추출한다. 추출 방법을 달리하여 추출한 포도씨 기름에 대한 관능검사를 실시한 결과, 최적조건으로 추출한 기름이 맛, 향기 및 색깔에서 가장 좋은 것으로 나타났고 그 다음이 분쇄 후 볶아 추출한 기름이 좋게 나타났으며 분쇄 후 볶아 증숙하여 압착한 기름순으로 나타났다.

• 설비공학논문집
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• 제20권12호
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• pp.844-861
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• 2008

The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.