• 에너지공학
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• 제27권4호
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• pp.20-26
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• 2018

지구온난화 현상이 세계적으로 점점 심각해지고 있으며 이에 대한 대책으로 에너지 원천의 다양화, 에너지 절감 기술 등이 필요하다. 본 연구에서는 태양열을 이용한 무동력 냉난방 겸용장치를 실현하기 위하여 태양열 집열기 흡수판의 재질변화, 무동력과 최소의 동력을 사용하였을 때의 특성을 비교하고자 하였다. 그 결과로서 하절기에 태양열 집열장치를 부착한 경우는 부착하지 않은 경우보다 실내온도가 약 $1^{\circ}C$ 낮았으며, 하절기에 냉원저장조가 없는 상태에서 태양열 집열장치에 의한 냉방효과는 적었다. 그러나 동절기에는 실내온도가 약 $3^{\circ}C$ 높았으며 무동력에 의한 난방효과의 가능성이 있었다. 간접적인 측정방법에 의해, Cu 재질의 태양열 집열장치의 성능은 Al 재질과 비교하여 약 2배 높았다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2002년도 추계 학술발표회 논문집
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• pp.171-184
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• 2002

우리나라 5개 정유사에서 일간 생산되는 중질잔사유 (Vacuum Residue) 량은 약 200,000 B/d이며, 일부는 Asphalt 또는 Sulfur fuel oil, 기타 탈황공정(RHD)둥에서 upgrading 되고 있다. 중질잔사유는 유황 및 중금속 물질의 함유량이 높아 가스화를 통한 효율적인 이용이 요구되고 있으며, 최근들어 효율적인 중질잔사유의 사용을 위하여 SK정유와 LG, Caltex에서 435-500 MWe IGCC 발전소 및 수소 제조공정을 위한 타당성 조사를 한 바 있다. 현재 한국에너지기술연구원에서는 습식분류상 가스화장치를 이용하여 중질잔사유가스화 특성에 관한 연구를 수행하고 있다. 실험은 반응온도 : 1,100~1,25$0^{\circ}C$, 반응압력 : 1~6kg/$ extrm{cm}^2$G, oxygen/V.R ratio : 0.8~0.9 and steam/V.R ratio : 0.4~0.5를 유지하며 수행되었으며, 실험을 통해 합성가스(CO+H$_2$) 조성 : 85~93%, 생성가스 유량 : 50~110Nm$^3$/hr., 발열량 : 2,300~3,000 ㎉/Nm$^3$, 탄소전환율 : 65~92 및 냉가스효율 = 60~70%를 얻을 수 있었다. 아울러, 평형모델을 이용하여 중질잔사유가스화 공정을 모형화 하였으며 계산결과를 실험결과와 비교하여 모델의 타당성을 검토하였다.

• 에너지공학
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• 제12권1호
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• pp.49-57
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• 2003

우리나라 5개 정유사에서 일간 생산되는 중질잔사유 (Vacuum Residue)량은 약 200.000 B/d이며, 일부는 Asphalt 또는 Sulfur fuel oil, 기타 탈황공정(RHD) 등에서 upgrading 되고 있다. 중질잔사유는 유황 및 중금속 물질의 함유량이 높아 가스화를 통한 효율적인 이용이 요구되고 있으며, 최근들어 효율적인 중질잔사유의 사용을 위하여 SK정유와 LG Caltex에서 435~500 MWe IGCC 발전소 및 수소 제조공정을 위한 타당성 조사를 한 바 있다. 현재 한국에너지기술연구원에서는 습식분류상 가스화장치를 이용하여 중질잔사유가스화 특성에 관한 연구를 수행하고 있다. 실험은 반응온도: 1,100~1,25$0^{\circ}C$, 반응압력: 1~6 kg/$\textrm{cm}^2$G, oxygen/V.R ratio: 0.8~0.9 and steam/V.R ratio: 0.4~0.5를 유지하며 수행되었으며, 실험을 통해 합성가스(CO+H$_2$) 조성 : 85~93%, 생성가스 유량: 50~110 Nm$^3$/hr. 발열량: 2,300~3,000 k㎈/Nm$^3$, 탄소전환율: 65~92 및 냉가스효율: 60~70%를 얻을 수 있었다. 아울러, 평형모델을 이용하여 중질잔사유가스화 공정을 모형화하였으며 계산결과를 실험결과와 비교하여 모델의 타당성을 검토하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.339-344
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• 2005

A PEMFC system model for FCEV was constructed and simulated numerically to examine the heat/water flow of the system and air/fuel humidification process for various operation conditions (ambient pressure /temperature/humidity, operating temperature, power load). We modeled PEMFC stack which can generate maximum electricity of about 80 kW. This stack consists of 400 unit cells and each unit cell has $250cm^2$ reacting area. Uniform current density and uniform operating voltage per each cell was assumed. The results show the flow characteristics of heat and water at each component of PEMFC system in macro-scale. The capacity shortage of the radiator occurred when the ambient was hot $(over\;40^{\circ}C)$ and power level was high (over 50 kW). In spite of some heat release by evaporation of water in stack, heat unbalance reached to 20kW approximately in such a severe operating condition. This heat unbalance could be recovered by auxiliary radiators or high speed cooling fan with additional cost. In cold environment, the capacity of radiator exceeded the net heat generation to be released, which may cause a problem to drop the operating temperature of stack. We dealt with this problem by regulating mass flow rate of coolant and radiator fan speed. Finally, water balance was not easily broken when we retrieved condensed and/or unused water.

• 방사성폐기물학회지
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• 제5권3호
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• pp.213-220
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• 2007

유리화공정 고온영역에서의 방사성 배기체 유동해석을 해석하기 위하여 상용 수치해석 범용 툴인 FLUENT를 이용하여 적용성을 검토하여 보았다. 수치해석을 통하여 유리화공정 원형설비에 영향을 미치는 인자를 파악하였는데, 저온용응로, 배관냉각기 및 고온필터 등의 세 단계로 나누어 해석을 수행하였다. 저온용융로의 경우 폐기물 처리용량에 따른 해석과 저온용융로 내부 과잉산소 공급 비에 따른 연소지연 가능성에 대한 수치해석을 수행하였다. 배관냉각기의 경우에는 각종 수치 모델 및 외벽 열전달계수를 확보하였으며 또한 방사성 핵종의 거동을 모사할 수 있는 수치적 기업을 검토하였다. 이러한 방법론을 적용하여 핵종의 열교환기 내부에서의 응고 특성에 대하여 고찰하였다. 수평 유입형식의 인입관이 있는 일반적인 형상과 유입구가 필터 내부에 수직으로 있는 고온필터의 수치해석을 통하여 인입관의 위치에 따른 고온필터의 작동 특성을 비교하였다.

• 방사성폐기물학회지
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• 제2권3호
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• pp.165-174
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• 2004

원자력발전소에서 발생하는 이온교환수지와 가연성잡고체 혼합폐기물을 유리화하기 위하여 유도 가열식 저온용융로를 이용한 실증시험을 수행하였다. 금속 티타늄 고리(Ti-ring)를 이용한 유리의 초기점화에 필요한 에너지는 약 290 kWh로 평가되었다. 혼합폐기물의 투입 중 고주파발생기의 출력은 160∼190 kW로 임피던스는 0.55∼0.65 $\Omega$ 범위 내에서 안정적으로 유지되었다. 이온교환수지 단독투입 시 보다 가연성잡고체와 혼합 할 경우 CO 발생농도는 1/40 정도로 낮아졌는데, 이는 1.8배 정도 높은 연소에너지를 갖는 가연성잡고체가 혼합폐기물의 완전연소를 유도한 것으로 평가되었다. 혼합폐기물의 공급량에 적당한 최적 산소 버블링에 의해 유리 용탕 내부로의 미연폐기물의 함침은 발생하지 않았으며 유리 용탕은 지속적으로 공정 건전성을 유지하였다. 유리 용탕의 부피가 증가하는 팽창(swelling) 현상 때와 정상 일 때 발생가스를 측정, 비교한 결과 swelling 현상 때는 NO와 같이 환원성 가스의 농도 보다 산화성 기체인 $NO_2$의 농도가 높은 것으로 나타났다. 실증시험에 사용된 이온교환 수지와 가연성잡고체의 각각 투입량은 368kg과 751kg 이었으며, 74 정도의 감용비를 달성하였다.

• 방사성폐기물학회지
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• 제16권1호
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• pp.123-136
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• 2018

본 연구의 목적은 고준위폐기물 처분기술 개발과 관련하여 현장실증 연구를 위해 사용될 공학규모 이상의 균질 완충재 블록을 제작하기 위한 새로운 방법론을 제시하는 것이다. 이와 관련하여 플롯팅 다이(floating die) 방식의 프레스 재하 및 냉간등방압프레스(CIP; Cold Isostatic Press) 기법을 국내 최초로 완충재 제작에 적용하였다. 또한 소요 밀도기준을 충족하는 완충재 블록을 생산하기 위한 최적의 제작조건(프레스 및 CIP의 소요 압력)과 현장 적용성을 분석하였다. 상기 기법의 적용을 통해 완충재 블록 내 밀도분포 편차가 현저히 감소하였으며, 이와 동시에 평균 건조밀도가 소폭 상승하고 약 5%의 크기가 감소하였다. 또한 CIP 적용을 통해 응력이완(stress release) 현상이 감소하고, 이로 인해 시간 경과에 따른 표면균열 발생이 현저히 저감됨을 시험제작을 통해 확인하였다. 본 연구에서 제시된 방법론은 공학규모 이상의 균질한 완충재 블럭을 성형할 수 있으며, 또한 이는 선진핵주기 고준위폐기물처분시스템(AKRS; Advanced Korea Reference Disposal System of HLW)의 완충재 소요 밀도기준을 충족하는 것으로 분석되었다.

• 설비공학논문집
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• 제21권12호
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• 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.

• 한국환경복원기술학회지
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• 제3권3호
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• pp.81-99
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• 2000

The shelterbelts are very important to conserve and protect the sandy land, vegetation coverage, farmland, livestock and human life in the desertified land. The shelterbelts are constructed by the several row-plantings of high-adaptable species in the desertified land. The shelterbelts have various kind of type, and there are shelterbelts for conservation of farmland in dry the region, the protective shelterbelts (windbreaks for blowing-sand, artificial sanddune fixation by revegetation, and construction of farmland shelterbelts to protect farmland and pasture from wind erosion, etc.) in the semi-dry steppe, shelterbelts around the villages and oasis for sanddune fixation, shelterbelts for protection of railroads, and so on. The shelterbelts consist of main she1terbelts and minor shelterbelts. The main shelterbelts were constructed by being perpendicular to main wind direction, and the minor shelterbelts were constructed by being perpendicular to the main shelterbelts. Generally, the width of shelterbelts is 8~20m, and the number of row-planting is 4~10. The grid sizes of shelterbelts networks are $400{\times}400m$, $300{\times}500m$, $100{\times}200m$, and so on, and there are ventilation type and closing type in the type of shelterbelt. The width, number of row-planting, grid size and type of shelterbelt are selected by the local characteristics. The effects of shelterbelts are mainly the climate improvement and mitigation, such as prevention of occurrence of strong wind, cold wind and blowing-sand. And, the other effects of shelterbelts are effect of reforestation, increase of agricultural productions, establishment of greenbelts and green forests, construction of landscape-eco shelterbelts, improvement of life environment of local villages, supply of fuel wood and agricultural wood, land amelioration, effect of revegetation and restoration of desertified land, and so on. The kinds of the tree species mainly used for the construction of shelterbelts have differences between regions, but main species are Populus euphratica, Populus simonii, Populus bolleana, Populus tomentosa, Salix flavida, Salix mongolica, Tamarix chinensis, Hedysarum scoparium, and so on.