• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.323-324
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• 2006

The nanostructure control of $Si_3N_4$ ceramics can be achieved by using fine starting powder and retardation of grain growth. The spark plasma sintering technique is useful to retard the grain growth by rapid heating. In the present work, the change of microstructure was investigated with emphasis on the particle size of starting powder, the amount of sintering additive and the heating schedule. The rapid heating by spark plasma sintering gave the fine microstructure consisting of equiaxed grains with the same size as starting particles. The spark plasma sintering of $Si_3N_4$ fine powder was effective to control the microstrucutre on nano-meter level.

• 토지주택연구
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• 제10권1호
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• pp.25-32
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• 2019

In this study, the case analysis data on underground temperature are presented. In addition, numerical analysis of the ventilation load reduction plan was derived according to the residence schedule change for the building with cool tube. The research scope and method are as follows. The overall system principle was examined through reviewing the theory of the Cool tube system. Case study and analysis were conducted. Numerical simulation was used to examine the change in energy usage. Also, the change of load energy in case of varying amount of ventilation was derived based on actual building room schedule. When the Cool tube system was applied to the residential buildings, the cooling load was reduced from 3,331 kW to 193 kW, which showed a reduction effect of about 90%.The heating load was reduced from 42,276kW to 32,575kW by 23%.Also, result shows that the cooling load decreased by 24% and the heating load decreased by 66% when the number of ventilation according to the occupancy schedule was applied.

• KIEAE Journal
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• 제14권4호
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• pp.47-52
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• 2014

The problem of energy consumption is more serious in university buildings than primary, middle and high school buildings. Because university buildings have generally heating and cooling systems, and various incidental facilities. In university, the library is one of the building that many people use and the most energy is spent. So, investigation on energy saving is very important and urgent. This study aims finally to present the guideline for low-energy design of University library by aiding a designer to select best solution in the side of energy-saving. In this paper, composition of space, utilization schedule and performance of construction materials are grasped, some primary factors that effect to energy saving are analyzed by energy simulation. The result of this study is as follows; First, the subject library has more cooling load than heating load because of cooling load generated during middle season. Second, green roofs is the most effective to heating load saving, but not to cooling energy. Third, outdoor air cooling is the most effective to cooling energy saving among the investigated strategies included in this study.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.33-38
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• 2009

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about $10.5{\sim}11.3%$, and cooling loads are decreased about $11.0{\sim}15.5%$ on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades, but the cooling peak load is hardly ever decreased. Because in the condition of cooling peak load, latent cooling loads accounts for large score of cooling loads. Difference of the energy loads by a schedule control method and an outdoor detection control was no more than 5% for a base model. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

• 한국세라믹학회지
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• 제34권6호
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• pp.553-560
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• 1997

A fine $\alpha$-Al2O3 powder was prepared by sol-gel process for membrane application. And it was carried out by adding 1.5wt% $\alpha$-Al2O3 powders(mean size : 87 nm) as seeds to the prepared sols and by controlling the heating schedule (the heating rate and the soaking time) to prevent the microstructural change, which occured during $\theta$-to $\alpha$Al2O3 phase transformation. The seeded $\alpha$-Al2O3 particles acted as the heterogeneous nucleation sites for the $\alpha$-Al2O3 nucleation during the transformation of $\theta$- to $\alpha$-Al2O3 and resulted in increasing the driving force of phase transformation to activate the formation of $\alpha$-Al2O3 phase at 82$0^{\circ}C$. By $\alpha$-Al2O3 seeding and controlling of heating condition the phase transformation of $\theta$- to $\alpha$-Al2O3 was accomplished at low temperature and the grain growth process was depressed. Therefore, the unsupported membrane could be fabricated in $\alpha$-Al2O3 . The average diameter of pores in the fabricated membrane was 7 nm and the porosity was 47%.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.230-233
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• 2004

The purpose of this study is to establish the optimal induction heating conditions of various preform types used for TR forging. The finite element model coupled electro-magnetic and transient heat transfer was employed to evaluate the distribution of temperature at the billet. Power control method was applied to control temperature of preform in induction heating because TR forging is not a continuous process. Power schedule that consists of heating and holding stage was suggested. In heating stage, power is inversely proportional to diameter of preform but the time of heating stage is directly proportional to the diameter of preform. But, in holding stage, the required power for thermal equilibrium per unit volume of the billet decreases with an increase in a diameter of billet due to the increase of efficiency.

• 동력기계공학회지
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• 제20권4호
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• pp.63-68
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• 2016

In this study, through portion of the blind control which the user can adjust the deration and the main loads, night for energy reduction during the review of the energy difference between the cooling and heating load periods in order to present the best operation schedules of the blind control. The result, Cooling period, the venetian blind is installed the day or the day and night CASE adjusted to $0^{\circ}$ was identified as optimal for the operating schedule. Heating period, the day, without installed the blinds, the Venetian blind is installed only at night CASE adjusted to $0^{\circ}$ or $45^{\circ}$ angle of the slats, which have been identified as optimal for the operating schedule.

• 태양에너지
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• 제11권2호
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• pp.29-33
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• 1991

본 연구는 일차원 열 성능 분석 프로그램인 SERI-RES를 이용하여 우리 고유의 난방 방식이라 할 수 있는 Radiant Floor Heating System의 운전 모드(Operation Modes)에 대한 시뮬레이션을 수행하였다. SERI-RES는 원래 공기 가열식 시스템을 주요 난방 방식으로 작성된 프로그램이라 본 연구의 시뮬레이션을 수행하기 위하여 Source Code에 대한 약간의 수정을 가하였다. 얻은 결과를 분석하여 보면 Radiant Floor Heating System은 그 운용 방법(Operation Modes)에 따라 건물의 동적 열 성능에 상당한 영향을 미치는 것으로 나타났으며 이는 Test Cell에 대한 간단한 실측 실험을 통해서도 확인되었다. SERI-RES는 비록 HVAC 시스템등에 대한 구체적인 시뮬레이션은 불가하나, 비록 일차원적이기는 하지만 Radiant Floor Heating 시스템과 건물의 동적 열 성능에 대한 분석에는 상당히 효율적인 Simulation Model을 제공하였다.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1419-1426
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• 2012

KNU 식물공장 모델의 냉난방 에너지 부하를 DesignBuilder를 이용하여 해석하였다. 실내설정온도, LED 보광주기, LED 보광량, 유리외피의 구조에 따른 에너지 소모량을 분석하였다. LED 보광이 없는 식물공장의 실내설정온도를 상추의 적정 생육온도인 $20^{\circ}C$를 중심으로 $15^{\circ}C$, $25^{\circ}C$로 변화시키면서 일정온도로 유지하는데 필요한 연간 냉난방부하를 분석하였다. $15^{\circ}C$일 때 냉방부하, $25^{\circ}C$일 때 난방부하가 가장 크게 나타났다. 상추 재배에 필요한 LED 보광 적용 시 난방부하는 감소하지만 냉방부하가 약 6배 증가한다. 또한 LED 보광 시 주간보다는 야간보광이 냉난방부하 감소에 유리한 결과를 주었다. 식물공장 외피가 냉난방부하에 미치는 영향을 비교하기 위하여 다섯 가지 종류의 외피를 적용하여 계산하였다. 이중창호의 열관류율이 작을수록 식물공장의 난방부하는 감소하고 냉방부하는 증가하였다. 재배할 작물의 적정생장온도 설정, LED 및 재배설비의 내부발열량에 따른 적절한 외피선택, 다양한 패시브 및 액티브 에너지 절감기술의 적용으로 냉방부하를 감소시키는 것이 식물공장 운영에 중요한 요소로 판단된다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.928-933
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• 2009

The purpose of this study is to examine the energy consumption, carbon dioxide emission & energy cost of district heating using sewage source. The annual TOE of heat pump using sewage source save 37.1 percent than city gas boiler. And annual carbon dioxide emission of heat pump cut down 41.3 percent than city gas boiler. If it charges the rate schedule for district heating to apartment resident, collected amount are 3,127,170 thousand won. As energy cost of heat pump & circulation pump are 1,378,072 thousand won. the profits are 1,749,098 thousand won. As payback period is 8.97years, applicability is low level. However, it has advantages in energy consumption, carbon dioxide emission & energy cost. Therefore, it needs to proceed through government assistance.