• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2007년도 제32회 학술대회 초록집
• /
• pp.91-91
• /
• 2007

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2007년도 제33회 하계학술대회 초록집
• /
• pp.85-85
• /
• 2007

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2005년도 제29회 학술발표회 초록집
• /
• pp.109-109
• /
• 2005

• 대한기계학회논문집B
• /
• 제30권8호
• /
• pp.772-779
• /
• 2006

Window is a critical component in the design of energy-efficient buildings. To minimize the heat loss, insulation performance of the glazing has to be improved. Manufacturing of vacuum glazing has been motivated by the possibility of making windows of very good thermal insulation properties for such applications. It is made by maintaining vacuum in the gap between two glass panes. Pillars are placed between them to withstand the atmospheric pressure. Edge covers are applied to reduce conduction through the edge. Accurate measurements have been made of the radiative heat transfer, the pillar conduction and the gas conduction using a guarded hot plate apparatus. Vacuum glazing is found to have low thermal conductance roughly below $1W/m^2K$. Among the heat transfer modes of residual gas conduction, conduction through support pillar and the radiative heat transfer between the glass panes, the last one is the most dominant to the overall thermal conductance. Vacuum glazing using very low emittance AI-coated glass has an overall thermal conductance of about $0.7W/m^2K$.

• Journal of the Korean Wood Science and Technology
• /
• 제37권3호
• /
• pp.192-199
• /
• 2009

본 연구에서는 수용재적 약 $3m^3$ 크기의 압체고주파진공건조시스템을 이용하여 Azobe (Lophira alata)와 국산 소나무(Pinus densiflora) 제재목을 건조하면서 건조시스템의 성능을 평가하였다. 압체고주파진공건조기의 진공도는 80~105 mbar를 유지시켰고, 건조 중 재온은 건조초기 $40^{\circ}C$에서 시작하여 건조말기 $60^{\circ}C$까지 상승시켰다. 全건조기간에 걸쳐 기전전극판측의 재온은 제어온도보다 항상 높게 유지되는 반면, 접지전극판측의 재온은 항상 낮게 유지되었다. 건조시간이 경과함에 따라 접지전극판측의 재온은 제어온도보다 더욱 낮고 기전전극판측의 재온은 제어온도보다 더욱 높게 나타났다. Azobe의 경우 입력포트측의 평균최종함수율보다 입력포트반대측의 평균최종함수율이 모든 잔적층에서 미미하게 높게 나타났으며, 잔적층의 수직방향으로의 최종함수율은 기전전극판측에서 접지전극판측을 향할수록 높게 나타났다. 기전전극판과 인접한 잔적층의 경우 재목당 평균할렬의 발생길이가 매우 경미하였으나, 접지전극판측을 향할수록 증가하는 경향을 보였다. 또한 투입된 에너지의 효율면에 있어 선진국의 상용설비와 유사한 수준을 보여 주는 것으로 평가되었다.

• 한국정밀공학회지
• /
• 제31권1호
• /
• pp.21-28
• /
• 2014

Recently, several researchers made their endeavor to manufacture the photobioreactor(PBR) with characteristic shapes form vacuum and blow forming process. Hence, behaviors of the transparent polycarbonate(PC) plate in the high temperature region should be examined to obtain the desired PBR case via vacuum and blow forming processes. The aim of this paper is to investigate tensile behavior of PC plate in the high temperature. Various tensile tests were performed using high temperature tensile testing machine. The influence of tensile speed, thickness and ambient temperature on tensile behavior in the high temperature was examined. The flow stress and tensile strength augmented when the tensile speed increased. In order to obtain proper flow curves with strain rate effects for different temperature of specimen, G'sell-Jonas model was adopted. The material constants of the G'sell-Jonas model were estimated. The flow curves of the PC plate considering the tensile speed, specimen thickness and temperature were obtained.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.389-394
• /
• 2008

Nowadays Plate Heat Exchanger (PHE) is widely used in different industries such as chemical, food and pharmaceutical process and refrigeration due to the efficient heat transfer performance, extreme compact design and efficient use of the construction material. In present work, PHE is applied in the fresh water generator system. Fresh water generators or desalinators are installed in ship to convert seawater to fresh water using heat from engines. PHE is an important part of a condensing or evaporating system. Among many of factors which should be concentrated on, the heat transfer and pressure drop is most important parts during sizing and rating the performance of PHE. Flow maldistribution is common but it will significantly reduce the heat exchanger performance. In this paper provide a overview of PHE cover basic of theory and conduct a numerical approach for flow distribution in plate channel. An experimental study on the performance of fresh water generator system which developed by plate heat exchanger will presented in future research. Thus, extensive experiment and analysis is required to study the thermal and fluid flow characteristics of PHE.

• 접착 및 계면
• /
• 제4권3호
• /
• pp.1-8
• /
• 2003

철판에 도금한 아연을 구리이온으로 치환하는 치환도금법과 철판에 직접 구리를 증착하는 진공증착법으로 두께가 다른 구리박막 피복철판을 제조하여 배합고무와 접착성질을 조사하였다. 구리박막 피복철판과 배합고무의 접착세기는 제조방법에 관계없이 구리박막 두께에 따라 결정되었다. 구리박막이 75 nm보다 얇으면 안정한 접착층이 형성되어 황동판에 못지 않게 고무와 강하게 접착되었으나, 90 nm보다 두터우면 구리황화물이 지나치게 성정하여 접착세기가 약하였다.

• Structural Engineering and Mechanics
• /
• 제10권3호
• /
• pp.245-262
• /
• 2000

The objective of this study is to analyze the deformational characteristics of a high-vacuum insulation panel that is evacuated to eliminate significant gas-phase conductance through its thickness. The panel is composed of a metal envelope and low thermal conductance spacers. The problem is very challenging because several nonlinearities are involved concurrently. Not only are various finite element models such as triangular, rectangular, beam and circular plate models used to simulate the panel, but also several finite element programs are used to solve the problem based on the characteristics of the finite element model. The numerical results indicate that the effect of the diameter of the spacer on the vertical deformation of the plate panel is negligibly small. The parameter that mainly influences the maximum sag is the spacing between the spacers. The maximum vertical deformation of the panel can be predicted for a practical range of the spacing between the spacers and the thickness of the plate. Compared with the numerical results obtained by the finite element models and the experimental tests, they have a good agreement. The results are represented in both tabular and graphical forms. In order to make the results useful, a curve fitting technique has been applied to predict the maximum deformation of the panel with various parameters. Moreover, the panel was suggested to be a "smart" structure based on thermal effect.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.663-668
• /
• 2008

This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.