• 한국태양에너지학회 논문집
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• 제36권4호
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• pp.49-56
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• 2016

The objective of this work is to analyze the variation in energy performance for each flat plate collector connected in series. In this study, it was assumed that solar water heating system with annual solar fraction of 60% was installed in an office building in Seoul, South Korea. The transient energy performance corresponding to four cases, which are selected using different solar radiation and outdoor air temperature, is studied by analyzing the variation in outlet temperature, solar useful heat gain, and thermal efficiency of each collector. It is observed that the useful heat gain and the collector efficiency decrease continuously, and outlet temperature increases when increasing the number of collector connected in series. The long-term performance is assessed by evaluating the thermal efficiency of each collector for two solar radiation conditions ranging from 780 to $820W/m^2$ and from 380 to $420W/m^2$. It is found that the differences between the intercept and slope of the efficiency curves for first and eighth collectors are 3.68% and 6.74% for solar radiation of $800{\pm}20W/m^2$ and 8.57% and 12.90% for solar radiation of $400{\pm}20W/m^2$, respectively. In addition, it is interesting to note that annual useful heat gain and collector efficiency are reduced with similar rate of about 6.13% when increasing the collector area by connecting the collectors in series.

• 한국태양에너지학회 논문집
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• 제23권2호
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• pp.81-90
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• 2003

UTAC(unglazed transpired air collector) system has unique advantage for space heating and tempering ventilation air over the conventional collector system such as flat plate and vacuum collector. UTAC can improve radiative and convective loss due to nonglazed component and enhanced plate surface configuration. and heating energy and its equivalent green house emission performance can be improved from the use of this like collector in building application. The Option D Calibration simulation approach of IPMVP(International Performance Measurement and Verification Protocol) in ESCO businesses has been recommended to use of the calibrated computer modules like these Energy-10. DOE2.1E and TRNSYS(transient system simulation). This study is to develop subroutine type-203 of TRNSYS15.2 program and appraise thermal performance of UTAC. With newely addeded subroutine type-203. 1) Thermal performance of unglazed transpired collector could be possible based on dimensionless variables such as efficiency and heat exchanger effectiveness. and 2) Assessement of energy consists of solar useful and insulation saving for UTAC could be possible.

• 문화기술의 융합
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• 제8권2호
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• pp.355-360
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• 2022

본 연구에서는 마이크로 데이터 센터의 환경 모니터링 시스템(EMS)을 설계하고 개발하는 방법을 나타낸다. 설계하는 환경 모니터링 시스템은 IoT 센서 및 싱글보드 컴퓨터를 이용하여 데이터센터 운영환경을 실시간으로 감지하여 데이터를 해석하고 운영환경을 모니터한다. 먼저, EMS 하드웨어 플랫폼 및 IoT 센싱 패키지 설계 방법에 대하여 나타낸다. 또한 서로 다른 프로토콜을 갖는 IoT 센서에 대한 데이터 수집 SW을 설계하고 원격에서 모니터링이 가능한 EMS 모니터링 SW를 개발한다. 데이터 수집 SW는 센서 수집 모듈과 수집 메니저 모듈로 구성된다. EMS 소프트웨어는 마이크로 서비스 아키텍츠(MSA) 개념을 적용하여 설계하며 각각의 서비스는 독립적인 비즈니스 로직을 포함한다.

• 에너지공학
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• 제23권4호
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• pp.189-195
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• 2014

신재생에너지 분야 중 특히 태양에너지를 이용하는 분야는 자원의 무한 및 청정성 때문에 그 사용량이 증가 추세에 있다. 우리나라에서 태양열에너지의 이용률이 전체 에너지 사용량 중 아직 미미한 실정이지만, 근래 정부의 정책적 지원에 힘입어 이 분야에 대한 연구가 활발히 이루어지고 있다. 본 연구는 태양열집열기의 형상 변화에 따른 집열효율을 조사하기 위하여 단일진공관 태양열집열기를 이용한 실험 및 이중진공관 태양열집열기와의 비교 실험을 수행하였다. 그 결과, 본 실험장치에서 히트 파이프의 최고온도의 차이로부터 태양열집열기 형상 변화에 따른 집열효율의 변화를 확인할 수 있었다. 또한 본 연구대상 태양열집열기의 히트파이프의 온도가 비교대상 태양열집열기보다 높음에도 불구하고 방열핀의 온도가 낮게 관측되었다. 이것은 본 연구대상의 태양열집열기는 히트파이프 방열부인 헤드부와 방열핀 사이의 접촉저항이 비교대상의 접촉저항보다 크다는 것을 나타내며, 집열효율을 높이기 위해서는 태양열집열기의 여러 부분의 성능개선뿐만 아니라 접촉저항에 의한 집열손실도 감소시켜야 함을 확인할 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.152-157
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• 2001

UTC(Unglazed Transpired Collector) system has recently emerged as a new solar air heating technology. It is relatively inexpensive because it has not a glazed material. And it demonstrates efficient particularly for the applications in which larger wall area facilities with a high outdoor air requirement. Mathematical algorithm for UTC thermal modeling has been understood for further improvement of the system. EES and TRNSYS model of actual solar wall panel could be developed for computer simulations under other conditions. Computer models could be validated with the measured data from fixed outdoor test cell in KIER(Korea Institute of Energy Research). Major design parameters could be identified such as panel configuration and absorptivity and emissivity values for UTC design.

• 한국표면공학회지
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• 제51권4호
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• pp.243-248
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• 2018

All solid state thin film batteries with two types of cell structure, Pt / $LiCoO_2$ / LiPON / Cu and Pt / $LiCoO_2$ / LiPON / $LiCoO_2$ / Cu, are prepared and their electrochemical performances are investigated to evaluate the effect of $LiCoO_2$ interlayer at the interface of LiPON / Cu. The crystallinity of the deposited $LiCoO_2$ thin films is confirmed by XRD and Raman analysis. The crystalline $LiCoO_2$ cathode thin film is obtained and $LiCoO_2$ as the interlayer appears to be amorphous. The surface morphology of Cu current collector after cycling of the batteries is observed by AFM. The presence of a 10 nm-thick layer of $LiCoO_2$ at the interface of LiPON / Cu enhances the interfacial adhesion and reduces the interfacial resistance. As a result, Li plating / stripping at the interface of LiPON / Cu during charge/discharge reaction takes place more uniformly on Cu current collector, while without the interlayer of $LiCoO_2$ at the interface of LiPON / Cu, the Li plating / stripping is localized on current collector. The thin film batteries with the interlayer of $LiCoO_2$ at the interface of LiPON / Cu exhibits enhanced initial coulombic efficiency, reversible capacity and cycling stability. The thickness of the anode current collector Cu also appears to be crucial for electrochemical performances of all solid state thin film batteries.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1106-1111
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• 2010

Conventional traffic network in the urban city has been constructed and operated under systems to collect and transmit based on the roadside AP(Acess Point). But This paper has investigated the new traffic network based on smart station which combined the power network. Futhermore, the smart station can collect and transmit the variable informations and functions that supply the vehicle moving lines, informative collector service and center interoperation etc.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.967-972
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• 2009

A dynamic model has been developed to investigate the operability of a single and double-effect solar energy assisted parallel type absorption chiller. In the study, main components and fluid transport mechanism were modeled. And solar radiation and the solar collector also were also modeled along with its control design. The model was run for the single mode with solar energy supply only and the solar/gas driving double effect mode. From the simulation results, it was found that the present configuration of the chiller is not capable of regulating solution flow rates according to variable solar energy input. And the issues of the excessive circulation flowrate and the mismatch between available solar power and cooling load discourages the use of the single mode, but the dual use of gas and solar power is recommendable in view of controllability and enhanced COP.

• 설비공학논문집
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• 제22권2호
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• pp.78-85
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• 2010

A dynamic model has been developed to investigate the operability of a single and double-effect solar energy assisted parallel type absorption chiller. In the study, main components and fluid transport mechanism were modeled. And solar radiation and the solar collector were also modeled along with its control design. The model was run for the single mode with solar energy supply only and the solar/gas driving double effect mode. From the simulation results, it was found that the present configuration of the chiller is not capable of regulating solution flow rates according to variable solar energy input. And the issues of the excessive circulation flow rate and the mismatch between available solar power and cooling load discourages the use of the single mode, but the dual use of gas and solar power is recommendable in view of controllability and enhanced COP.

• 한국태양에너지학회 논문집
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• 제22권4호
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• pp.1-9
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• 2002

This study is on the design and evaluation of Zero Energy Solar House(ZeSH) including active solar heating system. Various innovative technologies such as super insulation, passive solar systems, super window, ventilation heat recovery system...etc were analyzed by individual and combination for the success of ZeSH. The ESP-r simulation program was used for this. Simulation results shows that almost 77% of heating load can be reduced with the following configuration of 200mm super insulation, super windows, passive solar system and 0.3 ventilation rate per hour. Active solar heating system (ASHS) was designed for the rest of the heating load including hot water heating load. The solar assisted heat pump is used for the auxiliary heating device in order to use air conditioner but not included in this study. The yearly solar fraction is 87% with a solar collector area of $28m^2$. The parametric studies as the influence of storage volume and collector area on the solar fraction was analyzed.