• 한국태양에너지학회 논문집
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• 제35권3호
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• pp.73-79
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• 2015

In this study, a thermal storage performance and characteristics of daily operation were investigated when the air and the liquid were heated simultaneously by a hybrid solar air-water heater that can make hot water as well as heated air. The hybrid solar air-water heater is kind of a flat plate solar collector that can make hot water and heated air by installing air channel beneath absorber plate of traditional flat plate solar collector for hot water. As a result of daily operation, maximum water temperature reached in a thermal storage was shown $44^{\circ}C$ on 73kg/h of air mass flow rate and about $40^{\circ}C$ on 176kg/h of air mass flow rate. Thus, the necessity of heating water in thermal storage by operating only liquid side was confirmed when the temperature of liquid in thermal storage is lower than we need. In case of efficiency investigated on daily operation, the thermal efficiency of the liquid side was decreased with increment of the inlet liquid temperature and decrement of the solar radiation, but efficiency of the air side was increased with increment of inlet liquid temperature difference as the traditional solar air heater. Total thermal efficiency of the collector was shown from 65.85% to 78.23% and it was decreased with increment of the inlet liquid temperature and decrement of solar radiation same as the traditional system.

• 태양에너지
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• 제5권2호
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• pp.35-45
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• 1985

A solar hot water storage tank was designed and constructed to examine the heat exchange performances on load side for the solar thermal storage in a single loop solar water heating system. In the tank helically coiled tube was immersed. The hot water was circulated from either top or bottom. The circulation flow rate was varied from 500 ml/min to 20,000 ml/min. The effect of flow rate was observed. The thermal performances according to the flow rate and flow direction were examined. The temperature distributions in the tank and inside of the tubes were plotted along the process of cooling.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.245-250
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• 2008

This study is on the availability of solar thermal energy in Korean high-rise apartment complex depending on the installation type of solar collectors to roof or facade of building. Firstly, solar access evaluation on the roof and the facade of apartment buildings was carried out. The total thermal load of each apartment unit and building was investigated and matched with the energy which was produced by solar thermal systems on the facade. The considered layout patterns of apartment buildings were '一type', 'alternative 一type', 'ㄱtype' and 'ㅁtype' and that was analyzed in prior studies. Extensive dynamic hourly energy simulations with the solar thermal system were Performed with the TRNSYS of SEL. We assumed that the apartment complex is composed of 9 buildings and located in Daejeon. The collectors are the heat-pip evacuated tube collectors and the number of collectors are 45 tubes We assumed that the collectors are installed on the balcony of each unit and the angle of incilnation is $90^{\circ}$. As a result, the supply amount of solar thermal systems is about 4,850,086kJ/hr and the solar fraction is about 66%. The solar fraction according to each azimuth is about 66% on the south, 62% on the south-east $30^{\circ}$ and 56% on the south-east $60^{\circ}$. So, we quantitatively got a line on the optimal azimuth for installing the solar thermal systems. The solar fraction has differences from 5% to 15% of each floor, 6th, 12th and 20th and those tendencies are same in analyzed each 4 types of the apartment complexes.

• 대한기계학회논문집B
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• 제38권1호
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• pp.49-56
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• 2014

본 연구는 집광장치와 태양추적장치를 이용함으로서 제한된 면적을 가지는 집광형 태양전지의 발전효율을 증가시키는 연구를 진행하였다. 태양전지에서 발생된 열은 온수나 난방에 사용되도록 흡열기를 이용하여 회수하였다. 이로서 집광형 태양전지를 이용한 시스템은 전기와 열을 동시에 공급할 수 있다. 태양위치에 따른 실시간 추적, 일몰 이후 난방장치의 동쪽방향 원상복귀, 원상복귀후 자동종료는 조도센서와 Simulink 프로그램으로 구현하였다. 흡열기 입구 속도, 핀설치 유무, 입구위치에 따른 흡열기 온도를 해석하였으며 실험결과와 일치하였다.

• 한국태양에너지학회 논문집
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• 제34권5호
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• pp.23-31
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• 2014

This study was accomplished to get the foundation design data of VMD(Vacuum Membrane Distillation) system for Solar Thermal VMD plant. VMD experiment was designed to evaluate thermal performance of VMD using PVDF(polyvinylidene fluoride) hollow fiber hydrophobic membranes. The total membrane surface area in a VMD module is $5.3m^2$. Experimental equipments to evaluate VMD system consists of various parts such as VMD module, heat exchanger, heater, storage tank, pump, flow meter, micro filter. The experimental conditions to evaluate VMD module were salt concentration, temperature, flow rate of feed sea water. Salt concentration of feed water were used by aqueous NaCl solutions of 25g/l, 35g/l and 45g/l concentration. As a result, increase in permeate flux of VMD module is due to the increasing feed water temperature and feed water flow rate. Also, decrease in permeate flux of VMD module is due to increasing salinity of feed water. VMD module required about 590 kWh/day of heating energy to produce $1m^3/day$ of fresh water.

• 설비공학논문집
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• 제23권5호
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• pp.327-333
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• 2011

In the present work, a new freeze protection method has been proposed for a natural circulation system of solar water heater. Though electrothermal wire is popularly used for the purpose, there are freezing troubles by wire cut-off and shortage of excessive electric power consumption. In the experimental device, hot water in storage tank was used to heat the outlet pipe from the tank if the pipe surface temperature falls lower than a set point. The cold water pipe to the storage tank was installed to directly contact the hot water pipe surface temperature rose by transferred heat.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.91-96
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• 2009

First, the base model of multi-family residential buildings are selected, and then the $CO_2$ reduction building technologies that are applicable for multi-family residential buildings are induced by analyzing the examples and then an optimal plan for when the $CO_2$ reduction building technologies can be integrated and applied to the base model was formulated. In the results of converting the energy consumption and reduction amount from the building technologies into $CO_2$ emissions to analyze the distribution ratio compared to the entire $CO_2$ emissions; the heat recovery ventilator is 0.5%, the photovoltaic system is $1.9%{\sim}5.9%$, the solar hot water heating system is $6.3%{\sim}13.1%$ and the ge thermal heat-pump system is 39.0% when both heating and hot water heating are applied. An optimally integrated application method for the building technologies is in charge of heating and hot water heating through the geothermal source heat pump system and in charge of the electricity load through the photovoltaic system(45.2%).

• 설비공학논문집
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• 제26권1호
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• pp.8-14
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• 2014

We have performed experiments to enhance the stratification in a storage tank in order to raise the collector efficiency and solar fraction in solar thermal systems. The storage tank with a spiral jacket in the side wall has a scroll-shaped heat exchanger coil added to the upper part. The performance was compared between only the side and upper-side heating part through simulation using TRNSYS under the same weather conditions and initial conditions. As a result, the upper-side heating has a 4.2% advantage in solar fraction, but almost no increase in collector efficiency.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.109-114
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• 2009

The dominant heating system used in Korean residential apartment buildings is a hydronic radiant floor heating system, known as the Ondol system. The most common control strategy applied to this traditional hydronic radiant system is a simple on-off control that intermittently supplies "hot water of a fixed temperature" at a "constant flow rate" to each room. However, the current problems with the aforementioned control are as follows: (1) since the simple on-off control is usually based on a one point measured temperature (a signal from a thermostat installed in a living room) in each dwelling unit, heating energy use for unoccupied rooms as well as a difference in temperatures between spaces (master bedroom, living room, bedroom1, bedroom2) can occur occasionally. (2) the most widely used residential water splitter has static valves, and is thus not able to change the flow rate to each room depending on the space heating load. In other words, the ratio of flow rates to rooms is fixed after construction, resulting in over- or under-heating and an improper use of energy. The aim of this paper is therefore to investigate the differences in the system's performance between control strategies in terms of the flow rate control and sensor location. It is shown that energy savings of control strategies are strongly influenced by occupant schedule.

• 에너지공학
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• 제21권4호
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• pp.356-361
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• 2012

지열, 풍력, 태양열에너지 등과 같은 신재생에너지 분야에 관한 연구가 활발히 이루어지고 있으나 전체 에너지 중에서 차지하는 비율은 아직 미미하다. 본 논문은 주열원인 열사이폰관형 태양열집열기와 보조열원인 X-L 파이프 보일러장치를 서로 결합한 하이브리드 난방시스템에 관한 연구이다. 특히 새로운 형태의 열사이폰관형 태양열집열기에 관한 성능 평가와 함께 보조열원장치의 성능 및 안전성에 대해 조사하였다. 그 결과, 열사이폰관형 태양열집열기는 이중관형 태양열집열기보다 집열효율이 그 구조적 특성 때문에 최대 20.7% 더 증가하였다. 또한 보조열원장치의 X-L 파이프 내 특수열매체는 순수 물보다 약 20% 더 빠르게 온도가 상승하였으며, X-L 파이프 보일러는 안정성 때문에 팽창압력 해소장치가 필요함을 확인하였다.