• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.36-42
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• 2010

본 논문은 태양열이용 냉난방시스템 중에서 실제로 액체흡수제를 재생하는 재생탑 내의 충진층에 있어서의 열 및 물질전달의 실험치와 이론적 해석에 의한 결과치와의 비교를 나타내고 있다.특히 물질전달의 극대화를 위하여 충진층 내에서 공기와 흡수제의 접촉면적을 크게 할 필요가 있는데,이를 위해서 본 실험에서는 직경이 3cm인 플라스틱제 충진재를 사용하였으며, 흡수제로는 저농도의 염화리튬 수용액이 사용 되었다. 충진층 내에서의 최적 높이를 예측하기 위하여 해석의 모델인 실험장치를 직접 제작하여 실험을 수행하였고, 이론 해석에 있어서 체적 열전달을 고려한 정상상태를 모델화하여 해석하였다. 이 결과, 충진층 내에서 실험치와 이론적인 계산치가 잘 일치함을 알 수 있었으며, 충진층의 높이가 2m 이상인 경우에는 높이에 따른 재생량의 차이가 없어서 없음을 알 수 있었다.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3446-3451
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• 2007

The thermal behavior of a building in response to heat input from an active solar space heating system is analysed to determine the effect of the variable storage tank temperature on the cycling rate, on and off temperature of a heating cycle and on the comfort characteristics of room air temperature. A computer simulation of the system behavior has been performed and verified by comparisons with various parameters. Especially, this study is focused on the effect of the system's performance when subjected to dynamic cooling loads. The heat input to the absorption system is provided by an array of solar collectors that coupled to a thermal storage tank.

• Solar Energy
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• v.19 no.4
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• pp.45-53
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• 1999

This report Introduces a total heat exchanger in a solar air-conditioning system using Lithium Chloride(LiCl) solution. The hot and humid outside air is cooled and dehumidified by LiCl solution that is sprayed on the packed layer of the total heat exchanger. LiCl solution once diluted is concentrated again in a regenerator using solar energy. Three types as the packed materials were used in this experiment and the dehumidification performance was evaluated by the value of $k_xa(kg/h{\cdot}m^3{\cdot}{\Delta}x)$, overall mass transfer coefficient based on a humidity ratio potential difference, the influence of inlet LiCl solution flow rate, air flow rate, packed layer height on $k_xa$ was investigated. It was found that air flow rate, LiCl solution flow rate, packed layer height for all types had a great influnce on the value of $k_xa$.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.1-6
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• 2006

This paper presents the heating and cooling load estimations for the library of a cultural center building located in Gwangju Korea by TRNSYS with Type 56 of multi-zone building components. In this study, energy rate control mode is selected and the design temperatures for heating and cooling are specified respectively as 20oC and 26oC. Reading rooms of the library are located on the third floor of the cultural center building, and this third floor space is modeled as the five thermal zones for the TRNSYS simulation. Among the five zones, attention is given to the two zones which are the reading rooms 1 and 2. Since these two zones are to be heated and cooled by the solar thermal system which is planned to be installed in the building, dynamic thermal behaviors of the two zones are analyzed by the heating and cooling load estimations.

• Solar Energy
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• v.18 no.2
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• pp.19-29
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• 1998

Solar energy is a quantitatively unlimited, clean and non-pollutant source. It has a great potential for industrial commercial usages. For example, solar hot water system for domestic usage has been very popular in many counties. In Korea, the industries consume 47.7% of the total national energy, and the manufacturing sector uses 91.5% out of it. The main energy resoures available in Korea are oils, coals, and gases. There have been continuous efforts among the industries to reduce such energy consumptions by using alternative energy resources, such as solar energy, yet the technology has limited its proper applications to a level of satisfaction. In some advanced countries, research and development programs in solar energy applicable to the industrial usages are very active, and some systems are in the commercial market. Therefore, this paper describes the status and the feasibility for high-efficiency evacuated solar collector which was anticipated to applied for industrial process heat as an alternative of fossil energy.

• Information and Communications Magazine
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• v.27 no.4
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• pp.3-9
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• 2010

모든 경제활동이나 일상 생활의 바탕에는 전기에너지가 있다. 전기에너지로 공장을 운영하고 건물의 냉난방을 유지하고 전자기기들을 가동시킨다. 전기에너지는 화석연료나 원자력, 수력 등을 이용하여 발전소를 통해 얻을 수 있는 에너지다. 발전소의 대부분을 차지하고 있는 화석 연료는 최근에 환경오염문제와 자원고갈문제 등으로 인하여 한계점에 도달하였다. 그에 따른 문제가 심각해지면서 전 세계는 저탄소 녹색성장을 목표로 신재생 에너지원의 효율적인 사용을 연구하고 있다. 기존의 전력망으로는 태양광, 태양열, 풍력, 지열 등과 같은 신재생 에너지원을 발전원으로 사용하기에는 기술적 한계가 있다. 따라서 기존의 전력망과 다른 새로운 개념의 전력망이 필요한데, 이것이 스마트그리드이다. 스마트그리드는 환경오염문제, 자원고갈문제, 발전설비의 경제적 문제를 해결해주고 소비자에게 다양한 품질의 전력을 제공하는 소비자 위주의 전력망이 될 예정이다. 본고에서는 미래의 핵심 기술이 될 스마트그리드의 개념과 그 필요성에 대해 알아 보려고 한다.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.107-119
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• 2002

A review on the papers published in the Korean Journal of Solar Energy between 2000 and 2002 has been done. Focus has been put on current status of research in the aspect of Insolation. Solar Collector and Storage System, Solar Heating and Cooling System, Solar Cell and Lighting System, Active and Passive Solar Building, Heat Transfer in Solar Energy and Natural Energy. The conclusions are as follows. 1) Many studies on Insolation were conducted to optimize the usage of Solar Energy. 2) A review of the recent studies on solar thermal shows that there were many papers on solar collector and storage system. However, studies on the HVAC system using solar energy were relatively insufficient. 3) To produce high efficient solar cell. various experimental and numerical papers were published. However studies on control system, solar cell and lighting were seemed to be insufficient. 4) Studies on using solar energy in passive solar buildings were widely carried out, however, studies based on synthetic analysis of buildings and BIPV were insufficient. 5) Studies on heat transfer were mainly about heat exchanger, performance of heat pipe and multi air conditioner. 6) Studies on energy resources except for solar energy, such as hydraulic power and wind power etc. were very few.

• Solar Energy
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• v.20 no.4
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• pp.1-8
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• 2000

The suggested year round solar air conditioning system has been developed for cooling and heating. In particular, this system focused on cooling and dehumidification and it could reduce a peak time owing to the use of air conditioners in summer. This study was performed to find out how much heating loads could be saved and furthermore whether this suggested system would be possible to do heating without a switch of system in real situations. Through model house experiments, the following conclusions were obtained. 1) The collector efficiency was 36% at maximum, but more improved structure of suggested collector could increase its efficiency. 2) The temperature of outlet air was about $30^{\circ}C$ and it could reduce heating loads. 3) Measured temperature and calculated one agreed well within ${\pm}1.5^{\circ}C$.

• Solar Energy
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• v.19 no.4
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• pp.55-62
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• 1999

This study was performed to find out the influence of experimental factors on dehumidification performance and furthermore to suggest an optimal combination of factors of a total heat exchanger in a solar air conditioning system. The experimental apparatus was set up in a climate-controlled chamber where the temperature and humidity was maintained constant. In order to find out the contribution ratio of factors on dehumidification performance, the table of orthogonal arrays $L_8(2^7)$ was used. According to the results, the most influential factor on dehumidification performance was the concentration of LiCl(Lithium Chloride) solution. The next influential factors were the temperature of LiCl solution and the air flow rate. The packed layer height, packed material, and flow rate of LiCl solution had no influence on the dehumidification performance under these experimental conditions. Through the three level experiments of $L_{27}(3^{13})$, it was found that the optimal combination was $A_2B_0G_2$(concentration of solution 30 wt%, temperature of solution $15^{\circ}C$, air flow rate $253m^3/h$).