• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.6
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• pp.696-707
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• 1988

This study simulates a typical solar system using the transient simulation program TRNSYS, and calculates the maximum cooling load of the model room of $50m^2$. In this study, energy rate control method is used in calculating a maximum cooling load. On the ground of the maximum cooling load of the model room, the variables that have an effect on the solar collection performance of the solar system are made a selection. Also in this study the trend of the solar collection performance is shown as the variables change. The results show that the variables which have an effect on the collection performance are collector area, collector mass flow rate, collector slope and the volume of storage tank, and the optimal value of Ac/Vt is not constant but varies as the collector area and the collector mass flow rate. Also the results show that for cooling system the optimal value of the collector slope is latitude minus $15^{\circ}$ during the seasonal operations, and twenty percent of the maximum cooling load is saved with the aid of the solar energy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.1
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• pp.46-54
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• 1989

The purpose of this study is to obtain the dynamic characteristics of an absorption refrigerator powered by solar energy by experiments. Since the absorption refrigerator power by solar energy should have the characteristics which is suitable for the intermittence and rarity of solar energy, not only the characteristics of the steady state operations but also the partial load and the transient operations should be considered. The minimum available temperature of the storage tank should be known, and the absorption refrigerator can be suitably selected for air-conditioning systems. In this study, the experimental data of the transient state for on-off and warming-up operations has been obtained. Also the experiments are performed which test the minimum available temperature of the storage tank. The results show that it takes 1 hour to get to the steady state of the absorption refrigerator, and the minimum available temperature of the storage tank is about $68^{\circ}C$, and show that in the partial load operations the performance of the absorption refrigerator is improved by applying the modified control method to on-off operations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.11
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• pp.512-521
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• 2014

Recently, multiple glazing units, frames, complex fenestration systems, and windows with shading devices have been developed to save cooling energy in buildings. However, very little work has been conducted on developing a direct experimental test method of the solar heat gain coefficient(SHGC) for new fenestration techniques. This study aims to develop and evaluate a test apparatus to measure the SHGC, according to the KS L 9107 test method. The performance of the solar simulator was class A, B, and A, for spectral match, non-uniformity, and instability irradiance, respectively. The differences between the measured and calculated SHGC values were found to range between 0.001 and 0.011, and for all test specimens they agreed within 4%. These results establish the validity of the test apparatus. This system is thus expected to be useful in assessing the energy performance for various types of fenestration.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.8-15
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• 2011

제습기의 역할은 태양열제습냉방시스템 요소 중에서도 매우 중요하다. 본 논문은 이러한 특성에 맞추어 제작된 장치를 갖고서 제습능력에 영향을 미치는 유량비를 바꾸어 실험한 결과이다. 실험은 크기가 $40m^3$인 항온항습실을 대상으로 이루어졌으며, 향류형 제습기의 수직 높이는 0.4m로 고정되었다. 또한 충진층은 액체흡수제와의 접촉면을 넓게하기 위하여 플라스틱 충진재로 채워져 있으며, 흡수제의 온도는 빠른 변화를 보기 위하여 $15^{\circ}C$로, 농도는 40%로 고정하였다. 액체흡수제의 유량과 습도가 높은 공기의 유량을 각각 3단계로 바꾸어 실험한 결과, 풍량이 높을수록 제습기 효과는 낮아졌으나, 전체적인 제습량에서는 많아졌다. 한편, 제습기에서 액체흡수제 유량이 많을수록 제습되는 수분량이 많아졌으나, 시간의 변화에 따라 제습되는 속도는 현저하게 낮아졌다. 따라서, 향후 실험에서는 유량의 변화 폭을 더욱 확대해서 많은 실험 결과를 확보하고, 이를 모델링화 하여 높은 정확도를 예측할 필요가 있다.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.9-16
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• 2006

Geothermal-energy has been getting popular as a natural energy source for green buildings these days. Public building with gross area more than $3000m^2$, planned after March, 2005, should spend about 5% of total building cost for equipment run by natural energy source (e.g. geothermal, solar heat, solar power, etc) according to renewable energy promotion law in Korea. As a result geothermal-energy using heat pump system is emerging as a effective alternative for realistic and economic plan although design guidelines and construction code for the system is in progress and technical data is far from sufficient. The quantitative analysis on the performance of geothermal-energy using heat pump system is insufficient for appropriate design of it. In this paper, cooling performance of geothermal-energy using heat pump system of residential and retail etc. mixed-use building has been analyzed on the basis of temperature comparison between inlet and outlet of heat exchangers of the operating system. Additionally, dry-bulb temperature and relative humidity have been measured and analyzed together as an index of indoor thermal environment.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.58-63
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• 2014

A vertical closed loop ground source heat pump (GSHP) is used to produce heat from the low-grade energy source such as the outside air and ground source. It is known that a heat pump system type has better efficiency comparing to the electric heating system. This study only demonstrates that the vertical closed loop GSHP system is a feasible choice for space cooling of air conditioning. The coefficient of performance (COP) is the ratio of heat output to work supplied to the system in the form of electricity. For the vertical closed loop GSHP system in a cooling mode, the COP is the most commonly used way for judging the efficiency. For the purpose of this experiment, vertical closed loop GSHP system was installed in the laboratory and the experiment was executed. As a result, an average COP of vertical-closed loop GSHP system was 3.62 when the outside average temperature was $33^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.584-587
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• 2006

An energy generating greenhouse based on fluoropolymer envelope and fresnel lens is proposed. The outstanding properties of the fluoropolymer films make them very suitable for large scale solar applications. Extremely high optical transmission over the whole solar spectrum, combined with mechanical strength, and durability allows us to design a highly optimized greenhouses for both plant growing and energy generation. Systems such as photovoltaic triple junction cells are especially attractive since they have up to 35% efficiency with much less cell material when the sun beam is focused with concentrators such as fresnel lenses. Cooling such devices will enhance the efficiency and provide useful thermal energy that could be further utilized for various applications depending on the local demands. This article introduces the basic ideas and principles of the energy generating greenhouses as a first step towards the actual deployment of such systems under Korean environment.

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.201-206
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• 2000

A certain system to overcome high temperature should be introduced for the stable year-round cultivation in greenhouses. There are efficient methods to overcome high temperature such as ventilation system with shading screen, fan and pad system with screen, and fog system with screen. This study was carried out to find a means to determine the capacity of such system. Heat balance equations for each system were established and verified by experimental results. The calculated ventilation rates from heat balance equations showed a good agreement with the measured ones. The evapotranspiration coefficient was the most important parameter affecting the ventilation requirement among input parameter affecting the ventilation requirement among input parameters except weather data. When the evaportanspiration coefficient increased 1%, the ventilation requirement decreased 1.3%. Therefore the data of evapotranspiration coefficient should be accumulated by various experiments, and then design standards and selection guidelines should be provided. The simulation results for same design conditions shown that air exchanges requirement and evaporating water of fan and pad system were 5.1∼7.7% and 6.8∼9.3% larger than those of fog system, respectively.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.583-590
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• 2014

The purpose of this study is to analyze and compare the life cycle cost of window glass with insulation film and regular glass, to verify an economical window construction method. As an approach method, the thermal performance data of each type of glass was measured using Window 6.3 and ECO2-OD Simulation Program, applied it to the case building to calculate the air conditioning and heating maintenance costs and LCC, and compared the economic feasibility. As a result, installing an additional insulation film prevents the solar heat penetration in the summer, so it reduces the cooling cost, on the other hand, it increased heating cost in winter. From the life cycle cost perspective, the effect of cooling cost reduction does not counterbalance the increase in heating cost and the additional cost from film installation and repair; therefore, the installation of insulation film may not be a proper method.

• Journal of the Korean Solar Energy Society
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• v.37 no.1
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• pp.47-57
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• 2017

Solar energy is one of the important renewable energy resources. It can be used for air heating, hot water supply, heat source of desiccant cooling system and so on. And many researches for enhancing efficiency have been conducted because of these various uses of solar thermal energy. This study was performed to investigate the air heating performance of hybrid solar air-water heater that can heat air and liquid respectively or simultaneously and finding method for improving thermal performance of this collector. This collector has both liquid pipe and air channel different with the traditional solar water and air heater. Fins were installed in the air channel for enhancing the air heating performance of collector. Also air inlet & outlet temperature, ambient temperature and solar collector's inner part temperature were confirmed with different air velocity on similar solar irradiance. As a result, temperature of heated air was shown about $43^{\circ}C$ to $60^{\circ}C$ on the $30^{\circ}C$ of ambient temperature and thermal efficiency of solar collector was shown 28% to 73% with respect to air velocity. Also, possibility of improvement of thermal performance of this collector could be ascertained from the heat transfer coefficient calculated from this experiment. Thus, it is considered that the research for finding optimal structure of hybrid solar air-water heater for enhancing thermal performance might be needed to conduct as further study based on the method for improving air heating performance confirmed in this study.