• Journal of Biosystems Engineering
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• v.5 no.2
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• pp.15-25
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• 1980

본 연구는 현재 국내 농촌에서 문제시되고 있는 벼의 건조와 저장방법을 개선하기위한 한 가지 방법으로써 Grain bin의 이용에 따른 기술적인 적용가능성을 구명하는데 있었으며 건조열원으로서는 상온공기와 Solar collector 에 의한 보충가열공기를 사용하였다. 건조시험에서는 벼의 건조속도, 층별함수율의 변화, 동력소모량, 도청수율 등을 측정 비교하였으며 건조가 완료된 후에는 저장시험도 아울러 실시하였다. 본 시험을 통하여 얻은 결과는 다음과 같다. 1. 본시험에 사용된 Solar Collector 는 집열면적이 $27.7m^2M$의 Flat-plate 형식이며 내부에 태양열의 저장모체로서 약 $7m^2M$의 검은 돌을 사용하였다. Collector 의 효율은 35%이었으며 Collector를 통과하여 Bin으로 들어가는 공기의 온도는 외기온에 비하여 주간에는 약 $4^\circ C$, 야간에는 약 $8^\circ C$, 정도 상승된 것으로 나타났다. 2. 상온공기와 Collector를 이용한 건조험결과 안전저장함수율에 도달하는 데 약 7일과 약 5일이 소요되었다. 3. 태양열 건조는 상온통풍건조에 비하여 곡물층간의 함수율차이가 약간 크게 나타났으나 건조속도가 빠를뿐만 아니라 동력소모량도 적은 것으로 분석되었다. 4. 건조시험이 완료된 직후 이차에 걸쳐 Bin 내에서 저장시험을 실시한 결과 저장기간중 벼의 안전보전이 가능했으며 평균함수율이 12.0~14.5%범위에서 유지되었다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.6
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• pp.46-56
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• 1998

This study was performed to investigate thermal performances of two different types of flat-plate solar collector systems; natural circulation system and forced circulation system. Conclusions obtained from this study are summarized as follows; 1) In the natural circulation system, the total heat amounts retrieved by starting recovery soon after sunrise were ranged from 10.28 to 17.20MJ/m$^2$, while the total heat amounts retrieved by starting recovery after sunset were ranged from 5.31 to 10.77MJ/m$^2$. 2) The collector efficiency in natural circulation system were ranged from 51.1% to 54.1% when the collected heat was retrieved after sunrise and were 65.8~78.0% when the collected heat was retrieved soon after sunset. 3) According to the regression analysis between fluid flow rates and fluid temperature difference at inlet and outlet of collector pipe, there was high regressive corelations with regression coefficient, r, of 0.982. 4) The collector efficiencies estimated for forced circulation system were 73.1~88.6%, and 78.4~94.8%, and 64.2%~74.5%, respectively when fluid circulation rates were 4.2 l/min, and 7.0 l/min, respectively.

• Journal of Bio-Environment Control
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• v.9 no.3
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• pp.166-170
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• 2000

Three methods for heat collection, which were the flat solar collector, two fan with radiator, and square pipe method, were studied to sue efficiently solar energy in the three different glasshouses for two years. The flat plate solar collector method was made use of the commercial solar collector with collection area of 24$m^2$, the method of two fans with radiators collected solar energy at the top of the glasshouse. An thermal storage tank was constructed underneath in teach glasshouses. When an area of 1,000$m^2$ was heated to the minimum temperature of 9$^{\circ}C$, the decrease rate of heating fuel for the flat plate solar collector, the fan attached radiator and the square pipe methods were 7%, 19% and 28% respectively. The flat plate solar collector method, which could be heated approximately 40-50$m^2$, was currently used by most of the farmer. Under the condition, the decrease rate of annual heating fuel was 14% which was not better for an economic annual heating fuel. If the fan with radiator method was operated, the use of installation and maintenance were required. So, it could not be good economic efficiency of solar heating. The heating efficiency of the square pipe method was relatively better thant those of the flat plate solar collector or the fan attached radiator. Since the cost of materials and its installation of the use of square pipe method was lower than any other method. However, corrosion of the pipe, greater shade in the greenhouse and strength against the square pipe were problems that should be overcome in the square pipe method.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.61-65
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• 2009

Window integrated solar collector is to simply install inside of the existing double glass window frame. Double glass window frame is consist of inner glass of Low-E coating and Silver coating, and outer glass of low iron reinforced glass. In order to secure natural lighting in a room, only 50% of window frame is covered with solar collectors. Solar absorption or transmission rate varies seasonally depending on sun angles. Part of inner glass where right behind of the solar plate is covered with silver coating to increase absorption rate of solar plate. The collector is made of a copper serpentine where aluminum fins are soldering. To improve the effect of insulation of inside of the window frame is recommend vacuum. As a result, we are making the 3th sample and will archieve below $F_RU_L=7.5W/m^2^{\circ}C$ that is the account of heat lossed, and above $F_R({\tau}{\alpha})=0.45$.

• Journal of the Korean Solar Energy Society
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• v.38 no.5
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• pp.37-47
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• 2018

The heating performance of a solar thermal seasonal storage system applied to a glass greenhouse was analyzed numerically. For this study, the gardening 16th zucchini greenhouse of Jeollanam-do agricultural research & extension services was selected. And, the heating load of the glass greenhouse selected was 576 GJ. BTES (Borehole Thermal Energy Storage) was considered as a seasonal storage, which is relatively economical. The TRNSYS was used to predict and analyze the dynamic performance of the solar thermal system. Numerical simulation was performed by modeling the solar thermal seasonal storage system consisting of flat plate solar collector, BTES system, short-term storage tank, boiler, heat exchanger, pump, controller. As a result of the analysis, the energy of 928 GJ from the flat plate solar collector was stored into BTES system and 393 GJ of energy from BTES system was extracted during heating period, so that it was confirmed that the thermal efficiency of BTES system was 42% in 5th year. Also since the heat supplied from the auxiliary boiler was 87 GJ in 5th year, the total annual heating demand was confirmed to be mostly satisfied by the proposed system.

• Solar Energy
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• v.10 no.3
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• pp.19-26
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• 1990

Theoretical analysis for the thermal performance on the low-cost trickle collector, which is easy to manufacture and construct, has been performed. The results were in reasonably good agreement with those of the experiments. They have been applicable to predict long-term thermal performance on the low-cost solar collecting system. The dialogue type of computer program has been written based on the f-chart method and it can be used for designing a these collecting system, and investigating its economic feasibility.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1394-1399
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• 2004

Recently solar energy is representative in the technology development and spread of alternative energy. Specially in condition of solar collectors, they have had very various shape. This paper reports experimental study about the application of Oscillating Capillary Tube Heat Pipe to flat-plate solar collector. In conclusion, overall temperature distribution of OCHP was investigated by charging ratio and inclination angle. Respective charging ratio is 15%, 20%, 40% and respective inclination angle is horizontal, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, perpendicular. As a result of experiment, charging ratio 20% heat pipe has shown the most uniform temperature distribution and also performance of heat transfer has been the best.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2310-2315
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• 2008

In this paper, study on performance analysis of bubble pump on the domestic solar water heater system is presented. Device of this experiment is consisted of bubble pump, solar collector and heat exchanger. At the mean time, this system have attached temperature sensors and pressure sensors at bubble pump. In addition, the flow meter was installed at outlet of heat exchanger. And then result of experimental study, average value of the heat exchange amount in heat exchanger was about 7.9kcal/hr, the maximum value of the heat amount in water tank($0.4m^3$) was 489.7kcal/hr and the maximum value of the mass flow rate in bubble pump was about $0.5{\ell}/min$.

• Journal of Energy Engineering
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• v.22 no.3
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• pp.302-306
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• 2013

A simple method for balancing flow rates in arrays of parallel connected flat plate solar collectors has been developed. The method is based on a computer program which solves for the flow rate through each of the collectors in a reverse return plumbed array. The analysis uses conventional "K-value" techniques and assumes the effects of density variations within the system to to be negligible. It has been found that by appropriately sizing the inlet and outlet manifolds, flow maldistribution can be nearly eliminated without resorting to expensive or complicated balancing techniques.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.559-562
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• 2006

A low-temperature solar thermal system assisting a biological nitrogen treatment reservoir was designed and field-tested. A large tank whose temperature was maintained at about $25{\sim}30^{\circ}C$ to enhance the performance of a biological nitrogen treatment process was heated by an array of flat plate solar collectors. Test results revealed that the overall collector efficiency was above 50% for the most cases tested. This high efficiency was possible owing to the relatively low collector temperature that can be traced back to the reservoir temperature. A substantial enhancement in nitrogen treatment was observed as a result of maintaining the reservoir temperature higher.