• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.479-484
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• 1986

Two different types of solar collector for farm dryer- the flatplate type and the modified tubular type-were constructed and analyzed on their performances. The transparent plastic film, black painted galvanized iron sheet and black vinyl film were used for the cover and absorber of the flat-plate types. The simplified tubular type was constructed with transparent films for the cover and black vinyl films for the absorber Two elliptical iron rings were used to form a tubular shape through which air could pass. No remarkable differences were found in thermal efficiences between the absorbers made with galvanized iron sheet and black vinyl film. The average thermal efficiencies of the solar collectors were 42.8%(max.48.2%, min.38.2%) for flat plate type and 22.971 (max. 25.4%, min. 14.8%)) for tubular one. The empirical equations were proved to be applicable to the prediction of temperature elevation. The tubular solar heat collector was successfully applied to red peppers drying as a practical farm dryer. The drying rate was almost doubled compared to a conventional sun drying.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.39-47
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• 2017

In a hot water system using solar energy, solar heat is not simply collected by the heat collecting plate, but by heat exchange between the solar collector (flat or vacuum type) and the hot water storage tank. Therefore, the amount of collected solar energy depends on the hot water usage patterns that determine the temperature of the thermal storage tank. Also, if the temperature of the hot water stored in the storage tank exceeds the dangerous temperature during the summer, the heat must be released for safety. If the temperature of the hot water in the storage tank is low, it is necessary to heat by the auxiliary heat source. In this study, three buildings are defined as hotel, swimming pool, and school facilities. And we calculated the released heat energy, auxiliary heat source, and pure storage heat energy based on different hot water usage patterns and installation angle of the solar collectors.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.45-52
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• 2009

This study was conducted in the process that the basic plan of the formation of the thermal energy complex in the Iwon reclaimed land of Taean was being made. Targeting for the large-sized greenhouse to be made in this area, it examined the cooling and heating load and the amount of ventilation, and also analyzed the economic efficiency of heating. The research results are as per the below: The minimum ambient temperature of this area was measured on January 7, 2001, which was $-18.7^{\circ}C$, and the maximum ambient temperature of this area was measured on July 24, 1994, which was $36.7^{\circ}C$. The maximum heating load was 39,011 MJ/h, but the date when the maximum heating load was not consistent with the date when the minimum temperature was measured. The maximum cooling load was 88,562MJ/h, It was approximately 2.3 times of the maximum heating load, which was measured at 14:00 hours on September 4, 2000. The maximum amount of ventilation heat was 138,639MJ/h. Assuming the rate of solar heat use as 10%, 20%, 50%, and 100%, the total sum of cost-benefit would be ￦-193,450,000, ￦-634,930,000, ￦-3,372,960,000, and ￦-9,850,420,000, respectively 20 years later. The break-even point of the geothermal heat pump would be about 4 years for 10% use, about 3 years for 20% or 50% use, and approximately 6 years for 100% use. It was found that 50% use would be most advantageous. In case two systems are combined, the break-even point will be 10 years, 8 years, and 11 years respectively.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.56-64
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• 1979

Two types of fiat-plate collector were designed and constructed for utilizing the solar energy as heating source of red pepper drying. It was performed to investigate the basic factors on using the collectors and the drying effect on various types of red pepper, and the results obtained are summarized as follows. 1. The optimum tilted angles of the collector in Daejeon area were ${\phi}-15^{\circ}$ in summer season and ${\phi}+15^{\circ}$ in winter season when it was adjusted two times per a year: 2. In the conditions during experiment period, average atmospheric temperature and relative humidity were $25.6^{\circ}C$ and 52.6%, respectively, and $42.0^{\circ}C$, 74.2% in the control chamber. The temperature in the drying chamber connected to the water heater was the highest but relative humidity in the chamber connected to the air heater was the lowest among the chambers. 3. The drying velocity of whole red pepper in the chamber connected to the water heater was the fastest as 2.3 times as compared to the whole type on the mat drying followed by air heater and control in decreasing order. The horizontally cut red pepper in the chamber connected to the water heater was dried exceedingly fast among twelve plots. 4. The content of capsaicine as pungent principle and of capsanthine as red pigment in the red pepper were reduced during drying but there were no differences significantly on the drying method, and it could not affect much on the quality of dried product.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.28-34
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• 2019

Solar energy is one of the most abundant renewable energy sources on Earth but there are restrictions on the use of solar thermal energy due to the time-discrepancy between the solar-rich season and heating demand. In Europe and Canada, a seasonal solar thermal energy storage (SSTES), which stores the abundant solar heat in the summer and uses the heat for the winter heating load, is used. Recently, SSTES has been introduced in Korea and empirical studies are actively underway. In this study, a $2,000m^2$ flat plate type solar collector and $20,000m^2$ of borehole thermal energy storage (BTES) were studied for a greenhouse in Hwaseong City, which has a heating load of 2,164 GJ/year. To predict the dynamic performance of the system over time, it was simulated using the TRNSYS 18 program, and the solar fraction of the system with the control conditions was investigated. As a result, the solar BTES system proposed in this study showed an average solar fraction of approximately 60% for 5 years when differential temperature control was applied to both collecting solar thermal energy and discharging BTES. The proposed system simplified the configuration and control method of the solar BTES system and secured its performance.