• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.51-58
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• 2003

PSHC(Prismatic Solar Hybrid Collector) is a passive solar system composed of prismatic acrly glazing, glazing and ventilating fan. This PSHC system is applied to effectively reduce heating ventilation load as well as lighting load. But so far no method appraising thermal performance of this PSHC system has been developed yet. To assess thermal performance of the PSHC system, a prototype PSHC experimental facility and TRNSYS subroutine type-205 model have been developed in Korea Institute of Energy Research (KIER). The results indicated that l)TRNSYS empirical model of PSHC has been properly modeled with actual performance data, 2)a more reliable source of weather data such as NASA and KIER weather station have been also obtained, and therefore, 3)the annual energy performance of PSHC could be assessed based on this proposed TRNSYS model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.633-634
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• 2005

Transparent conducting glasses exhibit high ohmic losses that are apparent in the case of large size Dye Sensitized Solar Cells (DSSCs). In this study, we investigated the impact of current collectors over the efficiency of DSSCs. The Silver current collectors were prepared on both counter electrode and working electrode surface by screen printing method. For long term stability in electrolyte environment and also to avoid the charge recombination, current collectors are protected by sodium silicate overcoat layer. These current collectors were characterized for their microstructure parameters. Also current collector's stability in electrolyte environment has been investigated.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.3
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• pp.175-186
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• 1985

This paper presents a method for estimating the useful output of solar space heating system and estimates their performance with variance of collector size, storage volume, collector tilt and other factors . The analysis is performed by the computer simulation and by 'running' conceptual systems against solar intensities and ambient temperature for a model year stored in a computer. System performance is analyzed on monthly and yearly basis respectively and at the same time, the economics of various systems are evaluated . And also, this paper shows how an optimized design can be selected for any locality for which solar data, economic parameters and system performance are provided. It is shown that storage volume of 75 liter per $m^2$ of solar collector lead to the best design.

• 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.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.9-16
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• 2006

A solar collector surface coated with a low emission material is still imported from other developed countries expensively. Thus it is very significant to develop a new coating method with a cheap alternative coating material instead of the imported high-cost collector surface. A thermal spray method was adopted to coat a cheap Titania on a copper plate. Generally, a new coating on the copper plate was conducted successfully by selecting a proper ratio of carbon and acetylene. By measuring an absorption rate of solar and heat emission rate, all the plate types gained a high absorption rate of 98% approximately, more or less, but all of the types still have a high emission. Finally it was clear that more research is needed to advance the coated-plate to subdue the high emission from the hot plate surface and the higher the Titania's proportion is, the lower the emission is on the surface.

• Transactions of Materials Processing
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• v.23 no.3
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• pp.171-177
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• 2014

The current collector for the molten carbonate fuel cell (MCFC) which has sheared protrusions is manufactured by the three-stage forming process that integrates slitting, preforming and final forming. Due to the repetition of sheared protrusions, an effective simulation method is required to predict the mechanical behavior. In the current study, a sheet with sheared protrusions was assumed to be an orthotropic plate, which has the same length, width and height. FEM simulations were conducted to evaluate the homogenized properties of the current collector, which has 4 (longitudinal direction) x 4 (transverse direction) sheared protrusions. The simulation model was constructed using hexahedral mesh coarsening. From the verification examples, it was found that the proposed simulation method was efficient within reasonable accuracy. The calculated homogenized properties can be applied to the design of a stack for molten carbonate fuel cells and the prediction of mechanical behavior for other applications.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.229-236
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• 2018

A customized cleaning agent was investigated for improving the performance decreased by the pollution of collecting plates in an electric fume collector (EFC) which was developed and applied for the purification of effluent gas including oil mist from the textile industry. The pollutants on the surface of collecting plates were blackened by the condensation of oil mist for a long time and difficult to remove by general cleaning agents. The composition of an optimized cleaning agent consisted of alkali, alcohol, glycol and non-ionic surfactant sources was determined by considering the pollutant properties and effect on the damage of the basic metal of collecting plate and so on. The developed cleaning agent solution diluted by 9.1% was applied to the field test, and also the pollutants strongly adhered on collecting plate surfaces were successfully removed by a simple spraying method. The effluent gas purification efficiency of EFC increased significantly by cleaning of collecting plates.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.443-453
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• 2018

Radial collector wells have been widely used for large-capacity groundwater development in riparian environments, and many empirical equations have been developed for initial estimates of groundwater yield. We compare the initial yield estimates produced by several empirical equations for the radial collector well at the Anseongcheon stream site. The results of Babac's, Kordas', and Petrovic's methods are similar to the actual yield of $6,124m^3/d$, but Milojevic's method predicts a higher yield than the observed value. The conditions under which these methods are applicable explain the observed differences between the actual and estimated yields. The applicability of empirical equations is evaluated by changing the input variables of distance from well to river, number of horizontal wells, thickness of aquifer, length of horizontal well, and hydraulic conductivity. The results indicate that the conditions under which each method is applicable must be considered carefully when estimating groundwater yield, and hydraulic conductivity must be estimated accurately.

• 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.

• Journal of the Korean Institute of Telematics and Electronics
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• v.14 no.5
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• pp.1-6
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• 1977

When the input of synchronizer which is used for the purpose of synchronizing the master clock of computer with the interrupt system, a sort of random variable device, is gated with asynchronous intersection of the fall time of the master clock and the risetime oi the interrupt request, synchronizer is drived in Metastable region. This paper is presented circuit analysis of Metastable phenomena and analysis for transient process from metastable point to stable state, and also realities the collect logic with Inverter and open collector methods with a view to improving logic failure caused by the mishappen phenomena.