• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.13-14
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• 2011

Reinforced concrete structures are damaged by concrete carbonation, salt attack, and sulfate attack. The evaluation of the amount of chloride ion from the sea is very important to assess the life expectancy of Reinforced Concrete structures. The incoming salt collector which is developed in Japan has been used until the present, Unfortunately, the incoming salt collector has had a bad reputation which is caused by backward wind. The wind from backward causes the reduction of the amount of collected salt in collector's gauze. The collector was developed for excluding the effect of backward wind. The performance of it was verified from analytic and experimental methods.

• Journal of Korea Multimedia Society
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• v.24 no.12
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• pp.1653-1662
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• 2021

In this paper, we propose a small waste appliance collection system that can be used for efficient waste appliance collection, and implement an unmanned automatic small waste appliance collector system. First, we collected cases related to the collection of waste home appliances, compared and analyzed methods, and arranged the characteristics. We analyzed at the requirements for the collection and management system of waste appliances by dividing it into the aspect of the discharger and the recycling business company. The collection system consists of a client-server structure, which is a collector system and a collection management server. The unmanned automatic collector system is divided into a control unit and a machine/mechanical unit. We identified the functions that the collector system must perform and the hardware required to perform these functions. Based on this, the collector system was implemented as an embedded system. The hardware and software used in the implementation are described and the implementation results are described. The collection system developed in this paper will contribute to the development of urban mining industry by enabling the efficient collection of waste appliances.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.149-154
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• 2007

It is essential to know the heat transfer characteristics at the absorber plate of Flat-plate solar collector for optimum design. For flat-plate solar collector, it is difficult to experimentally study the effect for the Reynolds number of riser considering low mass flow rate being applied into the collector with one riser tube. So, this study were performed to show the heat transfer characteristics of flat-plate solar collector with single absorber plate and riser for various Reynolds number at riser using commercial code FLUENT 6.0. The base collector size is chosen with $0.4m^2$ as 0.2m by 2m with single riser in this study, Reynolds number at riser is from 200 to 1200 including about 530 at typical flat-plate collector with 10 risers considering the mass flow rate of 0.02kg/s per collector area for the certificate test Through the simulation, the results were presented as the temperature distribution at the absorber plate for various flow rate and solar irradiance conditions, then showed the effective length scale of the absorber plate The real solar irradiation condition is assumed as the constant heat flux condition of $500w/m^2$ considering the annual average solar irradiance in Korea.

• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.49-56
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• 2016

The objective of this work is to analyze the variation in energy performance for each flat plate collector connected in series. In this study, it was assumed that solar water heating system with annual solar fraction of 60% was installed in an office building in Seoul, South Korea. The transient energy performance corresponding to four cases, which are selected using different solar radiation and outdoor air temperature, is studied by analyzing the variation in outlet temperature, solar useful heat gain, and thermal efficiency of each collector. It is observed that the useful heat gain and the collector efficiency decrease continuously, and outlet temperature increases when increasing the number of collector connected in series. The long-term performance is assessed by evaluating the thermal efficiency of each collector for two solar radiation conditions ranging from 780 to $820W/m^2$ and from 380 to $420W/m^2$. It is found that the differences between the intercept and slope of the efficiency curves for first and eighth collectors are 3.68% and 6.74% for solar radiation of $800{\pm}20W/m^2$ and 8.57% and 12.90% for solar radiation of $400{\pm}20W/m^2$, respectively. In addition, it is interesting to note that annual useful heat gain and collector efficiency are reduced with similar rate of about 6.13% when increasing the collector area by connecting the collectors in series.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.799-805
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• 2013

An analytical study is conducted to assess the efficiency of a flat-plate solar collector using nanofluids. The nondimensionalized 2D heat diffusion equation is solved by assuming a wavelength-independent extinction coefficient and intensity to obtain the analytical solution of the temperature distribution in the flat-plate solar collector. The dimensionless temperature distribution is investigated as functions of the volume fraction of the nanofluids, magnitude of heat loss, and collector's depth based on the analytical solution when using water-based single-walled carbon nanohorn (SWCNH) nanofluids as a working fluid. Finally, the efficiency of the flat-plate solar collector using the nanofluids is predicted and compared with that of the conventional solar collector. The results indicate that the efficiency of the nanofluid solar collector is better than that of the conventional solar collector under specific geometrical conditions.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.87-92
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• 2011

The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. A photovoltaic-thermal(PVT)module is a combination of PV module with a solar thermal collector which forms one device that converts solar radiation into electricity and heat simultaneously. The performance of the PV/Thermal combined collector module is directly influenced by solar radiation that also has an effect on PV module temperature. It is also has believe that the energy performance of PV/T collector is related to absorber design as well as PV module temperature. The existing study has been paid to the PV/Thermal combined collector module with circle tube absorbers. The aim of this study is to analyze the experimental performance of the PV/Thermal combined collector rectangular tube absorbers according to solar radiation. The experimental result show that the average thermal and electrical efficiencies of the PVT collector were 43% and14.81% respectively. Solar radiation is one of the most influential factors to determine the energy performance of PVT collector, but from a certain level of solar radiation the PVT collector receives on, its efficiencies began to decrease.

• Journal of the Korean Solar Energy Society
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• v.39 no.2
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• pp.23-32
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• 2019

PVT (Photovoltaic/thermal) system is technology that combines PV and solar thermal collector to produce and use both solar heat and electricity. PVT has the advantage that the energy production per unit area is higher than any single use of PV or solar thermal energy systems because it can produce and use heat and electricity simultaneously. Air-type PVT collectors use air as the heat transfer medium, and the air flow rate and flow pattern are important factors affecting the performance of the PVT collector. In this study, a new air-type PVT collector with improved thermal performance was designed and manufactured. And then thermal and electrical performance and characteristics of air-type PVT collector were analyzed through experiments. For the thermal performance analysis of the PVT collector, the experiment was conducted under the test conditions of ISO 9806:2017 and the electrical performance was analyzed under the same conditions. As a result, the thermal efficiency increased to 26~45% as the inlet flow rate of PVT collector increased from $60{\sim}200m^3/h$. Also, it was confirmed that the air-type PVT collector prevents the PV surface temperature rise according to the operating conditions.

• Journal of the Korean Electrochemical Society
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• v.22 no.3
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• pp.122-127
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• 2019

In this study, we investigate the electrochemical performance of lithium terephthalate (LTA) battery using graphite coated metal current collector to overcome the disadvantages of organic batteries which is high interfacial resistance between current collector and electrode. The LTA anode material is synthesized by acid-based ion exchange reaction without impurities. The contact properties between stick-type LTA-based electrode and graphite coated current collector are estimated by the cross-section SEM and EIS. The graphite coated current collector significantly reduced the interfacial resistance of the LTA battery. The second discharge capacities of bare current collector LTA and graphite coated current collector LTA batteries are 107.6 mAh/g and 148.8 mAh/g at 0.1C, respectively. The graphite coated current collector LTA batteries show higher cycle life, higher discharge capacity, and higher rate-capability than bare LTA batteries.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.222-228
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• 2008

We conducted a dynamic analysis of an underwater test collector, which operates on extremely soft soil of deep-seafloor. The underwater test collector consists of nodule pick-up device, vehicle tracks, nodule crusher, loading frame and electric-electronic system. The weight of underwater test collector is about 8600 kg. The average normal pressure, that the underwater test collector supports, is about 6.0 kPa. The dynamic analysis model of underwater test collector is developed using commercial software RecurDyn-LM and Visual Fortran 90. A terramechanics model of extremely soft soil is implemented to the software based on user-written subroutine and applied to the dynamic analysis of the underwater test collector model. The dynamic responses of test collector are studied with respect to track velocities, terrain conditions, and coefficients of added mass and drag.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.155-160
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• 2007

This study shows the results on thermal performance test with domestic solar collector for low-temperature applications using KS, then reveals the efficiency difference between KS and EN standard. Using the test results, this study Presents the status of thermal performance with domestic solar collector including flat-plate, single evacuated, and double evacuated (with mirror or U-tube) solar collector.