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• Hybrid cooling techniques enhanced PV module performance with low energy consumption. • Low thermal conductivity of TPT layer inhibited natural convection cooling. • Thermoelectric cooler with fans as a unit was designed to cool the module from backside. • Water-thin film cooling system (WFCS) was applied to improve the efficiency of PV. • FEM simulation was effective in understanding the heat transfer within the module layers. Photovoltaic (PV) module efficiency is often impeded by concomitant temperature elevations, which may lead to cell degeneration and decreased electrical efficiency. Cooling techniques are commonly used to avoid this problem; however, current techniques, such as water-sprayer and active cooling systems, still have limitations, including the scattering and reflection of photons. In this study, we present a new active dual-cooling system design using two thermoelectric cooling (TEC) units fixed to the back of a PV module to provide rear-end cooling, which were experimentally and numerically studied. A water-thin film cooling system (WFCS) was maintained at the top surface of the module using a small affixed 72-W DC pump, for improving efficiency. For testing, the system was installed on the roof of an agricultural building in South Korea, and its performance efficiency was compared with that of a reference cooling-free PV module. The results showed that the innovation led to a decrease in the module temperature to 21 °C, which led to an efficiency improvement of 11.23 % with an increase in the daily output energy of 8.3 %. Additionally, a numerical simulation model based on the Finite Element Method (FEM) was used to evaluate the temperature profile of the PV module owing to the cooling technique and temperature distribution on the module's top surface. The maximum temperature reductions were 17.27 and 12 °C in the experimental and simulation results, respectively. [ABSTRACT FROM AUTHOR]

Currently, the Republic of Korea operates a total of 28 nuclear power plants, including those under construction. Although every part of a nuclear power plant is important for safe operation, most attention is paid to the nuclear fuel assembly. The assembly is divided into fuel rods containing fuel assembly fuel and spacer grids. The spacer grid is an important component for core cooling by keeping the fuel rods protected and spaced apart. The spacer grid is produced from a strap bar, which is the base plate, and by spot welding eight edges of the strap bar. However, the spot welding machine has a large capacity and power supply such that the welding quality varies depending on the weld metal and surface conditions. As a result, the welding point may be defective. Therefore, this study aims to analytically verify the performance of a newly designed spacer grid for metal 3D AM as well as present analytical criteria for product development. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate tensile properties of utgulisanji connection. The utgulisanji connection is a traditional wood-to-wood connection used in wood-frame buildings in Korea. Different sizes (120 × 120, 180 × 180, 180 × 240, 240 × 240 mm2) of glulam beam at 2.4 m length made from Larix kaempferi and Pinus koraiensis were used to determine the tensile properties of utgulisanji connection. Most failure occurred at the re-entrant corner of utgulisanji connections. Different elasto-plastic behaviors of utgulisanji connection made from different species under tension indicated that tensile properties of utgulisanji connection could not be determined by specific gravity, but by a combination of manufacturing parameters with properties of materials. Initial stiffness, yield load, and maximum load of utgulisanji connections determined using three different methods increased with the size of member, whereas the yield displacement showed an inconsistent trend with the size of member. [ABSTRACT FROM AUTHOR]

The lateral deflection of a cylindrical diaphragm wall and the associated ground movement induced by deep excavation are analyzed by performing site instrumentations and numerical analyses in the coastal area of Korea. Wall lateral deflection, rebar stress, and pore water pressure were measured and analyzed in eight directions. Variations of soil properties with the decrease of confining pressure are compared by performing various in situ tests before ad after excavation. To calculate the wall lateral deflection accurately, the effects of small strain nonlinearity, confining pressure, and the hysteresis loading/unloading loop developed during excavation are considered in the proposed numerical analysis. By comparing numerical results with measured ones, the importances of considering small strain nonlinearity and confining pressure reduction in the nonlinear (FEM) are emphasized. Also, the effects of wall stiffness on the performance of cylindrical diaphragm walls are studied for future similar excavation in the coastal area. [ABSTRACT FROM AUTHOR]