• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.179-184
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• 2011

The development of new energy has attracted consideration attention due to the high oil price and environmental problems. In advanced country, they have tried to carry out a long range plan for energy. We need to develop new energy for Low Carbon Green Growth in Korea. The building is 30% among ratio of energy consumption in Korea. And in the past, heating energy was high ratio for energy using at home. But recently, the demand for cooling energy keeps growing due to rising average temperature on the earth and improvement of life quality. In this situation, the energy of lake water and ocean water has studied to utilize in advanced country because of low temperature at underwater. But the study for deep water is still a lot left to do. In this study, we analyzed district cooling system and the present condition. Analyzing the deep lake water cooling system in Toronto, we found an application of district cooling system using deep ocean water. Deep lake water uses heat source for district cooling and water source for city in Toronto. So reducing the initial cost, this city had economic effect. When DLWC was applied at existing building, the heat exchanger was installed instead of cooling tower and refrigerator. And the heat exchanger used to connect main pipe with cool water on city. System using deep ocean water can be applied as a similar way to supply cool water from lake to building.

• Journal of Animal Science and Technology
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• v.61 no.4
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• pp.204-215
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• 2019

This experiment was conducted to evaluate the effect of dietary energy and crude protein (CP) levels on growth performance, blood profiles, and carcass traits in growing-finishing pigs. A total of 180 crossbred pigs ([Yorkshire ${\times}$ Landrace] ${\times}$ Duroc) with an average body weight of $30.96{\pm}3.068kg$ were used for a 12-week feeding trial. Experimental pigs were allotted to a $2{\times}3$ factorial arrangement using a randomized complete block (RCB) design. The first factor was two levels of dietary metabolizable energy (ME) density (13.40 MJ/kg or 13.82 MJ/kg), and the second factor was three dietary CP levels based on subdivision of growing-finishing phases (high: 18%/16.3%/16.3%/13.2% middle: 17%/15.3%/15.3%/12.2% and low: 16%/14.3%/14.3%/11.2%). Average daily gain (ADG) and gain-feed ratio (G:F ratio) decreased as dietary CP level was decreased linearly (linear, p < 0.05; p < 0.05, respectively) in the early growing period, and G:F ration also decreased as dietary CP level was decreased linearly (linearly, p < 0.05) over the whole growing phase. Over the entire experimental period, G:F ratio decreased as dietary ME level decreased (p = 0.01). Blood urea nitrogen (BUN) concentration was increased as dietary energy level decreased in growing period (p < 0.01). During finishing period, total protein concentration was decreased by lower dietary energy level (p < 0.05). In this study, there were no significant differences in proximate factors, physiochemical properties, muscle TBARS assay results, pH changes, or color of pork by dietary treatments. However, saturated fatty acid (SFA) increased (p < 0.01) and polyunsaturated fatty acid (PUFA) decreased (p < 0.05) when ME was decreased by 0.42 MJ/kg in growing-finishing pig diets. In addition, monounsaturated fatty acid (MUFA) tended to increase when CP level was decreased in growing-finishing pig diets (p = 0.06). A growing-finishing diet of 13.82 MJ/kg diet of ME with the high CP level can improve growth performance and show better fatty acids composition of pork.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.10 no.4
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• pp.15-24
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• 2014

This study conducted a computational fluid dynamics(CFD) analysis to find an appropriate diameter or sectional area of air ducts and fluid pipes which have an electromagnetic pulse(EMP) shied to protect indoor electronic devices in special buildings like military fortifications. The result shows that the optimized outdoor air intake size can be defined with either the ratio of the maximum air velocity in the supply duct to the air intake size, or the shape ratio of indoor supply diffuser to the outdoor air intake. In the case of water channel, the fluid velocity at EMP shield with the identical size of the pipe, decreases by 25% in average due to the resistance of the shield. The enlargement of diameter at the shield, 2 step, improves the fluid flow. It illustrated that the diameter of downstream pipe size is 1step larger than the upstream for providing the design flow rate. The shield increases friction and resistance, in the case of oil pipe, so the average flow velocity at the middle of the shield increase by 50% in average. In consideration of the fluid viscosity, the oil pipe should be enlarged 4 or 5 step from the typical design configuration. Therefore, the fluid channel size for air, water, and oil, should be reconsidered by the engineering approach when EMP shield is placed in the middle of channel.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.2
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• pp.79-88
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• 2017

One of the important applications of activity sensing in the home is energy monitoring. Many previous methodologies for detecting and recognizing household appliances have been proposed. This paper presents an approach that uses an energy metering circuit (EMC) to classify and identify the various electrical devices in home based on root-mean-square (RMS) consumed current value. EMC gathers the RMS current values created by appliance state transition (e.g., on to off) and apparatus operating process. In this paper, an identification algorithm is proposed to detect a change in current levels using the standard deviation of current signals and their average values. In addition, characteristic of the appliance is extracted concerning four feature parameters concerning the number of current levels, the minimum level, the maximum level, and signal-to-noise ratio (SNR) of them. Experiment results validate the reliable performance of the proposed identification method for 11 representative appliances.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1895-1901
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• 2024

The fission model, G4ParaFissionModel, was enhanced in this study, mainly focusing on refining the energy dependence of the peak-to-valley ratio in the mass distribution and the energy dependence of the average total kinetic energy (TKE). The enhanced model was employed to investigate the characteristics of fission products from ²³⁵U(n, f) reaction. The calculated results, including fission yield, TKE distribution, prompt fission neutron and gamma spectra, were compared with both evaluated and experimental data. The comparison shows that these physical observables related nuclear data, which are of importance for developments of the nuclear power and physics, can be reasonably well reproduced.

• Nuclear Engineering and Technology
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• v.22 no.4
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• pp.410-415
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• 1990

Prompt fission neutron energy spectrum as a function of energies of neutron inducing fission has been calculated en the basis of the Madland-Nix(MN) model. The resultant spectra have been weighted to excitation functions of $^{27}$ Al(n, $\alpha$), $^{32}$ S(n, p) and $^{115}$ In(n, n') threshold reactions in order to get the average cross sections and then spectral indices which are defined as the average cross section ratio for two selective threshold reactions among the above three. It is appeared that spectral indices together with the neutron spectra are varying with energies of neutron inducing fission. This may indicate that the prompt fission neutron energy spectrum can be determined by measuring experimentally the spectral index.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.58-63
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• 2014

A vertical closed loop ground source heat pump (GSHP) is used to produce heat from the low-grade energy source such as the outside air and ground source. It is known that a heat pump system type has better efficiency comparing to the electric heating system. This study only demonstrates that the vertical closed loop GSHP system is a feasible choice for space cooling of air conditioning. The coefficient of performance (COP) is the ratio of heat output to work supplied to the system in the form of electricity. For the vertical closed loop GSHP system in a cooling mode, the COP is the most commonly used way for judging the efficiency. For the purpose of this experiment, vertical closed loop GSHP system was installed in the laboratory and the experiment was executed. As a result, an average COP of vertical-closed loop GSHP system was 3.62 when the outside average temperature was $33^{\circ}C$.

• Nuclear Engineering and Technology
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• v.29 no.1
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• pp.45-57
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• 1997

The direct contact condensation phenomenon, which occurs when steam is injected into the subcooled water, has been experimentally investigated. Two plume shapes in the stable condensation regime are found to be conical and ellipsoidal shapes depending on the steam mass flux and the liquid subcooling. Divergent plumes, however, are found when the subcooling is relatively small. The measured expansion ratio of the maximum plume diameter to the injector inner diameter ranges from 1.0 to 2.3. By means of fitting a large amount of measured data, an empirical correlation is obtained to predict the steam plume length as a function of a dimensionless steam mass flux and a driving potential for the condensation process. The average heat transfer coefficient of direct contact condensation has been found to be in the range 1.0~3.5 ㎿/$m^2$.$^{\circ}C$. Present results show that the magnitude of the average condensation heat transfer coefficient depends mainly on the steam mass fin By using dynamic pressure measurements and visual observations, six regimes of direct contact condensation have been identified on a condensation regime map, which are chugging, transition region from chugging to condensation oscillation, condensation oscillation, bubbling condensation oscillation, stable condensation, and interfacial oscillation condensation. The regime boundaries are quite clearly distinguishable except the boundaries of bubbling condensation oscillation and interfacial oscillation condensation.

• Journal of Integrative Natural Science
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• v.15 no.2
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• pp.89-97
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• 2022

This paper presents the comprehensive feasibility study of solar mini-grid project located in Bajhang District, Sudur Paschim Province, Nepal. The study has been conducted with the aim of developing a suitable size solar mini-grid system to meet electricity demand of proposed settlements of the village people. The study forecasts that the estimated average daily peak power consumption of load is about 20kW and average daily energy demand of load is about 100-150kWh/day in the base year 2022. The shared ratio of productive end uses is about 25% of the total power consumption and about 27% of the total energy demand, which will be used for small business/income generation activities and required 45kWp size solar power generation mini-grid system. The estimated project cost for the proposed 45kW solar mini-grid system technology, including 3 years of operation & maintenance, as well as power distribution network up to end user's premises is about 0.24 million USD. It is concluded that 45kWp photovoltaic mini-grid is feasible for the location.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1587-1593
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• 2007

A single factorial experiment was conducted to test the effects of three dietary levels of energy on mRNA expression of fatty acid synthase (FAS-mRNA) and hormone-sensitive lipase (HSL-mRNA) and their association with intramuscular fat in finishing pigs. 72 crossbred (Large $White{\times}Rongchang$) barrows with an average initial body weight of 20.71 (s.e. 0.1) kg, were randomly allotted to three dietary treatments (11.75, 13.05 and 14.36 MJ DE/kg) and fed until slaughtered at 100 or 101 kg. The diets were iso-nitrogenous and iso-essential amino acids. The growth performances including the duration of finishing were changed linearly (p<0.05) or quadratically (p<0.05) with increased dietary energy levels. The effects of dietary energy content on the percentage of external fat, intramuscular backfat and the fat thickness were linear (p<0.05). The content of dietary energy increased FAS-mRNA linearly or quadratically, while HSL-mRNA decreased linearly or quadratically in backfat and Longissmus dorsi muscle. Meanwhile, significant positive correlations (p<0.05) were found between energy level and intramuscular fat, FAS-mRNA or the ratio of FAS-mRNA to HSL-mRNA, between the ratio of FAS-mRNA to HSL-mRNA and intramuscular fat. However, the correlations between HSL mRNA and dietary energy or intramuscular fat were negative (p<0.05). The results indicated that dietary energy level regulates lipid accumulation, especially intramuscular fat, possibly by modulating the mRNA of FAS and HSL together rather than individually.