• Journal of Energy Engineering
• /
• v.9 no.2
• /
• pp.95-101
• /
• 2000

The purpose of this study is to find plant utilities capacity for economical operation of combined heat & power by reducing energy expenditure. Using a numerical simulation program CHPSIM, a comparative analysis of additional heat expenditure (AHE) of combined heat & power plant in relation to size of district heating has been performed within the comparison of the difference capacity of gas turbine and steam turbine . As a results, if a 105.2MW gas turbine (exhaust gas temp ; 540$^{\circ}C$) installed in CHP plant can reduced 17-18% yearly the AHE than 75MW gas turbine (520$^{\circ}C$) installed. If a 130-150MW gas turbine (560-580$^{\circ}C$) installed, can reduced 34.7-35.8% of the yearly AHE.

• Journal of Power System Engineering
• /
• v.2 no.3
• /
• pp.27-33
• /
• 1998

The room temperature and air conditioning load in the underground space have been investigated numerically by the unsteady heat conduction equation. The model room has 3 m in height and 10 m in width, and it's position in the underground depth are 0.5 m to 5 m. When the room was located around surface, the room temperatures were strongly influenced by the atmosphere. But the underground depth is more than 2 m, the yearly temperature amplitude was small and the temperature phase was delayed. Up to 5 m of the depth, the cooling and heating load was decreased rapidly, but over 10 m of the depth, the air conditioning load was constant.

• Journal of Energy Engineering
• /
• v.7 no.2
• /
• pp.172-179
• /
• 1998

In this paper, an alternative method which can evaluate a marginal power exceeding yearly peak load for each load bus is proposed. The proportion of the marginal power to yearly peak load for each load bus is defined as Local Marginal Power Rate (LMPR). Furthermore, the composite system is separated base on the LMPR. The bottleneck facilities could be found, while the LMPR is estimated. Then, it is possible to provide information concerning improvement in the system reliability by bottleneck facilities. The IEEE Reliability Test System (RTS) is used to demonstrate the effectiveness of the proposed algorithm.

• Journal of Astronomy and Space Sciences
• /
• v.37 no.3
• /
• pp.165-170
• /
• 2020

Muons and neutrons are representative secondary particles that are generated by interactions between primary cosmic ray particles (mostly protons) and the nuclei of atmospheric gas compounds. Previous studies reported that muons experience seasonal variations because of the meteorological effects of temperature. The intensity of neutrons has a typical modulation with various periods and reasons, such as diurnal and solar variation or transient events. This paper reports that cosmic ray particles, which were observed by neutron monitors, have seasonal variations using the daily data at the Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily data were normalized by two different transformations: transformations with respect to the grand mean and yearly mean. The data after transformation with respect to the yearly mean showed more statistical stability and clear seasonal variations. On the other hand, it is difficult to determine if the seasonal variation results from terrestrial effects, such as meteorological factors, or extraterrestrial effects, such as the position of the Earth in its orbit of revolution.

• Architectural research
• /
• v.7 no.1
• /
• pp.11-18
• /
• 2005

In today's building industry the emphasis has been geared more towards construction, thus building maintenance and life cycle have been neglected until now. A direct result of this neglect is the rapid aging of building, which leads to more cost-effective decision making methods for the prolongation of building life span. The following study is conducted in the area of Daegu and Seoul in order to develop the estimation analysis method of the annual operation cost of the Korean high-rise condominiums for the cost-effective decision making support through mathematical and statistical analyses including the present value and standardized measurement corrections. Based on the assumption that the life expectancy of the high rise condominium is 50 years, initial cost is ￦421,212/$m^2$, and a total sum of yearly operation cost during life expectancy is ￦2,154,499//$m^2$), yearly accumulated operation cost is shown as below: $AOC=0.7097t^4-38.803t^3+806.95t^2+11045t-496.52$ ($R^2=0.98$) (Here, AOC = Accumulated Operation Cost, t = given years)

• KIEAE Journal
• /
• v.3 no.2
• /
• pp.17-24
• /
• 2003

The purpose of this study is to present rational methods of multi-criteria optimization of the envelope of buildings. The object is to determine the optimum R-value of the envelope of a building, based on the following criteria: minimum building costs (including the cost of materials and construction) and yearly heating costs. Mathematical model described heat losses and gains in a building during the heating season. It takes into consideration heat losses through wall, roof, floor and windows. Particular attention was paid to have a more detailed description of heat gains due to solar radiation. On the assumption that shape of building is rectangle in order to solve the problem, optimum R-value of the envelope of a building is determined by using non-linear programing methods(Kuhn-Tucker Conditions). The results constitute information for designers on the optimum R-value of a building envelope for energy saving buildings.

• KIEAE Journal
• /
• v.3 no.2
• /
• pp.51-58
• /
• 2003

The purpose of this study is to present rational methods of multi-criteria optimization of the shape of energy saving buildings. The object is to determine the optimum dimension of the shape of a building, based on the following criteria: minimum building costs (including the cost of materials and construction) and yearly heating costs. Mathematical model described heat losses and gains in a building during the heating season. It takes into consideration heat losses through wall, roof, floor and windows. Particular attention was paid to have a more detailed description of heat gains due to solar radiation. On the assumption that shape of building is rectangle in order to solve the problem, the proportions of wall length and building height are determined by using non-linear programing methods(Kuhn-Tucker Conditions). The results constitute information for designers on the optimum proportions of wall lengths, height, and the ratios of window to wall areas for energy saving buildings.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1147-1150
• /
• 2008

The goal of this research is to apply the neural networks models for the disaggregation of the pan evaporation (PE) data, Republic of Korea. The neural networks models consist of the support vector machines neural networks model (SVM-NNM) and multilayer perceptron neural networks model (MLP-NNM), respectively. The SVM-NNM in time series modeling is relatively new and it is more problematic in comparison with classifications. In this study, The disaggregation means that the yearly PE data divides into the monthly PE data. And, for the performances of the neural networks models, they are composed of training, cross validation, and testing data, respectively. From this research, we evaluate the impact of the SVM-NNM and the MLP-NNM for the disaggregation of the nonlinear time series data. We should, furthermore, construct the credible data of the monthly PE data from the disaggregation of the yearly PE data, and can suggest the methodology for the irrigation and drainage networks system.

• Journal of the Korean Home Economics Association
• /
• v.38 no.11
• /
• pp.31-42
• /
• 2000

The purpose of this study was to describe the general degree of expectation and performance of the housework socialization of rural homemakers, to investigate their relationships to demographic variables and to investigate the influence of the performance of housework socialization in relation to the expectation of it. The results of this study were as follows: 1. Rural homemakers’housework socialization score is the upper medium range. 2. The performance of housework socialization was somewhat affected by variables such as the education of homemakers, types of farm, years of residence in rural area, yearly income and employment of homemakers. 3. The expectation of housework socialization was significantly affected by variables such as the education of homemakers, types of farm and yearly income. 4. The expectation of housework socialization was significantly different depending on the utilization of grouped, the utilization of commodities and the utilization of household equipment, as subdomains of the performance on the housework socialization.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.413-416
• /
• 2009

Since the solar radiation is main input for sizing any solar photovoltaic system and solar thermal power system, it will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 and direct normal insolation data since December 1992 at 16 different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by solar energy system users as well as by research institutes. Among some significant results, the yearly averaged horizontal global insolation was turned out 3.61 kWh/$m^2$/day and the yearly mean 5.38 kWh/$m^2$/day of the direct normal insolation was evaluated for clear days.