• International Journal of Advanced Culture Technology
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• v.3 no.1
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• pp.120-128
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• 2015

In this paper, Residential roof top photovoltaic system with 9.9 kW design is proposed. The system composed of 200 Watts solar array 33 panels connecting in series 10 strings and parallels 3 strings which have maximum voltage and current are 350 V and 23.8 A. The 10 kW sinusoidal grid-connected inverter with window voltage about 270-350 is selected to convert and transfer DC Power to AC Power at PCC (Point of Common Coupling) of power system following to utility standard. However the impact of fluctuation and uncertainty of weather condition of PV may decrease the voltage stability and voltage collapse of power system. In order to solve this problem the energy storage such 120 V 1200 Ah battery bank and 30 kVAR capacitor are designed for voltage stability control. The other expensed for installing the system such battery charger, cable, accessories and maintenance cost are concerned. The economic analysis by using investment from money loan with interest about 7% and use own money which loss income of deposit about 3% are calculated as 671,844 and 547,044 for PV system with energy storage and non energy storage respectively. The solar energy from PV is about 101,616 Bath per year which evaluated by using the value of $5kWh/m^2/day$ from average peak sun hour (PSH) of the Thailand and 6.96 Bath/kWh of Feed in Tariff Incentive. The payback periods of four scenarios are proposed follow as i) PV system with energy storage and use loan money is 15 years ii) PV system with no energy storage and use loan money is 10 years iii) PV system with energy storage and use deposit money is 9 years iv) PV system with energy storage and use deposit money is 7 years. In addition, the other scenarios of economic analysis such no FIT support and other type of economic analysis such NPV and IRR are proposed in this paper.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.119-124
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• 2014

After the oil crisis in 1970s, many countries have tried to reduce oil dependency. Especially, in Korea, rapid declining oil consumption has speedily brought to electrification and a surge in electricity demand. This paper attempts to estimate the relationship between declining oil use and electrification in Korea using OECD panel data covering from 1985 to 2011. To this end, random effect model and fixed effect model are employed. The increase in the ratio of energy oil to total energy consumption by 10%p leads to reduce the electricity demand by about 15%. This result can be useful information to cope with the recent crisis of electric power. In addition, industrial sector is ranked in forth the ratio of industrial electricity use to total electricity use according to the result of comparative analysis of electricity consumption by use in OECD countries. Therefore, industrial sector should be treated as the main target of demand-side management policies for electricity.

• Journal of the Korean Solar Energy Society
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• v.36 no.3
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• pp.45-52
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• 2016

Remarkable air temperature increases in urban areas are known as heat island phenomenon. In this study, we analyzed the effects of renewable energy on the heat island phenomenon in urban area by numerical method. The results showed that the use of renewable energy reduces the building energy use in urban area and contributes the alleviation of the Urban Heat Island Effects.

• Journal of the Korean Home Economics Association
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• v.19 no.2
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• pp.11-24
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• 1981

The objectives of the study were to determine 1) if energy consumption and conservation vary in clothing, food, and housing with independent variables-size of household, homemaker's age, employment, and level of education, level of living, type of house, electricity use, and all energy use, and 2) if there is a correlation among energy conservation practices in clothing, food, and housing. Questionnaires wee given to the randomly selected homemakers in Seoul in July, 1980. Data from 620 responses were analyzed by F-test (Analysis of Variance) and Correlation. The results are as follows: 1. Clothing (1) the scores of the conservation practices I clothing were generally high. /However, it was found that a) they did not practice in wearing heavy under clothes and behavior outer clothing to cope with cool room temperature in the winter, b) they did not use bleach for laundry, but they used boiling method, and c) they did not have enough knowledge on Permanent Press finish. (2) energy conservation practices in clothing were significantly related to level of living and homemakrer's level of education. a) The higher the level of living, the higher scores in the knowledge were found. b) the higher the homeakcer's level of education, the higher scores in the knowledge and ironing were obtained. 2. Food (1) The scores of the conservation practices in food were generally high. However, it was found that scientific cooking methods were not performed such as a) to use measuring spoons, cups, and timers, b) to practice a simple method in using solor energy for warming water, c) to use thermos for the hot water tea or coffee, but they boiled water whenever necessary, and b) to use the pressure cooker whenever possible. (2) Energy conservation practices in food were significantly related to homemaker's employment and type of dwellings. a) The scores of full-time homemakers (not gainfully employed) were higher than gainfully employed homemakers. b) Families in traditional Korean dwellings revealed higher scores than those in apartment or western style dwellings. 3. Housing (1) The scores of the conservation practices in housing were generally high. However, it was found that a) they did not install fans in the kitchen, bathroom, and attic in the summer, b) they did not install a humidifier for tolerating a lower room temperature in the winer, c) they did not practice to make plans for the door of the refrigerator remained open for the shortest time, d) they did not install or use a local lighting with a general lighting for reading and cooking, and e) they usedaluminum foil without the knowledge of the heat reaction of its shiny and dull sides. (2) energy conservation practices in housing were significantly related to homemaker's employment and level of education, economic status, types of dwelling, and all energy use, a) Full-time homeakers had higher scores than gainfully employed homeakers. b) the higher the homemaker's level of education and economics status, the higher scores were obtained. c) Homeakers with their own house scored higher points than those with rented houses. And families in apartment or row houses scored higher points than those in traditional korean or western style dwellings. d) The higher the consumption rate of electricity and all energy, the higher scores were revealed. 4. correlation there was a significant correlation among energy conservation practices I clothing, food, and housing.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.220-225
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• 2011

Based on the supply status statistics of new renewable energy according to public obligation system, current status of overall application centered on solar heat, solar ray, and geothermal heat as energy sources that can be applied to buildings may be analyzed as follows. (1) After the public obligation system, the investment costs on the total construction costs by years were between 5.21% and 7.12%: they were 7.12% in 2004, where the system was initially implemented; and they were gradually declined from 2005 to 2011, 5.76% in average. The ratio of equipment investment per energy sources in the total construction costs was 5.9%, which was slightly more than the obliged ratio. The order of investment costs per energy source was solar ray, geothermal heat, and solar heat. (2) Among the 1,433 sites in the plan of new renewable energy installation based on the public obligation system, "for cultural & social use" was most in target institution, and facilities for education & research was most in use classification, followed by public working, culture & rally, and sports. The number of facilities applied according to the case for planning installation per use classification of the target institution was between 1.1 and 1.5, or 1.4 in average of energy source. Conclusively, the authors of this study investigated overall current status of new renewable energy supply from the analysis of statistic data, and it may be needed of further supplementation of various examinations by visiting investigation and interviews with practitioners based on classification of use of target institutions.

• Architectural research
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• v.19 no.1
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• pp.7-11
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• 2017

Energy consumption in university building has steadily increased over the last decade, and a strong upward trend in recent years. This study was undertaken to analyze the relationship between energy consumption and their affecting factors, six academic buildings were considered. The factors limited to heating and cooling, which is the main end use (nearly 60 per cent of total energy consumption in university buildings), encompassing system and operating schedules (user activity) and area use. To understand how to building is used, operated and managed, walk-through assessment was conducted as well as interview with university staff. The results show that the energy consumption of the humanities building was somewhat smaller than the consumption of the science and engineering building, and its range was from $31.26kgoe/m^2$ to $23.52kgoe/m^2$, depending on heating and cooling system and area use. And the energy consumption of the science and engineering building was related to operating schedules (user activity) as well as laboratory equipment characteristics. More analysis on a larger number of buildings is required in the future, including building form and material performance level to generalize the significant factors influencing building energy consumption.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.9-16
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• 2006

Geothermal-energy has been getting popular as a natural energy source for green buildings these days. Public building with gross area more than $3000m^2$, planned after March, 2005, should spend about 5% of total building cost for equipment run by natural energy source (e.g. geothermal, solar heat, solar power, etc) according to renewable energy promotion law in Korea. As a result geothermal-energy using heat pump system is emerging as a effective alternative for realistic and economic plan although design guidelines and construction code for the system is in progress and technical data is far from sufficient. The quantitative analysis on the performance of geothermal-energy using heat pump system is insufficient for appropriate design of it. In this paper, cooling performance of geothermal-energy using heat pump system of residential and retail etc. mixed-use building has been analyzed on the basis of temperature comparison between inlet and outlet of heat exchangers of the operating system. Additionally, dry-bulb temperature and relative humidity have been measured and analyzed together as an index of indoor thermal environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.515-524
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• 2010

Recently, many actions are taking to accelerate progress toward social consensus and implementation of Smart Grid. Smart Grid refers to a evolution of the electricity supply infrastructure that monitors, protects, and intelligently optimize the operation of the interconnected elements including various type of generators, power grid, building/home automation system and end-use consumers. The most distinguished element will be Advanced Metering Infrastructure (AMI) that will be installed to every end-use consumer's home or building and optimize the energy consumption of the end-use consumer. The key function of AMI is energy management capability that coordinates and optimally controls the various loads according to the operating condition and environments. In this study, we figure out the basic function of AMI in Smart Energy House that can be defined as a model house implementing in Smart Grid. This paper proposes the energy management algorithm that will be implemented in AMI at Smart Energy House. The paper also show how energy saving in Smart Energy House can be achieved applying the proposed algorithm to an actual house model that has mainly lighting, air-conditioning, TV loads.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.19-28
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• 1999

This study quantified shading, evapotranspiration and windspeed-reduction effects of trees on use and cost of heating and cooling energy in two residential neighborhoods of Chuncheon different in tree cover. Annual savings per residence of heating energy were approximately 1,210 MJ(1%) and those of cooling energy, 130 kWh(10%) in study district 1 having tree cover of about 10% . For district 2 with tree cover of about 20%, annual heating and cooling savings were 2,130 MJ(2%) and 180 kWh(19%) per residence, respectively. Trees annually saved energy costs by approximately ￦31,000 ($26, $1=￦1,200) per residence in district 1 and by ￦49,000($41) in district 2. One tree taller than 3 m resulted in annual energy savings of ￦8,000($7) in the study districts. Energy savings by trees in district 2, which had higher tree cover by 10% difference than district 1, were about 2 times greater than those in district 1. This implies that more tree plantings could enhance energy saving effects. Of the total costs saved, 58% was attributed to windspeed reduction and 47%, evapotranspiration. However, shading increased energy costs by 5% due to tree plantings at the wrong locations. Full tree plantings on the west and north of buildings and avoidance of shade-tree plantings of use of solar-friendly trees on the south are recommended to increase building energy savings efficiently.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.141-147
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• 2013

Electricity is a basis for human existence. This paper attempts to analyze the households' willingness to pay (WTP) for the residential electricity use. The WTP for the residential electricity use can be defined as the sum of actual price of and additional WTP for it. The former is easily observed in the market, but the second is not observed and thus should be obtained through a WTP survey of households. To this end, this study conducted a survey of randomly selected 1,000 households in Korea in November 2010. The results indicate that the mean additional WTP for the residential electricity use was estimated to be KRW 11.24 per kWh. Given that the average price of residential electricity was KRW 98.07 per kWh at the time of the survey, the economic benefit from the residential electricity use was computed as KRW 109.31 per kWh. This information can be compared with the cost involved in the supply of one kWh of residential electricity.