• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.123-129
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• 2009

In these days, the green building movement caused by the energy crisis is increasing, passive design is getting mere and more attention as it provides many possibilities for energy conservation. Moreover, with the increasing social intention for healthy life, the demand for indoor air Quality is increasing in Korea. As result, the ventilation system which can provide the sound outdoor air constantly has been obliged in Korea. So, the hybrid system which using natural power and mechanical power and makes up for the shortage of mechanical and natural ventilation attracts people's attention in Korea. As a hybrid ventilation system, in this study, the stack effect driven hybrid ventilation system in high-rise residential building will be suggested. And in this paper, the theoretical review for hybrid ventilation system suggested in this study will be addressed. Especially, the characteristics of pressure distribution and airflow caused by stack effect in high-rise residential building and the possibility of natural ventilation as results of stack effect will be described.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.151-155
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• 2005

An electricity consumption is closely related to the economic growth structure. The change of economic growth structure affects the pattern of electricity consumption widely and severely. This paper gives that the primary changing factors of electricity growth are economic growth, change of industry structure(the change of electricity consumption ratio in case of residential sector), and the effect of electricity saying. It gives a model to analyze the influence of GDP to the change of electricity consumption patterns by sector through the period of pre and post 1998(IMF, financial crisis) to observe the contribution of each factor to the growth of electricity demand. It is anticipated that this study shows the feasible scheme of economic structure to become the developed country.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.513-520
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• 2018

Since Paris Climate Change Conference in 2015, many policies to reduce the emission of greenhouse gas have been accelerating, which are mainly related to renewable energy resources and micro-grid. Presently, the technology development and demonstration projects are mostly focused on diversifying the power resources by adding wind turbine, photo-voltaic and battery storage system in the island-type small micro-grid. It is expected that the large-scaled micro-grid projects based on the regional district and town/complex city, e.g. the block type micro-grid project in Daegu national industrial complex will proceed in the near future. In this case, the economic cost or the carbon emission can be optimized by the efficient operation of energy mix and the appropriate construction of electric and heat supplying facilities such as cogeneration, renewable energy resources, BESS, thermal storage and the existing heat and electricity supplying networks. However, when planning a large residential town or city, the concrete plan of the energy infrastructure has not been established until the construction plan stage and provided by the individual energy suppliers of water, heat, electricity and gas. So, it is difficult to build the efficient energy portfolio considering the characteristics of town or city. This paper introduces an energy mix optimization(EMO) method to determine the optimal capacity of thermal and electric resources which can be applied in the design stage of the real large-scaled residential town or city, and examines the feasibility of the proposed method by applying the real heat and electricity demand data of large-scale residential towns with thousands of households and by comparing the result of HOMER simulation developed by National Renewable Energy Laboratory(NREL).

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.358-364
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• 1996

Recently, much power demand from domestic power consumer is weakening the allowable power reserve margin in summer, especially at midday for one day due to a steep increase of air cooling loads such as air conditioner. Therefore solar airconditioning system can'be considered as one of the best remedies to meet the increase of peak power. Generally in solar air conditioning system, the diode rectifier is used to build up DC link voltage from AC source. The diode rectifier is simple and cheap but it brings out the problems of low power factor and plentiful harmonics at the AC source. Also It can derate the utilization rate of solar energy because the reverse of power flow cannot be made. Hence, in this paper to overcome the peak power problem in summer and to endure good AC input characteristics, solar air conditioning system using the PWM converter is proposed. As results, obtained are the characteristics of the PWM converter such as low distorted current waveform, high power factor and bidirectional power control. And also the stability of proposed system is verified by examining the dynamics of step load change and power reversal testing. (author). refs., figs., tabs.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.431-432
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• 2014

Recently, the demand of LED(light-emitting diode) lighting is gradually enlarged by governmental saveenergy policy, which the LED lighting has been established compulsorily in new buildings, public institutions, and residential installations etc.. The LED lighting is driven by SMPS (switching mode power supply). The SMPS requires high efficiency because the SMPS changes a commercial ac power source to low voltage dc power source. Harmonic components that occur in the conversion process of SMPS decrease system power factor and deal great damage in electric power system. To improve such problems, this paper proposes a SMPS of high efficiency. The switching devices in the proposed SMPS are operated by soft switching technique using a new quasi-resonant circuit. The input ac current waveform in the proposed SMPS becomes a quasi-sinusoidal waveform proportional to the magnitude of input ac voltage under constant switching frequency. As a result, the proposed SMPS obtains low switching power loss and high efficiency, and its input power factor is nearly in unity.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.631-637
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• 2014

Recently, following the application of modular housing techniques to not only residential sector, but also to business sector, the scope of modular housing market b expanding. In the case of other developed countries, such markets are entering into the maturity stage, though the market in Korea is not fully formed yet. Thus, it is difficult to check its trend to estimated mid- to long-term prospects of the market. In this context, the study predicted demand of the modular housing market by using a non-linear prediction model based on time series analysis. To get the prospects for the modular housing market, the quantity of housing supply was estimated based on the estimated quantity of newly built housings, and assumed that a portion of the supplied quantity would be the demand for modular housings. Based on the assumption of demand for modular housings, several scenarios were analyzed and the prospects of the modular housing market was obtained by utilizing the non-linear prediction model.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.45-53
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• 2015

This paper is proposed mathematical load modelling based on system identification approach of energy consumption of residential air conditioning. Due to air conditioning is one of the significant equipment which consumes high energy and cause the peak load of power system especially in the summer time. The demand response is one of the solutions to decrease the load consumption and cutting peak load to avoid the reservation of power supply from power plant. In order to operate this solution, mathematical modelling of air conditioning which explains the behaviour is essential tool. The four type of linear model is selected for explanation the behaviour of this system. In order to obtain model, the experimental setup are performed by collecting input and output data every minute of 9,385 BTU/h air-conditioning split type with $25^{\circ}C$ thermostat setting of one sample house. The input data are composed of solar radiation ($W/m^2$) and ambient temperature ($^{\circ}C$). The output data are power and energy consumption of air conditioning. Both data are divided into two groups follow as training data and validation data for getting the exact model. The model is also verified with the other similar type of air condition by feed solar radiation and ambient temperature input data and compare the output energy consumption data. The best model in term of accuracy and model order is output error model with 70.78% accuracy and $17^{th}$ order. The model order reduction technique is used to reduce order of model to seven order for less complexity, then Kalman filtering technique is applied for remove white Gaussian noise for improve accuracy of model to be 72.66%. The obtained model can be also used for electrical load forecasting and designs the optimal size of renewable energy such photovoltaic system for supply the air conditioning.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.117-122
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• 2010

The solar cells and fuel cells power are being encouraged to reduce the environmental pollution and combat the global warming. And the electric generation hybrid system is usually more reliable and less costly than the systems that use a single source of energy. HOMER provides a platform to design and simulate the power system and then to choose the optimization results. Based on the electricity demand conditions during a year, this paper simulates with the HOMER and performs the monthly average electrical production and the most feasible economical case includes the net present costs and the annualized costs of the hybrid system components.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.14-21
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• 2009

The demand and installation for photovoltaic system(namely, PV) has grown steadily in Korea. However, the PV system has a various economic viability according to the PV system characteristic variables such as inverter efficiency, miscellaneous power conditioning losses, azimuth and slope of PV array, PV tracking mode, and so on. The other variables are the monthly consumed electric energy and economic related factor such as initial cost, government subsidy, maintenance cost, inflation rate, energy cost escalation rate, discount rate, etc. Therefore, this study is to present economic evaluation of PV system with those concerned factors by calculating internal rate of return, year-to-positive cash flow and net present value indices.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.87-93
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• 2007

The demand for solar electric power systems, namely, photovoltaic system has grown steadily in our country over the last 10 years. However, the main obstacle against using photovoltaic system is the financial viability especially concerned with initial cost. The other factors affecting the economic viability of photovoltaic system are cost of electric energy, amount of electric energy produced by the photovoltaic system, discount rate, energy cost escalation rate, inflation rate, project life, and so on. Therefore, this thesis studies on the effect of various relating factors on economic evaluation of photovoltaic system in residential building by calculating payback period.