• Journal of the Korean Institute of Gas
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• v.17 no.6
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• pp.83-89
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• 2013

Energy industry facilities can cause fatal damage for internal industry employee as well as external general people because handling various kinds of gas and harmful substance might be spread to large scale severe accident by fire, explosion, and toxic gas leakage. In order to prevent these accidents, quantification by damage effect on structure and human is tried by using quantitative risk assessment, but it is difficult to process instantly exceptional cases and requires knowledge of expert. This paper aims to minimize exceptional cases and knowledge of expert, and present risk with human perceptible. So, we designed and developed zone-base risk analysis system that can compute risk of zone in real time at that point using database and incremental model.

• Journal of the Korean Solar Energy Society
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• v.36 no.6
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• pp.37-46
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• 2016

In this study, long-term global illuminance data for 19 selected cities are calculated from modeled solar radiation data, AEER's TMY2. Perez model in Daysim daylight simulation tool is used for the solar radiation to illuminance conversion. And then, daylight availability in an unit office space is evaluated for the 19 cities. For this evaluation, various daylight performance indices are reviewed since static daylight performance index such as daylight factor (DF) and annual average global illuminance value is not suitable for actual performance evaluation in terms of visual comfort and light energy saving of a space. This study evaluated daylighting performance of prototypical office space module by introducing DA (daylight autonomy) and UDI (Useful Daylight Illuminance) index for major cities of Korea. Result shows that there is upto 18% of illuminance level difference with annual average global illuminance data, but if we consider useful daylight in a space the illuminance level difference among the cities are only within 5%. This means that for sustainable building design especially in daylight design, amount of annual global illuminance is not important factor even in cloudy cities. Daylight design and daylight harvesting system would return similar energy saving impact regardless of building location.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.1-10
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• 1998

In the dynamic soil-structure interaction(SSI) analysis, numerous uncertain parameters are involved. They include the uncertainties in the definition of input motions, modeling of soil-structure interaction systems. analysis techniques, etc. This paper presents the results of parametric studies of the seismic responses of a reactor containment structure built on the viscoelastic layered soil. Among the numerous parameter, this study concentrates on the effects of definition point of the input motion, embedment of structure to the base soil, thickness of the top soil layer, and rigidity of the base soil. The substructure method using frequency independent impedances is adopted. The method is based on the mode superposition method in time domain using the composite modal damping values of th SSI system computed from the ratio of dissipated energy to the strain energy for each model. From the study results, the sensitivity of each parameter on the earthquake responses has been suggested for the practical application of the substructure method of SSI analysis.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.1
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• pp.27-39
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• 2023

This study was to quantitatively evaluate periodic and maximum energy loads for broiler-standard design models by the Ministry of Agriculture, Food and Rural Affairs (2016). Building energy simulation method was used to compute heating and cooling loads of the designed broiler houses according to regional locations and insulation characteristics of wall and roof. It considered sensible and latent heat generation from broilers, dynamic operation of ventilation system according to environment variations. It was found that variation of periodic heating loads was relatively higher than that of periodic cooling loads according to thickness changes of wall and roof. Assuming that broiler was raised at every even-month, periodic heating and cooling loads were 6 and 18% lower, respectively than odd-month raising condition. When recommendation rules of insulation characteristics (wall and roof thickness) by the Ministry of Land, Infrastructure and Transport was adopted, periodic heating load of Jeju-si was 20.3% higher than national average values. Based on the BES computed periodic and maximum energy loads under the designed experimental condition, these results can contribute to reestablishing standard design of broiler houses, especially for insulation characteristics, and designing management strategies for efficient energy uses.

• Spatial Information Research
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• v.20 no.4
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• pp.1-16
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• 2012

There is no doubt that the urban heat island (UHI) is a mounting problem in built-up environments, due to energy retention by the surface materials of dense buildings, leading to increased temperatures, air pollution, and energy consumption. To investigate the UHI, three-dimensional (3-D) information is necessary to analyze complex sites, including dense building clusters. In this research, 3-D building geometry information is combined with two-dimensional (2-D) urban surface information to examine the relationship between urban characteristics and temperature. In addition, this research introduces spatial regression models to account for the spatial spillover effects of urban temperatures, and includes the following steps: (a) estimating urban temperatures, (b) developing a 3-D city model, (c) generating urban parameters, and (d) conducting statistical analyses using both Ordinary Least-Squares (OLS) and Spatial Regression Models. The results demonstrate that 3-D urban characteristics greatly affect temperatures and that neighborhood effects are critical in explaining temperature variations. Finally, the implications of the results are discussed, providing guidelines for policies to reduce the UHI.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.278-284
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• 2023

Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.

• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.42-52
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• 2011

As environmental issues are rising recently efforts to reduce environmental stress are emerging in all industry segments. Especially environmental impact of buildings occupy a critical portion, so each country is operating green building rating system for life cycle of buildings. Accordingly green building rating system for every facility is operating in Korea. And acquisition of grade I for building energy efficiency is mandatory for every new public buildings since 2010. To design green building efficiently and systematically eco-friendly elements should be considered and checked from the schematic design phase. But in many cases eco-friendly elements are checked at the end of constructed design phase. So applying eco-friendly elements at the value engineering process, which is performing through schematic and constructed design phase, could make a efficient and systematic green building design. Value engineering process is divided into pre workshop, workshop and post workshop stages. And subject selection in pre workshop stage is the step that finds out the subjects which has the great possibility to be improved to perform efficient value engineering workshop. So this study present the Green VE subject selection model to select the most considerable eco-friendly subjects in projects.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.224-232
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• 1999

Latent heat storage system using micro-encapsuled phase change material is effective method for floor heating of house and building. The temperature profile in capsule block and flow rate of hot water are important parameters for the development of heat storage system. In the present study, a mathematical model based on 3-D, non-steady state, Navier-Stokes equations, scalar conservation equations and turbulence model ($\kappa$-$\varepsilon$), is used to predict the temperature profiles in capsule and the velocity vectors in hot water pipe. The multi-block grids and fine grids embedding are used to join the circle in hot water pipe and square in capsule block. The phase change process of the capsule is quite complex not only because the size of phase change material is very small, but also because phase change material is mixed with the cement to form thermal storage block. In calculation, it's assumed that the phenomena of phase change is limited only the thermal properties of phase change material and the change of boundary is not happened in capsule. The purpose of this study is to calculate the temperature profiles in capsule block and velocity vectors in hot water pipe using the numerical calculation. Two kinds of thermal boundary condition were considered, the first (case 1) is the adiabatic condition for the both outside surfaces of the wall, the second (case 2) is the case in which one surface is natural convection with atmosphere and another surface is adaibatic. Calculation results are shown that the temperature profile in capsule block for case 1 is higher than that for case 2 due to less heat loss in adaibatic surface. Specially, in the domain of near Y=0, the difference of temperature is greater in case 1 than in case 2. The detailed experimental data of capsule block on the temperature profile and the thermal properties such as specific heat and coefficient of heat transfer with the various temperature are required to predict more exact phenomena of heat transfer.

• The Korean Journal of Community Living Science
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• v.27 no.2
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• pp.281-294
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• 2016

This study was conducted to promote consumer interest in Geothermal Heat Pump (Ground Source Heat Pump, GSHP) and district heating and cooling (District Heating & Cooling, DHC) systems, which are competing with each other in the heating and cooling field. Considering not only the required cost data of energy itself, but also external influence factors, the optimal mix ratio of these two energy systems was studied as follows. The quantitative data of the two energy systems was entered into a database and the non-quantitative factors of external influence were applied in the form of coefficients. Considering both of these factors, the optimal mix ratio of GSHP and DHC systems and minimum Life Cycle Cost (LCC) were obtained using an algorithm model design. The Optimal Energy Mix of GSHP & DHC (OEMGD) algorithm was developed using a software program (Octave 4.0). The numerical result was able to reflect the variety of external influence factors through the OEMGD algorithm. The OEMGD model found that the DHC system is more economical than the GSHP system and was able to represent the optimal energy mix ratio and LCC of mixed energy systems according to changes in the external influences. The OEMGD algorithm could be of help to improve the consumers' experience and rationalize their energy usage.

• Land and Housing Review
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• v.9 no.4
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• pp.25-32
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• 2018

Application of geothermal energy in buildings has been gaining popularity as it provides the benefits of both heating and cooling a building. Among the various types of geothermal energy systems, ground-coupled heat pump system is the most commonly applied one in South Korea. A ground heat exchanger plays an important role as a heat source in winter and a heat sink in summer. For the stable operation of a ground-coupled heat pump system, a ground heat exchanger should be sized so that it provides sufficient heating and cooling energy. Heating and cooling energies generated in ground heat exchangers mainly depend on the temperature difference between the heating medium in ground heat exchangers and the surrounding ground. In addition, the performance of ground heat exchangers influences the change in ground temperature. Therefore, it is necessary to consider this interrelation between the change in the ground temperature and the performance of ground heat exchanger for an accurate estimation of its performance. However, previous thermal analysis models for ground heat exchangers are not competent enough to allow a complete understanding of this interrelation. Therefore, this study proposes a three-dimensional equivalent, transient ground heat exchanger analysis model. First, a previous thermal analysis model for ground heat exchangers, including an analytical model, a g-function, and a numerical model are analyzed. Next, to overcome the limitations of the previous models, a three-dimensional equivalent, transient ground heat exchanger model is proposed. Finally, this study validated the proposed model with the measurement data of the thermal response test, sandbox test, and TRNSYS DST model. All validation results showed a good agreement. These findings helped us to investigate the thermal performance of ground heat exchangers more accurately than the analytical models, and faster than the numerical models. Furthermore, the proposed model contributes to the design of ground heat exchangers by considering the different operation conditions of buildings.