• Journal of the Korean Society of Safety
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• v.28 no.2
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• pp.6-13
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• 2013

This study focuses on finding ECO driving patterns which consider driving safety of the ATO system train and reliability and which optimize efficiency of the driving energy consumption. Research results derived by performing simulation of those 5 models show that the emergency braking which affects safety of passenger and the machinery is minimized, and safe driving speed is maintained by the prohibition of drastic acceleration/deceleration, coasting and constant-speed driving. Therefore if this result is applied to the urban railway train by amending or making ATO program to save energy usage that improve environmental quality, its effects as ECO driving pattern is huge.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1053-1058
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• 2008

Porous medium was considered in the present study for the heat transfer enhancement. This was attributed to its high surface area to volume ratio as well as intensive flow mixing by tortuous flow passages. But when the air or water flow through in the porous medium, it is occurred the pressure drop between inlet and outlet. So in the present study investigated simulation result about the pressure drop in the porous medium before apply to heat exchanger. In this simulation, the thickness of the solid inside the porous medium region was varied 0.2 mm to 0.4 mm. And then the simulation result were compared the pressure drop in the same unit cell ($0.5\;mm{\times}0.5\;mm{\times}0.5\;mm$). To make the analysis model, it was assumed the 14-sided tetrakaidecahedron cell which has long been considered the optimal packing cell first proposed by the Lord Kelvin in 1887. And then the simulation is carried out using by STAR-CCM+ which is commercial software. The simulation result can be showed quantified pressure drop by solid effect in the porous medium.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.547-558
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• 2008

With the advent of super cargo ship due to the explosive increase in the amount of cargo shipped via seas, some mega ports are under construction in South Korea, to accommodate the super cargo ship, and some of them already enter their final phase. To sustain the harbor tranquility, mega ports usually comprise huge vertical type breakwaters which are intrinsically vulnerable to the attack of long waves. In this rationale, we present the chamber type breakwater with a circular curtain wall - Eco-breaker 2, to alleviate the reflection of long waves and numerically investigate the hydraulic characteristics of Eco-breaker 2. As a wave driver, we use the Navier-Stokes eq., the most robust wave driver, using SPH (Smoothed Particle Hydrodynamics) and LES (Large Eddy Simulation). For the verification of numerical results, we also carried out hydraulic model test. It is shown that Eco-breaker 2 can effectively alleviate the reflection of long waves with its inherited large organized eddies encompassing the water chamber and some region off the curtain wall of varying size. It is also shown that the scope and strength of large organized eddies strongly depends on the incident wave period, and the reflection coefficient can be lowered to 0.18 by tuning the size of water chamber such that resident time at the chamber is just short of the half period of incident waves. Based on these results, we present the specification of Eco-breaker 2 to boost its use on the development of water environment friendly harbor worldwide.

• Journal of the Korean Solar Energy Society
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• v.39 no.3
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• pp.1-7
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• 2019

As part of the government's energy policy, Zero Energy Building certification was launched on January of 2017. However, the three passive-housing rental housing projects are the only ZEB-certified detached housing since the certification's launch. The reason is that, in order for a detached housing to earn ZEB certification, it has to secure self-reliance in energy, and a photovoltaic system is the only viable renewable energy system. Therefore, conducting an analysis to optimize the photovoltaic system in an early design stage is strongly recommended. This study aimed to propose an optimal photovoltaic system design for a detached housing after analyzing through the ECO2 energy simulation of 44 cases, varying in a module type and efficiency, inclination and azimuth. As a result, 15 cases out of 44 cases were analyzed to satisfy ZEB evaluation criteria, and it is thought that these data could contribute greatly to the expansion of ZEB certification dissemination.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.72-78
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• 2013

The turbulent flow behavior of air supply and exhaustion in the Shin-gum-ho subway station is analyzed for ordinary and emergency state. The depth of Shin-gum-ho station is 43.6m which consists of the island-type platform(8th floor in underground) and a two-story lobby (first & second floor in underground). An emergency stairway connects between the platform and the lobby. Ventilation operation mode for ordinary state is set up as a combination of air supply and exhaustion in the lobby and platform, while for emergency state it is set up as a full air supply in the lobby and a full exhaustion in the platform. The entire station is covered for simulation. The ventilation diffusers are modeled as 95 square shapes of $0.6m{\times}0.6m$ in the lobby and as 222 square shapes of $0.6m{\times}0.6m$ and 4 rectangular shapes of $1.2m{\times}0.8m$ in the platform. The total of 7.5million grids are generated and whole domain is divided to 22 blocks for MPI efficiency of calculation. Large eddy simulation(LES) is applied to solve the momentum equation and Smagorinsky model($C_s$=0.2) is used as SGS(subgrid scale) model. The time-averaged velocity fields are compared to experimental data and show a good agreement with it.

• Land and Housing Review
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• v.6 no.4
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• pp.215-220
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• 2015

The purpose of this study was to comparative analyses of energy performance in apartment houses adopted window frame-type natural ventilation, under-floor air distribution ventilation and heat recovery ventilation. As the object of energy simulation, the three type ventilation system with area of $84m^2$ was selected in apartment house. As a result, when the ECO2 simulation was performed, the 1st requirement quantity per annual were $159.9kWh/m^2yr$(CASE1, Natural Ventilation), $179.7kWh/m^2yr$(CASE2, Under-floor Air Distribution Ventilation) and $161.0kWh/m^2yr$(CASE3, Heat Recovery Ventilation).

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.181-184
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• 2009

This study aimed at framing alternative urban planning scenarios reflecting urban planning factors, performing urban climate simulation and evaluating eco-friend and low energy characteristics of each scenario on the viewpoint of urban temperature and energy savings on the target of the costal city including Haeundae District in Busan The results are as follows. 1)The fact that urban higher temperature is approximately 2.5 times higher in the building constructed area than whole urban area was represented severe higher temperature phenomenon in the built-up area. Ground greening, water scenario and soil scenario could be expected peek air temperature alleviating effect in order. Especially water scenario had significant effect(maximum $2.5^{\circ}C$) on lowering of air temperature.

• Journal of the Korean Institute of Rural Architecture
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• v.19 no.2
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• pp.9-16
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• 2017

The study analyzed the heat losses and the building energy efficiency grade by the energy simulation using the ENERGY# and ECO2 programs for the three types of Standard design of rural houses. It was calculated the energy efficiency rating by the ECO2 program for the rural housing standard design, and the energy demand and the energy consumption by each factor were compared and analyzed. And it analyzed energy consumption by element of each house by ENERGY # program. As a result, first in the evaluation of the energy efficiency grade of buildings by the ECO2 program, the rating for primary energy requirement for the housing newly built by the standard design of rural house is expected to range from 2 to 4 with 189.3 to $238.7kWh/m^2.a$. Second, the energy loss of each part of standard design of rural housing occurs in the order of ventilation 39%, window 33%, outer wall 14%, roof 9%, bottom 5%, and energy loss through ventilation and window occurs more than 70%. Third, the most beneficial effects on the energy efficiency grade is obtained the lowest grade of all three types by 2 when the lowering of the window and door heat transmission rate and the lowering of the light density, and the heat exchange ventilation device is not installed. Fourth, in the standard design of rural housing, the energy demand is occupied by heating > hot water > lighting order, and the order of the weight is changed in order of heating > lighting > ventilation > hot water. Fifth, building energy efficiency assessment system needs to establish policy for fixing rural housing energy as a practical device to ensure energy performance and quality.

• Journal of Environmental Science International
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• v.16 no.8
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• pp.973-983
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• 2007

The eco-hydrologic effects of maintenance water supply on Oncheon stream are studied using hydrologic, hydraulic and ecologic models. SWMM (Storm Water Management Model) is used for long-term simulation of runoff quantity and water quality from Oncheon stream watershed. Using the output hydrologic variables from SWMM, HEC-RAS (River Analysis System) is then used to simulate the hydraulics of water flow through Oncheon stream channels. Such hydrologic, hydraulic and water quality output variables from SWMM and HEC-RAS are served as input data to execute PHABSIM (Physical Habitat Simulation) for the purpose of predicting the micro-habitat conditions in rivers as a function of stream flow and the relative suitability of those conditions to aquatic life. It is observed from the PHABSIM results that the weighted usable area for target fishes has the maximum value at $2m^3/s$ of instream flow. However, mid and down stream areas that have concrete river bed and covered region are unsuitable for fish habitat regardless of instream flow increment. The simulation results indicate that the simple maintenance water supply is limited in its effect to improve the ecological environment in Oncheon stream. Therefore, it is imperative to improve water quality and to recover habitat conditions simultaneously.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.3
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• pp.369-385
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• 1996

The eco-hydrodynamic model was used to estimate the primary productivity of the oyster culture grounds in Kamak Bay. It is composed of the three-dimensional hydrodynamic model for the simulation of water flow and ecosystem model for the simulation of phytoplankton. The ecosystem model was applied to simulate phytoplankton biomass during culturing period in condition of no oyster culture grounds. The field surveys were conducted from May, 1994 to March, 1995 in Kamak bay. The results showed the concentration of chlorophyll $\alpha$ to be $1.00\~23.28\;{\mu}g/l$ in the surface layer, $1.27\~29.97\;{\mu}g/l$ in the middle layer and $1.23\~23.08\;{\mu}g/l$ the bottom layer. In monthly variations of chlorophyll $\alpha$ concentration, very high concentration were found in July, 1994 and very low concentrations in December, 1994. As the results of three-dimensional hydrodynamic simulation, the computed tidal currents ave mainly toward the inner part of bay through Yeosu Harbor and the southern mouth of a bay during the flood tide. The computed residual currents were dominated southward in Yeosu Harbor and eastward in the mouth of bay and also showed strong clockwise water circulation at the mouth of bay. The pattern between the simulated and observed tidal ellipses at three stations was very similar. The mean relative errors of all levels between the simulated and observed phytoplankton biomass at 14 stations in Kamak Bay were $13.81\%,\;9.31\%\;and\;17.84\%$, respectively. The results of phytoplankton biomass simulation showed that the biomass increased from June to September and rapidly decreased to December and then slowly increased to March. Primary productivity was estimated in the range of $0.99\~10.20gC/m^2/d$ with the average value of $4.43gC/m^2/d$ in condition of no oyster culture grounds. Primary productivity was rapidly increased from lune to August and rapidly decreased to December and then slowly increased from January to March in Kamak Bay.