• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.979-988
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• 2014

Recently, the interest in the thermal comfort is ever increasing as the time people stay in the automobile is gradually increasing. So far, however, the cooling performance of the HVAC(heating and ventilation air conditioning) system is evaluated by thermal environment criteria such as indoor air velocity and temperature, not by a thermal comfort index. Furthermore, the precise criteria has not been established yet when the thermal comfort for the automobile is evaluated using numerical analysis. In this study, the numerical analysis of automobile indoor thermal comfort according to various parameters such as HVAC operating mode, airflow, passenger boarding conditions is performed during the HVAC system's initial operating time(20 minutes). The solar ray tracing model and S2S radiation model are used and validated to simulate an external heat source. Based on this study, an evaluation model which can predict the thermal comfort index for the combination of the above parameters is presented.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.69-72
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• 2022

This paper actually investigates the load on major large-scale buildings in the downtown area, examines the economic feasibility of installing PV and ESS in a microgrid target building, and evaluates whether an electric vehicle capable of V2G through two buildings is effective as an economical analysis program (HOMER) was analyzed using. It is economical to install a mixture of ESS rather than using the whole PV, and it is shown that if there is an electric vehicle using the V2G function of EV, there is an economic effect to replace the PV. So that Incentives and policies are needed to replace a large area of PV and utilize the existing parking lot to lead EV as a resource of the microgrid. Currently, P2X technology that stores power as ESS or converts it to other energy to control when surplus renewable energy occurs in large-capacity solar power plants and wind farms, etc. This is being applied, and efforts are being made to maintain the stability of the system through the management of surplus power, such as replacing thermal energy through a heat pump. Due to the increase in electric vehicles, which were recognized only as a means of transportation, technologies for using electric vehicles are developing. Accordingly, existing gas stations do not only supply traditional chemical fuels, but electricity, and super stations that also produce electricity have appeared. Super Station is a new concept power plant that can produce and store electricity using solar power, ESS, V2G, and P2G. To take advantage of this, research on an urban microgrid that forms an independent system by tying a large building and several buildings together and supplies power through a super station around the microgrid is in full swing.

• KIEAE Journal
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• v.3 no.2
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• pp.37-44
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• 2003

The aim of this study was to analyze the thermal performance through Test-Cell of TI-wall in domestic climate. This study was carried out as follows: 1) The TI-wall was studied for ability to reduce heat loss through the building envelope and analyzed to TIM properties. 2) Test models of TI-wall were designed through the investigation of previous paper and work, measured for winter and spring, and the thermal effects were analyzed. The type of the TIM used in test model is small-celled(diameter 4mm and thickness 50mm) capillary and cement brick(density $1500kg/m^3$) was used by thermal mass. 3) Test-cell of TI-wall was calibrated from measured data and the dynamic simulation program ESP-r 9.0. In these simulations, the measured climate conditions of TaeJon were used as outdoor conditions, and the simulation model of Test-cell was developed. 4) The sensitivity analysis is executed in various aspects with standard weather files and ESP-r 9.0, and then most suitable system of TI-wall are predicted. Finally, The suitable system of TI-wall was analysed according to sizes of air gap, kinds, thickness, and the surface absorption of therm wall. The result is following. In TI-wall, Concrete is better than cement brick, at that time the surface absorption is 95%, and the most efficient thickness is 250mm. As smaller of a air gap, as reducer of convection heat loss, it is efficient for heating energy. However, ensuring of a air gap at least more than 50mm is desirable for natural ventilation in Summer.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.6
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• pp.767-773
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• 2017

Infrared stealth is an important technology for naval ships. This technology helps improve the anti-detection performance and survivability of naval ships. In general, the infrared signature of naval ships are categorized into internal and external heat source. External signature are generated by ship surface heating by solar flux as well as the complicated heat transfer process with the surrounding weather condition. Modern naval ships are equipped with seawater injection nozzles on the outside for nuclear, biological and, chemical, and these nozzles are used to control external signature. Wide nozzle placement intervals and insufficient injection pressure, however, have reduced seawater dispersion area. To address this problem, nozzle installation standards must be established. In this study, an actual-scale experimental system was implemented to provide the evidence for nozzle installation standards in order to reduce the infrared signature of naval ships. In addition, the environmental conditions of the experiment were set up through computational fluid dynamics considering the ocean climate data and naval ship management conditions of South Korea. The dispersion distance was measured using a high-resolution thermography system. The flow rate, pipe pressure, and dispersion distance were analyzed, and the evidence for the installation of seawater injection nozzles and operation performance standards was suggested.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.35-35
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• 2011

Phase change material(PCM) has thermal energy storage and been attracted attention. Latent heat of the organic PCM can keep maintaining temperature when the change of outside energy conditions influence to PCM. Thus, many researchers have interested to thermal energy storage ability and investigated to applications such as thermal storage of solar energy, bioclimatic building, icebank, medical application, clothing industry and so on. Among the many applications, investigation of the PCM in clothing industry is also important because the people has interest functional factor called health-care in the clothing. In addition, PCM can give them mild environment condition such suitable temperature control or humidity. To fabrics, the PCM has various methods such as microcapsule, padding and modified cross-section formation(Sheath/core). Sheath core PCM fabric has a better benefit of durability than other method. However, PCM sheath/core spinning is difficult. In addition, dyeing property is important to use clothing industry due to visual images. In this study, we investigated dyeing properties of Nylon/PCM sheath/core fabrics. Especially, we observed the relation between dyeing property and PCM including ratio. Various temperature and pH conditions were also studied to optimize dyeing properties as acid dye.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.325-330
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• 2006

Modern people spend more and more time in an automobile in their daily life. In this life, drivers and passengers should create HVAC environment in the automobile interior which is not only for convenient transportation but also give comfortable feeling with dwelling culture. Also, the latest cars give much importance for the role of HVAC system that controls the environment of the area for passengers more than just basic capability. There are solar radiant heat, surface temperature, refrigeration system(temperature, humidity, air current, velocity), and dust for the factor which have an effect on the HVAC environment in the automobile interior, also these are being carried for the HVAC environment delivered an individual character. In this study, we drew the automobile interior as three dimension and arranged a method of numerical analysis on HVAC environment in the automobile interior displaying air current distribution and temperature distribution through simulation of the automobile interior on the ventilation volume and outlet area. The aim of this study is to develop the estimated method for HVAC environment. in the automobile interior.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.176-179
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• 2009

In this study, Urban Climate Simulation was performed using 3-Dimensional Urban Canopy Model. The characteristics of urban thermal environment was analyzed by classifying land coverage and increasing natural land coverage ratio. The results are as follows. The characteristics of the land coverage on urban thermal environment formation can be summarized by the effects like higher temperature on the artificial coverage, and the contrary effects on the natural coverage. When the water coverage 100% was made up, maximum temperature was declined by $5.5^{\circ}C$, humidity by the 6.5g/kg, wind velocity by 0.6m/s, convective sensible heat by $400W/m^2$ and the evaporative latent heat was increased by $370W/m^2$ compared to when artificial coverage 100% was formed. These simulation results need to be constructed as DB which shows urban quantitative thermal characters by the urban physical structure. These can be quantitative base for suggesting combinations of the building and urban planning features at the point of the desirable urban thermal environment as well as analysing urban climate phenomenon.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.188.1-188.1
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• 2014

Aluminum is widely used as a material for electrode on silicon based devices. Especially, aluminum films are used as backside and front-side electrodes in silicon quantum dot (QD) solar cells. In this point, the diffusion of aluminum is very important for the enhancement of power conversion efficiency by improvement of contact property. Aluminum was deposited on a Si (100) wafer and a Si QD layer by ion beam sputter system with a DC ion gun. The Si QD layer was fabricated by $1100^{\circ}C$ annealing of the $SiO_2/SiO_1$ multilayer film grown by ion beam sputtering deposition. Cs ion beam with a low energy and a grazing incidence angle was used in SIMS depth profiling analysis to obtain high depth resolution. Diffusion behavior of aluminum in the Al/Si and Al/Si QD interfaces was investigated by secondary ion mass spectrometry (SIMS) as a function of heat treatment temperature. It was found that aluminum is diffused into Si substrate at $450^{\circ}C$. In this presentation, the effect of heat treatment temperature and Si nitride diffusion barrier on the diffusion of Al will be discussed.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.1
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• pp.1-13
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• 2023

Many government in the world have conducted building energy performance certification program to reduce building energy consumption. In this study, a reference building and its HVAC system was modeled, and the energy load and consumption were estimated by the ECO2 program. The software is a simple building energy simulation program based on monthly calculated method. The building energy efficiency rating the the reference building was 1+ under baseline condition. The simulation results showed that the insulation performance slightly affected building energy load and consumption, but light density had a significant effect on them. The application of geothermal heat pumps gave improvement of building energy efficiency rating but it could not make it possible to get zero energy building(ZEB) certification. The ZEB 5 certification could be achieved by using photovoltaics, however getting better grade was difficult. The simulation results showed that the ZEB 4 certification, one grade higher than ZEB 5, could be attained by using more than one renewable energy source such as geothermal and solar energy in this study.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.195-200
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• 2020

With the growing interest in fossil fuel depletion and environmental pollution, railroad cars operating in Korea are in progress as the conversion from diesel to electric vehicles expands. The photovoltaic system, which is applied as an example of the conversion of electric vehicles, is infinite and pollution-free, and can produce energy without generating hazards such as air pollution, noise, heat, and vibration, and maintain fuel transportation and power generation facilities. There is an advantage that is rarely needed. However, the amount of electricity produced depends on the amount of solar radiation by region, and the energy density is low due to the power generation of about 25㎡/ kWp, so a large installation area is required and the installation place has limited problems. In view of these problems, many studies have been applied to fuel cells in the railway field. In particular, the plan to link the fuel cell power generation system railroad power supply system must be linked to the power supply system that supplies power to the railroad, unlike solar and wind power. Therefore, it has a close relationship with railroad cars and the linkage method can vary greatly depending on the system topology. Therefore, in this paper, we study the validity through simulation modeling related to linkage analysis according to system topology.