• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.33-43
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• 2010

Geothermal energy is gaining wide attention as a highly efficient renewable energy and being increasingly used for heating/cooling systems of buildings. The standing column well (SCW) is especially efficient, cost-effective, and suitable for Korean geological and hydrological conditions. However, a numerical model that simulates the SCW has not yet been developed and applied in Korea. This paper describes the development of the SCW numerical model using a finite-volume analysis program. The model, through hydro-thermal coupled analyses, simulates heat transfer through advection, convection, and conduction. The accuracy of the model was verified through comparisons with field data measured at SCWs in the U.S. and Korea. Comparisons indicated that the SCW numerical model can closely predict the performance of a SCW. The numerical model was used to perform a comprehensive parametric study in the companion paper.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.5
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• pp.23-33
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• 2008

Extra dosed bridge among the Cabled-stayed bridges have been increasingly built in korea in recently. But such bridges were often damaged by fire due to car collison. In this study Extra dosed bridges among the cabled-supported bridges are selected to analysis model frequently to be designed and/or constructed in recent and furture in this study. COSMOS FloWorks 2007 software are used for Heat Transfer Analysis and Thermal Stress Analysis. The safety of wire, HDPE pipe and stainless steel pipe are investigated. In the case of the constant of the temperature of the heat source, the significant three variables for the analysis are selected for study : (1) the distance between the fire-proof bulk head and the heat source, (2) wind velocity, (3) the height of the end of Stainless steel pipe.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.470-476
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• 2010

The thermodynamic performance of closed ocean thermal energy conversion (OTEC) cycle with 1 MW gross power was evaluated to obtain the basic data for the optimal design of OTEC. The basic thermodynamic model for OTEC is Rankine cycle and the thermal effluent from power plant was used for the heat source of evaporator. The cycle performance such as efficiency, heat exchanger capacity, etc. was analyzed on the temperature variation of thermal effluent. The saturated pressure of evaporator increased with respect to the increase of thermal effluent temperature, so the cycle efficiency increased and necessary capacity of evaporator and condenser decreased under 1 MW gross power. As the thermal effluent temperature increases about $15^{\circ}C$, the cycle efficiency increased approximately 44%. So, it was revealed that thermal effluent from power plant is important heat source for OTEC plant. Also, if there is an available waste heat, it can be transferred heat to the working fluid form the evaporator through heat exchanger and cycle efficiency will be increased.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.660-667
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• 2020

This study focused on the epoxy resin production process, which uses the steam of 155 ℃ or higher as a heat source, and discards all condensate generated. A part of the process is operated at low temperatures of 70 ℃ or below, thus there are opportunities to reduce the steam consumption by recycling wasted condensate as a heat source for the low temperature section of process. In this study, we developed process models that can reduce steam by recovering waste heat through recycling condensate and conducted a case study to find an optimal condensate recycling system. Three different process designs were proposed and economic evaluations were performed by comparing annual capital costs and steam savings in each case. Finally, an annual steam consumption of the low-temperature section could be reduced by up to 67.6%, which could also bring an additional economic benefit of 522.1 million won/yr.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.639-647
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• 2019

Recently, as the semiconductor integration technology due to miniaturization and high density of electronic equipment have developed, it is importantly recognized the application of thermal control system in order to release inner heat generated from chips, modules, In this study, we considered the heat transfer and pressure drop characteristics in a horizontal channel with four blocks using k-${\omega}$ SST turbulence model During CFD (Computational Fluid Dynamics) analysis, the parameters applied block width, block height, heat source and turbulence generator placement etc. As the boundary conditions of analysis, the channel inlet temperature and flow velocity were respectively 300 K and 3.84 m/s, the heat flux was $358W/m^2$. As a result, the heat transfer performance was decreased as the block width ratio (w/h) was increased, while it was increased as the block height ratio (h/w) was increased. In addition, as the arrangement of heat source size was increased to high heat flux from low heat flux, it was influenced by heat source size and the heat transfer coefficient showed a tendency to increase, When the turbulence generator was installed in the upper part of block No. 1 position the closely to the channel entrance, the heat transfer characteristics was greatly influenced on the whole of four heating blocks. and in oder to consider the pressure drop characteristics, we are able to select the most appropriate turbulence generator's position.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.51-56
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• 2012

This paper reports the generation efficiency and the thermal performance of a thermoelectric generator (TEG) harvesting energy from the waste heat of high power electronic components. A thermoelectric (TE) model containing thermal boundary resistances is used to predict generation efficiency and junction temperature of a high power electronic component. The predicted results are verified with measured values, and the discrepancy between prediction and measurement is seen to be moderate. The verified TE model predicts generation efficiencies, junction temperatures of the component, and temperature differences across a TEG at various source heat flows associated with various electrical load resistances. This study explores effects of the load resistance on the generation efficiency, the temperature difference across a TEG, and the junction temperature.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.62-72
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• 2008

In this study, an analytical model has been developed to predict the build-up of heat field due to a point heat source in the presence of sharp cross-flow depth change. The model has been applied to investigate the effect of the depth change and flow pattern on the heat field. Model results show that, when there is a sharp depth change in cross-flow direction, the heat transport across the boundary of the depth change is enhanced or diminished according to the increasing or decreasing of the horizontal diffusion flux. Including residual components as well as tidal currents give rise to reduce the effect of the horizontal diffusion on the heat transport because of increasing the advection of heat.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.36-42
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• 2012

본 논문은 고파워 전자소자로부터 에너지를 수확하는 열전생성기의 성능에 pellet의 기학학적 구조가 미치는 영향들을 보고한다. 열경계저항을 포함하는 열전모델을 적용하여, 다양한 경계조건들과 열원의 열율들에 대해 pellet의 높이, pellet의 단면적, thermocouple의 수를 최적화 하고, 이처럼 최적화된 pellet의 기하학적 구조를 갖는 열전생성기의 성능과 일반적인 pellet으로 구성된 열전생성기의 전력생성성능과 효율이 예측되고 비교되어진다. 예측된 결과는 최적화된 pellet으로 구성된 열전생성기가 일반적인 pellet으로 구성된 열전생성기보다 2-10배까지 생성효율이 우수함을 보여준다. 최적화된 pellet으로 구성된 열전생성기와 일반적인 pellet으로 구성된 열전생성기의 열적성능도 예측되고 비교된다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.6
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• pp.427-433
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• 2007

Generally, H.V.A.C load capacity in early planning phase can presume with maximum thermal load. Basic data can prove by air conditioning equipment system data analysis at existing building. There are poor and not reliable alternative presentation. In this paper, measured data after use H.V.A.C load calculation K-load program reply choosing standard building and variables simulation. And I founded peak load correlation graph and mode for several kinds of variable and contents of size. I wish that equipment designer is beaconed to produce optimum capacity at building as quantitative through this result.