• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.333-338
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• 2010

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.53-56
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• 2010

• Journal of Wetlands Research
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• v.22 no.1
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• pp.15-23
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• 2020

The purpose of this study is to investigate how the degree of distribution influences the calibration of snow and runoff in distributed hydrological models using a multi-criteria calibration method. The Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) developed by NOAA-National Weather Service (NWS) is employed to estimate optimized parameter sets. We have 3 scenarios depended on the model complexity for estimating best parameter sets: Lumped, Semi-Distributed, and Fully-Distributed. For the case study, the Durango River Basin, Colorado is selected as a study basin to consider both snow and water balance components. This study basin is in the mountainous western U.S. area and consists of 108 Hydrologic Rainfall Analysis Project (HRAP) grid cells. 5 and 13 parameters of snow and water balance models are calibrated with the Multi-Objective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm. Model calibration and validation are conducted on 4km HRAP grids with 5 years (2001-2005) meteorological data and observations. Through case study, we show that snow and streamflow simulations are improved with multiple criteria calibrations without considering model complexity. In particular, we confirm that semi- and fully distributed models are better performances than those of lumped model. In case of lumped model, the Root Mean Square Error (RMSE) values improve by 35% on snow average and 42% on runoff from a priori parameter set through multi-criteria calibrations. On the other hand, the RMSE values are improved by 40% and 43% for snow and runoff on semi- and fully-distributed models.

• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.945-958
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• 2014

Soil temperature is one of the most important environmental factors that govern hydrological and biogeochemical processes related to diffuse pollution. In this study, considering the snowmelting and the soil freezing-thawing processes, a set of computer codes to estimate winter soil temperature has been developed for CAMEL (Chemicals, Agricultural Management and Erosion Losses), a distributed watershed model. The model was calibrated and validated against the field measurements for three months at 4 sites across the study catchment in a rural area of Yeoju, Korea. The degree of agreement between the simulated and the observed soil temperature is good for the soil surface ($R^2$ 0.71~0.95, RMSE $0.89{\sim}1.49^{\circ}C$). As for the subsurface soils, however, the simulation results are not as good as for the soil surface ($R^2$ 0.51~0.97, RMSE $0.51{\sim}5.08^{\circ}C$) which is considered resulting from vertically-homogeneous soil textures assumed in the model. The model well simulates the blanket effect of snowpack and the latent heat flux in the soil freezing-thawing processes. Although there is some discrepancy between the simulated and the observed soil temperature due to limitations of the model structure and the lack of data, the model reasonably well simulates the temporal and spatial distributions of the soil temperature and the snow water equivalent in accordance with the land uses and the topography of the study catchment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.787-792
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• 2022

In winter, the excessive use of deicing salt deteriorates concrete pavement durability. To reduce the amount of deicing salt used, phase-change materials (PCMs) potentially offer an alternative way to melt snow through their latent heat storage characteristics. In this research, thermal energy storage concrete was developed by using PCM-impregnated expanded clay as 50 % replacement to normal aggregate by volume. In addition, to improve the thermal efficiency of PCM lightweight aggregate (PCM-LWA)-incorporated concrete, multi-walled carbon nanotubes (MWCNTs) were incorporated in proportions of 0.10 %, 0.15 %, and 0.20 % by binder weight. Compressive strength testing and programmed thermal cycling were performed to evaluate the mechanical and thermal responses of the PCM-LWA concrete. Results showed a significant strength reduction of 54 % due to the PCM-LWA; however, the thermal performance of the PCM-LWA concrete was greatly improved with the addition of MWCNTs. Thermal test results showed that 0.10 % MWCNT-incorporated concrete had high thermal fatigue resistance as well as uniform heat flow, whereas specimens with 0.15 % and 0.20 % MWCNT content had a reduced thermal response due to supercooling when the ambient temperature was varied between -5℃ and 10℃.

• 월간 기계설비
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• s.93
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• pp.60-75
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• 1998

지표면으로부터 일정한 깊이 이하의 토양이 보유하고 있는 지열에너지는 에너지자원을 절약하기 위해서는 매우 유용한 에너지원이 될 수도 있다. 따라서 지중에너지를 활용하기 위한 지중온도분포에 대한 해석과 그 활용면에서 도로 융설시스템 및 건물의 냉난방의 에너지원으로 이용할 수 있는 에너지절약 방안에 대한 연구개발이 추진되고 있다.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.265-272
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• 2007

This study uses the SWAT model to analyze the characteristics of long-term runoff at the Ssang-cheon Basin located in the city of Sokcho, which is located in the province of Gangwon. The study considers the effect of snow packing and snow melting in a runoff simulation. In this simulation, the study examines the need to introduce a snow pack and snow melt model to evaluate the water resources of the mountainous region of the Gangwon province. The findings of this study indicate that the runoff hydrograph that was produced approximates the true measured flow when the effect of the snow pack and snow melt are considered, compared to when they are not factored in. The analysis of the flow duration curve indicates that the stream flow largely increases when the effect of the snow pack and snow melt are considered. The wet stream flow was shown to increase by nearly 3% due to the melting effect, while the normal stream flow, low stream flow and drought stream flow were shown to increase by slightly more than 10%. Specifically, it was found that as the stream flow decreases, the effect of the snow pack and snow melt on the stream flow increases.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.45-52
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• 2010

The relationship between climate changes and transportation could be separated by two approaches. One of methods was to find how climate changes affected transportation, and the other way was how transportation affected climate changes. In this study, we reported from the former standpoint, how climate changes affected transportation fields. When there is a lot of snowfall in Seoul, it starts ripple effect through the travel patterns. They can be explained by travel time and operating cost. The travel costs were calculated in this paper for analysing the effect of disbenefit by climate changes. Snow Melting System was also studied for relieving negative influences under the unpredictable weather condition. As a result, the system was effective for minimizing disbenefit by climate changes.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.136.1-136.1
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• 2011

This paper proposes the method to implement the railroad switching point heating system using the hybrid of the photovoltaic and wind power. The goal of the implementation of the railroad switching point heating system is to prevent freezing of the snow in the winter. The heating system of railway used to supply electricity through photovoltaic and wind power to prevent freezing. Hot wires of the railroad switching point heating system are used about 2kW of electric energy at the day. The electric energy of 2kW used the length of the hot wires about 3m. As the ON and/or OFF mode considering the tracks temperature and the ambient temperature, so the way the use of power-saving effect. In addition, the system can be used the railroad switching point heating system in winter and railway signal and street lights around the track in summer. In experiment, we acquired the power data according to time at the day of photovoltaic and wind power. We confirmed the temperature rise using the heating cable for 3m of $85^{\circ}C$, 30W/m. The temperature rise of the heating cable changes the temperature of $5^{\circ}C$ after 10 minutes and $11^{\circ}C$ after 10 minutes. We have confirmed the possibility of the railroad switching point heating system using the hybrid of the photovoltaic and wind power.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.1
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• pp.7-12
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• 2012

This study proposes a hybrid geothermal system combined with heating mode and snow-melting mode for winter season in order to increase the annual operating efficiency of the GSHP(Ground Source Heat Pump). The purpose of this study is to get effectiveness of the hybrid geothermal system by the site experiments. In case of snow-melting only mode, the GSHP COP is 0.7 higher than system COP in average. And in case of hybrid mode, heating GSHP COP is 0.5 higher than snow-melting GSHP COP. And it is also found out that all COP obtained through measurement periods is higher than nominal COPs given by GSHP manufacturer. As a conclusion, it is clear that the proposed hybrid geothermal system is expected as a highly efficient system.