• Membrane Journal
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• v.32 no.5
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• pp.336-347
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• 2022

Reverse electrodialysis (RED) is one of the promising eco-friendly renewable energy technologies which can generate electricity from the concentration difference between seawater and freshwater by using ion-exchange membranes as a diaphragm. The ion-exchange membrane is a key component that determines the performance of RED, and must satisfy requirements such as low electrical resistance, high permselectivity, excellent durability, and low manufacturing cost. In this study, pore-filled anion-exchange membranes were fabricated using porous polymer substrates having various thicknesses and porosity, and the effects of ion-exchange polymer composition and membrane thickness on the power generation performance of RED were investigated. When the electrical resistance of the ion-exchange membrane is sufficiently low, it can be confirmed that the RED power generation performance is mainly influenced by the apparent permselectivity of the membrane. In addition, it was confirmed that the apparent permselectivity of the membranes can be improved through IEC, crosslinking degree, membrane thickness, surface modification, etc., and the optimum condition must be found in consideration of the trade-off relationship with electrical resistance.

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.53-59
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• 2014

Ice Rink is energy intensive building type. Concern of energy saving from buildings is one of very important issues nowadays. New and renewable energy sources for buildings are especially important when we concern about energy supply for buildings. Among new and renewable energy sources, use of seawater for heating and cooling is an emerging issue for energy conscious building design. The options of energy use from sea water heat sources are using deep sea water for direct cooling with heat exchange facilities, and using surface layer water with heat pump systems. In this study, energy consumptions for an Ice Rink building are analyzed according to the heat sources of air-conditioning systems; existing system and sea water heat source system, in a coastal city, Kangnung. The location of the city Kangnung is good for using both deep sea water which is constant temperature throughout the year less than $2^{\circ}C$, and surface layer water which should be accompanied with heat pump systems. The result shows that using sea water from 200m and 30m under sea lever can save annual energy consumption about 33% of original system and about 10% of that using seawater from 0m depth. Annual energy consumption is similar between the systems with seawater from 200m and 30m. Although the amount of energy saving in summer of the system with 200m depth is higher than that with 30m depth, the requirement of energy in winter of the system with 200m depth is bigger than that with 30m depth.

• Journal of Environmental Science International
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• v.9 no.3
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• pp.253-259
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• 2000

The purpose of this study is to investigate the physicochemical characteristics of salinization of groundwater at the estern area of Cheju island. For this purpose, the major ions of groundwater, spring water are analyzed. The concentration of $Cl^-$ and Na^++K^+$/ contained in the groundwater at near the coastline are higher than those at inland area away from the coastline. The water quality components of groundwater observed at this area can be classified into 4 types such as Na-Cl, $HCO_3, Na-Cl-HCO_3$ and Ca-HCO$_3$. The concentration ratio of $SO_4^1 to Cl^- is 0.1354(R^2=0.972)$ at this area. This value is very similar with Dittomer's ratio of 0.13. For Na^+, K^+, and Mg^{2+}/ versus Cl^-$, their ratios also show a significant relationship between sea water and groundwater in this area. From the chloride-bicarbonate ratio, it can be estimated that the intrusion distance of seawater from coastline to inland area is 2.8km at Onpyung-Nansan, Sangdo and Pyungdae areas, and 5.4km at Kosung-Susan area. The mixing ratio between seawater and fresh water by the intrusion of seawater is decreased with the distance toward inland from coastline. This ratio(fresh water : seawater) is 80:20 in spring water adjacent the coastlines, Onpyung area and 99.8:0.2 in the well at No.3 of Susan located at inland away from the coastline. The concentration of $Na^+$ observed at field is 25~45% lower than that theoretically calculated by this mixing ratio. Based on the data of EC, the equipotential line of 500$\mu$mhos/cm is located at 4~5km poing at Kosung-Susan area and 2.5km point at the other area. The equation of correlation between $Cl^-$ concentration and EC values is $Cl^-$=0.1927EC-16.683 for the area lower than 500 $\mu$mhos/cm and $Cl^-$=0.2773EC for the area beyond 500 $\mu$mhos/cm.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.43-49
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• 2011

For the improvement of water quality in a harbor, several studies have been carried out on SEB (Seawater Exchange Breakwater) in recent years, but a problem has been shown whereby the water on the inside area far from the SEB cannot be easily exchanged. In order to solve the problem of the SEB, the Manifold channel, a new concept of the SEB, is introduced in this paper. By using the manifold channel, it is possible to exchange the water of the inside area for seawater from the outside. Here, to assess the outflow gates of the manifold channel governing flow behavior, a virtual manifold channel controlled the location, width and direction of outflow gates applied to the Jumunjin fishery port, where the SEB has been established. In addition, the desirable flow pattern of the port by utilizing the two layer current model is identified, and five general cases of the manifold channel are described in this paper. The model is verified by comparing with observation of the SEB model, and the results are in general agreement. From the results of the manifold channel, in the case of the Jumunjin fishery port, the small circulation of counter clockwise is necessary for the water exchange on the inside area, but it should be controlled by the outflow gates for other areas. Using the two layer current model, the desirable flow pattern of the port can be predicted, and the water exchange for the upper and lower layer can be examined. For the practical use of the manifold channel, further studies on the manifold channel will be necessary, and it may then be used broadly for the design of breakwater in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.101-108
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• 1985

The sea water exchange of Koje Bay in the southeastern part of the Korean Peninsula was estimated on the basis of current measurements and oceanographic observation. The exchange ratio was estimated by salinity differences and tidal prism method. The range of exchange ratio at the central part at the entrance of the bay is estimated to be around $26\%$ at spring tide and 5 to $15\%$ at neap tide. The magnitude of exchange ratio, however, can be changed due to water exchange, hydrometeorological and geomorphological conditions. The flushing time deduced by tidal prism was about 48 hours at spring tide and 81 hours at neap tide. Tidal induced eddy motion may play an important role on the seawater exchange in the bay.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.699-707
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• 2021

Hwajinpo Lagoon, located on the eastern coast of Korea, is a unique environment where freshwater and saltwater are mixed. Systematic management of the lagoon is required because it is a biodiversity-rich and area of high conservation value. The existing environment of the lagoon was evaluated by identifying the distribution of the groundwater level and groundwater flow characteristics. In addition, hydrogeochemical fluctuations were analyzed to determine the effect of seawater intrusion into the aquifer. The results demonstrate that the freshwater-saltwater interface is distributed throughout the aquifer and rises when water of the lagoon evaporates due to prolonged periods of low rainfall and high temperature, thereby increasing the possibility of seawater inflow through groundwater. As for the ionic delta properties (difference between the measured and theoretical concentration of mixed waters), it was estimated that the cation-exchange and precipitation reactions occurred in the aquifer due to seawater intrusion. The ratio of seawater mixed at each point was calculated, using oxygen isotopes and chloride as tracers, resulting in an average of 0.3 and a maximum of 0.87. The overall seawater mixing ratio appears to be distributed according to the distance from the coast. However, some of the results were deviated from the theoretical expectations and reflected the characteristics of the nearby aquifers. Further research on seasonal changes and simulation of seawater intrusion mechanisms is required for specific analysis.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.159-162
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• 2007

The numerical efforts are presented for investigation of irregular waves passing a slit cassion and a warock block breakwater. In the numerical model, the Reynolds equations are solved by a finite difference method and $k-\varepsilon$ model is employed for the turbulence analysis. To track the free surface displacement, the volume of fluid method(VOF) is employed. Numerical predictions of reflection and transmission coefficients are compared with those of the warock block breakwater with the slit caisson. Energy dissipation and seawater exchange rates of the slit caisson are better than those of the warock block breakwater.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.110-117
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• 2003

해수교환방파제란 방파제에 설치된 통수구를 통해 해수가 항내로 일방향으로 유입되거나 통수구에서 양방향 흐름이 발생함으로써 종국에는 항내ㆍ외간의 해수교환이 활발하게 이루어지게 하는 방파제를 말한다. 그리고 방파제를 통한 순유입유량이 클수록 해수교환의 영향은 항내의 넓은 수역까지 미친다. (중략)

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.118-123
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• 2003

재래식 방파제는 투수성이 작아 항내ㆍ외간 해수유통을 저하시켜 조석간만의 차가 작은 해역의 항만에서는 오염원이 유입될 때 수질이 쉽게 악화된다. 특히 방파제 후면 수역을 매립하여 선착장으로 이용하는 경우에 이 현상은 심화된다 이를 해결하려면 육상으로부터의 오염원 유입을 저감시킴과 함께 정체된 항에 흐름이 존재하도록 하는 건설 공법을 도입할 필요가 있다. (중략)

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.298-302
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• 2003

재래식 방파제를 설치하여 조성한 항내 수역은 항내ㆍ외로 해수유통이 원활하게 일어나지 않는 폐쇄성 수역이 될 수가 있다. 이런 수역에 항내의 자정능력을 초과하는 오염원이 유입되면 수질이 악화되어 항내수는 사용하지 못하게 될 뿐 아니라 항 전체가 오염되어 주민들의 폐적한 생활공간이 훼손되며, 주민의 보건도 악영향을 받는다. 이를 해결할 수 있는 1차적인 방안은 항내로의 오염원을 줄여 나가며 바닥에 가라앉은 오염물을 준설하는 것이고, 2차적으로 해수유통을 원활하게 할 수 있는 해수교환시설을 설치하는 것이다. (중략)