• Membrane and Water Treatment
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• 제6권6호
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• pp.451-476
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• 2015

Membrane distillation (MD), which can utilize low-grade thermal energy, has been extensively studied for desalination. By incorporating solar thermal energy, the solar membrane distillation desalination system (SMDDS) is a potential technology for resolving the energy and water resource problems. Small-scale SMDDS (s-SMDDS) is an attractive and viable option for the production of fresh water for small communities in remote arid areas. The minimum-cost design and operation of s-SMDDS are determined by a systematic method, which involves a pseudo steady state approach for equipment sizing and the dynamic optimization using overall system mathematical models. The s-SMDDS employing three MD configurations, including the air gap (AGMD), direct contact (DCMD) and vacuum (VMD) types, are optimized. The membrane area of each system is $11.5m^2$. The AGMD system operated for 500 kg/day water production rate gives the lowest unit cost of $5.92/m^3$. The performance ratio and recovery ratio are 0.85 and 4.07%, respectively. For the commercial membrane employed in this study, the increase of membrane mass transfer coefficient up to two times is beneficial for cost reduction and the reduction of membrane heat transfer coefficient only affects the cost of the DCMD system.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.762-766
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• 2017

에너지 회수장치는 역삼투 공정에서 에너지 소모량을 줄이기 위해 사용된다. 그러나 해수담수화 시장에서 소규모 에너지 회수장치(<$100m^3/d$)를 찾기는 쉽지 않다. 우리나라에서 음용수 생산을 위한 역삼투 해수담수화 시설은 대부분 도서지역이나 선박에서 소규모로 운영되고 있다. 즉, 국내에는 소규모 에너지 회수장치 수요가 잠재하고 있다. 본 연구에서는 고압펌프의 현실적인 효율과 국내 전력비 단가 등을 고려하여, 소규모 역삼투 공정의 에너지 소모량을 에너지 회수장치의 적용 여부 및 설치 장소(예: 육상, 도서, 선박)에 따라 비교 분석하였다. 분석 결과, 에너지 회수장치 적용 시 전력비는 1,914.1원/$m^3$ 까지 절감될 수 있고 소규모 시설과 선박에서는 절감효과가 증가되는 것을 확인하였다. 소규모 역삼투 담수화 시설이 대부분을 차지하는 국내 현실과 규모가 작아질수록 에너지 회수장치에 대한 전력비 절감효과가 커지는 본 연구의 결과를 고려한다면, 소규모 에너지 회수장치의 개발 필요성이 크다고 할 수 있다.

• 한국수자원학회논문집
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• 제44권10호
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• pp.809-817
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• 2011

한국수자원공사에서 위탁 관리하고 있는 서남해안 도서지역 역삼투 해수담수화 시설 40여곳에 대한 비용 분석을 통하여 비용에 큰 영향을 미치는 요소를 찾아내고 담수화 비용 절감방안을 제시하였다. 시설에 공급되는 원수의 염도(TDS)는 담수로 취급될 수 있는 1,000mg/L 이하에서부터 해수수준인 3,000mg/L 이상까지 다양한 범위를 보이고 있다. 2005년부터 5년 동안의 비용분석 결과 유지보수비가 50.6%, 인건비가 36.9%, 그리고 에너지비가 7.8%의 순으로 나타났다. 본 연구에서는 일반적으로 잘 알려진 에너지 비용은 물론 담수화 비용의 가장 큰 비중을 차지하는 유지보수 비용도 원수의 TDS 농도에 직접적인 영향을 받고 있음을 밝혔다. 이는 원수의 TDS 농도가 담수화 비용의 60%에 달하는 부분에 영향을 끼치므로 담수화 비용 절감을 위해서는 저염도 원수 확보에 노력을 기울여야 한다는 것을 의미한다.

• 상하수도학회지
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• 제23권2호
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• pp.251-255
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• 2009

Foreign and domestic seawater desalination plant market investigation was performed to analyze the worldwide trend of seawater desalination plant market and to establish the activation plan for seawater desalination plant application. Water demand and seawater desalination related laws and regulations were investigated and analyzed for the activation plan. RO type and large scale plants are popular nowadays however there are only small plants in island region in Korea. There will be about $1 million\;m^3/day$ deficit in 2015 according to the water demand forecasting from Ministry of Environment and Ministry of Land, Transportation, and Maritime Affairs in Korea. Therefore, it is necessary to activate the domestic application of seawater desalination plant to secure stable water resources. To activate the domestic application of seawater desalination plant, first, we need to establish regulations, support system in the water service law for seawater desalination plant. Second, related Ministry should increase the support for the operation and management of seawater desalination plant and suggest the construction of seawater desalination plant for water resources security near seaside region.

• Membrane and Water Treatment
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• 제6권1호
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• pp.43-52
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• 2015

A small-scale electro-dialysis system was constructed for domestic use. It is composed of six compartments in which five special polystyrene ionic membranes are housed. A series of experiments on the transport of sodium and chloride ions through polystyrene membranes was performed and the effects of electric current and voltage on the pH of water were investigated. This electrodialyser could reduce the NaCl content to an acceptable level (5307 mg/L) when water containing 9945 mg/L of sodium chloride is fed to the electrodialyser. The reduction was by the action of direct current 60 mA/100 mA when a 15 V / 20 V potential is maintained across the membrane. The results showed that the pH of the treated water attained a value in the range of 7-8, with the chloride concentration of 5307 mg/L when the voltage was in the range of 20 volts. This was achieved when two of the small-scale electro-dialysers were placed in series and the solutions from the respective compartments were mixed. This is considered useful because this complies to the requirement of drinking water standard both in terms of chloride and pH. Therefore, this type electrodialyserhas the potential for domestic uses in isolated houses where potable water supply is not available.

• 한국인터넷방송통신학회논문지
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• 제19권3호
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• pp.179-184
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• 2019

전기가 부족한 개발도상국 같은 많은 나라에서는 Off Grid 형태의 소형풍력발전이 전력공급 문제를 해결하기 위한 효율적인 핵심 솔루션이다. 몇몇 국가에서는 전력계통의 확장과 전기가 부족한 지역의 감소로 소규모 풍력을 도시의 도로 조명, 모바일 통신 기지국, 양식업 및 해수 담수 등의 분야에 이용하기도 한다. 이런 변화에 따라 소형 풍력 산업 규모는 대규모 풍력보다 큰 잠재력이 기대되고 있다. 소형 풍력발전의 경우 발전기는 가변 속도로 제어되는 특성이 있으며 발전기에서 발생하는 전압 및 전류에는 많은 고조파 성분을 가지고 있다. 이를 해결하기 위해서 본 논문에서는 소형 풍력발전시스템의 직류전원 적용을 위한 운전제어 및 AC/DC 변환 통합장치를 제안하며 기존 AC to DC 컨버터는 단일 스위치를 갖는 3상 승압형 방식의 컨버터로서 인덕터 전류가 불연속모드로 제어되며, 입력전류의 고조파를 제거하여 단위역률을 갖는 특성을 갖는다. 제안된 컨버터는 입력단에 LCL 필터 및 3상 정류 승압형 컨버터, 계통연계를 위한 단상 풀브릿지 형태로 구성되어 있으며 에너지저장시스템(ESS) 기능이 부가된 제어 시스템으로 풍력발전을 이동 평준화 방식에 의해 급변하는 전력에 대해 계통 안정화를 추구할 수 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2169-2175
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• 2009

This research aims to evaluate the concept of eco-efficient water infrastructure and provides a list of case studies in order to help understand the applicability of eco-efficient water infrastructure to Asia and the Pacific. A set of indicators have been explored to assess eco-efficiency in water infrastructure for the region on a micro and macro scale. The core idea of eco-efficiency, 'more value with less impact (on the environment)', has proven to be applicable in management of water infrastructure. The fundamental elements in eco-efficient water infrastructure should encompass physical infrastructure and non-physical infrastructure, which is more needed particularly in Asian countries. The case studies have demonstrated the applicability of the concept of eco-efficient water infrastructure. The Republic of Korea has provided the case of the eco-friendly approaches to enhance dam management and its innovative solutions how to use water more efficiently through state-of-art technologies. The experiences of Singapore are some of the best evidence to establish eco-efficient water infrastructure, for instance, the NEWater project via application of cutting edge technologies (recycled water) and institutional reform in water tariff systems to conserve water as well as enhance water quality. A list of indicators to assess eco-efficiency in water infrastructure have been discussed, and the research presents a myriad of project cases which are good to represent eco-efficiency in water infrastructure, including multipurpose small dams, customized flood defense systems, eco-efficient ground water use, and eco-efficient desalination plants. The study has presented numerous indicators in five different categories: 1) the status of water availability and infrastructure; 2) production and consumption patterns of freshwater; 3) agricultural products and sources of environmental loads; 4) damages from water-caused natural disaster; and 5) urban water supply and sanitation. There are challenges as well as benefits in such indicators, since the indicators should be applied very carefully in accordance with specific socio-economic, political and policy contexts in different countries in Asia and the Pacific Region. The key to success of establishment of eco-efficient water infrastructure in Asia primarily depends on the extent to which each country is committed to balancing its development of physical as well as non-physical water infrastructure. Particularly, it is imperative for Asian countries to transform its policy focus from physical infrastructure to non-physical infrastructure. Such shift will help lead to implementation of sustainable in Asian countries.