• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.61-64
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• 2006

Recently the development of small hydropower generation with using water pipes is revitalized by the water works facilities. However, when the tubine generator is in case of emergency stop by the internal and external accidents, it causes water hammer in water pipes and suspension of water supply. To prevent these problems of small hydropower generator, we has analyzed water supply patterns, installation position and water pipe systems.

• Membrane and Water Treatment
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• v.6 no.6
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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.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.226-233
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• 2018

Small-scale wastewater discharge facilities account for 98% of all workplaces, but in the generation and emission of major pollutants, they account for 27.5 % and 23.5 %, respectively. Since the proportion of the emission load of the small-scale workplace is not large, the national environmental policy has been established mainly around large-scale wastewater discharge facilities. However, in the case of specific hazardous substances in water, the amount of the discharge load of the small-scale wastewater discharge facility was 2.4 times higher than that of the generation load. Certain types of specific hazardous substances in water, which have a higher discharge load than large-scale wastewater discharge facilities, account for 24 ~ 32 %. There are also cases in which the discharge load from a small-scale discharge facility is more than four times higher, depending on the specific kind of water pollutant. As a result of inspections, the violation rate of the small-scale wastewater discharge facility among the total violations by facilities is 93.9 ~ 97.5 %. As a result, the ecotoxicity value of small-scale wastewater discharge facilities was high in most industries, and there was a fluctuation in the measured value. This indicates that the ecological integrity of the water system can be largely influenced by small-scale wastewater discharge facilities. Therefore, it is necessary to expand the environmental management of small-scale wastewater discharge facilities, and in some cases, the effect of the improvement in quality may be more significant than in the management of large-scale wastewater discharge facilities.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.9 no.2
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• pp.93-103
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• 1980

A small domestic solar water heating system in thermosyphonic flow was tested in Seoul. The system consisted of four flat plate aluminium roll bond type collectors of total effective area $3.28m^2$ and a $280{\iota}$ storage tank. It was tilted $52^{\circ}$ relative to the horizon. And the collector plate, collector tube and storage tank were equiped with 14 thermocouples. As the results, the following facts were found; 1) To provide water at $55^{\circ}C$ for a family of four in Seoul, a collector area of $3-4m^2$ and a storage capacity of $180{\iota}- 200{\iota}$ are suggested. And this system can supply hot water at above $45^{\circ}C$ day about. 2) In the late afternoon hours, it might be advantageous to stop the flow in the system as heat losses to the environment increase unduly. 3) Without any hot water consumption throughout the day, water temperature distributions inside the storage tank was found almost linear. This indicates essentially no mixing inside the storage tank. 4) In case of a small domestic solar water heating system, it is better to employ a single transparent cover rather than double one.

• Journal of Advanced Navigation Technology
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• v.18 no.3
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• pp.254-260
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• 2014

We studied water level rising of drum versus time in the small hydraulic vertical water turbine system in this paper. The water level rises continuously up to a certain point with the passage of time if the constant incoming water is supplied, while it stops rising and maintains equilibrium state without any more rising because it increases position energy and evatually makes outgoing velocity and outgoing water quantities of runner area. The water level of drum is determined independent of size, height, width, figure of drum or runner configuration. It comes out that the water level is dependent only on the incoming and outgoing water quantities, and the output power has similar behavior. Therefore, desirable water level and output power are not available unless incoming water quantities is abundant. We validate this phenomina through applyng our methodolgies to the real small hydraulic vertical water turbine system under constructing and testing in industrial facilities in Korea.

• Journal of Korean Society of Rural Planning
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• v.7 no.1 s.13
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• pp.3-13
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• 2001

In an effort to effectively manage and evaluate a water environment at a small watershed, a decision support system for a water environment management and evaluation has been developed. This paper described the overall features and functions of the water environment management and evaluation systems (WEMES) for environmental management, conservation, and evaluation at a small watershed. WEMES consisted of fore subsystems: data, simulation model, evaluation model, and user interface. Each of the systems were briefly described. And special features like simulation and evaluation models were also introduced.

• Proceedings of the KIEE Conference
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• summer
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• pp.950-952
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• 2004

The developments of small hydropower plants in korea have been delayed by rising construction cost/low feasibility, local people's disagreement even though the capacity of water resources are enough. However, the recent raising of electricity purchasing price, the government's enlarging plan of small hydropower plants caused the newly development to be accelerated. In this paper, the design of remote control of small hydropower plants are proposed for better economy and easy control. The operation and monitoring of power plants are planned based on One(1)-man control from the central control room of regional area water works/ operating station and engineering station multipurpose dam offices with the equipments of OS, RTU(PLC), KT leased lines, WMPS, CSU and etc.

• Bulletin of the Korean Chemical Society
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• v.3 no.3
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• pp.83-88
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• 1982

Viscosity and zeta-potential of 11.0 wt. % aqueous bentonite suspension containing various electrolytes and hydrogen-ion concentration were measured by using a Couette type automatic rotational viscometer and Zeta Meter, respectively. The effects of pH and elcctrolytes on the rheological properties of the suspension were investigated. A system, which has a large zeta-potcntial, has a small intrinsic relaxation time ${\beta}$ and a small intrinsic shear modulus $1/{\alpha}$ in the Ree-Eyring generalized viscosity equation, i.e., such a system has a small viscosity value, since ${\eta}={\beta}/{\alpha}$. In general, a stable suspension system has large zeta-potential. The stability condition of clay-water suspension can be estimated by viscometric method since stable suspension generally has small viscosity. The correlation between the stability, viscosity and zeta-potential has been explained by the Ree-Eyring theory of viscous flow.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.675-682
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• 2010

Groundwater is an essential drinking water source in Gyungbuk, South Korea. The primary source of nitrate in groundwater is from nitrogen fertilizers. Efficient management of a small drinking water plant requires a good understanding of its status such as the objective and the cognition of users. The objective of this study is to understand user situation and produce useful user-friendly policy based on user cognition. Most people who participated in this study, should take their groundwater from a good quality source. Even though they would like to have a good facility for getting safe water, they were reluctant to do it due to the cost used. It means that people who drink groundwater have no idea that health safety is affected by groundwater quality. The volume used depended upon personal activities such as agriculture and stockbreeding. We can easily find groundwater with nitrate that exceeds drinking water standards. Therefore, we have to carry out groundwater management with two categories ; 1) drinking water only and 2) others according to objectives in small drinking water systems.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.241-245
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• 2011

Small hydropower is one of the many types of new and renewable energy, which South Korea is planning to develop, as the country is abundant in endowed resources. In order to fully utilize small hydropower resources, there is a need for greater precision in quantifying small hydropower resources and establish an environment in which energy sources can be discovered using the small hydropower resource management system. This study has given greater precision to calculating annual electricity generation and installed capacity of small hydropower plants of Han river system by inquiring into average annual rainfall, basin area and runoff coefficient, which is anticipated to promote small hydropower resources utilization. Small hydropower resource management system was also established by additionally providing base information on quantified small hydropower resources and analysis function and small hydropower generator status, rivers, basin, rainfall gauging station, water level gauging station etc.. Small hydropower resource management system can be used gather basic information for positive applications of small hydropower energy nationwide.