• 상하수도학회지
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• 제35권6호
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• pp.517-531
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• 2021

The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. Meanwhile, the level of water supply service demanded by consumer is also steadily getting higher in keeping with economic growth. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, Bursts caused by pipe aging brought about an enormous economic loss of about 6,161 billion won as of 2019. These problems are not only worsening water supply management, also increasing the regional gap in water supply services. The purpose of this study is to classify hazard evaluation indicators and to rank the water distribution network hazard by cluster using the TOPSIS method. In conclusion, in this study, the entropy-based multi-criteria decision-making methods was applied to rank the hazard management of the water distribution network, and the hazard management ranking for each cluster according to the water supply conditions of the county-level municipalities was determined according to the evaluation indicators of water outage, water leakage, and pipe aging. As such, the hazard ranking method proposed in this study can consider various factors that can impede the tap water supply service in the water distribution network from a macroscopic point of view, and it can be reflected in evaluating the degree of hazard management of the water distribution network from a preventive point of view. Also, it can be utilized in the implementation of the maintenance plan and water distribution network management project considering the equity of water supply service and the stability of service supply.

• 상하수도학회지
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• 제13권2호
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• pp.23-33
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• 1999

This study is to investigate the effect of C factor errors on the analysis of water distribution systems. For this purpose, an artificial distribution network and a real distribution network were selected as the study networks. Results are as follows. 1. The C factor of a pipe which has small velocity didn't give significant effect on the analysis of a water distribution system. 2. The effect of decreased value of C factors give more influence on the analysis of water distribution systems than that of the increased values. 3. For the C factor calibration, errors of the residual water heads as well as those of the head losses should be considered together. 4. In the analysis of water distribution systems, changes of C factors can give influences only on the nodes which locate behind the pipe. Therefore, this characteristics should be considered in the selection of nodes for the measurement of water heads.

• 물과 미래
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• 제27권4호
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• pp.161-171
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• 1994

관수로시스템 최적설계는 수리학적 및 시스템 운영제약조건 아래서 시스템의 전체비용을 최소비용으로 구하는 것이다. 본 연구에서는 논관개용 수지상배관 시스템설계에 관해 상술하였다. 이는 선형계획론을 이론적 배경으로 하여 관로의 비용과 에너지비용을 함께 고려함으로서 시스템 전체비용으로 구하는 것을 시도하였으며 논 관개용 관수로시스템 설계에 있어서 두 개의 수요양상과 가압펌프를 고려함으로서 전체 시스템의 최소비용을 구하였다.

• KIEAE Journal
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• 제14권4호
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• pp.119-125
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• 2014

This study investigated the effects of pipe network materials and distance on system performance utilizing unused energy sources in large-scale horticulture facility. For this, the modeling was performed with a 100 m long and 100 m wide rectangular shaped glass house having an area of 1ha ($10,000m^2$) using EnergyPlus software. The heat sources considered were air source, geothermal heat, power plant waste heat, sea water heat, and river water. The temperature variation of the fluid with regard to pipe material and distance from the heat source and the resultant heat pump electricity consumptions were calculated. It turned out that the fluid temperature reaching the heat pump increased as the distance from the heat source increased in case of sea water and river water, which have higher temperatures than the surrounding soil, improving the heat pump efficiency. It was vice versa in case of the power plant waste heat. In addition, pipe material of PVC showed the smallest effect on the system performance variation due to the lowest thermal conductivity, compared to PB and HDPE.

• 수도
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• 통권67호
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• pp.39-50
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• 1994

• 한국수자원학회논문집
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• 제51권11호
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• pp.959-969
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• 2018

노후화된 상수관로는 단수유발, 수압부족 및 수질악화, 싱크홀 발생 피해와 누수로 인한 경제적 손실 등을 초래한다. 하지만 모든 노후관로를 일시에 보수 및 교체하는 것은 불가능하므로, 사용 중인 관로의 노후도를 정량적으로 판단하여 상수관로의 개량 우선순위를 결정해야 한다. 본 연구에서는 ANN(Artificial Neural Network)-Clustering 기법이 상수관로의 노후도 평가를 위한 새로운 평가방법이 될 수 있음을 제시하였다. 본 연구는 전라남도 YG지역의 배수관로를 적용대상으로 진행하였으며, 관망성능평가 항목을 이용하여 전체 관로를 세 개의 등급으로 분류하여 노후도를 평가하였다. 또한, 본 연구의 적용 가능성을 판단하기 위하여 실무에서 적용 중인 점수평가법 결과와 비교분석을 실시하였으며, 전체 대상관로의 노후도 정도를 직관적으로 파악할 수 있도록 산정된 노후도 등급을 관망도에 도시하였다. 본 연구에서 제안한 노후관로 평가기법은 관로의 다양한 특성값을 손쉽게 변경하여 적용할 수 있으며, 점수평가법과 더불어 상수관로의 유지관리를 위한 객관적이고 합리적인 관망성능평가법이 될 수 있을 것으로 기대한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.169-169
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• 2023

Most distributed water is not used effectively due to water loss occurring in pipe networks. These water losses are caused by leakage, typically due to high water pressure to ensure adequate water supply. High water pressure can cause the pipe to burst or develop leaks over time, particularly in an aging network. In order to reduce the amount of leakage and ensure proper water distribution, it is important to apply pressure management. Pressure management aims to maintain a steady and uniform pressure level throughout the network, which can be achieved through various operational schemes. The schemes include: (1) installing a variable speed pump (VSP), (2) introducing district metered area (DMA), and (3) operating pressure-reducing valves (PRV). Applying these approaches requires consideration of various hydraulic, economic, and environmental aspects. Due to the different functions of these approaches and related components, an all-together optimization of these schemes is a complicated task. In order to reduce the optimization complexity, this study recommends a sequential optimization method. With three network operation schemes considered (i.e., VSP, DMA, and PRV), the method explores all the possible combinations of pressure management paths. Through sequential optimization, the best pressure management path can be determined using a multiple-criteria decision analysis (MCDA) to weigh in factors of cost savings, investment, pressure uniformity, and CO₂ emissions. Additionally, the contribution of each scheme to pressure management was also described in the application results.

• 물과 미래
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• 제29권5호
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• pp.161-172
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• 1996

상용관 마찰계수 산정을 위해 개발된 기존의 Hazen-Williams 식, Colebrook-White 식과 유동훈(1995)이 제안한야 영점높이 평균법과 마찰계수 평균법의 산정식들을 비교 검토하였다. 간단한 관망에 대하여 관종류, 관경, 유속, 관길이를 변화시켜 수리조건을 구성하였으며, 네가지 상용관 마찰계수 산정식을 적용하여 구한 압력차이를 비교하여 각각의 산정식들이 가지는 특징을 논하였고, 입력자료의 변화에 따라 마찰손실이 어떠한 거동을 하는지 알아보았다. 관경을 소형관 및대형관으로 변화시켰을 때의 분석결과와 중형관일 때의 분석결과를 세 종류의 강관에 대하여 비교하였고, 유속 변화와 압력 변화와의 비교를 통하여 기존 상용관 마찰 계수 산정식의 문제점에 대하여 논하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.265-269
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• 2017

Because of abrupt changes for velocity in water, transient flow is occurred in practical life. To reduce and avoid the high or low pressure of pipe network system, various surge protection facilities are used to prevent the risk in pipe network system. Especially, we focused on study not only preventing positive and negative pressure but also selecting adequate equipment for high pressurized pipelines. Several critical cases were considered by undertaking a steady state hydraulic study and transient dynamic simulation and we suggested that the surge vessel of various surge protection system was recommended to control high and low pressures on pipeline system in perspective.

• 상하수도학회지
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• 제26권5호
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• pp.669-683
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• 2012

The water supply pipes are buried across wide range of areas, so it is hard to spot them using excavation and takes a large amount of expense. Thus, there is a high risk for direct research and application, accompanying many difficulties in implementation of them. Therefore, it is more economical and convenient to use indirect evaluation variables than direct evaluation of the buried pipes in assessing the degree of pipe deterioration. To assess the degree of pipe deterioration using the indirect evaluation variables, it should be done first to identify how and to what extent they affect the degree of deterioration. This study measured the evaluation variables for pipe deterioration using the pipe endoscope and analyzed the measurement results and the degree of impact on the pipes. In addition, this study attempted to evaluate the adequateness of the pipe deterioration evaluation using the indirect variables based on the analysis results. The evaluation variables measured through the pipe endoscope were the thickness of sediments, size of scale, degree of desquamation and condition of connections. For the indirect evaluation variables, the data such as the property data from GIS pipe network map as well as the material, diameter, age and pipe lining material of the pipe, road type, leakage frequency, average water velocity and water pressure using the leakage repair records was collected. Using the collected data, this study comparatively analyzed the indirect evaluation variables for the degree of pipe deterioration and the results from the pipe endoscope to choose appropriate variables for pipe deterioration evaluation and calculated the weights of the indirect variables on the degree of deterioration. The results showed that the order of the impact of indirect variables on deterioration was pipe age > pipe lining material > road type > leakage frequency > average water velocity with their weights of 0.45, 0.20, 0.15, 0.10, and 0.10, respectively. Conclusively, the results suggest that the measures of sediment thickness, scale size, degree of desquamation and condition of connections are appropriate for the evaluation of pipe deterioration and sufficient for the analysis of the impact of the indirect variables on deterioration.