• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2015년도 학술발표회
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• pp.293-293
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• 2015

농촌용수는 자연계의 물순환과 융합한 형태로 반복과 순환의 특징을 갖고 있으며, 지역의 건전한 물순환 형성에 중요한 역할을 담당하고 있다. 또한 식량생산 기반으로서의 역할뿐만 아니라 환경 보전, 전통문화 및 지역사회 등과 밀접한 관련이 있어 사회적 자본으로서의 큰 역할을 하고 있다. 그러나 최근 쌀 소비의 급격한 감소로 논 경작면적이 축소되면서 밭 경작면적이 증가하고 있어 우리나라 농업형태가 논 관개 시스템에서 밭 관개 시스템의 특용작물 재배와 같은 첨단시설의 하우스 농업 형태로 변화하고 있음을 알 수 있다. 농촌용수의 활용은 감소하고 있고 관개 형태의 변화로 용수관리 시스템에 대한 중요성이 대두되고 있고, 관개시스템에서 농촌용수의 효율적인 이용을 위한 수로형태의 변화는 개수로 중심에서 관수로 중심으로 진화하고 있는 상황이다. 농촌용수를 저장, 운용 실태를 보면 노후 된 농업기반시설들로 인하여 저수량 감소가 발생하며, 확보된 용수를 재래식으로 운용함으로 인한 관리 손실발생으로 농촌용수 부족사태를 발생시키고 있으며, 농촌용수 관개를 위한 개수로에서의 용수 손실률은 약 15%에 달하며 이는 약 20억$m^3$으로 추정되고 우리나라 총 수자원의 6%에 해당되는 양이다. 본 연구에서는 관개지구의 급수관리 계획 및 사례 분석을 통해 기존의 모의에 의한 농촌용수 추정 값의 불확실성을 확인하고 실측에 의한 정량화 분석을 통해 관수로 시스템 구축의 타당성 제시 및 효과 분석을 하고자 한다.

• Journal of Korea Water Resources Association
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• 제56권9호
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• pp.587-602
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• 2023

Due to climate change, population growth, and economic development, the demand for water in the urban water system (UWS) and the energy required for water use constantly increase. Therefore, beyond the traditional method of considering only the water sector, the Nexus approach, which considers synergies and trade-offs between the water and energy sectors, has begun to draw attention. In previous researches, the Nexus methodology was used to demonstrate that the UWS is an energy-intensive system, analyze the water-energy efficiency relationship surrogated by energy intensity, and identify climate (long-term climate change, drought, type), geographic characteristics (topography, flat ratio, location), system characteristics (total supply water amount, population density, pipeline length), and operational management level (water network pressure, leakage rate, water saving) effects on the UWS. Through this, it was possible to suggest the direction of policies and institutions to UWS managers. However, there was a limit to establishing and implementing specific action plans. This study built the energy intensity matrix of the UWS, quantified the impact of city conditions, external influences, and operational management levels on the UWS using the water-energy Nexus model, and introduced water-energy efficiency criteria. With this, UWS managers will be able to derive strategies and action plans for efficient operation management of the UWS and evaluate suitability and validity after implementation.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.6-13
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• 2018

Utilizing the heat of cooling water discharge of coal-fired power plant, pipeline investment costs for businesses that supply heat to agricultural facilities near power plants increase in proportion to installation distance. On one hand, the distance from the power plant is a factor that brings difficulties to secure economic efficiency. On the other, if the installation distance is short, there is a problem of securing the heating demands, facility houses, which causes economical efficiency to suffer. In this study, the economic efficiency of 1km length of standard heat pipeline was evaluated. The sensitivity of the heat pipe to the new length variation was analyzed at the level of government subsidy, amount of heating demand and the incremental rate of pipeline with additional government subsidy. As a result of the analysis, it was estimated that NPV 131 million won and IRR 15.73%. The sensitivity analysis showed that NPV was negative when the length of heat pipe facility exceeded 2.6 km. If the government supports 50% of the initial investment, the efficiency is secured within the estimated length of 5.3 km, and if it supports 80%, the length increases within 11.4 km. If the heat demand is reduced to less than 62% at the new length of the standard heat pipe, it is expected economic efficiency is not obtained. If the ratio of government subsidies to initial investment increases, the elasticity of the new bloc will increase, and the fixed investment, which is the cost of capital investment for one unit of heating demand, will decrease. This would result in a reduction in the cost of production per unit, and it would be possible to supply heat at a cheaper price level to the facility farming. Government subsidies will result in the increased economic availability of hot plumbing facilities and additional efficiencies due to increased demand. The greater government subsidies to initial investment, the less farms cost due to the decrease in the price per unit. The results of the study are significant in terms of the economic evaluation of the effectiveness of the government subsidy for the thermal power plant heat utilization project. The implication can be applied to any related pilot to come.

• Journal of Korean Society of Water and Wastewater
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• 제34권1호
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• pp.9-21
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• 2020

The proper operation and safety management of water and wastewater treatment systems are essential for providing stable water service to the public. However, various natural disasters including floods, large storms, volcano eruptions and earthquakes threaten public water services by causing serious damage to water and wastewater treatment plants and pipeline systems. Korea is known as a country that is relatively safe from earthquakes, but the recent increase in the frequency of earthquakes has increased the need for a proper earthquake management system. Interest in research and the establishment of legal regulations has increased, especially since the large earthquake in Gyeongju in 2016. Currently, earthquakes in Korea are managed by legal regulations and guidelines integrated with other disasters such as floods and large storms. The legal system has long been controlled and relatively well managed, but technical research has made limited progress since it was considered in the past that Korea is safe from earthquake damage. Various technologies, including seismic design and earthquake forecasting, are required to minimize possible damages from earthquakes, so proper research is essential. This paper reviews the current state of technology development and legal management systems to prevent damages and restore water and wastewater treatment systems after earthquakes in Korea and other countries. High technologies such as unmanned aerial vehicles, wireless networks and real-time monitoring systems are already being applied to water and wastewater treatment processes, and to further establish the optimal system for earthquake response in water and wastewater treatment facilities, continuous research in connection with the Fourth Industrial Revolution, including information and communications technologies, is essential.

• Journal of the Korean Institute of Gas
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• 제10권4호
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• pp.34-40
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• 2006

This paper provides a fusion technology between a district cooling energy system and an environment conservation policy based on the energy savings and reusable cold energy resources. The district heating and cooling systems are very effective ways for an energy saving, a cost reduction and a safety control. It is necessary to equalize the energy savings and an environmental preservation policy for an improved human lift. A gasification process of a liquefied natural gas, cooling water from deep seawater and an ice water thermal storage system may produce a cold energy. A district cooling system is used to cool an apartment, office buildings and factory facilities with a cooling energy supply pipeline. LNG cooling energy will switch a conventional air-conditioning system, which is operated by on electrical energy and a Freon refrigerant. Coincident with significant clean energy and operating cost savings, LNG cold energy system owen radical reductions in an air-borne pollutant, $CO_2$ and the release of environmentally harmful refrigerants compared with that of the conventional air-conditioning system. This study provides useful information on the fusion technology of a LNG cold energy usage and energy savings, and environmental conservation.

• Journal of Korean Society of Environmental Engineers
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• 제34권7호
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• pp.473-479
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• 2012

Water reuse has been highlighted as a representative alternative to solve the lacking water resource. This study carried out a study on the pipe corrosion and water quality change which can occur through the supply of reclaimed water, using a simulated reclaimed water distribution pipeline. Galvanized steel pipe (GSP), cast iron pipe (CIP), stainless steel pipe (STSP) and PVC pipe (PVCP) were used for the pipe materials. Reclaimed water(RW) and tap water(TW) were respectively supplied into simulated reclaimed water distribution pipelines. As a result of performing a loop test to supply reclaimed water to simulated reclaimed water distribution pipelines, the weight reduction of pipe coupons showed the sequence of CIP > GSP > STSP ${\approx}$ PVCP. In addition, reclaimed water showed a high corrosion rate comparing to that of tap water. In case of CIP, the initial corrosion rate showed 3.511 mdd(milligrams per square decimeter per day) for reclaimed water and 2.064 mdd for tap water and the corrosion rate for 90 days showed 0.833 mdd for reclaimed water and 0.294 mdd for tap water. Also in case of GSP, the initial corrosion rate showed 2.703 mdd for reclaimed water and 2.499 mdd for tap water and the corrosion rate for 90 days showed 0.349 mdd for reclaimed water and 0.248 mdd for tap water, which was a tendency similar to that appeared in CIP with a tendency to reduce the corrosion rate. As a result of water quality changes of reclaimed water at pipe materials to carry out the loop test, there was higher conversion ratio of ammonia into nitrate in CIP and GSP with higher corrosion rate than that in STSP and PVCP where no corrosion has occurred. The highest denitrification rate of nitrate could be observed from CIP with the most particles generated from corrosion. In CIP, it could be confirmed that there was MIC (Microbiologically Induced Corrosion) as a result of EDS (Energy Dispersive X-ray spectrometer System) analysis results.

• Journal of the Korean Geosynthetics Society
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• 제16권2호
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• pp.139-148
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• 2017

Ground subsidence caused by damaged water pipe and sewer is recently increasing due to the aging of city and pipeline in many city. Although many recent studies have verified characteristics of ground subsidence due to wastewater pipe breakdown, research about characteristics of ground subsidence due to water pipe is insignificant. subsidence due to water pipe is insignificant. This study aims to identify the ground failure mechanism caused by water and sewer pipe breakdown. Accordingly, we conducted an indoor model experiment to verify characteristics of ground subsidence considering characteristics of ground and ground failure. The water pipe pressure and velocity head was considered to find out ground subsidence mechanism. Also comparative analysis is conducted by analyzing relative density and fine-grain content considering embedded condition of water pipe. When the relative density and seepage pressure is low, small scale ground subsidence can occur, but when the conditions are opposite, ground subsidence occur in large scale and expands to ground level over time. Furthermore, it is acknowledgeable that ground cavity that is formed after soil run off due to seepage in deep earth, maintains steady strength and stays on the ground level for long period.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제46권3호
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• pp.285-292
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• 2023

As various accidents have occurred in underground spaces, we aim to improve the quality validation standards and methods as specified in the Regulations on Producing Integrated Map of Underground Spaces devised by the Ministry of Land, Infrastructure and Transport of the Republic of Korea for a high-quality integrated map of underground spaces. Specifically, we propose measures to improve the quality assurance of pipeline-type underground facilities, the so-called life lines given their importance for citizens' daily activities and their highest risk of accident among the 16 types of underground facilities. After implementing quality validation software based on the developed quality validation standards, the adequacy of the validation standards was demonstrated by testing using data from two-dimensional water supply facilities in some areas of Busan, Korea. This paper has great significance in that it has laid the foundation for reducing the time and manpower required for data quality inspection and improving data quality reliability by improving current quality validation standards and developing technologies that can automatically extract errors through software.

• Journal of Energy Engineering
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• 제28권1호
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• pp.22-29
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• 2019

A heat pump system using wasted heat from thermal effluent to supply the heating energy can reduce energy consumption and emissions of greenhouse gases by greenhouse facilities nearby. The Jeju National University consortium constructed a heat pump system using the thermal effluent from the Jeju thermal power plant of KOMIPO to provide with cool or hot water to greenhouse facilities located 3 km from the power station. In this paper, the system configuration of the heat pump system was summarized, and the results of operations for demonstration of a heating performance carried out during the winter season in 2018 were investigated. The preoperational tests proved that the water temperature drop through the pipeline transporting extracted heat was less than $2^{\circ}C$. The COP (coefficient of performance) of the heat pump was higher than 4.0, and hot water with the maximum temperature of $50^{\circ}C$ could be supplied to greenhouse facilities by utilizing wasted heat from thermal effluent.

• Journal of Internet of Things and Convergence
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• 제8권5호
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• pp.11-16
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• 2022

As an interest in the development of artificial intelligence(AI) technology in the water supply sector increases, we have developed an AI algorithm that can predict improvement decision-making ratings through repetitive learning using the data of pipe condition evaluation results, and present the most reliable prediction model through a verification process. We have developed the algorithm that can predict pipe ratings by pre-processing 12 indirect evaluation items based on the 2020 Han River Basin's basic plan and applying the AI algorithm to update weighting factors through backpropagation. This method ensured that the concordance rate between the direct evaluation result value and the calculated result value through repetitive learning and verification was more than 90%. As a result of the algorithm accuracy verification process, it was confirmed that all water pipe type data were evenly distributed, and the more learning data, the higher prediction accuracy. If data from all across the country is collected, the reliability of the prediction technique for pipe ratings using AI algorithm will be improved, and therefore, it is expected that the AI algorithm will play a role in supporting decision-making in the objective evaluation of the condition of aging pipes.