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Decomposition Analysis of Energy Use for Water Supply: From the Water-Energy Nexus Perspective (물 공급을 위한 에너지 사용 요인분해 분석: Water-Energy Nexus 관점에서)

  • Yoo, Jae-Ho;Jo, Yeon Hee;Kim, Hana;Jeon, Eui Chan
    • Journal of Korean Society on Water Environment
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    • v.38 no.5
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    • pp.240-246
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    • 2022
  • Water and energy are inextricably linked and referred to as 'Water-Energy Nexus'. Recently, this topic has been drawing a lot of attention from various studies due to the exacerbated water availability. Korea's water and energy consumption has been increasing consistently, which calls for better management. This paper aims to identify changes in electricity consumption in relation to water intake and purification processes. Using Log Mean Divisia Index (LMDI) Decomposition Analysis method, this study attributes the changes to major factors such as; Total population (population effect), household/population (structure effect), GDP/household (economic effect), and water-related energy use/GDP (unit effect). The population effect, structure effect, and economic effect contributed to an increase in water-related electricity consumption, while the unit effect contributed to a decrease. As of 2019, the economic effect increased the water supply sector's electricity consumption by 534 GWh, the population effect increased by 73 GWh, and the structure effect increased by 243 GWh. In contrast, the unit effect decreased the electricity consumption by -461 GWh. We would like to make the following suggestions based on the findings of this study; first, the unit effect must be improved by increasing the energy efficiency of water intake and purification plants and installing renewable energy power generation facilities. Second, the structure effect is expected to increase over time, and to mitigate it, water consumption must be reduced through water conservation policies and the improvement of water facilities. Finally, the findings of this study are expected to be used as foundational data for integrated water and energy management.

Estimation of the Probable Maximum Water Thermal Energy in Korean Dams based on the Water-Energy Nexus Concept (물-에너지 넥서스기반 국내 댐 가능최대 수열에너지 산정)

  • Jung, Younghun
    • Journal of The Korean Society of Agricultural Engineers
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    • v.60 no.2
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    • pp.45-53
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    • 2018
  • Demand for essential resources including water, energy and food is rapidly increasing due to climate change, population growth and urbanization. To solve this problem, the concept of water-energy-food nexus has been introduced, and many countries have been trying to acquire the Nexus technology that can maximize the efficiency by analyzing the interconnection between resources. In this regard, this study attempted to estimate the probable maximum water thermal energy in the dam based on the water-energy nexus concept. The estimation of the probable maximum water thermal energy was implemented to monthly water storage of the largest dams in the four major river systems. As a result of analyzing the estimated monthly water thermal energy from 2000 to 2016, Soyang River dam has the largest probable maximum water thermal energy, and Sumjin River dam has the smallest. However, the probable maximum water thermal energy was small in common between March and April, between September and October due to the small temperature difference between the ambient air and the dam water. Also, according to the characteristics of the dam, Daecheong dam and Soyang River dam were beneficial for supplying water thermal energy for heating, and Sumjin River dam and Andong dam were advantageous for supplying water thermal energy for cooling. Our findings can be useful to realize the water-energy-food nexus by increasing the utilization and value of water resources as well as expanding the roles and functions of dams as a starting point to use dam water thermal energy.

Evaluation of Water Temperature Difference Energy of the Raw Water from Paldang Water Intake Station (수도권 팔당취수장 원수 이용 온도차에너지 부존량 조사)

  • Cho, Yong;Park, Jin-Hoon;Kim, Youngjoon;Park, Tae Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.170.2-170.2
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    • 2010
  • The amount of the heating and cooling energy of water source heat pump using the raw water from the Paldang water intake station is investigated in the study. The Han river water is conveyed in the large-size shallowly buried pipe. Averaged water temperature at the position, 27 km from the Paldang water intake station, is increased by $1.11^{\circ}C$ due to the geothermal energy transfer under the ground, therefore the raw water has more thermal energy than the river water. To estimate of the thermal energy for the raw water, it is assumed that the water source heat pump is used for the heating and cooling ventilation. When $5.0^{\circ}C$ temperature difference energy of the raw water is used in the heat pump system all the year except for the January and February in which $3.0^{\circ}C$ temperature difference energy is used. It is predicted that total 5,766.3 Tcal could be used in the metropolitan area a year, which is about 3.0% of the river water unutilized energy resources.

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Quantifying Energy Consumption to the Level of Service Pressure in Water Distribution Network

  • Marlim, Malvin S.;Choi, Jeongwook;Kang, Doosun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.458-458
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    • 2022
  • It is essential to reduce global carbon emissions, mainly from energy use. The water supply and distribution sector is a vital part of human society and is one of the primary energy consumers. The procurement and distribution of water require electricity to operate the pump to deliver water to users with sufficient pressure. As the water users are spatially distributed over a wide area, the energy required to deliver water to each user differs depending on the corresponding supplying element (reservoir, tank, pipe, pump, and valve). This difference in energy required for each user also comes with a difference in pressure availability which affects the level of service for individual users and the whole network. Typically, there is a disproportion where users close to the source experience excessively high pressure with low energy consumption. In contrast, remote users need more energy to get the minimum pressure. This study proposes the Energy Return Index (ERI) to quantify the pressure return from particular energy consumption to supply water to each node. The disproportionality can be quantified and identified in the network using the proposed ERI. The index can be applied to optimize the network elements such as pump operation and tank location/size to reach a balanced energy consumption with the appropriate level of service.

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Molecular Simulation of Influence of Surface Energy on Water Lubrication (표면 에너지가 물 윤활 현상에 미치는 영향에 대한 분자시뮬레이션 연구)

  • Hyun-Joon Kim
    • Tribology and Lubricants
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    • v.39 no.6
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    • pp.273-277
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    • 2023
  • This paper presents a molecular dynamics simulation-based numerical investigation of the influence of surface energy on water lubrication. Models composed of a crystalline substrate, half cylindrical tip, and cluster of water molecules are prepared for a tribological-characteristic evaluation. To determine the effect of surface energy on lubrication, the surface energy between the substrate and water molecules as well as that between the tip and water molecules are controlled by changing the interatomic potential parameters. Simulations are conducted to investigate the indentation and sliding processes. Three different normal forces are applied to the system by controlling the indentation depth to examine the influence of normal force on the lubrication of the system. The simulation results reveal that the solid surface's surface energy and normal force significantly affect the behavior of the water molecules and lubrication characteristics. The lubrication characteristics of the water molecules deteriorate with the increasing magnitude of the normal force. At a low surface energy, the water molecules are readily squeezed out of the interface under a load, thus increasing the frictional force. Contrarily, a moderate surface energy prevents expulsion of the water molecules due to squeezing, resulting in a low frictional force. At a high surface energy, although squeezing of the water molecules is restricted, similar to the case of moderate surface energy, dragging occurs at the soil surface-water molecule interface, and the frictional force increases.

Simultaneous water and energy saving of wet cooling towers, modeling for a sample building

  • Ataei, Abtin;Choi, Jun-Ki;Hamidzadeh, Zeinab;Bagheri, Navid
    • Advances in environmental research
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    • v.4 no.3
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    • pp.173-181
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    • 2015
  • This article outlines a case study of water and energy savings in a typical building through a modelling process and analysis of simultaneous water-energy saving measures. Wet cooling towers are one of the most important equipments in buildings with a considerable amount of water and energy consumption. A variety of methods are provided to reduce water and energy consumption in these facilities. In this paper, thorough the modeling of a typical building, water and energy consumption are measured. Then, After application of modern methods known to be effective in saving water and energy, including the ozone treatment for cooling towers and shade installation for windows, i.e. fins and overhangs, the amount of water and energy saving are compared with the base case using the Simergy model. The annual water consumption of the building, by more than 50% reduction, has been reached to 500 cubic meters from 1024 cubic meters. The annual electric energy consumption has been decreased from 405,178 kWh to 340,944 kWh, which is about 16%. After modeling, monthly peak of electrical energy consumption of 49,428 has dropped to 40,562 kWh. The reduction of 18% in the monthly peak can largely reduce the expenses of electricity consumption at peak.

A Study on the Improvement of the Water Source Energy Distribution Regulation for High Efficient Data Center Cooling System in Korea (데이터센터 냉방시스템 고효율화를 위한 국내 수열에너지 보급 제도 개선에 관한 연구)

  • Cho, Yong;Choi, Jong Min
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.17 no.3
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    • pp.21-29
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    • 2021
  • In this study, the current regulation of the water source energy, one of the renewable energy, was analyzed, and the improvement plan for the high efficient data center cooling system was suggested. In the improvement plan, the design and construction guidelines of the water source energy system permit to adopt the cooling and heating system with or without heat pump. In addition, it should also include the system operated in the cooling mode only all year-round. The domestic test standards to consider the water source operating conditions should be developed. Especially, it is highly recommended that the test standards to include the system with forced cooling and free cooling modes related with the enhanced data center cooling system adopting the water source energy.

Global technologies for the removal of water scaling & water recovery - Department of Energy (DOE) USA

  • Ramakrishna, Chilakala;Thriveni, Thenepalli;Whan, Ahn Ji
    • Journal of Energy Engineering
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    • v.27 no.1
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    • pp.21-32
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    • 2018
  • In this paper, we reported the current technologies of water scaling removal and also water recovery from the flue gases, which are funded by Department of Energy (DOE), USA. Globally, water resources are limited due to the climate change. The potential impacts of climate change is food and water shortages. In the $21^{st}$ century, water shortages and pollution are expected to become more acute as populations grow and concentrate in cities. At present, the water stress increases over 62.0 ~ 75.8% of total water basin area and decreases over 19.7 ~ 29.0%. Many renewable energy sources demand secure water resources. Water is critical for successful climate change mitigation, as many efforts to reduce greenhouse gas emissions depend on reliable access to water resources. Water hardness is one of the major challenge to coal power plants. Department of energy (DOE) funded and encouraged for the development of advanced technologies for the removal of hardness of water (scaling) and also water recovery from the flue gases from coal power plants.

Study on Utilizing Resources in Ecopolis - Evaluation of Energy floors of Sewage for Enhanced energy system of residence - (생태도시에서의 자원활용에 관한 연구 - 주택 에너지 시스템 개선을 위한 하수 에너지흐름 분석 -)

  • 정용현
    • Journal of Environmental Science International
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    • v.12 no.9
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    • pp.911-919
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    • 2003
  • When the city water was heated for the optimum use of unused energy, the energy flows and losses were calculated and evaluated to improve the value of heated water systems at dwelling side. To obtain this purpose, it was simulated on heat flows under two conditions like with heat pumps or not and calculated the energy sayings. Furthermore, recycling water system was suggested for enhancing the value of heated water system. From this results, the energy flows without heat pumps showed that it was 3-4 percents of heat losses from pipes, 62 percents of energy savings from hot water uses and 34 percents of unutilized heat. When the heated water system adopt the recycling water system at dwelling side, it was improved 12 percents of total energy sayings.

The Effects of Hot Water Supply on Energy Consumption for Floor Radiant Heating System (바닥복사 난방시스템의 공급온수특성에 따른 에너지 소비특성 연구)

  • Song, Jae-Yeob;Ahn, Byung-Cheon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.15 no.4
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    • pp.32-38
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    • 2019
  • In this study, the effect of hot water supply flow rates on energy consumption for radiant floor heating system in apartment were researched by computer simulation. The parametric study of different hot water supply flow rates was done with regard to energy performance and control characteristics, respectively. Also the effect of different hot water supply flow rates on the hot water supply temperatures is studied. As a result, energy consumption were reduced but the response time is increased by reducing the supply flow rate. And energy consumption can be saved by adjusting the hot water supply temperatures with different supply flow rates.