• Title, Summary, Keyword: Variable Water Volume

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A Calculation Method for Temperature Distribution of Hot Water Pipe under Unsteady Condition (비정상조건하의 온수배관의 온도분포에 관한 수치계산법 연구)

  • Choi, C.H.;Suh, S.J.
    • Solar Energy
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    • v.19 no.3
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    • pp.13-21
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    • 1999
  • Calculation method about the water temperature variable inside hot water pipe had proposed in the past does not correspond with branch pipe system, variable of water volume, variable of entrance water temperature, using and so on. A calculation method proposed in this paper can solve above problems, and calculate the kinds variation of the water temperature inside pipe in the real use state of the hot water pipe.

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A Study of applying VAV and VWV System to reduce Energy Consumption of Office building (VAV 및 VWV시스템 적용에 따른 업무용 건축물의 에너지저감에 관한 연구)

  • Song, Ji-Yong;Hong, Won-Hwa;Kim, Ji-Yeon;Park, Hyo-Soon
    • KIEAE Journal
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    • v.13 no.1
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    • pp.57-63
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    • 2013
  • Building Energy Efficiency Rating system was enforced in 2001 to enhance spreading high-energy performance and saving buildings. It was only for the new apartments, but expanded to new office buildings in 2010, and moreover, government offices require 1st grade of Building Energy Efficiency Rating system. Green Building Act, which is established to reduce the emissivity of carbon dioxide by reducing building energy consumption, will be enforced in 2013, and new apartments and office buildings will be subjected to it. Henceforward, it will extend to other types of buildings and will be phased in. In general, pumps and fans consume approximately half of the air-conditioning energy consumption, and about a quarter of the total building energy consumption when office buildings have total floor area of more than 10000 square meters. This study analyzed the energy demand when applying VAV(Variable Air Volume) and VWV(Variable Water Volume) System to reduce energy returns of the pumps and the fans by ECO2, which is a computer simulation program used for Building Energy Efficiency Rating system.

A Evaluation of Calculation Method for Temperature Distribution of Hot Water Pipe with Changing Flow Rate (유량변화를 고려한 온수배관의 온도분포 계산법평가에 관한 연구)

  • Suh, S.J.;Choi, C.H.
    • Solar Energy
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    • v.19 no.3
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    • pp.53-61
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    • 1999
  • We already presented new calculation method about the temperature distribution in hot water pipe flow of the unsteady condition. In this paper, we introduce consequence of the case study to confirm appropriation of the calculation method, and case study performs to establish actual hot water use supposed two model that is; the CWV(constant water volume) and VWV(variable water volume).

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Energy Auditing Using a Building Energy Simulation Program BLDSYM

  • Lee, E.J.;Yoon, J.H.;Kang, Y.H.;Jeon, H.S.
    • Solar Energy
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    • v.15 no.3
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    • pp.53-58
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    • 1995
  • The objectives of this study are to introduce the energy simulation program BLDSYM, to verify the approach, and to demonstrate the energy saving opportunities. A case study model for Hoover Middle School, OK, USA has been introduced as a base case simulation. Air-side variable air volume(VAV) and water-side variable flow hydronic(VFH) system have been recommended, modeled and simulated to quantify the energy savings compared with the base system, which is typically constant air and water flow system. More than 30% of energy savings could be obtained with the optimum variable flow system.

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Hydraulic Model Experiment on Circulation in Sagami Bay, Japan (IV) -Time-Varying States of Flow Pattern and Water Exchange in Baroclinic Rotating Model-

  • Choo, Hyo-Sang;Takasige Sugimoto
    • Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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    • v.3 no.1
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    • pp.57-73
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    • 1999
  • Baroclinic hydraulic model experiments on the time-varying states of the flow pattern and water exchange in Sagami Bay were carried out based on quasi-steady state experiments on the flow pattern. For the model experiments, density changes as well as time changes in the volume transport of the upper layer were executed to investigate the flow response of the bay in the case of a sudden inflow of low density water and variable volume transport into the Sagami Bay. The results of the model experiments showed that when the volume transport was increased frontal eddies or frontal wave streamers from the Kuroshio Through Flow were transferred to the inner part of the bay along with cyclonic circulation in the bay. In addition, density boundary currents appeared and flowed along the eastern boundary of the bay. As the upper layer density decreased, frontal eddies, frontal streamers and coastal boundary density currents occurred and proceeded along the eastern boundary of the bay at a high speed.

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Characteristics of water relations paramenters obtained from pressure-volume curves in pinus koraiensis needles (P-V 曲線法에 의한 잣나무葉에 水分 特性에 關한 硏究)

  • Han, Sang-Sup
    • The Korean Journal of Ecology
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    • v.15 no.1
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    • pp.47-58
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    • 1992
  • This study is to investigate the change of the seasonal patterns of relative water relations parameters by the pressure-volume curves in pinus koraiensis needles. The osmotic potentials at full water saturated(Ψ0, sat) and at incipient plasmolysis(Ψ0, tlp) increased in growing season, while decreased in non-growing season. The maximum bulk modulus of elasticity(Emax), relative water content(RWCTLP), and relativefree water content(FWCtlp) at incipient plasmolysis in non-growing season were higher than these of growing season. The maximum pressure potential(Ψp, max) varied from 1.16 to 2.18MPa, torgor index(TI) varied from 3.1 to 4.7. The osmole number(Ns/dw) and symplastic water (Vo/DW) were variable seasonally. The maximum water content(Vt/DW) and apoplastic water(AW) were relatively high in early growing stage, and then decreased to needle aging. The pressure potential(Ψp) and water potential(Ψ) in winter needles were rapidly decreased with decreasing of relative water content. The matric potential occupied over 10 percent of water potential with less than-2.0 MPa.

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A Study on the Variation of Physical Properties by the Water to Cement Ratio and the Mixing Speed for Grout Materials (그라우트재의 물시멘트비 및 혼합속도에 의한 물성변화에 관한 연구)

  • 천병식;김진춘;장의웅;송성호;이준우
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.445-452
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    • 2001
  • Generally, OPC(ordinary portland cement) is used for grouting in Korea, and bentonite has usually been added to prevent the deposition of cement particles. The dispersion of CB(cement bentonite) grout is influenced by variable factors i.e. water to cement ratio, particle size of cement, kind of bentonite, adding volume, methods of adding, viscosity of CB grout materials and curdling time. Among variable factors, the viscosity of CB grout materials is influenced by the dispersion, and dispersion is improved as increasing the mixing speed. In this paper, described a suitable mixing speed of the High Speed Mixer in field, engineering characteristics of CB grout materials vary with the water to cement ratio and the mixing speed as well as confirming the state of dispersion.

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A Study on the Measurement Uncertainty of Pipe Prover (파이프 프루버의 측정불확도에 관한 연구)

  • Lim, Ki-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.10
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    • pp.1388-1398
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    • 2000
  • A pipe prover is a flowmeter calibrator used in flow measurement field. Gravimetric and volumetric methods were applied to determine the basic volume of the pipe prover. Uncertainty of its basic volume measurement was evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainty of determining the basic volume was estimated from the sensitivity coefficient and the standard uncertainty of independent variables. It was found that the uncertainties of the weighing and volume measurements have dominant influence on that of the basic volume determination. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of the basic volume is shown clearly.

Assessment and Analysis of Coal Seam Gas Water Management Study for Water Resource Production -1. Water Production (물 자원 생산을 위한 Coal Seam Gas Water Management Study의 평가 및 분석 -1. 용수 생산)

  • Shin, Choon-Hwan
    • Journal of Environmental Science International
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    • v.23 no.8
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    • pp.1395-1407
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    • 2014
  • Coal seam gas (CSG) production involves extracting methane from coal seams with ground water which is so called a primary by-product of this process, and is often rich in salts and other constituents. The predicted large volume and variable quality of this water make water management a topic associated with CSG production. In the past, the amount of this water used to be pumped into the vacant aquifer, or into the river during the life of individual production wells. Australian government make a strategies for management and beneficial use of the water. From this point of view, a detailed assessment has not been undertaken, it is necessary for water resource production to analysis the "Coal Seam Gas Water (CSG Water) Management Policy Study" published in Queensland, Australia.

LONG-TERM RESERVOIR SEDIMENT MANAGEMENT CONSIDERING OTHER OPERATIONAL OBJECTIVES

  • Ko, Seok-Ku;Kim, Woo-Gu;Lee, Gwang-Man
    • Water for future
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    • v.35 no.5
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    • pp.43-50
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    • 2002
  • The Yellow River Basin located in the Northern part of China is well-known not only as the seriously limited water sources but the greatest sediment-carrying stream in the world. The observed annual average sediment concentration in this area is $37.6kg/\textrm{mm}^3$, and 3.1% of the water volume is occupied by sediments. Due to the reason, water development has been extremely limited and it has been appeared as one of the most difficult problems in reservoir development and management. The major obstacle to surface water uses is reservoir sedimentation so that it has been strongly requested to seek the method managing sediment by optimal fashion. To solve this problem, KOWACO (Korea Water Resources Corporation) has developed various methods on the optimal reservoir management schemes including sediment management for the Upper Fenhe Basin Reservoir System at the cooperation project with Chinese. Information Variable Dynamic Programming. which is one of them, was developed for the reservoir sediment management and a set of non-dominated solutions are generated to choose the best alternative in water supply and reservoir sediment objective problem.

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