• Title/Summary/Keyword: 지중열교환기

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Thermal Property Measurement of Bentonite-Based Grouts and Their Effects on Design Length of Vertical Ground Heat Exchanger (벤토나이트 그라우트의 열물성 측정 및 열물성이 수직 지중열교환기 설계 길이에 미치는 영향)

  • Sohn, Byonghu
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.15 no.2
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    • pp.1-9
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    • 2019
  • In a ground-source heat pump (GSHP) system, a vertical ground heat exchanger (GHE) is widely accepted due to a higher thermal performance. In the vertical GHE, grout (also called grouting material) plays an important role in the heat transfer performance and the initial installation cost of the GHE. Bentonite-based grout has been used in practice because of its high swelling potential and low hydraulic conductivity. This study evaluated the thermo-physical properties of the bentonite-based grouts through lab-scale measurements. In addition, we conducted performance simulation to analyze the effect of mixed ratio of grouts on the design length and thermal performance of the vertical GHE. The simulation results show that thermally-enhanced grouts improve the heat transfer performance of the vertical GHE and thus reduce the design length of GHE pipe.

연구원_2015 연구과제 ⑤ - 대용량 지열설비 이용을 위한 개방형 지중열교환기 용량 설계 Tool 개발

  • Ryu, Hyeong-Gyu;Yun, Hui-Won;Choe, Seung-Hyeok
    • 월간 기계설비
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    • pp.48-50
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    • 2016
  • 대한기계설비산업연구원(원장 이언구)은 지난해 4월 연구심의위원회에서 선정된 ${\triangle}$기계설비건설업 동향분석을 위한 기초연구 ${\triangle}$기계설비건설업체의 부도예측 모형 연구 ${\triangle}$기계설비건설공사 시공상세도면 작성비 산정기준 연구 ${\triangle}$플랜트 건설현장 외국인력 고용 개선방안 ${\triangle}$녹색기술 기준에 근거한 연구과제 도출을 위한 기초연구 ${\triangle}$대용량 지열설비 이용을 위한 지중열교환기 용량 설계 툴 개발 ${\triangle}$기계설비배관 및 장비 단열 기준 연구 등의 기본과제와 외부기관과 공동으로 수행한 ${\triangle}$플랜트 건설현장 외국인력 고용 개선방안 ${\triangle}$기계설비건설업 관련법규 개선방안 연구를 추진했다. 본지는 지난 2월호부터 연구결과 요약 보고서를 연재하고 있다.

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Application textile-type geothermal heat exchanger for tunnel (텍스타일형 지중열교환기의 터널에서의 적용)

  • Lee, Chul-Ho;Lee, Kang-Ja;Gil, Hu-Jeong;Jeoung, Jae-Hyeung;Choi, Hang-Seok
    • 한국신재생에너지학회:학술대회논문집
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    • pp.604-607
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    • 2009
  • The geothermal energy have been developed as the pro-environmental and the substantial long-term energy. Recently energy foundations and other thermo-active ground structures have been developed to enhance the use of geothermal energy. In this research, a tunnel wall is focused as a source of geothermal energy. If the tunnel wall can be used for geothermal source, it can provide relatively lower cost because it is not necessary to make a deep borehole like in case of closed-loop vertical ground heat exchanger. For analyzing efficiency of heat exchanger in tunnel, laboratory tests and the numerical analyses are performed.

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Development of High Peformance Geothermal heatexchanger (고성능저가형 지중열교환기 개발연구)

  • An, Hyung-Jun;Baek, Sung-Kwon;Im, Sung-Kyun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.470-473
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    • 2007
  • Geothermal heat exchanger(GHEX) is a major component of Geothermal heat pump system(GSHPs). In Common, We use the vertical type GHEX in Korea. But vertical type GHEX needs a high cost for installation, because of drilling the hole which has 200m depth at max. So, We suggest the use of horizontal type GHEX. When we construct buildins, We excavate the ground and we can install the horizontal type GHEX at the excavated underground. It's very cheap and convenient method compare to vertical type GHEX installation. This study is peformed to estimate the peformance of horizontal type GHEX and to analyze effects of heat exchanger types and undergroundwater. As the result, slinky type GHEX has a 66% efficiency compare to vertical type GHEX and mat type has a 201% efficiency at the undergroundwater zone.

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A study on the Heat Transfer Performance according to Ground Heat Exchanger Types (지중열교환기의 종류에 따른 열전달 성능에 관한 연구)

  • Hwang, SuckHo;Song, Doosam
    • KIEAE Journal
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    • v.10 no.4
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    • pp.75-80
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    • 2010
  • Generally, ground-source heat pump (GSHP) systems have a higher performance than conventional air-source systems. However, the major fault of GSHP systems is their expensive boring costs. Therefore, it is important issue that to reduce initial cost and ensure stability of system through accurate prediction of the heat extraction and injection rates of the ground heat exchanger. Conventional analysis methods employed by line source theory are used to predict heat transfer rate between ground heat exchanger and soil. Shape of ground heat exchanger was simplified by equivalent diameter model, but these methods do not accurately reflect the heat transfer characteristics according to the heat exchanger geometry. In this study, a numerical model that combines a user subroutine module that calculates circulation water conditions in the ground heat exchanger and FEFLOW program which can simulate heat/moisture transfer in the soil, is developed. Heat transfer performance was evaluated for 3 different types ground heat exchanger(U-tube, Double U-tube, Coaxial).

Development of low-cost, low-depth unit-type ground heat exchanger (저심도 저비용 유닛형 지중열교환기의 개발)

  • Oh, Jin-Hwan;Nam, Yujin;Chae, Ho-Byung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.166-167
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    • 2014
  • Recently, in according to increase cognizance of energy and resources exhaustion, renewable energy system is received attention. In particular, ground heat pump system(GSHP) utilizing annually stable ground temperature for energy saving have been attracted in many buildings. However, GSHP system have disadvantage due to increase of initial installation and boring cost. In this study, in order to reduce the initial cost and to supply ground heat pump system into small scale house, an unit-type ground heat exchanger was developed.

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An Experimental Study on the Performance of Semi-Closed Loop Ground Heat Exchanger (반밀폐형 지중열교환기 성능에 관한 실험적 연구)

  • Kim, Ook-Joong;Yeom, Han-Kil;Lee, Chun-Woo
    • 한국신재생에너지학회:학술대회논문집
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    • pp.542-545
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    • 2007
  • A semi-closed loop ground heat exchanger is proposed and its performance is compared through the measuring the effective thermal conductivity of the ground. In-situ tests based on the line source model are carried out to evaluate the thermal characteristics of each ground heat exchanger which has different penetration water flow rate. The test results show the increasing effective thermal conductivity of ground as the penetration water flow rate(PWFR) is increased. Therefore, the higher thermal performance of the proposed semi-closed ground heat exchanger can be expected.

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Thermal Conductivity Measurement of Sand-Water Mixtures Used for Backfilling Materials of Vertical Boreholes or Horizontal Trenches (지중열교환기 수직 보어홀 및 수평 트렌치 뒤채움재로서 모래-물 혼합물의 열전도도 측정)

  • Sohn, Byong-Hu
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.5
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    • pp.342-350
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    • 2008
  • This paper presents the results of a laboratory study on the thermal conductivity of sand (silica, quartzite, limestone and masonry sand)-water mixtures used in ground heat exchanger backfilling materials. Nearly 150 tests were performed in a thermal conductivity measuring system (TPSYS02) to characterize the relationships between the thermal conductivity of mixtures and the water content. The results show that the thermal conductivity of mixtures increases with increasing dry density and with increasing water content. The results also show that for constant water contents and a dry density value, the thermal conductivity of mixtures increases with increasing thermal conductivity of solid particles. The measurement results were also compared with the most widely used empirical prediction models for the thermal conductivity of soils.