• Title/Summary/Keyword: Vertical-type Geothermal Heat Exchanger

Search Result 22, Processing Time 0.033 seconds

Development of High Peformance Geothermal heatexchanger (고성능저가형 지중열교환기 개발연구)

  • An, Hyung-Jun;Baek, Sung-Kwon;Im, Sung-Kyun
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2007.06a
    • /
    • pp.470-473
    • /
    • 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.

  • PDF

Experimental Study on Heat Exchange Efficiency of Combined Well & Open-Closed Loops Geothermal System (지하수정호와 결합한 복합지열시스템의 열교환 효율에 대한 실험적 연구)

  • Song, Jae-Yong;Lee, Geun-Chun;Park, Namseo
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.34 no.5
    • /
    • pp.43-50
    • /
    • 2018
  • The temperature of underground water generally remains constant regardless of the season. therefore, it is possible to get plenty of energy if we use characteristics of underground water for both cooling and heating. This study evaluates efficiency of real size coaxial and U-tube type complex geothermal system which is combined with underground water well. This study also evaluates relative efficiency/adaptability through comparison with existing geothermal systems(vertical closed loop system, open loop system(SCW)). The heat exchange capacity of complex geothermal system according to temperature difference between circulating water and underground water shows very high significance by increasing proportionally. The temperature change of underground water according to injection energy, shows very high linear growth aspect as injection thermal volume heightens. As a result of evaluation of heat exchange volume between complex geothermal system and comparative geothermal system, coaxial type has 26.1 times greater efficiency than comparative vertical closed type and 2.8 times greater efficiency than SCW type. U-tube type has 26.5 tims greater efficiency than comparative vertical closed type and 2.8 times greater than SCW type as well. This means complex geothermal system has extremely outstanding performance.

Evaluation of the Annual Performance of the Direct Expansion Vertical Closed-Loop Ground Source Heat Pump (직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가)

  • Kim, Min-Sung;Woo, Joung-Son;Baik, Young-Jin;Jang, Jea-Chul;Kim, Ji-Young;Ra, Ho-Sang
    • 한국태양에너지학회:학술대회논문집
    • /
    • 2012.03a
    • /
    • pp.534-542
    • /
    • 2012
  • Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

  • PDF

Annual Performance Evaluation of Direct Expansion Vertical Closed-Loop Ground Source Heat Pump for Residential Application (주거용 직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가)

  • Kim, Min-Sung;Baik, Young-Jin;Ra, Ho-Sang
    • Journal of the Korean Solar Energy Society
    • /
    • v.32 no.3
    • /
    • pp.114-122
    • /
    • 2012
  • Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed -loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.

Numerical Simulations for Optimal Utilization of Geothermal Energy under Groundwater-bearing Conditions (지하수 부존지역에서 최적 지열에너지 활용방식 수치 모의)

  • Kim, Jin-Sung;Cha, Jang-Hwan;Song, Sung-Ho;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
    • /
    • v.24 no.4
    • /
    • pp.487-499
    • /
    • 2014
  • While the vertical open type of heat exchanger is more effective in areas of abundant groundwater, and is becoming more widely used, the heat exchanger most commonly used in geothermal heating and cooling systems in Korea is the vertical closed loop type. In this study, we performed numerical simulations of the optimal utilization of geothermal energy based on the hydrogeological and thermal properties to evaluate the efficiency of the vertical open type in areas of abundant groundwater supply. The first simulation indicated that the vertical open type using groundwater directly is more efficient than the vertical closed loop type in areas of abundant groundwater. Furthermore, a doublet system with separated injection and extraction wells was more efficient because the temperature difference (${\Delta}$) between the injection and extraction water generated by heat exchange with the ground is large. In the second simulation, we performed additional numerical simulations of the optimal utilization of geothermal energy that incorporated heat transfer, distance, flow rate, and groundwater hydraulic gradient targeting a single well, SCW (standing column well), and doublet. We present a flow diagram that can be used to select the optimal type of heat exchanger based on these simulation results. The results of this study indicate that it is necessary to examine the adequacy of the geothermal energy utilization system based on the hydrogeological and thermal properties of the area concerned, and also on a review of the COP (coefficient of performance) of the geothermal heating and cooling system.

The Comparison of the EWT&LWT between Field Measurement and CFD of Vertical-type Geothermal Heat Exchanger (수직형 지열교환기의 입.출구온도에 대한 실측과 CFD 결과 비교)

  • Woo, Sang-Woo;Kim, Joong-Hun;Shin, Seung-Ho;Hwang, Kwang-Il
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.3 no.1
    • /
    • pp.11-16
    • /
    • 2007
  • The purpose of this study is to use the CFD(Computational Fluid Dynamics) method for the ground source heat pump(GSHP) system with vertical U-tube ground heat exchangers. In order to predict LWT(leaving water temperature) in the length of time, This simulation is used by utilizing FLUENT which is commercial CFD code. It was performed by based on four boreholes in the field. Comparing with the results of CFD and field measurement for LWT, the results of CFD was presented very good agreement with 1.0% average difference.

  • PDF

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
    • /
    • 2009.06a
    • /
    • pp.604-607
    • /
    • 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.

  • PDF

Heating and Cooling Effect of Portected Horticulture by Geothermal Heat Pump System with Horizontal Heat Exchanger (수평형 지열히트펌프 시스템의 시설원예 냉난방 실증 효과)

  • Ryou, Young-Sun;Kang, Youn-Ku;Kim, Young-Jung;Kang, Keun-Chun
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2008.05a
    • /
    • pp.630-633
    • /
    • 2008
  • Geothermal heat pump systems use the earth as a heat source in heating mode and a heat sink in cooling mode. These systems can be used for heating or cooling systems in farm facilities such as greenhouses for protected horticulture, cattle sheds, mushroom house and etc. A horizontal type means that a geothermal heat exchanger is laid in the trench buried in 1.2 to 1.8 m depth. Because a horizontal type has advantages of low installation, operation and maintenance costs compared to a vertical type, it is easy to be adopted to agriculture. In this study, to heat and cool farm facilities and obtain basic data for practical application of horizontal geothermal heat pump system in agriculture, a horizontal geothermal heat pump system of 10 RT was installed in greenhouse. Heating and cooling performance of this system was estimated. The horizontal geothermal heat pump used in this study had heating COP of 4.57 at soil temperature of $14^{\circ}C$ with depth of 1.75m and heating COP of 3.75 at soil temperature of $7^{\circ}C$ with the same depth. The cooling COP was 2.7 at ground temperature at 1.75m depth of $25.5^{\circ}C$ and 2.0 at the temperature of $33.5^{\circ}C$.

  • PDF

The Comparison of the In-Situ Thermal Response Tests and CFD Analysis of Vertical-type Geothermal Heat Exchanger (수직형 지중 열교환기의 현장 열응답 시험과 CFD 해석 비교)

  • Sim, Yong-Sub;Lee, Hee-Sang
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.7
    • /
    • pp.3164-3169
    • /
    • 2013
  • In this study, a series of CFD analysis was performed in order to predict the leaving water temperature and the slope of in-situ thermal response tests of the vertical-type geothermal heat exchangers. The geothermal heat exchanger and surrounding ground formation were modeled using GAMBIT and simulation was used by utilizing FLUENT which is commercial CFD code. Comparing with the results of CFD and in-situ thermal response tests, the results of CFD was presented good agreement with $0.5^{\circ}C$ difference of Leaving Water Temperature and with 1.6% difference of the Slope.

Regional Distribution of Ground Thermal Conductivity for Vertical Closed Type Ground Heat Exchanger Design (수직 밀폐형 지중열교환기 설계를 위한 지중 열전도도의 지역별 분포)

  • Jung, Kye-Hoon;Sohn, Byong-Hu;Lim, Hyo-Jae
    • Proceedings of the SAREK Conference
    • /
    • 2007.11a
    • /
    • pp.423-428
    • /
    • 2007
  • This study was performed to construct a geothermal data base about thermal conductivity of ground heat exchanger and thermal properties of grouting material which used to refill the borehole. We have acquired geothermal data sets from 39 sites over wide area of South Korea except to Jeju island. From data analysis, the range of thermal conductivity is 1.5$\sim$4.0 W/mK. It means that thermal conductivity varies with grouting material as well as regional geology and ground water system.

  • PDF