Journal of the Korean Society for Geothermal and Hydrothermal Energy (한국지열·수열에너지학회논문집)

Korean Society for Geothermal and Hydrothermal Energy (한국지열·수열에너지학회)
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Study on the Optimum Design of Ground Source Heat Pumps

지열원 히트펌프 시스템의 최적 설계 기법 연구

  • Choi, Jong Min (Department of Mechanical Engineering, Hanbant National University)
  • Received : 2018.10.15
  • Accepted : 2018.11.28
  • Published : 2018.12.01
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Abstract

Among the various ground source heat pump systems, vertical-type heat pump systems have been distributed greatly. Most of the vertical-type ground source heat pump systems have been designed based on the Korean Ministry of Knowledge Economy Announcement in Korea. In this study, the design process of the vertical-type ground source heat pump system in the announcement was analyzed, and the effects of the design parameters on the ground loop heat exchanger were investigated. Borehole thermal conductivity was the highest dominant design parameter for ground loop heat exchangers. The borehole thermal conductivity was changed according to the pipe and grout thermal conductivity. For optimal design of the ground heat pump system, it is highly recommended that the design process in the announcement will be revised to adopt the various tubes and grout which have higher thermal conductivity. In addition, the certification standard for heat pump unit should be revised to develop the heat pump with a small flow rate.

Keywords

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Fig. 1. Design process of the vertical-type ground loop heat exchanger.

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Fig. 2. Variation rate of GLHX length as a function of distance between boreholes.

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Fig. 3. Variation rate of GLHX length as a function of radial pipe placement.

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Fig. 4. Variation rate of GLHX length as a function of thermal conductivity.

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Fig. 5. Variation rate of GLHX length as a function off low rate.

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Fig. 6. Structure of a vertical-type GLHX.

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Fig. 7. Temperature variation in TRT test.

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Fig. 8. Thermal conductivity as a function of HDPE pipe conductivity.

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Fig. 9. Thermal conductivity as a function of grout conductivity.

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Fig. 10. Thermal conductivity as a function of ground conductivity.

Table 1. Design parameters

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Table 2. Variation rate of GLHX length according to parameter's property

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