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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Cooling Performance Analysis of Ground-Source Heat Pump (GSHP) System with Hybrid Ground Heat Exchanger (HGHE)

하이브리드 지중열교환기 적용 히트펌프 시스템의 냉방 성능 분석

  • 손병후 (한국건설기술연구원 녹색건축연구센터)
  • Received : 2018.10.31
  • Accepted : 2018.11.28
  • Published : 2018.12.01
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Abstract

This paper presents the cooling performance analysis results of a ground-source heat pump (GSHP) system using hybrid ground heat exchanger (HGHE). In this paper, the HGHE refers to the ground heat exchanger (GHE) using both a vertical GHE and a surface water heat exchanger (SWHE). In order to evaluate the system performance, we installed monitoring sensors for measuring temperatures and power consumption, and then measured operation data with 4 different load burdened ratios of the hybrid GHE, Mode 1~Mode 4. The measurement results show that the system with HGHE mainly operates in Mode 1 and Mode 2 over the entire measurement period. The average cooling coefficient of performance (COP) for heat pump unit was 5.18, while the system was 2.79. In steady state, the heat pump COP was slightly decreased with an increase of entering source temperature. In addition, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further research are needed to optimize the design data for various load ratios of the HGHE.

Keywords

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Fig. 1. Main components of experimental heat pump system with hybrid ground heat exchanger.

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Fig. 2. Schematic diagram of experimental heat pump system with hybrid ground heat exchanger.

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Fig. 3. Hourly average temperature variations on source and load sides.

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Fig. 4. Water temperature variation on source and load sides for a typical cooling week.

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Fig. 5. Cooling capacity, heat release of HGHE, and power consumption: August 5, 2017.

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Fig. 6. Patterns on water temperature variations for source and load sides.

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Fig. 7. Patterns on heat release of HGHE and power consumption of system.

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Fig. 8. Cooling COP of heat pump and system: August 5, 2017.

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Fig. 9. Patterns on cooling COP of heat pump and system.

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Fig. 10. Capacity, power consumption, and COP of system with EST: Jul. 31∼Aug. 6, 2017.

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Fig. 11. COP with outdoor air temperature: Jul. 31~Aug. 6, 2017.

Table 1. Parameters and uncertainties

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Table 2. Capacity ratios of SWHE and VGHE in hybrid ground heat exchanger

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