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KONG Gangqiang, CHEN Yu, YANG Qing. System monitoring and evaluation and thermo-mechanical characteristics of energy piles during winter operation[J]. Chinese Journal of Geotechnical Engineering, 2024, 46(6): 1309-1317. DOI: 10.11779/CJGE20230203
Citation: KONG Gangqiang, CHEN Yu, YANG Qing. System monitoring and evaluation and thermo-mechanical characteristics of energy piles during winter operation[J]. Chinese Journal of Geotechnical Engineering, 2024, 46(6): 1309-1317. DOI: 10.11779/CJGE20230203

System monitoring and evaluation and thermo-mechanical characteristics of energy piles during winter operation

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  • Received Date: March 07, 2023
  • Available Online: June 04, 2024
  • To address the winter heating demand of a 25 m2-area building room in Yichang, Hubei Province, a ground source heat pump system coupled with energy piles (referred to as "energy pile system") is constructed, which includeds energy piles, a water collector and distributor, heat pump units and a circulating water pump. Under the actual continuous or intermittent operation of the energy pile system, the thermo-mechanical characteristics of energy piles and system performance are studied. The tests on the conventional borehole buried pipe-based ground source heat pump system and the air source heat pump system are conducted for comparison and analysis as well. The study focuses on the similarities and differences of thermo-mechanical characteristics of energy piles under actual operation and the traditional TRT or TPT test conditions, and the heating performances and COP of the energy pile system are monitored. Under the test conditions in this study, corresponding to the continuous tests, the maximum temperature reduction value of 3.78℃ and the maximum thermally induced stress of 0.70 MPa (about 57.5% of the upper limit of the fully confining stress) occur at the pile top. The maximum observed strain differences between the operating piles and the non-operating piles corresponding to the cap structures at the upper and lower layer are 19.98με and 17.78με, respectively. The measured COP of the energy pile system is about 3.03, which is about 12.2%~21.2% higher than that of the related air source heat pump system (the normative reference COP is 2.50~2.70). The energy pile system has a faster start-up speed than the conventional air source heat pump, which reaches the preset temperature about 2.5 h earlier.
  • [1]
    刘汉龙, 孔纲强, 吴宏伟. 能量桩工程应用研究进展及PCC能量桩技术开发[J]. 岩土工程学报, 2014, 36(1): 176-181. doi: 10.11779/CJGE201401018

    LIU Hanlong, KONG Gangqiang, NG W W C. Applications of energy piles and technical development of PCC energy piles[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(1): 176-181. (in Chinese) doi: 10.11779/CJGE201401018
    [2]
    HAMADA Y, SAITOH H, NAKAMURA M, et al. Field performance of an energy pile system for space heating[J]. Energy and Buildings, 2007, 39(5): 517-524. doi: 10.1016/j.enbuild.2006.09.006
    [3]
    FANG J, KONG G, MENG Y, et al. Thermomechanical behavior of energy piles and interactions within energy pile-raft foundations[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2020, 146(9): 4020079. doi: 10.1061/(ASCE)GT.1943-5606.0002333
    [4]
    桂树强, 程晓辉. 能源桩换热过程中结构响应原位试验研究[J]. 岩土工程学报, 2014, 36(6): 1087-1094. doi: 10.11779/CJGE201406014

    GUI Shuqaing, CHENG Xiaohui. In-situ tests on structural responses of energy piles during heat exchanging process[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(6): 1087-1094. (in Chinese) doi: 10.11779/CJGE201406014
    [5]
    WOOD C J, LIU H, RIFFAT S B. An investigation of the heat pump performance and ground temperature of a piled foundation heat exchanger system for a residential building[J]. Energy, 2010, 35(12): 4932-4940. doi: 10.1016/j.energy.2010.08.032
    [6]
    MOON C E, CHOI J M. Heating performance characteristics of the ground source heat pump system with energy-piles and energy-slabs[J]. Energy, 2015, 81(10): 27-32.
    [7]
    CAPOZZA A, ZARRELLA A, DE CARLI M. Long-term analysis of two GSHP systems using validated numerical models and proposals to optimize the operating parameters[J]. Energy and Buildings, 2015, 93(2): 50-64.
    [8]
    REN L W, XU J, KONG G Q, et al. Field tests on thermal response characteristics of micro-steel-pipe pile under multiple temperature cycles[J]. Renewable Energy, 2020, 147(9): 1098-1106.
    [9]
    LI R R, KONG G Q, CHEN Y H, et al. Thermomechanical behaviour of an energy pile-raft foundation under intermittent cooling operation[J]. Geomechanics for Energy and the Environment, 2021, 28(2): 100240.
    [10]
    CHEN Y, KONG G Q, MENG Y D, et al. Thermal mechanical behavior of energy piles with cap under embedded depth[J]. Geomechanics for Energy and the Environment, 2023, 33(1): 100425.
    [11]
    BAE S M, NAM Y. Economic and environmental analysis of ground source heat pump system according to operation methods[J]. Geothermics, 2022, 101(2): 102373.
    [12]
    MCCARTNEY J, MURPHY K D. Strain distributions in full-scale energy foundations[J]. DFI Journal-The Journal of the Deep Foundations Institute, 2012, 6(2): 26-38.
    [13]
    YOU S, CHENG X H, GUO H X, et al. Experimental study on structural response of CFG energy piles[J]. Applied Thermal Engineering, 2016, 96(11): 640-651.
    [14]
    AMATYA B L, SOGA K, BOURNE-WEBB P J, et al. Thermo-mechanical behaviour of energy piles[J]. Géotechnique, 2012, 62(6): 503-519.
    [15]
    LUO J, ZHANG Q, ZHAO H F, et al. Thermal and thermomechanical performance of energy piles with double U-loop and spiral loop heat exchangers[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2019, 145(12): 4019101-4019109.
    [16]
    MURPHY K D, MCCARTNEY J S, HENRY K S. Evaluation of thermo-mechanical and thermal behavior of full-scale energy foundations[J]. Acta Geotechnica, 2015, 10(2): 179-195.

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