Heat exchange behavior of the phase change energy pile under cooling condition
CUI Hongzhi1, ZOU Jinping1, BAO Xiaohua1, QI Xuedong1, QI He2
1. Underground Polis Academy, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China; 2. China Construction Science and Technology Group Co., Ltd., Shenzhen 518000, China
Abstract：Phase change materials which absorb large amounts of heat can be used as backfill material around heat transfer piles to improve the heat transfer efficiency and reduce the underground space required by the heat transfer piles. This paper describes a scale model test of a 0.2 m diameter and 1.5 m long concrete phase-change energy storage pile. The pile was buried in saturated sand in a 2.45 m×2.45 m×2 m box. The heat transfer fluid temperature was kept constant by a temperature controller. The three tests used flow rates of 0.15, 0.30 and 0.45 m3/h. Each case included three cooling-heating cycles. The tests measured the thermal response and the heat transfer rates to the phase change energy pile including the pile-soil temperature differences for various flow rates and the influence of the flow rate and the flow temperatures on the heat transfer capacity of the phase change concrete pile. The results are compared with the heat transfer capacity of an ordinary concrete pile. Cooling test results show that the heat transfer to the phase change energy pile in the saturated sand is mainly in the radial direction with the sand temperature influenced over an area about twice the pile diameter as the heat transfer approached steady state. The temperature difference between the system inlet and outlet decreased as the heat transfer capacity of the phase change pile increased with increasing flow rate.
崔宏志, 邹金平, 包小华, 亓学栋, 齐贺. 制冷工况相变能源桩热交换规律[J]. 清华大学学报（自然科学版）, 2020, 60(9): 715-725.
CUI Hongzhi, ZOU Jinping, BAO Xiaohua, QI Xuedong, QI He. Heat exchange behavior of the phase change energy pile under cooling condition. Journal of Tsinghua University(Science and Technology), 2020, 60(9): 715-725.
[1] GASHTI E H N, UOTINEN V M, KUJALA K. Numerical modelling of thermal regimes in steel energy pile foundations:A case study[J]. Energy and Buildings, 2014, 69:165-174. [2] ZARRELLA A, DE CARLI M, GALGARO A. Thermal performance of two types of energy foundation pile:Helical pipe and triple U-tube[J]. Applied Thermal Engineering, 2013, 61(2):301-310. [3] BOZIS D, PAPAKOSTAS K, KYRIAKIS N. On the evaluation of design parameters effects on the heat transfer efficiency of energy piles[J]. Energy and Buildings, 2011, 43(4):1020-1029. [4] YANG W B, LU P F, CHEN Y P. Laboratory investigations of the thermal performance of an energy pile with spiral coil ground heat exchanger[J]. Energy and Buildings, 2016, 128:491-502. [5] WANG D Q, LU L, CUI P. A novel composite-medium solution for pile geothermal heat exchangers with spiral coils[J]. International Journal of Heat and Mass Transfer, 2016, 93:760-769. [6] 郭红仙, 李翔宇, 程晓辉. 能源桩热响应测试的模拟及适用性评价[J]. 清华大学学报(自然科学版), 2015, 55(1):14-20, 26. GUO H X, LI X Y, CHENG X H. Simulation and applicability of thermal response tests in energy piles[J]. Journal of Tsinghua University (Science and Technology), 2015, 55(1):14-20, 26. (in Chinese) [7] LALOUI L, NUTH M, VULLIET L. Experimental and numerical investigations of the behaviour of a heat exchanger pile[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2006, 30(8):763-781. [8] YOU S, CHENG X H, GUO H X, et al. Experimental study on structural response of CFG energy piles[J]. Applied Thermal Engineering, 2016, 96:640-651. [9] AMATYA B L, SOGA K, BOURNE-WEBB P J, et al. Thermo-mechanical behaviour of energy piles[J]. Géotechnique, 2012, 62(6):503-519. [10] 孔纲强. 能量桩换热管新型埋管方式技术比较分析[J]. 建筑节能, 2014, 42(12):104-108. KONG G Q. Comparative analysis on heat exchange tube in energy pile with various embedded manners[J]. Building Energy Efficiency, 2014, 42(12):104-108. (in Chinese) [11] NG C W W, GUNAWAN A, SHI C, et al. Centrifuge modelling of displacement and replacement energy piles constructed in saturated sand:A comparative study[J]. Géotechnique Letters, 2016, 6(1):34-38. [12] STEWART M A, MCCARTNEY J S. Centrifuge modeling of soil-structure interaction in energy foundations[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(4):04013044. [13] 刘汉龙, 王成龙, 孔纲强, 等. U型、W型和螺旋型埋管形式能量桩热力学特性对比模型试验[J]. 岩土力学, 2016, 37(S1):441-447. LIU H L, WANG C L, KONG G Q, et al. Comparative model test on thermomechanical characteristics of energy pile with U-shaped, W-shape and spiral-shape[J]. Rock and Soil Mechanics, 2016, 37(S1):441-447. (in Chinese) [14] 崔宏志, 李宇博, 包小华, 等. 饱和砂土地基相变桩的热力学特性试验研究[J]. 防灾减灾工程学报, 2019, 39(4):564-571. CUI H Z, LI Y B, BAO X H, et al. Investigation on Thermo-mechanical characteristics of phase change pile in saturated sand foundation by model tests[J]. Journal of Disaster Prevention and Mitigation Engineering, 2019, 39(4):564-571. (in Chinese) [15] 崔宏志, 邹金平, 李宇博, 等. 饱和砂土地基中相变能源桩的热响应研究[C]//中国土木工程学会2019年学术年会论文集. 上海, 中国:中国土木工程学会, 2019:32-44. CUI H Z, ZOU J P, LI Y B, et al. Thermal response of phase change energy piles in saturated sand soil[C]//Proceedings of China Civil Engineering Society Academic Annual Meeting. Shanghai, China:China Civil Engineering Society, 2019:32-44. (in Chinese) [16] BAO X H, LI Y B, FENG T J, et al. Investigation on thermo-mechanical behavior of reinforced concrete energy pile with large cross-section in saturated sandy soil by model experiments[J]. Underground Space, 2019, DOI:10.1016/j.undsp.2019.03.009. [17] ESLAMI-NEJAD P, BERNIER M. A preliminary assessment on the use of phase change materials around geothermal boreholes[M]. Atlanta:ASHRAE Transactions, 2013. [18] DEHDEZI P K, HALL M R, DAWSON A R. Enhancement of soil thermo-physical properties using microencapsulated phase change materials for ground source heat pump applications[J]. Applied Mechanics and Materials, 2011(110-116):1191-1198. [19] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. 自密实混凝土应用技术规程:JGJ/T 283-2012[S]. 北京:中国建筑工业出版社, 2012. General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of China. Technical specification for application of self-compacting concrete:JGJ/T 283-2012[S]. Beijing:China Architecture & Building Press, 2012. (in Chinese)
2020, Vol. 60 
