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.
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