浅层地埋管换热器是地源热泵系统的核心部分，其换热性能受众多因素的影响，地埋管换热器2支管之间存在的热短路现象就是其中之一。在地埋管的施工过程中，2支管之间的实际间距存在差异，导致不同程度的热短路，从而影响换热器的换热性能。基于实际地源热泵工程的热响应试验数据，建立了 3D 数值模型，研究了管间热短路对换热性能的影响。结果表明，增大2支管间的距离能显著提升地埋管换热器的换热性能，直径为32 mm的U型管换热器，2支管的最大轴心距离113 mm相较于最小距离33 mm的换热效率提高了22.7%，延米换热量与管轴心距之间呈线性关系式。
Shallow geothermal energy is an important part of clean energy, and its development and utilization meet the needs of national and social development. The technology of ground source heat pump with borehole heat exchanger (BHE) is the main technology for developing shallow geothermal energy. BHE is the core part of ground source heat pump system (GSHP), and its heat transfer performance is affected by many factors. Because the distance between the two branches of the BHE is very small, there is a serious thermal short circuit phenomenon. In the construction process of BHE, the actual distance between two branches is unknown. And different spacing will lead to different degrees of thermal short circuit, which will affect the performance of BHE. Based on the thermal response test (TRT) of GSHP project, through the combination of field test and numerical simulation, a 3D numerical model is established to study the effect of thermal short circuit between two branches of BHE on its heat transfer performance. The results show that increasing the distance between the two branches can significantly improve the heat transfer performance of the BHE. The maximum distance of two branch pipes is 22.7% higher than that of the minimum distance. The linear relationship between heat exchange and branch distance in linear meter is presented. It is suggested that pipe clamps should be strictly used in the construction of buried pipes to ensure sufficient distance between the two branches.
[1] 王贵玲, 刘彦广, 朱喜, 等. 中国地热资源现状及发展趋势[J]. 地学前缘, 2020, 27(1): 1-9.
[2] Cheng S W Y, Kurnia J C, Ghoreishi-Madiseh S A, et al. Optimization of geothermal energy extraction from abandoned oil well with a novel well bottom curvature design utilizing Taguchi method[J]. Energy, 2019, 188: 116098.
[3] 吕灿. 研究地热开发利用过程中的环境效应及环境保护[J]. 环境与发展, 2020, 32(8): 241-242.
[4] Tang F, Nowamooz H. Factors influencing the performance of shallow Borehole Heat Exchanger[J]. Energy Conversion and Management, 2019, 181: 571-583.
[5] 王畅, 曹晓玲, 袁艳平, 等. 夏季间歇运行工况下相变温度对相变回填地埋管换热器传热性能的影响[J]. 太阳能学报, 2020, 41(3): 234-241.
[6] 宋英峰, 吴学红, 龚毅 . 流速对垂直双 U 形地埋管换热器热交换的影响[J]. 郑州轻工业学院学报(自然科学版), 2013, 28(1): 57-61.
[7] Cai W, Wang F, Liu J, et al . Experimental and numerical investigation of heat transfer performance and sustainability of deep borehole heat exchangers coupled with ground source heat pump systems[J]. Applied Thermal Engineering , 2019, 149(2): 975-986.
[8] 高宽, 崔文智, 周世玉 . 地温未恢复时热响应试验的线热源叠加法[J]. 暖通空调, 2016, 46(4): 111-114.
[9] Hu P E, Meng Q F, Sun Q M, et al. A method and case study of thermal response test with unstable heat rate[J]. Energy and Buildings, 2012, 48: 199-205.
[10] 黄珂, 卢垠, 张丽英, 等 . 岩土热响应试验最短持续时间的确定[J]. 煤气与热, 2012, 32(12): 1-4.
[11] 段新胜, 顾湘, 李鹏, 等 . 加热过程间断的热响应试验数 据 处 理 方 法 研 究 [J]. 太 阳 能 学 报 , 2018, 39(10): 2685-2690.
[12] 齐子姝. 地埋管换热器内循环工质流速影响分析[J]. 吉林建筑大学学报, 2016, 33(2): 52-54.
[13] Beier R A, Acuña J, Mogensen P, et al. Borehole resistance and vertical temperature profiles in coaxial borehole heat exchangers[J]. Applied Energy, 2013, 102: 665-675.
[14] Sliwa T, Rosen M A. Efficiency analysis of borehole heat exchangers as grout varies via thermal response test simulations[J]. Geothermics, 2017, 69: 132-138.
[15] 张山 . 地埋管换热器换热效率影响因素综述[C]//2019供热工程建设与高效运行研讨会论文集 . 昆山: 中国市政工程华北设计研究院, 2019: 89-92.
[16] 李永强, 徐拴海, 张卫东, 等 . 套管式地埋管换热器热短路及换热性能[J]. 煤田地质与勘探, 2020, 48(1): 183-188.
[17] 陈颢, 阴继翔, 李涛, 等 . 渗流条件下地埋管换热器热短路现象的数值研究[J]. 上海电力大学学报, 2022, 38(3): 209-214.
[18] 徐玲玲, 蒲亮 . 基于热短路问题的仿生地埋管换热器模拟[J]. 化工学报, 2021, 72(S1): 134-139.
[19] 罗朗 . 竖直单 U 型地埋管换热器热短路现象研究与分析[D]. 南京: 南京师范大学, 2017.
[20] 范军, 刘福胜, 胡玉秋 . 并联和串联连接的竖直双 U型埋管地热换热器热短路的分析[J]. 制冷与空调, 2014, 28(2): 219-222.
[21] 王瑾, 李为, 郭威, 等 . 竖直 U 形地埋管换热器热短路现象及换热性能研究[J]. 暖通空调, 2014, 44(2): 89-94.
