Heat transfer analysis of short helical borehole heat exchangers
Heat transfer analysis of short helical borehole heat exchangers
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DOI：
10.1016/j.apenergy.2012.09.012
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发表时间：
2013-02
期刊：
影响因子：
11.2
通讯作者：
A. Zarrella;M. Carli
中科院分区：
文献类型：
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作者：
A. Zarrella;M. Carli
本文提出了一种分析螺旋管垂直埋管换热器传热特性的数值模型。这种类型的配置可以是传统地埋管换热器的合适替代方案，特别是当建筑物的加热和冷却负荷非常低时。该模型描述了热传递问题的互连热阻和电容的网络装置。此外，由于所研究的地埋管换热器通常安装在较浅的深度，该模型考虑了地面和周围环境之间的相互作用，这会影响进入热交换器的流体热载体温度，从而影响热泵的能效。通过对网格参数的敏感性分析，将所建模型与实验数据进行了比较，仿真结果与实验结果吻合较好。最后，分析了两种地面条件下气象条件、螺旋管轴向传热和螺旋管螺距的影响。
In this paper a numerical model to analyze the thermal behaviour of vertical ground heat exchangers with a helical shaped pipe is presented. This type of configuration can be a suitable alternative to conventional ground heat exchangers, especially when the heating and cooling loads of the building are very low. The model describes the heat transfer problem by means of a network of interconnected thermal resistances and capacitances. Moreover, as the investigated ground heat exchanger is usually installed in shallow depth, the model takes into account the interaction between the ground and the ambient environment which affects the fluid heat carrier temperature into the heat exchanger and, as a consequence, the energy efficiency of the heat pump. After a sensitivity analysis on the mesh parameters, the presented model is compared with experimental data and the simulation results show good agreement with the measurements. Finally, analyses to investigate the influence of the weather conditions, of the axial heat transfer and of the pitch between the turns of the helical pipe for two types of ground are carried out.