To explore the thermal performance of vertical U‐tube ground heat exchanger (GHE) during short‐term thermal energy storage (TES) and heat extraction process, a novel and well‐controlled sandbox with a plate heat exchanger at the bottom of GHE was proposed and established. According to the experiments of short‐term TES and heat extraction under different inlet temperature with Re between 2677 and 2823, we found that the thermal performance of GHE was mainly determined by the dynamic soil temperature distribution around GHE, which was induced by the inlet temperature and operation process of GHE. Furthermore, the energy was concentrated within a limited radius (0.4 m) around the GHE during the 8 hours TES and heat extraction process, which was of benefit to the efficient operation of GHE and the thermal environment of soil. Moreover, compared to the simple extraction process C10 (−/8°C) without TES, the heat extraction process of C5 (35/8°C) obtained a 47.8% increase of average heat extraction rate. In addition, approximately 35% of the injected heat was left in the experimental soil under thermal balance conditions C3, C5, and C7. These results show the superiority and characteristic of short‐term TES and heat extraction for GHE operation.

中文翻译：

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垂直U型管地面换热器在短期井筒热能存储（BTES）和排热过程中的热性能的室内研究

为了探索立式U型管地面热交换器（GHE）在短期热能存储（TES）和排热过程中的热性能，提出了一种新颖且控制良好的沙箱，在其底部装有板式热交换器并成立。根据Re在2677和2823之间不同入口温度下的短期TES和热提取实验，我们发现GHE的热性能主要取决于入口温度引起的GHE周围的动态土壤温度分布。和GHE的运作过程。此外，在8小时的TES和热量提取过程中，能量集中在GHE的有限半径内（0.4 m），这有利于GHE的有效运行和土壤的热环境。此外，与不使用TES的简单萃取过程C10（-/ 8°C）相比，C5的热萃取过程（35/8°C）的平均热萃取率提高了47.8％。另外，在热平衡条件C3，C5和C7下，大约35％的注入热量留在了实验土壤中。这些结果显示了短期TES和GHE操作排热的优势和特点。