Abstract:

Borehole thermal energy storage (BTES) can solve the contradiction between energy supply and demand in time and space, which is an important means to improve energy utilization efficiency. In this paper, the three-dimensional transient numerical model of the buried pipe thermal storage is established to realize the full-cycle dynamic monitoring of the three types of characteristic temperatures of the buried pipe thermal storage and the boundary heat flow, as well as to evaluate the thermal characteristics of the system under long-cycle operation. The results show that after the full-cycle operation, the average soil volume temperature increases by 10% compared with the initial state, and the lateral heat loss of the heat storage body accounts for 66%—90% of the total heat loss. The BTES efficiency of the system increases year by year, and basically reaches stability in the 7th year, when the efficiency can reach 55.2%. This research aims to provide a certain reference for the actual engineering design and application of BTES system.

Key words: borehole thermal energy storage, numerical simulation, computational fluid dynamics, dynamic simulation, characteristic temperature

摘要：

跨季节埋管蓄热技术（BTES）可以解决能源供需在时间与空间上不匹配的矛盾，是一种提高能源利用效率的重要手段。通过建立埋管蓄热体的三维瞬态数值模型，实现了埋管蓄热体的三类特征温度以及边界热流的全周期动态监测，同时对系统长周期运行下的热特性进行评估。结果表明，经过全周期运行后土壤体积平均温度与初始状态相比提升10%，蓄热体侧面热损失占总热损失的66%~90%，系统BTES效率逐年上升，运行至第7年基本达到稳定，此时效率可达55.2%。可为BTES系统实际工程设计应用提供一定的参考。

关键词: 跨季节埋管蓄热技术, 数值模拟, 计算流体力学, 动态仿真, 特征温度