Investigating scalability of deep borehole heat exchangers: Numerical modelling of arrays with varied modes of operation
Investigating scalability of deep borehole heat exchangers: Numerical modelling of arrays with varied modes of operation
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DOI：
10.1016/j.renene.2022.11.100
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发表时间：
2022-11
期刊：
影响因子：
8.7
通讯作者：
C. Brown;I. Kolo;G. Falcone;D. Banks
中科院分区：
文献类型：
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作者：
C. Brown;I. Kolo;G. Falcone;D. Banks
深钻孔热交换器（DBHE）是通过碳中性空间加热闭环系统开发地热资源的潜在重要方法。过去的研究主要集中在单井系统上，很少研究多个DBHE阵列作为提取更多热能的方法。在这项研究中，一系列的阵列使用OpenGeoSys软件建模，了解阵列的几何形状，井间间距和操作模式对热性能和系统效率的影响。OpenGeoSys软件是一个有限元模型，它使用双连续体方法求解通过井筒和围岩的热通量。对阵列的寿命（20年）进行了模拟，其中操作测试模式为1）长期恒定热负荷应用和2）间歇操作（6个月提取，然后是恢复期）。结果表明，几何形状和操作模式对井间间距和系统性能有显着影响。对于每个DBHE 50 kW的长期恒定热负荷应用，线性和方形阵列所需的最小间距应为40 m和30 m。当考虑间歇操作时，恢复期允许在钻孔周围补充热量，这意味着可以使用更小的间距。
Deep Borehole Heat Exchangers (DBHEs) are a potentially important method of developing geothermal resources through closed-loop systems for carbon neutral, spatial heating. Past research has primarily focused on single-well systems, with few investigating arrays of multiple DBHEs as a method of extracting more thermal energy. In this study, a series of arrays were modelled using OpenGeoSys software, with the aim of understanding the influence of array geometry, inter-borehole spacing and the mode of operation on the thermal performance and system efficiency. OpenGeoSys software is a finite-element model which solves thermal fluxes through the wellbore and surrounding rock using the dual-continuum method. Simulations were undertaken for the lifetime of an array (20 years) with modes of operation testing 1) long-term constant heat load application and 2) intermittent operation with 6 months of extraction followed by a recovery period. Results indicate geometry and mode of operation had a significant impact on inter-borehole spacing and system performance. For long term constant heat load application of 50 kW per DBHE, the minimal spacing required for line and square arrays should be 40 and 30 m. When considering intermittent operation, recovery periods allow replenishment of heat around the borehole, meaning smaller spacing can be utilised.