Simulating heat transfer in an aquifer with one or more vertical Borehole Heat Exchangers (BHEs) of a Ground Source Heat Pump (GSHP) system by means of a finite difference code is difficult because of the square or rectangular geometry grid and computational times thus limiting the types of evaluations that can be performed. The aim of this work is to explore through MODFLOW-USG code (public domain software) a different approach towards simulating a borefield that would be more efficient computationally, in order to enable simulations of larger domains with multiple BHEs. The Connected Linear Network (CLN) package, introduced in MODFLOW-USG, generally simulates 1-D linear computational cells in a 3-D grid, such as hydraulic pipes in subsoil, but for the first time has been adapted to reproduce vertical closed loop U-pipe of a BHE. Therefore, this work evaluates the MODFLOW-USG and CLN package capability to reproduce the yearly operation of one or more BHEs in an aquifer as a simpler and faster approach compared to a very fine finite-difference discretization. Once the CLN package was adapted, a sensitivity analysis on the grid size refinement was performed. There were several findings from this work. The results of the different numerical models were in good agreement with an already validated model, in terms of exchanged energies and aquifer thermal perturbation. Same analyses were carried out for different groundwater flow velocities and it was confirmed that the exchanged energy by a BHE increases with the groundwater flow velocity in accordance with literature studies. At last, a borefield of 7 BHEs was implemented in a numerical model in a more expeditious and efficient way and without any computational effort.

由于是正方形或矩形几何网格，并且计算时间有限，因此难以通过有限差分代码模拟具有地源热泵（GSHP）系统的一个或多个垂直钻孔换热器（BHE）的含水层中的传热。可以执行的评估类型。这项工作的目的是通过MODFLOW-USG代码（公共领域软件）探索一种不同的方法来模拟钻孔场，这种方法在计算上会更加高效，从而能够对具有多个BHE的更大区域进行模拟。MODFLOW-USG中引入的Connected Linear Network（CLN）程序包通常可模拟3-D网格中的一维线性计算单元，例如地下土壤中的液压管，但首次适用于复制垂直闭环。 BHE的U型管。所以，这项工作评估了MODFLOW-USG和CLN软件包在水层中再现一个或多个BHE的年度操作的能力，这是与非常精细的有限差分离散化相比更简单，更快速的方法。一旦修改了CLN程序包，就对网格大小进行了敏感性分析。这项工作有几个发现。在交换能量和含水层热扰动方面，不同数值模型的结果与已经验证的模型非常吻合。对于不同的地下水流速进行了相同的分析，并且根据文献研究证实，BHE交换的能量随地下水流速的增加而增加。终于，