Shallow bore ground heat exchangers have been investigated in recent years because they have the potential to reduce the initial cost of the ground source heat pump system. Correctly modeling the transient heat transfer between the ground heat exchanger and the surrounding soil is essential for predicting a ground heat exchanger's performance. Simplification of the soil model could increase computation speed but sacrifice accuracy. This study investigates the impact of the soil model complexity on the annual performance prediction of a new shallow bore ground heat exchanger, the underground thermal battery (UTB). A simple 1D soil model and a more detailed 2D soil model were implemented, and they were validated against a 3D soil model. The resulting predictions of the UTB’s response from the 1D and 2D models to a given thermal load in different climates were compared. The results show that the root mean square differences between the hourly temperatures of the UTB during a year predicted using the two soil models range from 1.17 °C to 3.39 °C. As a result, the difference in the annual power consumption of the heat pump was between 0.7% and 3.4%. Furthermore, the dimensions of the UTB affected its performance, and a longer UTB was less sensitive to the soil models.

近年来，人们对浅孔地热换热器进行了研究，因为它们有可能降低地源热泵系统的初始成本。正确模拟地热交换器与周围土壤之间的瞬态热传递对于预测地热交换器的性能至关重要。简化土壤模型可以提高计算速度，但会牺牲精度。本研究调查了土壤模型复杂性对新型浅孔地面热交换器地下热电池 (UTB) 年度性能预测的影响。实施了简单的 1D 土壤模型和更详细的 2D 土壤模型，并针对 3D 土壤模型进行了验证。比较了 UTB 从 1D 和 2D 模型对不同气候下给定热负荷的响应的预测结果。结果表明，使用两种土壤模型预测的一年中 UTB 每小时温度的均方根差在 1.17°C 到 3.39°C 之间。结果，热泵年耗电量的差异在0.7%到3.4%之间。此外，UTB 的尺寸影响其性能，较长的 UTB 对土壤模型不太敏感。