本文对单U形管和双U形管钻孔的替代方案进行了理论研究。这些非标准配置由半圆或象限排列的通道组成。通道隔热，以减少向下和向上支腿之间的热短路。利用一组耦合的线性能量平衡微分方程组的解析解，评估了所提出的配置的稳态热性能，该方程组考虑了热相互作用和不考虑热相互作用。在湍流和层流状态下，评估了抽热过程中的井眼热阻和循环流体温度，并用于比较。 结果表明，新配置可使钻孔热阻降低20%，从而缩短钻孔。对于低质量流率（层流），当向上和向下流动的流体之间的热相互作用变得更加重要时，通道之间的隔热可以将拟定配置的钻孔热阻比标准双U形管钻孔配置降低高达15%。引文:ASHRAE交易——第120卷第2部分，华盛顿州西雅图

Atheoretical study on the alternatives to single and double U-tube boreholes is presented in this work. These nonstandard configurations consist of channels arranged in a semicircle or in quadrants. Channels are thermally insulated to reduce the thermal short circuit between the downward and the upward legs.The steady-state thermal performance of the proposed configurations is evaluated using an analytical solution for a set of coupled linear differential equations of energy balances with and without thermal interaction. The borehole thermal resistance and the circulating-fluid temperature during heat extraction are evaluated in the turbulent and laminar regimes and are used for comparison purposes. Results show that the new configurations offer up to a 20% reduction in borehole thermal resistance leading to shorter boreholes. For low mass flow rates (laminar flow), where thermal interaction between the upward and downward flowing fluid becomes more important, thermal insulation between channels can reduce the borehole thermal resistance of the proposed configurations by up to15%over a standard double U-tube borehole configuration.