Few deep wells have been drilled in the Cheshire Basin, resulting in high geological and financial risk of geothermal developments. Although the geothermal gradient in the basin can be predicted, the transmissivity of aquifers at depth are unknown. This has led to an investigation of lower risk strategies such as deep coaxial borehole heat exchangers (BHEs) for spatial heating, rather than traditional doublet methods. A model of a deep coaxial BHE was designed within MATLAB using the finite-difference method. The model produces accurate results in comparison to an analytical solution with a fast computational time. Results indicate that under best case geological parameters sustainable heat loads in excess of 298.7 kW can be produced from deep coaxial borehole heat exchangers at a depth of 2.8 km over the duration of a 20 year operational cycle. The thermal gradient and conductivity for this scenario were set at 27 °C/km and 3 W/m°C, respectively.

The thermal gradient, depth of borehole, volumetric flow rate and thermal conductivity of the surrounding rock all impact the heat load and outlet temperature of a deep coaxial borehole heat exchanger. The coefficient of system performance decreases with increased volumetric flow rates due to an increase in power consumption within the borehole heat exchanger. For an optimal flow rate of 4 l/s (calculated as the flow rate to produce most net power at the end of a heating season), the coefficient of system performance was 5.29. The thermal performance and efficiency of the system provides confidence that the geothermal resource of the Cheshire Basin has significant potential to be developed via deep coaxial borehole heat exchangers. Additionally, regression analysis was undertaken in this study. These models can be used to predict heat loads and outlet temperatures at the end of a heating season without the need for complex numerical modelling.

柴郡盆地很少钻探深井，导致地热开发的地质和财务风险很高。尽管可以预测盆地中的地热梯度，但尚不清楚深层含水层的透射率。这导致了对较低风险策略的研究，例如用于空间加热的深同轴孔换热器（BHE），而不是传统的doublet方法。使用有限差分法在MATLAB内设计了一个深同轴BHE模型。与具有快速计算时间的分析解决方案相比，该模型可产生准确的结果。结果表明，在最佳的地质参数下，在20年的运行周期中，深的同轴钻孔热交换器在2.8 km的深度处可产生超过298.7 kW的可持续热负荷。

热梯度，钻孔深度，体积流量和围岩的热导率都影响深同轴钻孔热交换器的热负荷和出口温度。由于井眼热交换器内功耗的增加，系统性能系数随体积流量的增加而降低。对于4 l / s的最佳流速（以在加热季节结束时产生最大净功率的流速计算），系统性能系数为5.29。该系统的热性能和效率使人们相信，柴郡盆地的地热资源具有很大的潜力，可以通过深同轴孔换热器进行开发。另外，在这项研究中进行了回归分析。