Article ID: 689
This study evaluates the shallow-geothermal potential of the Dushanbe Artesian Basin (DAB) for ground source heat pump (GSHP) deployment. One of the two 105 m vertical boreholes of a pilot installation was instrumented with a double U-tube and optical-fibre distributed temperature sensing (DTS) and tested by a single thermal response test (TRT); 95 groundwater samples (2022–2024) provided basin-wide hydrochemical characterisation. Analytical inversion of the TRT data, with Monte Carlo uncertainty quantification (1000 realisations, percentile confidence intervals), yielded an average effective ground thermal conductivity λ̄ ≈ 1.9 W·m¹·K¹ (95 % CI 1.71–2.04) and a depth-dependent contrast between the unsaturated (1.4–1.7 W·m¹·K¹) and saturated (2.0–2.4 W·m¹·K¹) zones, with a stable undisturbed temperature near 16.5 °C. Hydrochemical analysis identifies scaling and corrosion risks for open-loop and semi-openloop configurations but confirms that closed-loop circuits are unaffected. First-order multipole calculations for the asbuilt double U-tube show that an optimised quartz-enhanced grout (CEM I 42.5R + 40 wt% quartz, λ g= 2.1 W·m¹·K¹) reduces the borehole thermal resistance Rbfrom 0.177 to 0.090 m·K·W¹. At a fixed fluid-to-ground temperature difference this raises the specific heat-transfer rate by ≈ 20 % after one year of continuous operation (26 % at one month, 16 % at ten years), in either heat-extraction or heat-injection mode. The work provides a reproducible interpretation framework and engineering recommendations for GSHP deployment in arid, lithologically heterogeneous basins.
