Borehole resistance and vertical temperature profiles in coaxial borehole heat exchangers

► Proposed model calculates vertical temperature profile in borehole heat exchanger. ► Borehole fluid circulates through coaxial pipes. ► Distributed temperature sensing (DTS) system verifies model in a test borehole. ► Proposed model estimates the borehole thermal resistance using temperature profile. ► Proposed model estimates borehole resistance better than conventional methods.