A Short Review on Wellbore Heat Exchangers

Wellbore geothermal heat exchanger (GHE) with a single well system is a promising technology for geothermal energy extraction from hot dry rock resources and abandoned wells. In comparison to the conventional two-well geothermal energy extraction systems, a single-well geothermal heat exchanger may reduce the cost and environmental impact. However, the optimization of the wellbore GHE is necessary to achieve higher thermal power due to higher outlet fluid temperature. Thus, the paper briefly reviews various wellbore GHEs and their thermal performance. The effect of the various parameters viz. geothermal gradient, inlet fluid temperature, mass flow rate, and operating time on the system’s thermal performance is also reviewed. Thus, the present study may aid the development of novel wellbore GHEs with higher heat extraction efficiencies.