Evaluating Heat Extraction Performance of Closed-Loop Geothermal Systems with Thermally Conductive Enhancements in Conduction-Only Reservoirs: Preprint
Conference
·
OSTI ID:2324601
We investigated the impact of disc-shaped and linear thermal enhancements on performance of closed-loop geothermal systems using steady-state and transient COMSOL numerical simulations. Thermal enhancements refer to thermally conductive material introduced in the rocks surrounding a wellbore to compensate for the relatively low rock thermal conductivity and increase heat extraction. Materials proposed include composite cements with thermally conductive additives such as metals or graphite to obtain overall cement thermal conductivities of 10 to 100x the rock thermal conductivity. Our simulation approach was modeling a subsegment (e.g., 100 m long) of a wellbore with idealized (e.g., perfect disc-shaped) thermal enhancements, and we report results as relative increase in heat extraction with respect to systems without thermal enhancements. We did not evaluate technical feasibility or cost of installing thermal enhancements. Simulations indicate that for 5-mm thick disc-shaped thermal enhancements with 5-m radius, repeated every 1 m along the wellbore and with thermal conductivity of 100x the rock thermal conductivity, the thermal output increases roughly 20% with respect to a closed-loop system without thermal enhancements. For fishbone structure thermal enhancements, we estimate a roughly 7% increase in thermal output for 5-m long radially outward pipes with half the radius of the main wellbore, repeated every 2.5 m, with thermal conductivity of 100x the rock thermal conductivity.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Geothermal Technologies Office
- DOE Contract Number:
- AC36-08GO28308;
- OSTI ID:
- 2324601
- Report Number(s):
- NREL/CP-5700-88557; MainId:89336; UUID:7a0503bd-1e8f-4330-b711-77ccc99d1b75; MainAdminId:72091
- Conference Information:
- Presented at the 49th Stanford Geothermal Workshop, 12-14 February 2024, Stanford, California
- Country of Publication:
- United States
- Language:
- English
Similar Records
COMSOL Models and Simulation Results for Closed-Loop Geothermal Systems with Thermal Enhancements
Influence of Reservoir Convection on Heat Extraction with Closed-Loop Geothermal Systems
Thermal conductivity, diffusivity and expansion of Avery Island salt at pressure and temperature
Dataset
·
Thu Dec 14 23:00:00 EST 2023
·
OSTI ID:2282853
Influence of Reservoir Convection on Heat Extraction with Closed-Loop Geothermal Systems
Conference
·
Sun Jan 26 23:00:00 EST 2025
·
OSTI ID:2524541
Thermal conductivity, diffusivity and expansion of Avery Island salt at pressure and temperature
Conference
·
Tue Mar 03 23:00:00 EST 1981
·
OSTI ID:6617760