Work

A computational fluid dynamics (CFD) study on extraction of geothermal energy in Bangladesh

Year: 2025

Type: article

Abstract: Addressing the energy concerns Bangladesh, this study models a U-shaped geothermal well system using computational fluid dynamics (CFD) to investigate geothermal energy extraction in the country. Due to Bangladesh’s elevated geothermal gradients for its tectonic position, geothermal energy can be harnessed through directionally drilled U-shaped wells, enhancing current designs by removing internal pipes and optimizing contact with elevated subsurface temperatures. An analysis of a 12,080-meter pipeline system with two 4000-meter vertical wells and a 4000-meter horizontal section was done using simulations in ANSYS Fluent. The system produced an exit temperature of 117.691 °C with an intake temperature of 20 °C, a flow rate of 9 kg/s, and a geothermal gradient of 29.5 °C/km. Predicted power output for Organic Rankine Cycle (ORC) efficiencies of 6–10 % varied from 119.039 kW to 266.22 kW, while Carnot efficiency reached 817.78 kW. Geothermal gradient and well depth significantly impacted production, according to parametric calculations; the highest power output was 320.345 kW (10 % ORC efficiency) at Barapukuria region. Decreasing well diameters (6 inches) decreased output temperature and efficiency by up to 12 %, whereas optimal flow rates (9 kg/s) maximized power generation. Although the advantages decreased with thickness, increasing insulation in the upward well portion improved production; 3 cm of insulation increased power by 8 %. To fully utilize the geothermal resources of Bangladesh, the findings underscore the need for accurate design and operational optimization, stressing the need for high geothermal gradients, insulated well designs, and optimized flow rates contingent upon thorough analysis and evaluation of relevant aspects and design considerations.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2025.105120