| Title | Parametric Sensitivity Study of Operating and Design Variables in Wellbore Heat Exchangers |
|---|---|
| Authors | Gopi Nalla, G. Michael Shook, Gregory L. Mines, K. Kit Bloomfield |
| Year | 2004 |
| Conference | Stanford Geothermal Workshop |
| Keywords | WELLBORE HEAT EXCHANGERS, sensitivity analysis, engineered geothermal system |
| Abstract | A numerical study was conducted to evaluate the potential for using a Wellbore Heat Exchanger model for power generation. Variables studied included operational parameters such as circulation rates, wellbore geometries and working fluid properties, and regional properties including basal heat flux and formation rock type. Energy extraction is strongly affected by fluid residence time and heat transfer contact area, and by formation thermal properties. Water appears to be the most appropriate working fluid. Aside from minimal tubing insulation, tubing properties are second order effects. On the basis of the sensitivity study, a Best Case model was simulated, and results compared against existing, low-temperature power generation plants. Even assuming ideal work conversion to electric power, a wellbore heat exchange model cannot generate 200 kW at the onset of pseudo-steady state. Using realistic conversion efficiency, the method is unlikely able to generate 50 kW. |