| Title | QGECE Mobile Geothermal Test Plant & ORC Cycle Challenges |
|---|---|
| Authors | Andrew S. Rowlands and Jason Czapla |
| Year | 2010 |
| Conference | Australian Geothermal Energy Conference |
| Keywords | Geothermal Energy, Organic Rankine Cycle, Working Fluids |
| Abstract | Geothermal energy reserves in Australia have the potential to provide electrical energy for hundreds of years. However, due to the variety of temperatures in geothermal resources a one-size-fits-all approach to surface power infrastructure is not appropriate. Furthermore, the use of traditional steam as a working fluid is rarely a feasible option because resource temperatures lie in the range of 100-200°C. To overcome this, organic fluids with lower boiling points than steam may be utilised as working fluids in organic rankine cycles (ORC) in binary power plants. Due to differences in thermodynamic properties, certain fluids are able to extract more heat from a given resource than others over certain temperature and pressure ranges. This phenomenon enables the tailoring of power cycle infrastructure to best match the geothermal resource through careful selection of the working fluid and turbine design optimisation to yield the optimum overall cycle performance. Here we look at a selection of promising ORC cycles using a range of high-density working fluids operating at sub-, or trans-critical conditions that are being studied by QGECE as potential binary cycle systems; discuss the challenges facing design of ORC cycles and how some of these challenges are being addressed in the QGECE Mobile Geothermal Test Plant. |