SEMINAR: Physics Seminar

Metropolitan Perth sits above rocks of the Perth Sedimentary Basin. These rocks have significant moderate temperature geothermal waters at economically feasible depths associated with moderate to high natural hydraulic permeability aquifers. While not quite as attractive as regions near active volcanic zones (e.g. Taupo in New Zealand, or areas in the Philippines, Indonesia, Iceland, or California), these resources are sitting right underneath a city of about 1.5 million people. This fact opens the door for applications that use the heat directly (rather than generating electricity and transporting that energy, which typically requires higher temperatures than we think are economically available underneath Metro Perth).

Given Perth's climate, air-conditioning consumes a large quantity of electrical energy (and much of W.A.'s peak electrical power generation capacity). Offsetting some of that electricity consumption with geothermally powered heat-driven chilling systems (i.e. absorption and adsorption chillers) will yield substantial greenhouse gas emissions benefits, as well as financial savings in the running costs.

I will outline two large-scale air-conditioning projects that WAGCOE is involved with: one plans to provide base-load air-conditioning (~2 MW thermal) to the UWA campus, while the other plans to provide 24/7 cooling (~10 MW thermal) to the Pawsey Centre supercomputing facility being built near Technology Park in Kensington to support the Australian Square Kilometre Array Pathfinder radio-telescope project.

The other major application of direct-use geothermal heat to problems of interest in Metro Perth is desalination. Instead of Reverse Osmosis desalination systems (requiring work), Multi-Effect-Distillation systems can desalinate water using only geothermal heat, resulting in less electrical energy per unit volume of desalinated water. (The electrical consumption is mainly due to the pumping required to extract the water from the rocks at useful flow rates.)

I will also outline the thermodynamic challenges to using such relatively low enthalpy geothermal systems such as ours, as well as present a smorgasbord of problems in the geothermal arena potentially of interest to physicists.