NOVELTY - The system (100) has a turbine rotor coupled to a turbine shaft. The rotor is structured to receive working fluid from a down-hole heat exchanger (107) and redirect the working fluid to flow in opposed axial directions. Bearings support the shaft, and are placed between the shaft and a turbine casing. The bearings are lubricated by the working fluid. A circumferential inlet is formed through the casing and constructed to direct the working fluid to the rotor. The shaft is constructed to direct the working fluid redirected by the rotor in an outlet direction toward a turbine-generator.    USE - Geothermal power system.    ADVANTAGE - The system utilizes geothermal fluid to cool a region between a canister and the inner rotor so as to reduce performance losses in transferring input torque from the outer rotor to the inner rotor. The thrust bearings and the radial foil bearings are constructed to be lubricated by the working fluid passing through a turbine, thus eliminating a need for an auxiliary lubrication fluid and an associated lubrication system. The system allows a downward force to counteract an upward force caused by fluid pressure in a lower chamber, thus limiting an axial upward translation of the shaft, and hence achieving equilibrium between an upper chamber and the lower chamber in which the shaft is hydraulically balanced.    DETAILED DESCRIPTION - The working fluid is selected from a group consisting of a vaporized working fluid i.e. halocarbon and organic working fluid e.g. hydrocarbon alkane, hydro fluorocarbon (HFC) refrigerant such as HFC-236fa and HFC-245fa. The bearings are selected from a group consisting of a thrust bearing and a radial bearing. The rotor is an inner rotor or an outer rotor. INDEPENDENT CLAIMS are also included for the following:    (1) an expander pumping unit for a geothermal power system    (2) a turbine for use in a geothermal well of a geothermal power system.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a geothermal power system.    Geothermal power system (100)    Generating turbine (103)    Accumulator (105)    Electric generator (106)    Down-hole heat exchanger (107)