Heat Efficiency of Geothermal Electrical Stations with Hydrosteam Turbines

Abstract

A thermodynamic analysis of world geothermal electrical generating stations (GHES) shows the significant losses of flow exergy occur in separators or flash vessels where thermal water is flashed and then separated to produce dry saturated steam for conventional intermediate steam turbines. These losses can be greatly reduced by using hydrosteam flashing flow turbines instead of conventional separated steam system, as shown in Barilovich (1982,1993), Barilovich et al.,(1985,1998). In spite of low internal relative heat efficiency (presently hoi=0.32 ... 0.42) such turbines, when used in GHES under low dryness degree of thermal water (x<0.2) at temperature of 430...450K can raise the actual power of the station by 5...20%.