Optimization of the electricity production from geothermal sources by binary system

It is becoming popular to search new energy sources to produce electricity, due to the limited amount of the fossil fuel sources. Renewable energy is a promising alternative solution because it is clean and environmentally safe. Currently, renewable energy sources supply 14% of the total world energy demand. Within this scope, geothermal is one of the most important energy sources for the future.The total geothermal potential in Turkey is estimated to be about 38.000 MW. Although, Turkey is one of the 10 richest countries in terms of geothermal potential in the world, just the few of these sources, having enough temperatures to use flash system in order to produce electricity. Most of them are using for drying, cooling, heating houses or greenhouses, fermentation, fish breeding etc. On the other hand, most of the limited high temperature sources chemical properties are not suitable for using flash system. Such dirty geothermal fluids may contain; noncondensable gases, hazardous compounds, corrosive ions and insoluble materials.The purpose of the study is to investigate the determination of the optimum electricity production by binary system, from low temperature and dirty fluids containing noncondensable compounds. Several secondary fluid types were used at various geothermal fluid temperatures and also at different turbine inlet pressures.Although in the range of 121-167 °C geothermal fluid temperatures hydrocarbons can be used as secondary fluid, between 150 °C - 230 °C, hydrocarbons can not be used, so ammonia must be considered. Also at 121-130 °C range if the flow rate is high, ammonia must be used as a secondary fluid.By this method, because these secondary fluids have low temperature vapor densities considerably greater than steam, much smaller and less expensive turbines will be required for the same power output.Keywords : Geothermal energy, power plant, binary system,electricity generation