ENERGY EFFICIENCY COMPARISON BETWEEN GEOTHERMAL POWER SYSTEMS

The geothermal water which can be considered for generating electricity with the temperature ranging from 80 degrees C to 150 degrees C in China because of shortage of electricity and fossil energy. There are four basic types of geothermal power systems: single-flash, double flash, binary cycle, and flash-binary system, which can be adapted to geothermal energy utilization in China. The paper discussed the performance indices and applicable conditions of different power system. Based on physical and mathematical models, simulation result shows that, when geofluid temperature ranges from 100 degrees C to 130 degrees C, the net power output of double flash power is bigger than flash-binary system. When the geothermal resource temperature is between 130 degrees C and 150 degrees C, the net power output offlash-binary geothermal power system is higher than double flash system by the maximum value 5.5%. However, the sum water steam amount of double flash power system is 2 to 3 times larger than flash-binary power system, which will cause the bigger volume of equipment of power system. Based on the economy and power capacity, it is better to use flash-binary power system when the geofluid temperature is between 100 degrees C and 150 degrees C