Exergetic performance assessment of a binary geothermal power plant

Abstract

Electricity generation is achieved by means of the medium-temperature geothermal water in the range of 90–140 ºC in binary plants with the organic Rankine cycle. So, we investigate a binary geothermal power plant as a case study, from the energy and exergy point of view. Also, exergy destruction rates throughout the plant are quantified and illustrated for comparison purposes. In the plant considered, the brine injection and reinjection temperatures are 140 and 80 ºC, with a mass flow rate of 64.87 kg/s, respectively. The energy and exergy efficiencies are calculated as 5.34 and 30.84 %, respectively, based on the heat and exergy input rates to the system at the net power. Furthermore, we examine the effects of some parameters on energy and exergy efficiencies and net power output (e.g., brine injection temperature, brine mass flow rates, turbine inlet temperature and inlet pressure).