Thermodynamic comparison of the geothermal -based power plants

Geothermal energy is a recognized form of renewable energy at low and medium temperatures. It has garnered attention from researchers due to the ample available resources and cost-effectiveness, prompting numerous studies on its potential applications. This energy source has been harnessed to drive various energy conversion systems. The current thesis focuses on utilizing geothermal energy to power four different generation cycles: the simple organic Rankine cycle, trilateral cycle, organic flash Rankine cycle (all using R۱۲۳ as the working fluid), and the Kalina cycle (using water-ammonia as the working fluid). The functions of the sought-after systems are compared and examined in terms of energy, exergy, and hydrogen. Out of the cycles studied, the trilateral organic cycle demonstrates the highest level of output work and hydrogen production rate, followed by the simple organic Rankine cycle, the Kalina cycle, and the organic flash Rankine cycle. The generated hydrogen rate decreases in all cases as the pinch temperature increases. Similarly, an increase in the condenser temperature results in a reduction of the generated hydrogen rate across the analyzed configurations.

Keywords:

Geothermal energy , cogeneration system , ORC , Kalina , simulation