Simulação e análise termodinâmica de ciclo Rankine orgânico

Abstract

Energy production is a focal point when it comes to industries and technological development by means of a constant search for more economical, efficient and cost-effective ways for energy generation. Currently, much of the energy production is obtained in thermoelectric plants, whether through coal, natural gas, oil or other fossil fuels. This production is mostly performed using the principles of a Rankine cycle, which converts the heat from the fuels into work (power). Aiming to attain higher yields and lower costs, adaptations were performed in conventional system leading to the Rankine organic cycle (ORC), which is characterized by the use of an organic working fluid requiring less energy for cycle operation and that inhibits damages due to friction in machines. In this context, the purpose of this work is to perform a simulation and analysis of an organic Rankine cycle for comparing different working fluids and implementing changes in the conventional cycle in order to verify effects on performance. It was observed that all proposed fluids showed greater efficiencies than water, mainly below 200 °C of boiler temperature, which is the range where a pronounced decay of the cycle's thermal efficiency curve occurs when water is the working fluid. Between efficiencies associated to water and ammonia, there are n-pentane and n-hexane. Moreover, propanestands out for operating at a higher thermal efficiency than all other working fluids considered.