Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
THE INFLUENCE OF TURBINE ISENTROPIC EFFICIENCY, PRESSURE AND TEMPERATURE ON A SUBCRITICAL ORGANIC RANKINE CYCLE (ORC) WITH SUPERHEAT USING ISENTROPIC FLUIDS
Submission Author:
Douglas Ricardo Fumes , SP
Co-Authors:
Douglas Ricardo Fumes, Aline Jauch Antônio, Santiago del Rio Oliveira
Presenter: Douglas Ricardo Fumes
doi://10.26678/ABCM.COBEM2019.COB2019-0157
Abstract
A thermodynamic model was developed for fluid selection in order to obtain an optimal thermal efficiency of an organic Rankine cycle (ORC). The purpose of this study is to perform a thermodynamic analysis, developing a mathematical model to compare the cycle thermal efficiency (CTE) for different isentropic fluids, considering its critical pressure, its critical temperature and the turbine isentropic efficiency. The theoretical model used to obtain the CTE was developed based on thermodynamic laws. The results showed a direct proportionality between the CTE and the turbine isentropic efficiency. The others parameters of interest, such as dimensionless pressure and dimensionless temperature, presented similar influence for each fluid tested. However, different behaviors were observed for different ranges of values. For dimensionless pressure between 0.1 and 0.4 (10% to 40% of the fluid critical pressure), the CTE values are directly proportional to the dimensionless pressure and to the dimensionless temperature. For dimensionless pressure between 0.5 and 0.8 (50% to 80% of the fluid critical pressure), the CTE values are directly proportional to the dimensionless temperature and practically stable to pressure variation. For dimensionless pressures above 0.9 (90% of the fluid critical pressure) the CTE values are inconsistent. Besides, the CTE was also expressed according to the modified Jacob number in order to gather the process relevant variables into a single one.
Keywords
Thermal Efficiency, organic Rankine cycles, isentropic efficiency, isentropic fluids
