Energy and exergy analysis of an organic Rankine cycle under different heat source and turbine inlet temperature conditions

Year 2018, Volume: 5 Issue: 3, 140 - 146, 13.12.2018

Ali Kahraman , Remzi Şahin , Sadık Ata

https://doi.org/10.31593/ijeat.444461

Abstract

In this study, the effect of turbine inlet temperature change on organic fluid performance in three different Organic Rankine Cycle (ORC) models designed using R113, R123 and isopentane fluid was determined. With the MATLAB and EES program, 17 different models have been formed for the heat source temperature that changes with the turbine inlet temperature. By analyzing the determined organic fluids on the generated models, the amount of heat entering the system, the work produced by the turbine, thermal efficiency, total exergy destruction and exergy efficiency were determined. While turbine inlet temperature is 80oC and heat source temperature is 110oC, isopentane fluid can reach maximum 8.8% while R113 fluid has reached 12.4% in same design conditions. With all cases examined, it is stated that isopentane fluid needs more heat input per unit mass compared to other fluids. While the maximum value of 531.7 kJ/kg heat input is required for isopentane fluid, R113 and R123 fluids require a maximum of 220.2 kJ/kg and 246.8 kJ/kg respectively. When the work values obtained from the turbine are examined, it is stated that R113 and R123 fluids show close properties. In this study, a maximum of 21.63 kJ/kg and 26.98 kJ / kg turbines were obtained for R113 and R123, while a 45.35 kJ/kg turbine work was obtained in the model using isopentane fluid. In exergy analysis, it was found that the best exergy efficiency performance was obtained in R113 fluid with 56.3%. In addition, the effect of overheating the organic fluid on the energy and exergy efficiency of the system was determined by the constant acceptance of the turbine inlet pressure.

Keywords

Organic Rankine Cycle (ORC), Engineering Equation Solver (EES), Energy, Exergy, Dry Fluids

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