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Uncertainty Assessment of Equations of State Applied to Organic Rankine Cycles



Ian H. Bell, Kenneth G. Kroenlein, John P. O'Connell, Jens Abildskov, Jerome Frutiger, Gurkan Sin


This study presents a generic method to analyze and select equations of state (EoS) based on detailed uncertainty analysis of the respective EoS property parameters. A Cubic EoS (i.e. Soave-Redlich-Kwong SRK) is compared to PC-SAFT EoS. The uncertainty analysis methodology is applied to an Organic Rankine Cycle (ORC) system for heat recovery from the exhaust gas of a marine diesel engine using cyclopentane as working fluid. The uncertainties of the input parameters to the EoS including their corresponding correlation structure is quantified from experimental measurements using a bootstrap method. The Monte Carlo procedure is used to propagate the influence of the fluid parameter input uncertainty on the ORC model outputs. Variance-based sensitivity analysis is used to compare the different sources of uncertainties in the EoS, such as the departure functions and the ideal gas contribution. The uncertainties in the departure function of the EoS (SRK or PC-SAFT EoS) dominates the total uncertainties of the ORC model output. The predicted ORC net power output uncertainties are smaller for SRK than for PC-SAFT. Hence, for the given application and working fluid, SRK is better suited from an uncertainty analysis point-of-view than PC-SAFT.
Molecular Physics


Bell, I. , Kroenlein, K. , O'Connell, J. , Abildskov, J. , Frutiger, J. and Sin, G. (2017), Uncertainty Assessment of Equations of State Applied to Organic Rankine Cycles, Molecular Physics, [online], (Accessed April 18, 2024)
Created January 27, 2017, Updated June 2, 2021