A cubic equation of state for water and its application to power cycle calculations

A generalized cubic equation of state proposed by one of the authors has been modified, used to calculate some physical and thermodynamic properties of water, and applied to the modeling and simulation of vapor power cycles. The cubic equation contains four generalized constants, which are calculated using the acentric factor and the critical compressibility factor. In this work, the constants for water have been specifically recalculated so values of all properties of interest in the calculation of thermodynamic cycles can be accurately predicted. Saturation temperature–pressure data have been used to determine the constants and several other properties (volume, enthalpy and entropy of both liquid and vapor phases, and saturation pressure), have been calculated in a wide range of pressure and temperature. Also an application of the proposed equation to a vapor cycle is shown and result compared to other methods. The equation and the proposed parameters have shown to be accurate enough for the prediction of all properties involved in processes that use water as a working fluid.