A Predictive Equation of State to Perform an Extending Screening of Working Fluids for Power and Refrigeration Cycles

This chapter presents the features of the Enhanced - Predictive -PR78 equation of state (E-PPR78), a model highly suitable to perform “ physical fluid screening ” in power and refrigeration cycles. It enables, in fact, the accurate and predictive (i.e., without the need for its preliminary optimization by the user) determination of the thermodynamic properties of pure and multicomponent fluids usable in power and refrigeration cycles: hydrocarbons (alkanes, alkenes, alkynes, cycloalkane, naph-thenic compounds, and so on), permanent gases (such as CO 2 , N 2 , H 2 , He, Ar, O 2 , NH 3 , NO 2 /N 2 O 4 , and so on), mercaptans, fluorocompounds, and water. The E-PPR78 equation of state is a developed form of the Peng-Robinson equation of state, which enables both the predictive determination of binary interaction parameters and the accurate calculation of pure fluid and mixture thermodynamic properties (saturation properties, enthalpies, heat capacities, volumes, and so on).