[Determination of the thermodynamic characteristics of organic fluids by means of a programmed vapour table]

When evaluating the performances of a low or medium temperature heat recovery system based on an organic Rankine cycle, it appears to be indispensable to have at one's disposal a programmed vapour table able to compute automatically the thermodynamic functions of each of the fluids to be examined. The author presents the most classical formulations of equations of state, vapour-pressure equations, saturated liquid density relations and heat capacity of ideal gas relations. In a second step, he describes the choice that has been made among these various equations. It has been governed on the one hand by the intrinsic quality of the equations and on the other hand by the reduction of the number of physical characteristics relative to the fluid one must dispose of. The accuracy obtained allows one to foresee a good reliability of this table for a wide range of fluids, thanks to the knowledge of a reduced number of parameters.