Molecular-level Monte Carlo simulation at fixed entropy

A Monte Carlo computer simulation method is presented for performing property predictions for fluid systems at fixed entropy using a molecular-level system model. The method can be applied to the design of isentropic processes important in refrigeration and heat pump cycles, and for fluid compression and expansion processes. The details of the method are presented, and we illustrate its application for isentropic calculations involving compression of the alternative refrigerant HFC-32 (CH2F2). The method’s computational efficiency is compared with a ‘brute-force’ method based on a sequence of constant-pressure constant-temperature Monte Carlo simulations.