Saturated liquid density equation for pure refrigerants including CFCs, HCFCs, HFCs, HCs, HFOs, HFEs, PFAs and ISs based on the scaling law and the law of rectilinear diameter

This work aims to develop a simple saturated liquid density equation (SLDE) with good modeling, extrapolation and prediction capabilities for pure refrigerants based on the well-known scaling law and law of rectilinear diameter. Saturated liquid densities, critical temperatures and critical densities of 53 refrigerants from 8 different categories including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), hydrocarbons (HCs), hydrofluoroolefins (HFOs), hydrofluoroethers (HFEs), perfluoroalkanes (PFAs) and inorganic substances (ISs) have been studied using the proposed SLDE. The equation exhibits a good modeling behavior with a total mean absolute relative deviation (MARD) of 0.105%, and presents reasonable extrapolation accuracy, especially the extrapolations from medium temperature range to low and high temperature ranges, with total MARDs of 0.286% and 0.467%, respectively. The three parameters in the equation were generalized for different categories to better predict saturated liquid densities. The generalized equation shows a more competitive prediction performance than the commonly used generalized SLDEs, with a total MARD of 0.783%. Furthermore, critical temperatures and critical densities were simultaneously predicted using the generalized equation with total MARDs less than 0.743% and 0.998%, respectively.