Isobaric heat capacity prediction for HC, HFC, HFO and HCFO refrigerants in liquid phase

Abstract

ABSTRACT In this work, it was found that the experimental heat capacity difference (cp-cv)exp has a linear relationship with the heat capacity difference calculated by using PR equation (cp-cv)PR. Based on this linear relationship, a predicted model of isobaric heat capacity for liquid refrigerants was presented. The accurate isobaric heat capacity of refrigerants in liquid phase can be obtained if the critical temperature, critical pressure, critical density, acentric factor and several experimental isobaric heat capacity data (at least two, more is better) are known. The proposed model was applied to 17 refrigerants (including HC, HFC, HFO and HCFO refrigerants) and a comparison was performed between the calculations by the proposed model and the experimental heat capacity data to validate the prediction. The results indicated the proposed method can represent the isobaric heat capacity of 17 refrigerants in liquid state with an average absolute deviation of 1.00%. The performance of this proposed method was then compared with that of other models (including Helmholtz equation, Peng-Robinson equation and a generalized corresponding state principle equation). It can be concluded that the proposed method generally shows better performance than other models. In addition, the proposed model reveals a good extrapolation ability in low temperature regions for refrigerants.