OPTIMIZATION OF THE COMPOSITIONS FOR CFC ALTERNATIVE MIXTURE REFRIGERANTS

In this work, eight commonly used and recently developed cubic EOSs ha ve been extensively tested for the calculation of thermodynamic proper ties, including vapor pressure, vapor and liquid densities and heat of vaporization for 26 pure CFCs and their alternatives. The modified Du -Guo EOS is recommended for the vapor-liquid equilibria calculations o f mixtures for its good accuracy. A method for the development of the optimized mixture compositions of CFC alternatives has been proposed b y using minimization of deviations between the vapor pressures of CFC and the alternative mixtures of interest. As examples, two binary mixt ures R22-R142b and R22-R152a, and a ternary R22-R142b-R152a have been tested. The results show that the vapor pressure of R12 can be well du plicated by a mixture refrigerant with the optimized composition. On t he other hand, the deviations between the heat of vaporization are som ewhat apparent within 10 percent. Moreover, all the mixtures discussed here are of the characteristics of being near azeotropic, and promisi ng refrigerants to replace R12, as far as their thermodynamic properti es are concerned.