Use the Analysis>Pure tool in Aspen Plus with the Peng-Robinson equation of state to compute the vapor pressures of the refrigerants R12 (dichlorodifluoromethane, or Freon 12), R124 (1-chloro-1,2,2,2,-tetrafluoroethane), and R134a (1,1,1,2-tetrafluoroethane) over the temperature range of 0 to 100°C.