from __future__ import division

from CoolProp import CoolProp as CP

Fluid = 'CO2'
R = 8.314472/CP.Props(Fluid,'molemass')
Tc = CP.Props(Fluid,'Tcrit')
pc = CP.Props(Fluid,'pcrit')
w = CP.Props(Fluid,'accentric')

a = 0.457235*R**2*Tc**2/pc
b = 0.077796*R*Tc/pc
kappa = 0.37464+1.54226*w-0.26992*w**2

T = 298.15
rho = 1000
v = 1/rho
Tr = T/Tc
alpha = (1+kappa*(1-Tr**0.5))**2

p = R*T/(v-b)-a*alpha/(v**2+2*b*v-b**2)
print p, CP.Props('P', 'T', T, 'D', rho, Fluid)