@classmethod
def _Liquid_Density(cls, T):
    """Auxiliary equation for the density of saturated liquid

        Parameters
        ----------
        T : float
            Temperature, [K]

        Returns
        -------
        rho : float
            Saturated liquid density, [kg/m³]

        References
        ----------
        IAPWS, Revised Supplementary Release on Saturation Properties of
        Ordinary Water Substance September 1992,
        http://www.iapws.org/relguide/Supp-sat.html, Eq.2
        """
    eq = cls._rhoL['eq']
    Tita = 1 - T / cls.Tc
    if eq == 2:
        Tita = Tita ** (1.0 / 3)
    suma = 0
    for n, x in zip(cls._rhoL['ao'], cls._rhoL['exp']):
        suma += n * Tita ** x
    Pr = suma + 1
    rho = Pr * cls.rhoc
    return rho
