Propiedades Del Refrigerante 134A

Technical Information
T-134a—SI

DuPont™ Suva

®

refrigerants

Thermodynamic
Properties
of

HFC-134a
(1,1,1,2-tetrafluoroethane)

DuPont Product Names:
DuPont™ Suva® 134a Refrigerant
DuPont™ Formacel® Z-4 Blowing Agent
DuPont™ Dymel® 134a Aerosol Propellant
DuPont™ Dymel® 134a/P Aerosol Propellant (Pharmaceutical Grade)

The DuPont Oval Logo, The miracles of science™,
andSuva®, are trademarks or registered trademarks of
E.I. du Pont de Nemours and Company.

Thermodynamic Properties of HFC-134a Refrigerant
(1,1,1,2-tetrafluoroethane)
SI Units
Equations

New tables of the thermodynamic properties of HFC-134a
have been developed and are presented here. These tables
are based on experimental data from the database at the
National Institute of Standards andTechnology (NIST).
Equations have been developed, based on the Modified
Benedict-Webb-Rubin (MBWR) equation of state, which
represent the data with accuracy and consistency throughout the entire range of temperature, pressure, and density.

The Modified Benedict-Webb-Rubin (MBWR) equation of
state was used to calculate the tables of thermodynamic
properties. It was chosen as the preferredequation of state
because it provided the most accurate fit of the thermodynamic data over the entire range of temperatures and
pressures presented in these tables. The data fit and calculation of constants for HFC-134a were performed for
Du Pont at the National Institute of Standards and Technology (NIST) under the supervision of Dr. Mark O.
McLinden.

Physical Properties
Chemical FormulaMolecular Weight
Boiling Point at
One Atmosphere
Critical Temperature
Critical Pressure
Critical Density
Critical Volume

CH2FCF3
102.03
–26.06°C
101.08°C
374.23 K
4060.3 kPa (abs)
515.3 kg/m3
0.00194 m3/kg

The constants were calculated in SI units. For conversion
of thermodynamic properties to Engineering (I/P) units,
properties must be calculated in SI units and converted toI/P units. Conversion factors are provided for each property
derived from the MBWR equation of state.

(–14.9°F)
(213.9°F)
(673.6°R)
(588.9 psia)
(32.17 lb/ft3)
(0.031 ft3/lb)

1. Equation of State (MBWR)
15
9
P
= Σ an/Vn + exp (–Vc2/V2) Σ an/V2n–17
n=10
100 n=1
where the temperature dependence of the coefficients is
given by:

Units and Factors
t = temperature in °C
T =temperature in K = °C + 273.15
P = pressure in kiloPascals absolute [kPa (abs)]
vf = volume of saturated liquid in m3/kg
vg = volume of saturated vapor in m3/kg
V = volume of superheated vapor in m3/kg
df = 1/vf = density of saturated liquid in kg/m3
dg = 1/vg = density of saturated vapor in kg/m3
hf = enthalpy of saturated liquid in kJ/kg
hfg = enthalpy of vaporization in kJ/kg
hg =enthalpy of saturated vapor in kJ/kg
H = enthalpy of superheated vapor in kJ/kg
sf = entropy of saturated liquid in kJ/(kg) (K)
sg = entropy of saturated vapor in kJ/(kg) (K)
S = entropy of superheated vapor in kJ/(kg) (K)
Cp = heat capacity at constant pressure in kJ/(kg) (°C)
Cv = heat capacity at constant volume in kJ/(kg) (°C)
vs = velocity of sound in m/sec

a1 = RT
a2 = b1T + b2T0.5 + b3+ b4/T + b5/T2
a3 = b6T + b7 + b8/T + b9/T2
a4 = b10T + b11 + b12/T
a5 = b13
a6 = b14/T + b15/T2
a7 = b16/T
a8 = b17/T + b18/T2
a9 = b19/T2
a10 = b20/T2 + b21/T3
a11 = b22/T2 + b23/T4
a12 = b24/T2 + b25/T3
a13 = b26/T2 + b27/T4

The gas constant, R = 8.314 J/(mole) (K)
for HFC-134a, R = 0.0815 kJ/kg • K
One atmosphere = 101.325 kPa
Reference point for enthalpy and entropy:
hf =200 kJ/kg at 0°C
sf = 1 kJ/kg • K at 0°C

a14 = b28/T2 + b29/T3
a15 = b30/T2 + b31/T3 + b32/T4
where T is in K = °C + 273.15, V is in liters/mole
(= m3/kg × MW), Vc = 0.199334 liters/mole, P is in kPa,
and R = 0.08314471 bar (absolute) × liters/mole × K.

1

Properties calculated in SI units from the equation and
constants listed above can be converted to I/P units
using the...