coolprop-db

CoolProp Database Skill

Query thermodynamic and transport properties for over 100 pure and pseudo-pure fluids using the CoolProp open-source thermophysical property library.

Overview

CoolProp is a comprehensive thermophysical property database that provides:

• Pure Fluids: Water, air, ammonia, carbon dioxide, and 100+ others
• Refrigerants: R134a, R410A, R32, R404A, R407C, R507A, and many more
• Industrial Fluids: Methane, ethane, propane, butane, nitrogen, oxygen, argon
• Transport Properties: Viscosity, thermal conductivity, surface tension
• Thermodynamic Properties: Enthalpy, entropy, density, specific heat
• Phase Information: Saturation properties, two-phase behavior, critical points

CoolProp uses high-accuracy equations of state (Helmholtz energy formulations) and is validated against NIST REFPROP data.

Installation

Python

pip install CoolProp

Verify Installation

import CoolProp
print(CoolProp.__version__)
print(CoolProp.get_global_param_string("version"))

Core API Functions

PropsSI - Primary Property Query Function

from CoolProp.CoolProp import PropsSI

# Syntax: PropsSI(output, input1_name, input1_value, input2_name, input2_value, fluid)
value = PropsSI('D', 'T', 298.15, 'P', 101325, 'Water')

Props1SI - Single Input Properties

from CoolProp.CoolProp import Props1SI

# For properties requiring only fluid name
T_crit = Props1SI('Tcrit', 'Water')  # Critical temperature
P_crit = Props1SI('Pcrit', 'Water')  # Critical pressure

Property Codes (Input/Output Parameters)

Thermodynamic Properties

Code	Property	SI Unit	Description
T	Temperature	K	Absolute temperature
P	Pressure	Pa	Absolute pressure
D	Density	kg/m³	Mass density
H	Enthalpy	J/kg	Specific enthalpy
S	Entropy	J/kg/K	Specific entropy
U	Internal Energy	J/kg	Specific internal energy
Q	Quality	-	Vapor mass fraction (0-1)
Dmolar	Molar Density	mol/m³	Molar density
Hmolar	Molar Enthalpy	J/mol	Molar enthalpy
Smolar	Molar Entropy	J/mol/K	Molar entropy

Transport Properties

Code	Property	SI Unit	Description
V	Viscosity	Pa·s	Dynamic viscosity
L	Thermal Conductivity	W/m/K	Thermal conductivity
C	Specific Heat (const P)	J/kg/K	Cp at constant pressure
O	Specific Heat (const V)	J/kg/K	Cv at constant volume
PRANDTL	Prandtl Number	-	Pr = μ·Cp/k
I	Surface Tension	N/m	Liquid-vapor interface

Phase Properties

Code	Property	SI Unit	Description
Phase	Phase Index	-	0=Liquid, 3=Supercritical, 5=Gas, 6=Two-phase
Q	Quality	-	0=Saturated liquid, 1=Saturated vapor

Critical/Triple Point Properties (Use with Props1SI)

Code	Property	SI Unit	Description
Tcrit	Critical Temperature	K	Critical point temperature
Pcrit	Critical Pressure	Pa	Critical point pressure
Ttriple	Triple Point Temp	K	Triple point temperature
Ptriple	Triple Point Press	Pa	Triple point pressure
M	Molar Mass	kg/mol	Molecular weight
ACENTRIC	Acentric Factor	-	Pitzer acentric factor

Common Fluids

Water and Air

• Water - Pure water (H₂O)
• Air - Dry air (pseudo-pure mixture)

Common Refrigerants

• R134a - HFC, common in automotive AC
• R410A - HFC blend, residential AC/heat pumps
• R32 - HFC, lower GWP alternative
• R404A - HFC blend, commercial refrigeration
• R407C - HFC blend, AC systems
• R507A - HFC blend, low-temperature refrigeration
• R22 - HCFC (being phased out)
• R717 - Ammonia (NH₃)
• R744 - Carbon dioxide (CO₂)

Hydrocarbons

• Methane, Ethane, Propane, n-Butane, IsoButane
• n-Pentane, Isopentane, n-Hexane, n-Heptane, n-Octane
• n-Nonane, n-Decane

Cryogenic Gases

• Nitrogen, Oxygen, Argon, Helium, Neon, Hydrogen

Industrial Gases

• CO2 - Carbon dioxide
• CO - Carbon monoxide
• H2S - Hydrogen sulfide
• SO2 - Sulfur dioxide
• Ammonia - NH₃

Query Examples

Example 1: Water Properties at Standard Conditions

from CoolProp.CoolProp import PropsSI

# Water at 25°C (298.15 K) and 1 atm (101325 Pa)
T = 298.15  # K
P = 101325  # Pa

density = PropsSI('D', 'T', T, 'P', P, 'Water')  # kg/m³
enthalpy = PropsSI('H', 'T', T, 'P', P, 'Water')  # J/kg
entropy = PropsSI('S', 'T', T, 'P', P, 'Water')  # J/kg/K
viscosity = PropsSI('V', 'T', T, 'P', P, 'Water')  # Pa·s
cp = PropsSI('C', 'T', T, 'P', P, 'Water')  # J/kg/K

print(f"Water at {T-273.15}°C and {P/1000:.1f} kPa:")
print(f"  Density: {density:.2f} kg/m³")
print(f"  Enthalpy: {enthalpy/1000:.2f} kJ/kg")
print(f"  Entropy: {entropy/1000:.4f} kJ/kg·K")
print(f"  Viscosity: {viscosity*1000:.4f} mPa·s")
print(f"  Cp: {cp/1000:.4f} kJ/kg·K")

Example 2: Refrigerant Saturation Properties

from CoolProp.CoolProp import PropsSI

# R134a saturation properties at 25°C
T_sat = 298.15  # K
fluid = 'R134a'

# Get saturation pressure at this temperature
P_sat = PropsSI('P', 'T', T_sat, 'Q', 0, fluid)  # Pa

# Saturated liquid properties (Q=0)
rho_liquid = PropsSI('D', 'T', T_sat, 'Q', 0, fluid)
h_liquid = PropsSI('H', 'T', T_sat, 'Q', 0, fluid)
s_liquid = PropsSI('S', 'T', T_sat, 'Q', 0, fluid)

# Saturated vapor properties (Q=1)
rho_vapor = PropsSI('D', 'T', T_sat, 'Q', 1, fluid)
h_vapor = PropsSI('H', 'T', T_sat, 'Q', 1, fluid)
s_vapor = PropsSI('S', 'T', T_sat, 'Q', 1, fluid)

# Latent heat
h_fg = h_vapor - h_liquid

print(f"{fluid} at {T_sat-273.15}°C:")
print(f"  Saturation pressure: {P_sat/1000:.2f} kPa")
print(f"  Liquid density: {rho_liquid:.2f} kg/m³")
print(f"  Vapor density: {rho_vapor:.2f} kg/m³")
print(f"  Latent heat: {h_fg/1000:.2f} kJ/kg")

Example 3: Pressure-Enthalpy (P-H) State Point

from CoolProp.CoolProp import PropsSI

# Find temperature at known pressure and enthalpy
P = 500000  # 5 bar = 500 kPa
h = 250000  # 250 kJ/kg

T = PropsSI('T', 'P', P, 'H', h, 'R134a')
Q = PropsSI('Q', 'P', P, 'H', h, 'R134a')

print(f"R134a at {P/1000:.0f} kPa and {h/1000:.0f} kJ/kg:")
print(f"  Temperature: {T-273.15:.2f}°C")
print(f"  Quality: {Q:.4f} (0=liquid, 1=vapor)")

Example 4: Critical and Triple Point Data

from CoolProp.CoolProp import Props1SI

fluids = ['Water', 'CO2', 'Nitrogen', 'R134a']

for fluid in fluids:
    T_crit = Props1SI('Tcrit', fluid)
    P_crit = Props1SI('Pcrit', fluid)
    T_triple = Props1SI('Ttriple', fluid)
    M = Props1SI('M', fluid)

    print(f"\n{fluid}:")
    print(f"  Critical point: {T_crit-273.15:.2f}°C, {P_crit/1e6:.2f} MPa")
    print(f"  Triple point: {T_triple-273.15:.2f}°C")
    print(f"  Molar mass: {M*1000:.2f} g/mol")

Example 5: Viscosity Temperature Dependence

from CoolProp.CoolProp import PropsSI
import numpy as np

# Calculate water viscosity from 0°C to 100°C at atmospheric pressure
P = 101325  # Pa
temperatures = np.linspace(273.15, 373.15, 11)  # 0 to 100°C

print("Water viscosity vs temperature:")
print("T(°C)    μ(mPa·s)")
for T in temperatures:
    mu = PropsSI('V', 'T', T, 'P', P, 'Water') * 1000  # Convert to mPa·s
    print(f"{T-273.15:5.0f}    {mu:.4f}")

Example 6: Two-Phase Properties

from CoolProp.CoolProp import PropsSI

# R134a at 10 bar with 50% quality
P = 1000000  # 10 bar = 1 MPa
Q = 0.5  # 50% vapor

T = PropsSI('T', 'P', P, 'Q', Q, 'R134a')
h = PropsSI('H', 'P', P, 'Q', Q, 'R134a')
s = PropsSI('S', 'P', P, 'Q', Q, 'R134a')
rho = PropsSI('D', 'P', P, 'Q', Q, 'R134a')

print(f"R134a two-phase at {P/1e6:.1f} MPa, quality = {Q}:")
print(f"  Temperature: {T-273.15:.2f}°C")
print(f"  Enthalpy: {h/1000:.2f} kJ/kg")
print(f"  Entropy: {s/1000:.4f} kJ/kg·K")
print(f"  Density: {rho:.2f} kg/m³")

Temperature and Pressure Effects

Temperature Ranges

• Each fluid has valid temperature ranges between triple point and maximum temperature
• Typical range: Triple point temperature < T < 2000 K (varies by fluid)
• Check limits using Props1SI('Tmin', fluid) and Props1SI('Tmax', fluid)

Pressure Ranges

• Each fluid has valid pressure ranges
• Typical range: Triple point pressure < P < 1000 MPa (varies by fluid)
• Check limits using Props1SI('pmin', fluid) and Props1SI('pmax', fluid)

Phase Regions

1. Subcooled Liquid: T < T_sat at given P, or P > P_sat at given T
2. Two-Phase: T = T_sat and 0 < Q < 1
3. Superheated Vapor: T > T_sat at given P, or P < P_sat at given T
4. Supercritical: T > T_crit and P > P_crit

Input Pair Restrictions

Not all input pairs are valid in all regions:

• (T, P): Valid in single-phase regions only (not in two-phase)
• (P, Q): Valid for two-phase and saturation (0 ≤ Q ≤ 1)
• (T, Q): Valid for two-phase and saturation (0 ≤ Q ≤ 1)
• (P, H): Valid in all regions
• (P, S): Valid in all regions
• (H, S): Valid in all regions (useful for isentropic processes)

Error Handling

Common Errors and Solutions

Error: "CoolProp error: [PropsSI] Two saturation inputs are not valid"

• Problem: Trying to use (T, P) in two-phase region
• Solution: Use (T, Q) or (P, Q) for two-phase states

Error: "CoolProp error: Value is outside range"

• Problem: Temperature or pressure outside valid range
• Solution: Check fluid limits with Props1SI('Tmin', fluid), etc.

Error: "CoolProp error: Fluid not found"

• Problem: Incorrect fluid name or spelling
• Solution: Use exact fluid names (case-sensitive), check documentation

Error: "Unable to match the inputs"

• Problem: Invalid input combination or iteration failed
• Solution: Check that input values are physically reasonable

Safe Query Pattern

fro

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