name	coolprop-db
description	Query thermodynamic properties for 100+ fluids from CoolProp database
category	databases
domain	fluids
complexity	basic
dependencies	["CoolProp"]

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

Subcooled Liquid: T < T_sat at given P, or P > P_sat at given T
Two-Phase: T = T_sat and 0 < Q < 1
Superheated Vapor: T > T_sat at given P, or P < P_sat at given T
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

from CoolProp.CoolProp import PropsSI

def safe_props(output, input1, value1, input2, value2, fluid):
    """Query CoolProp with error handling"""
    try:
        result = PropsSI(output, input1, value1, input2, value2, fluid)
        return result
    except ValueError as e:
        print(f"Error querying {fluid}: {e}")
        return None
    except Exception as e:
        print(f"Unexpected error: {e}")
        return None

# Usage
density = safe_props('D', 'T', 300, 'P', 101325, 'Water')
if density is not None:
    print(f"Density: {density:.2f} kg/m³")

Engineering Applications

HVAC System Design

Refrigerant cycle analysis (evaporator, condenser, compressor, expansion)
Heat exchanger calculations
Coefficient of performance (COP) calculations

Power Cycles

Rankine cycle (steam turbines)
Brayton cycle (gas turbines)
Organic Rankine Cycle (ORC)

Process Engineering

Heat transfer calculations
Pipe flow and pressure drop
Phase equilibrium
Storage tank design

Cryogenic Systems

Liquefaction processes
Storage and handling
Heat leak calculations

References

Official Documentation

CoolProp Website: http://www.coolprop.org/
Python Documentation: http://www.coolprop.org/coolprop/HighLevelAPI.html
Fluid Properties: http://www.coolprop.org/fluid_properties/PurePseudoPure.html
Validation Data: http://www.coolprop.org/validation/index.html

Key Papers

Bell, I. H., Wronski, J., Quoilin, S., & Lemort, V. (2014). "Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp." Industrial & Engineering Chemistry Research, 53(6), 2498-2508.

Equation of State References

Lemmon, E. W., Huber, M. L., & McLinden, M. O. (2013). NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties (REFPROP), Version 9.1. National Institute of Standards and Technology.

Source Code

GitHub: https://github.com/CoolProp/CoolProp
Issue Tracker: https://github.com/CoolProp/CoolProp/issues

Best Practices

Always use SI units for inputs and outputs (K, Pa, J/kg, etc.)
Check phase regions before choosing input pairs
Handle errors gracefully with try-except blocks
Validate ranges before querying (especially temperature and pressure)
Use quality (Q) for two-phase calculations
Cache critical properties if querying multiple times
Use Props1SI for fluid-only properties (critical points, molar mass)
Prefer (P, H) or (P, S) for robust queries across all phase regions

Quick Reference Table

Task	Function	Example
Two-input property	`PropsSI(output, in1, val1, in2, val2, fluid)`	`PropsSI('D', 'T', 300, 'P', 101325, 'Water')`
Single-input property	`Props1SI(param, fluid)`	`Props1SI('Tcrit', 'Water')`
Saturation liquid	Use Q=0	`PropsSI('H', 'T', 300, 'Q', 0, 'R134a')`
Saturation vapor	Use Q=1	`PropsSI('H', 'T', 300, 'Q', 1, 'R134a')`
Two-phase	Use 0<Q<1	`PropsSI('D', 'P', 500000, 'Q', 0.5, 'R134a')`
List all fluids	`CoolProp.__fluids__`	`import CoolProp; print(CoolProp.__fluids__)`

This skill provides access to one of the most comprehensive open-source thermophysical property databases available, suitable for research, engineering design, and educational applications.