A simple, full-featured, lightweight CoolProp wrapper for Python.

Navigation

• How to install
• Project structure
• Units systems
  • Available units systems
  • Available types of configuration files
    • pyfluids.ini example
    • pyfluids.json example
    • pyproject.toml example
    • tox.ini example
• List of properties
  • Properties of Fluid and Mixture instances
  • Properties of HumidAir instances
• List of methods
  • Methods of Fluid instances
  • Methods of Mixture instances
  • Methods of HumidAir instances
• Examples
  • Pure fluids
  • Incompressible binary mixtures
  • Mixtures
  • Humid air
  • Equality of instances
  • Converting to a JSON string
  • Converting to a Python dict
  • Deep cloning
  • Adding other properties
  • Adding other inputs

How to install

Run the following command:

pip install pyfluids

Project structure

• Fluid class - an implementation of pure fluids and binary mixtures.
• Mixture class - an implementation of mixtures with pure fluids components.
• FluidsList enum - the list of all available fluids.
• Input class - the inputs for the Fluid and Mixture classes.
• HumidAir class - an implementation of real humid air.
• InputHumidAir class - the inputs for the HumidAir class.

Units systems

Using a configuration file, you can choose the units system that will be used in your project (for both inputs and outputs of PyFluids).

Available units systems

• SI (UnitsSystem.SI):
  • temperature unit - Kelvin (K);
  • decimal fraction unit - dimensionless (from 0 to 1);
• SI with Celsius (UnitsSystem.SIWithCelsius):
  • temperature unit - degree Celsius (°C);
  • decimal fraction unit - dimensionless (from 0 to 1);
• SI with Celsius and percents (UnitsSystem.SIWithCelsiusAndPercents) - by default:
  • temperature unit - degree Celsius (°C);
  • decimal fraction unit - percent (%, from 0 to 100).

Available types of configuration files

• pyfluids.ini;
• pyfluids.json;
• pyproject.toml;
• tox.ini.

pyfluids.ini example

[pyfluids]
units_system = SI

pyfluids.json example

{
    "pyfluids": {
        "units_system": "SIWithCelsius"
    }
}

pyproject.toml example

[tool.pyfluids]
units_system = "SIWithCelsiusAndPercents"

tox.ini example

[pyfluids]
units_system = SI

List of properties

If the required property is not present in the instance of the fluid, then you can add it by extending the Fluid, Mixture or HumidAir classes (see how to add other properties).

Properties of Fluid and Mixture instances

• compressibility - compressibility factor (dimensionless).
• conductivity - thermal conductivity (W/m/K).
• critical_pressure - absolute pressure at the critical point (Pa).
• critical_temperature - temperature at the critical point (by default, °C; see how to change it).
• density - mass density (kg/m3).
• dynamic_viscosity - dynamic viscosity (Pa*s).
• enthalpy - mass specific enthalpy (J/kg).
• entropy - mass specific entropy (J/kg/K).
• freezing_temperature - temperature at the freezing point (for incompressible fluids) (by default, °C; see how to change it).
• internal_energy - mass specific internal energy (J/kg).
• kinematic_viscosity - kinematic viscosity (m2/s).
• max_pressure - maximum pressure limit (Pa).
• max_temperature - maximum temperature limit (by default, °C; see how to change it).
• min_pressure - minimum pressure limit (Pa).
• min_temperature - minimum temperature limit (by default, °C; see how to change it).
• molar_mass - molar mass (kg/mol).
• phase - phase state (enum).
• prandtl - Prandtl number (dimensionless).
• pressure - absolute pressure (Pa).
• quality - mass vapor quality (by default, %; see how to change it).
• sound_speed - sound speed (m/s).
• specific_heat - mass specific constant pressure specific heat (J/kg/K).
• specific_volume - mass specific volume (m3/kg).
• surface_tension - surface tension (N/m).
• temperature - temperature (by default, °C; see how to change it).
• triple_pressure - absolute pressure at the triple point (Pa).
• triple_temperature - temperature at the triple point (by default, °C; see how to change it).
• units_system - configured units system (enum).

Properties of HumidAir instances

• compressibility - compressibility factor (dimensionless).
• conductivity - thermal conductivity (W/m/K).
• density - mass density per humid air unit (kg/m3).
• dew_temperature - dew-point temperature (by default, °C; see how to change it).
• dynamic_viscosity - dynamic viscosity (Pa*s).
• enthalpy - mass specific enthalpy per humid air (J/kg).
• entropy - mass specific entropy per humid air (J/kg/K).
• humidity - absolute humidity ratio (kg/kg d.a.).
• kinematic_viscosity - kinematic viscosity (m2/s).
• partial_pressure - partial pressure of water vapor (Pa).
• prandtl - Prandtl number (dimensionless).
• pressure - absolute pressure (Pa).
• relative_humidity - relative humidity ratio (by default, %; see how to change it).
• specific_heat - mass specific constant pressure specific heat per humid air (J/kg/K).
• specific_volume - mass specific volume per humid air unit (m3/kg).
• temperature - dry-bulb temperature (by default, °C; see how to change it).
• wet_bulb_temperature - wet-bulb temperature (by default, °C; see how to change it).
• units_system - configured units system (enum).

List of methods

For more information, see the docstrings.

Methods of Fluid instances

• factory - returns a new fluid instance with no defined state.
• with_state - returns a new fluid instance with a defined state.
• update - updates the state of the fluid.
• reset - resets all non-trivial properties.
• specify_phase - specify the phase state for all further calculations.
• unspecify_phase - unspecify the phase state and go back to calculating it based on the inputs.
• clone - performs deep (full) copy of the fluid instance.
• isentropic_compression_to_pressure - the process of isentropic compression to a given pressure.
• compression_to_pressure - the process of compression to a given pressure.
• isenthalpic_expansion_to_pressure - the process of isenthalpic expansion to a given pressure.
• isentropic_expansion_to_pressure - the process of isentropic expansion to a given pressure.
• expansion_to_pressure - the process of expansion to a given pressure.
• cooling_to_temperature - the process of cooling to a given temperature.
• cooling_to_enthalpy - the process of cooling to a given enthalpy.
• heating_to_temperature - the process of heating to a given temperature.
• heating_to_enthalpy - the process of heating to a given enthalpy.
• bubble_point_at_pressure - bubble point at a given pressure.
• bubble_point_at_temperature - bubble point at a given temperature.
• dew_point_at_pressure - dew point at a given pressure.
• dew_point_at_temperature - dew point at a given temperature.
• two_phase_point_at_pressure - two-phase point at a given pressure.
• mixing - the mixing process.
• as_json - converts the fluid instance to a JSON string.
• as_dict - converts the fluid instance to a dict.

Methods of Mixture instances

• factory - returns a new mixture instance with no defined state.
• with_state - returns a new mixture instance with a defined state.
• update - updates the state of the mixture.
• reset - resets all non-trivial properties.
• specify_phase - specify the phase state for all further calculations.
• unspecify_phase - unspecify the phase state and go back to calculating it based on the inputs.
• clone - performs deep (full) copy of the mixture instance.
• cooling_to_temperature - the process of cooling to a given temperature.
• heating_to_temperature - the process of heating to a given temperature.
• as_json - converts the mixture instance to a JSON string.
• as_dict - converts the mixture instance to a dict.

Methods of HumidAir instances

• factory - returns a new humid air instance with no defined state.
• with_state - returns a new humid air instance with a defined state.
• update - updates the state of the humid air.
• reset - resets all properties.
• clone - performs deep (full) copy of the humid air instance.
• dry_cooling_to_temperature - the process of cooling without dehumidification to a given temperature.
• dry_cooling_to_enthalpy - the process of cooling without dehumidification to a given enthalpy.
• wet_cooling_to_temperature_and_relative_humidity - the process of cooling with dehumidification to a given temperature and relative humidity ratio.
• wet_cooling_to_temperature_and_absolute_humidity - the process of cooling with dehumidification to a given temperature and absolute humidity ratio.
• wet_cooling_to_enthalpy_and_relative_humidity - the process of cooling with dehumidification to a given enthalpy and relative humidity ratio.
• wet_cooling_to_enthalpy_and_absolute_humidity - the process of cooling with dehumidification to a given enthalpy and absolute humidity ratio.
• heating_to_temperature - the process of heating to a given temperature.
• heating_to_enthalpy - the process of heating to a given enthalpy.
• humidification_by_water_to_relative_humidity - the process of humidification by water (isenthalpic) to a given relative humidity ratio.
• humidification_by_water_to_absolute_humidity - the process of humidification by water (isenthalpic) to a given absolute humidity ratio.
• humidification_by_steam_to_relative_humidity - the process of humidification by steam (isothermal) to a given relative humidity ratio.
• humidification_by_steam_to_absolute_humidity - the process of humidification by steam (isothermal) to a given absolute humidity ratio.
• mixing - the mixing process.
• as_json - converts the humid air instance to a JSON string.
• as_dict - converts the humid air instance to a dict.

Examples

Pure fluids

To calculate the specific heat of saturated water vapor at 1 atm:

from pyfluids import Fluid, FluidsList

water_vapour = Fluid(FluidsList.Water).dew_point_at_pressure(101325)
print(water_vapour.specific_heat)  # 2079.937085633241

Incompressible binary mixtures

To calculate the dynamic viscosity of propylene glycol aqueous solution with 60 % mass fraction at 100 kPa and -20 °C:

from pyfluids import Fluid, FluidsList, Input

propylene_glycol = Fluid(FluidsList.MPG, 60).with_state(
    Input.pressure(100e3), Input.temperature(-20)
)
print(propylene_glycol.dynamic_viscosity)  # 0.13907391053938878

Mixtures

To calculate the density of ethanol aqueous solution (with ethanol 40 % mass fraction) at 200 kPa and 4 °C:

from pyfluids import Mixture, FluidsList, Input

mixture = Mixture([FluidsList.Water, FluidsList.Ethanol], [60, 40]).with_state(
    Input.pressure(200e3), Input.temperature(4)
)
print(mixture.density)  # 883.3922771627963

Humid air

To calculate the wet bulb temperature of humid air at 300 m above sea level, 30 °C and 50 % relative humidity:

from pyfluids import HumidAir, InputHumidAir

humid_air = HumidAir().with_state(
    InputHumidAir.altitude(300),
    InputHumidAir.temperature(30),
    InputHumidAir.relative_humidity(50),
)
print(humid_air.wet_bulb_temperature)  # 21.917569033181564

Equality of instances

You can simply determine the equality of Fluid, Mixture and HumidAir instances by its state. Just use the equality operators (== or !=). Exactly the same way you can compare inputs (Input and InputHumidAir).

For example:

from pyfluids import HumidAir, InputHumidAir

humid_air = HumidAir().with_state(
    InputHumidAir.altitude(0),
    InputHumidAir.temperature(20),
    InputHumidAir.relative_humidity(50),
)
same_humid_air = HumidAir().with_state(
    InputHumidAir.pressure(101325),
    InputHumidAir.temperature(20),
    InputHumidAir.relative_humidity(50),
)
print(humid_air == same_humid_air)  # True
print(InputHumidAir.altitude(0) == InputHumidAir.pressure(101325))  # True

Converting to a JSON string

The Fluid, Mixture and HumidAir classes have a method as_json, which performs converting of instance to a JSON string. For example, converting a Fluid instance to an indented JSON string:

from pyfluids import Fluid, FluidsList

refrigerant = Fluid(FluidsList.R32).dew_point_at_temperature(5)
print(refrigerant.as_json())

As a result:

{
    "compressibility": 0.8266625877210833,
    "conductivity": 0.013435453854396475,
    "critical_pressure": 5782000.0,
    "critical_temperature": 78.10500000000002,
    "density": 25.89088151061046,
    "dynamic_viscosity": 1.2606543144761657e-05,
    "enthalpy": 516105.7800378023,
    "entropy": 2136.2654412978777,
    "fraction": 100,
    "freezing_temperature": null,
    "internal_energy": 479357.39743435377,
    "kinematic_viscosity": 4.869105418289953e-07,
    "max_pressure": 70000000.0,
    "max_temperature": 161.85000000000002,
    "min_pressure": 47.999893876059375,
    "min_temperature": -136.80999999999997,
    "molar_mass": 0.052024,
    "name": "R32",
    "phase": "TwoPhase",
    "prandtl": 1.2252282243443504,
    "pressure": 951448.019691762,
    "quality": 100.0,
    "sound_speed": 209.6337575990297,
    "specific_heat": 1305.7899441785378,
    "specific_volume": 0.03862363664945844,
    "surface_tension": 0.010110117241546162,
    "temperature": 5.0,
    "triple_pressure": 47.999893876059375,
    "triple_temperature": -136.80999999999997,
    "units_system": "SIWithCelsiusAndPercents"
}

Converting to a Python dict

The Fluid, Mixture and HumidAir classes have a method as_dict, which performs converting of instance to a Python dict. For example:

from pyfluids import Fluid, FluidsList

refrigerant = Fluid(FluidsList.R32).dew_point_at_temperature(5)
print(refrigerant.as_dict())  # {'compressibility': 0.8266625877210833, 'conductivity': ... 

Deep cloning

The Fluid, Mixture and HumidAir classes have a method clone, which performs deep (full) copy of instance:

from pyfluids import Fluid, FluidsList, Input

origin = Fluid(FluidsList.Water).with_state(
    Input.pressure(101325), Input.temperature(20)
)
clone = origin.clone()
print(origin == clone)  # True
clone.update(Input.pressure(101325), Input.temperature(30))
print(origin == clone)  # False

Adding other properties

• An example for the Fluid and Mixture.
• An example for the HumidAir.

Adding other inputs

• An example for the Fluid and Mixture.
• An example for the HumidAir.