returns the psychrometric properties of moist air for the specified parameters.


returns the specified property for the given parameters.

Details and Options

  • spec should be an association with keys corresponding to the following parameters:
  • "DewPointTemperature"dew point temperature
    "DryBulbTemperature"dry bulb temperature
    "HumidityRatio"humidity ratio or specific humidity
    "Pressure"air pressure
    "RelativeHumidity"relative humidity
    "WetBulbTemperature"wet bulb temperature
  • "DryBulbTemperature" is necessary, as is the inclusion of one of the other temperature or humidity measures. "Pressure" is optional.
  • In the case of inclusion of multiple humidity measures, values will be used in the following order of precedence: "DewPointTemperature", "RelativeHumidity", "HumidityRatio", "DewPointTemperature".
  • A list of a single parameter can be supplied to calculate a range of values at once.
  • Unless specified, "Pressure" is assumed to have the value of Quantity[101325,"Pascals"].
  • PsychrometricPropertyData["Properties"] can be used to obtain a list of psychrometric properties.
  • Available properties include:
  • "CompressibilityFactor"compressibility factor
    "DewPointTemperature"dew point temperature
    "DryBulbTemperature"dry bulb temperature
    "HumidityRatio"humidity ratio or specific humidity
    "MolarEnthalpy"molar enthalpy
    "MolarEntropy"molar entropy
    "MolarIsobaricHeatCapacity"isobaric molar heat capacity
    "MolarIsochoricHeatCapacity"isochoric molar heat capacity
    "MolarMass"average molar mass
    "MoleFractionDryAir"mole fraction that is dry air
    "MoleFractionWater"mole fraction that is water vapor
    "PrandtlNumber"ratio of momentum diffusivity to thermal diffusivity
    "Pressure"air pressure
    "PsychrometricConstant"psychrometric constant
    "RelativeHumidity"relative humidity
    "SaturationDegree"degree of saturation
    "SoundSpeed"speed of sound
    "SpecificEnthalpy"specific enthalpy
    "SpecificEntropy"specific entropy
    "SpecificIsobaricHeatCapacity"isobaric specific heat
    "SpecificIsochoricHeatCapacity"isochoric specific heat
    "SpecificVolume"specific volume
    "ThermalConductivity"thermal conductivity
    "ThermalDiffusivity"thermal diffusivity
    "WetBulbTemperature"wet bulb temperature
  • Properties are returned using Quantity where appropriate.
  • Entropy and enthalpy properties are calibrated to be approximately zero for dry air at standard atmospheric pressure and 0 degrees Celsius.
  • PsychrometricPropertyData takes the option UnitSystem, which has the settings "Imperial" and "Metric".
  • PsychrometricPropertyData is based on a wide range of sources, with enhancement at Wolfram Research by both human and algorithmic processing.


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Basic Examples  (1)

Determine the relative humidity from other psychrometric parameters:

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Calculate the dew point temperature:

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Include pressure in calculations for the humidity ratio:

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Scope  (3)

Options  (2)

Applications  (3)

Properties & Relations  (1)

Possible Issues  (2)

Neat Examples  (2)

Introduced in 2017