honeybee_energy.material.gas module

Gas materials representing gaps within window constructions.

They can only exist within window constructions bounded by glazing materials (they cannot be in the interior or exterior layer).

class honeybee_energy.material.gas.EnergyWindowMaterialGas(*args, **kwargs)[source]

Bases: honeybee_energy.material.gas._EnergyWindowMaterialGasBase

Gas gap layer.

Parameters
  • identifier – Text string for a unique Material ID. Must be < 100 characters and not contain any EnergyPlus special characters. This will be used to identify the object across a model and in the exported IDF.

  • thickness – Number for the thickness of the air gap layer [m]. Default: 0.0125

  • gas_type – Text describing the type of gas in the gap. Must be one of the following: ‘Air’, ‘Argon’, ‘Krypton’, ‘Xenon’. Default: ‘Air’

Properties:
  • identifier

  • display_name

  • thickness

  • gas_type

  • conductivity

  • viscosity

  • specific_heat

  • density

  • prandtl

ToString()

Overwrite .NET ToString.

conductivity_at_temperature(t_kelvin)[source]

Get the conductivity of the gas [W/m-K] at a given Kelvin temperature.

convective_conductance(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in a vertical position.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

convective_conductance_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in an angle.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

density_at_temperature(t_kelvin, pressure=101325)

Get the density of the gas [kg/m3] at a given temperature and pressure.

This method uses the ideal gas law to estimate the density.

Parameters
  • t_kelvin – The average temperature of the gas cavity in Kelvin.

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

duplicate()

Get a copy of this construction.

classmethod from_dict(data)[source]

Create a EnergyWindowMaterialGas from a dictionary.

Parameters

data – A python dictionary in the following format

{
"type": 'EnergyWindowMaterialGas',
"identifier": 'Argon_Gap_0010',
"display_name": 'Argon Gap',
"thickness": 0.01,
"gas_type": 'Argon'
}
classmethod from_idf(idf_string)[source]

Create EnergyWindowMaterialGas from an EnergyPlus text string.

Parameters

idf_string – A text string fully describing an EnergyPlus material.

grashof(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Grashof number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

lock()
nusselt(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a vertical cavity given the temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

nusselt_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a cavity at a given angle, temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

prandtl_at_temperature(t_kelvin)

Get the Prandtl number of the gas at a given Kelvin temperature.

radiative_conductance(emissivity_1=0.84, emissivity_2=0.84, t_kelvin=273.15)

Get the radiative conductance of the cavity given emissivities on both sides.

Parameters
  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

rayleigh(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Rayleigh number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

specific_heat_at_temperature(t_kelvin)[source]

Get the specific heat of the gas [J/kg-K] at a given Kelvin temperature.

to_dict()[source]

Energy Material Gas dictionary representation.

to_idf()[source]

Get an EnergyPlus string representation of the material.

u_value(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

u_value_at_angle(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle – An angle in degrees between 0 and 180. 0 = A horizontal cavity with downward heat flow through the layer. 90 = A vertical cavity 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

unlock()
viscosity_at_temperature(t_kelvin)[source]

Get the viscosity of the gas [kg/m-s] at a given Kelvin temperature.

CONDUCTIVITYCURVES = {'Air': (0.002873, 7.76e-05, 0.0), 'Argon': (0.002285, 5.149e-05, 0.0), 'Krypton': (0.0009443, 2.826e-05, 0.0), 'Xenon': (0.0004538, 1.723e-05, 0.0)}
GASES = ('Air', 'Argon', 'Krypton', 'Xenon')
MOLECULARWEIGHTS = {'Air': 28.97, 'Argon': 39.948, 'Krypton': 83.8, 'Xenon': 131.3}
SPECIFICHEATCURVES = {'Air': (1002.73699951, 0.012324, 0.0), 'Argon': (521.92852783, 0.0, 0.0), 'Krypton': (248.09069824, 0.0, 0.0), 'Xenon': (158.33970642, 0.0, 0.0)}
VISCOSITYCURVES = {'Air': (3.72e-06, 5e-08, 0.0), 'Argon': (3.38e-06, 6e-08, 0.0), 'Krypton': (2.21e-06, 8e-08, 0.0), 'Xenon': (1.07e-06, 7e-08, 0.0)}
property conductivity

Conductivity of the gas in the absence of convection at 0C [W/m-K].

property density

Density of the gas at 0C and sea-level pressure [J/kg-K].

property display_name

Get or set a string for the object name without any character restrictions.

If not set, this will be equal to the identifier.

property gas_type

Get or set the text describing the gas in the gas gap layer.

property identifier

Get or set the text string for material identifier.

property is_gas_material

Boolean to note whether the material is a gas gap layer.

property is_glazing_material

Boolean to note whether the material is a glazing layer.

property is_shade_material

Boolean to note whether the material is a shade layer.

property is_window_material

Boolean to note whether the material can be used for window surfaces.

property molecular_weight

Get the gas molecular weight.

property prandtl

Prandtl number of the gas at 0C.

property specific_heat

Specific heat of the gas at 0C [J/kg-K].

property thickness

Get or set the thickess of the gas layer [m].

property viscosity

Viscosity of the gas at 0C [kg/m-s].

class honeybee_energy.material.gas.EnergyWindowMaterialGasCustom(*args, **kwargs)[source]

Bases: honeybee_energy.material.gas._EnergyWindowMaterialGasBase

Custom gas gap layer.

This object allows you to specify specific values for conductivity, viscosity and specific heat through the following formula:

property = A + (B * T) + (C * T ** 2)

where:

  • A, B, and C = regression coefficients for the gas

  • T = temperature [K]

Note that setting properties B and C to 0 will mean the property will be equal to the A coefficient.

Parameters
  • identifier – Text string for a unique Material ID. Must be < 100 characters and not contain any EnergyPlus special characters. This will be used to identify the object across a model and in the exported IDF.

  • thickness – Number for the thickness of the air gap layer [m]. Default: 0.0125

  • conductivity_coeff_a – First conductivity coefficient. Or conductivity in [W/m-K] if b and c coefficients are 0.

  • viscosity_coeff_a – First viscosity coefficient. Or viscosity in [kg/m-s] if b and c coefficients are 0.

  • specific_heat_coeff_a – First specific heat coefficient. Or specific heat in [J/kg-K] if b and c coefficients are 0.

  • conductivity_coeff_b – Second conductivity coefficient. Default = 0.

  • viscosity_coeff_b – Second viscosity coefficient. Default = 0.

  • specific_heat_coeff_b – Second specific heat coefficient. Default = 0.

  • conductivity_coeff_c – Third conductivity coefficient. Default = 0.

  • viscosity_coeff_c – Third viscosity coefficient. Default = 0.

  • specific_heat_coeff_c – Third specific heat coefficient. Default = 0.

  • specific_heat_ratio – A number for the the ratio of the specific heat at contant pressure, to the specific heat at constant volume. Default is 1.0 for Air.

  • molecular_weight – Number between 20 and 200 for the mass of 1 mol of the substance in grams. Default is 20.0.

Properties:
  • identifier

  • display_name

  • thickness

  • conductivity_coeff_a

  • viscosity_coeff_a

  • specific_heat_coeff_a

  • conductivity_coeff_b

  • viscosity_coeff_b

  • specific_heat_coeff_b

  • conductivity_coeff_c

  • viscosity_coeff_c

  • specific_heat_coeff_c

  • specific_heat_ratio

  • molecular_weight

  • conductivity

  • viscosity

  • specific_heat

  • density

  • prandtl

Usage:

co2_gap = EnergyWindowMaterialGasCustom('CO2', 0.0125, 0.0146, 0.000014, 827.73)
co2_gap.specific_heat_ratio = 1.4
co2_gap.molecular_weight = 44
print(co2_gap)
ToString()

Overwrite .NET ToString.

conductivity_at_temperature(t_kelvin)[source]

Get the conductivity of the gas [W/m-K] at a given Kelvin temperature.

convective_conductance(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in a vertical position.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

convective_conductance_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in an angle.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

density_at_temperature(t_kelvin, pressure=101325)

Get the density of the gas [kg/m3] at a given temperature and pressure.

This method uses the ideal gas law to estimate the density.

Parameters
  • t_kelvin – The average temperature of the gas cavity in Kelvin.

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

duplicate()

Get a copy of this construction.

classmethod from_dict(data)[source]

Create a EnergyWindowMaterialGasCustom from a dictionary.

Parameters

data – A python dictionary in the following format

{
"type": 'EnergyWindowMaterialGasCustom',
"identifier": 'CO2_0010_00146_0000014_82773_140_44',
"display_name": 'CO2'
"thickness": 0.01,
"conductivity_coeff_a": 0.0146,
"viscosity_coeff_a": 0.000014,
"specific_heat_coeff_a": 827.73,
"specific_heat_ratio": 1.4
"molecular_weight": 44
}
classmethod from_idf(idf_string)[source]

Create EnergyWindowMaterialGasCustom from an EnergyPlus text string.

Parameters

idf_string – A text string fully describing an EnergyPlus material.

grashof(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Grashof number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

lock()
nusselt(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a vertical cavity given the temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

nusselt_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a cavity at a given angle, temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

prandtl_at_temperature(t_kelvin)

Get the Prandtl number of the gas at a given Kelvin temperature.

radiative_conductance(emissivity_1=0.84, emissivity_2=0.84, t_kelvin=273.15)

Get the radiative conductance of the cavity given emissivities on both sides.

Parameters
  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

rayleigh(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Rayleigh number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

specific_heat_at_temperature(t_kelvin)[source]

Get the specific heat of the gas [J/kg-K] at a given Kelvin temperature.

to_dict()[source]

Energy Material Gas Custom dictionary representation.

to_idf()[source]

Get an EnergyPlus string representation of the material.

u_value(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

u_value_at_angle(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle – An angle in degrees between 0 and 180. 0 = A horizontal cavity with downward heat flow through the layer. 90 = A vertical cavity 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

unlock()
viscosity_at_temperature(t_kelvin)[source]

Get the viscosity of the gas [kg/m-s] at a given Kelvin temperature.

CONDUCTIVITYCURVES = {'Air': (0.002873, 7.76e-05, 0.0), 'Argon': (0.002285, 5.149e-05, 0.0), 'Krypton': (0.0009443, 2.826e-05, 0.0), 'Xenon': (0.0004538, 1.723e-05, 0.0)}
GASES = ('Air', 'Argon', 'Krypton', 'Xenon')
MOLECULARWEIGHTS = {'Air': 28.97, 'Argon': 39.948, 'Krypton': 83.8, 'Xenon': 131.3}
SPECIFICHEATCURVES = {'Air': (1002.73699951, 0.012324, 0.0), 'Argon': (521.92852783, 0.0, 0.0), 'Krypton': (248.09069824, 0.0, 0.0), 'Xenon': (158.33970642, 0.0, 0.0)}
VISCOSITYCURVES = {'Air': (3.72e-06, 5e-08, 0.0), 'Argon': (3.38e-06, 6e-08, 0.0), 'Krypton': (2.21e-06, 8e-08, 0.0), 'Xenon': (1.07e-06, 7e-08, 0.0)}
property conductivity

Conductivity of the gas in the absence of convection at 0C [W/m-K].

property conductivity_coeff_a

Get or set the first conductivity coefficient.

property conductivity_coeff_b

Get or set the second conductivity coefficient.

property conductivity_coeff_c

Get or set the third conductivity coefficient.

property density

Density of the gas at 0C and sea-level pressure [J/kg-K].

property display_name

Get or set a string for the object name without any character restrictions.

If not set, this will be equal to the identifier.

property identifier

Get or set the text string for material identifier.

property is_gas_material

Boolean to note whether the material is a gas gap layer.

property is_glazing_material

Boolean to note whether the material is a glazing layer.

property is_shade_material

Boolean to note whether the material is a shade layer.

property is_window_material

Boolean to note whether the material can be used for window surfaces.

property molecular_weight

Get or set the molecular weight.

property prandtl

Prandtl number of the gas at 0C.

property specific_heat

Specific heat of the gas at 0C [J/kg-K].

property specific_heat_coeff_a

Get or set the first specific heat coefficient.

property specific_heat_coeff_b

Get or set the second specific heat coefficient.

property specific_heat_coeff_c

Get or set the third specific heat coefficient.

property specific_heat_ratio

Get or set the specific heat ratio.

property thickness

Get or set the thickess of the gas layer [m].

property viscosity

Viscosity of the gas at 0C [kg/m-s].

property viscosity_coeff_a

Get or set the first viscosity coefficient.

property viscosity_coeff_b

Get or set the second viscosity coefficient.

property viscosity_coeff_c

Get or set the third viscosity coefficient.

class honeybee_energy.material.gas.EnergyWindowMaterialGasMixture(*args, **kwargs)[source]

Bases: honeybee_energy.material.gas._EnergyWindowMaterialGasBase

Gas gap layer with a mixture of gasses.

Parameters
  • identifier – Text string for a unique Material ID. Must be < 100 characters and not contain any EnergyPlus special characters. This will be used to identify the object across a model and in the exported IDF.

  • thickness – Number for the thickness of the air gap layer [m]. Default: 0.0125

  • gas_types – A list of text describing the types of gas in the gap. Text must be one of the following: ‘Air’, ‘Argon’, ‘Krypton’, ‘Xenon’. Default: (‘Argon’, ‘Air’)

  • gas_fractions – A list of fractional numbers describing the volumetric fractions of gas types in the mixture. This list must align with the gas_types input list and must sum to 1. Default: (0.9, 0.1).

Properties:
  • identifier

  • display_name

  • thickness

  • gas_types

  • gas_fractions

  • gas_count

  • conductivity

  • viscosity

  • specific_heat

  • density

  • prandtl

ToString()

Overwrite .NET ToString.

conductivity_at_temperature(t_kelvin)[source]

Get the conductivity of the gas [W/m-K] at a given Kelvin temperature.

convective_conductance(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in a vertical position.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

convective_conductance_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get convective conductance of the cavity in an angle.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

density_at_temperature(t_kelvin, pressure=101325)

Get the density of the gas [kg/m3] at a given temperature and pressure.

This method uses the ideal gas law to estimate the density.

Parameters
  • t_kelvin – The average temperature of the gas cavity in Kelvin.

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

duplicate()

Get a copy of this construction.

classmethod from_dict(data)[source]

Create a EnergyWindowMaterialGasMixture from a dictionary.

Parameters

data – A python dictionary in the following format

{
'type': 'EnergyWindowMaterialGasMixture',
'identifier': 'Argon_Mixture_001_095_005',
'display_name': 'Argon Mixture',
'thickness': 0.01,
'gas_types': ['Argon', 'Air'],
'gas_fractions': [0.95, 0.05]
}
classmethod from_idf(idf_string)[source]

Create EnergyWindowMaterialGas from an EnergyPlus text string.

Parameters

idf_string – A text string fully describing an EnergyPlus material.

grashof(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Grashof number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

lock()
nusselt(delta_t=15, height=1.0, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a vertical cavity given the temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

nusselt_at_angle(delta_t=15, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get Nusselt number for a cavity at a given angle, temp difference and height.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle

    An angle in degrees between 0 and 180.

    • 0 = A horizontal cavity with downward heat flow through the layer.

    • 90 = A vertical cavity

    • 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

prandtl_at_temperature(t_kelvin)

Get the Prandtl number of the gas at a given Kelvin temperature.

radiative_conductance(emissivity_1=0.84, emissivity_2=0.84, t_kelvin=273.15)

Get the radiative conductance of the cavity given emissivities on both sides.

Parameters
  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

rayleigh(delta_t=15, t_kelvin=273.15, pressure=101325)

Get Rayleigh number given the temperature difference across the cavity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

specific_heat_at_temperature(t_kelvin)[source]

Get the specific heat of the gas [J/kg-K] at a given Kelvin temperature.

to_dict()[source]

Energy Material Gas Mixture dictionary representation.

to_idf()[source]

Get an EnergyPlus string representation of the material.

u_value(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

u_value_at_angle(delta_t=15, emissivity_1=0.84, emissivity_2=0.84, height=1.0, angle=90, t_kelvin=273.15, pressure=101325)

Get the U-value of a vertical gas cavity given temp difference and emissivity.

Parameters
  • delta_t – The temperature difference across the gas cavity [C]. This influences how strong the convection is within the gas gap. Default is 15C, which is consistent with the NFRC standard for double glazed units.

  • emissivity_1 – The emissivity of the surface on one side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • emissivity_2 – The emissivity of the surface on the other side of the cavity. Default is 0.84, which is typical of clear, uncoated glass.

  • height – An optional height for the cavity in meters. Default is 1.0, which is consistent with NFRC standards.

  • angle – An angle in degrees between 0 and 180. 0 = A horizontal cavity with downward heat flow through the layer. 90 = A vertical cavity 180 = A horizontal cavity with upward heat flow through the layer.

  • t_kelvin – The average temperature of the gas cavity in Kelvin. Default: 273.15 K (0C).

  • pressure – The average pressure of the gas cavity in Pa. Default is 101325 Pa for standard pressure at sea level.

unlock()
viscosity_at_temperature(t_kelvin)[source]

Get the viscosity of the gas [kg/m-s] at a given Kelvin temperature.

CONDUCTIVITYCURVES = {'Air': (0.002873, 7.76e-05, 0.0), 'Argon': (0.002285, 5.149e-05, 0.0), 'Krypton': (0.0009443, 2.826e-05, 0.0), 'Xenon': (0.0004538, 1.723e-05, 0.0)}
GASES = ('Air', 'Argon', 'Krypton', 'Xenon')
MOLECULARWEIGHTS = {'Air': 28.97, 'Argon': 39.948, 'Krypton': 83.8, 'Xenon': 131.3}
SPECIFICHEATCURVES = {'Air': (1002.73699951, 0.012324, 0.0), 'Argon': (521.92852783, 0.0, 0.0), 'Krypton': (248.09069824, 0.0, 0.0), 'Xenon': (158.33970642, 0.0, 0.0)}
VISCOSITYCURVES = {'Air': (3.72e-06, 5e-08, 0.0), 'Argon': (3.38e-06, 6e-08, 0.0), 'Krypton': (2.21e-06, 8e-08, 0.0), 'Xenon': (1.07e-06, 7e-08, 0.0)}
property conductivity

Conductivity of the gas in the absence of convection at 0C [W/m-K].

property density

Density of the gas at 0C and sea-level pressure [J/kg-K].

property display_name

Get or set a string for the object name without any character restrictions.

If not set, this will be equal to the identifier.

property gas_count

An integer indicating the number of gasses in the mixture.

property gas_fractions

Get or set a tuple of numbers the fractions of gases in the gas gap layer.

property gas_types

Get or set a tuple of text describing the gases in the gas gap layer.

property identifier

Get or set the text string for material identifier.

property is_gas_material

Boolean to note whether the material is a gas gap layer.

property is_glazing_material

Boolean to note whether the material is a glazing layer.

property is_shade_material

Boolean to note whether the material is a shade layer.

property is_window_material

Boolean to note whether the material can be used for window surfaces.

property molecular_weight

Get the gas molecular weight.

property prandtl

Prandtl number of the gas at 0C.

property specific_heat

Specific heat of the gas at 0C [J/kg-K].

property thickness

Get or set the thickess of the gas layer [m].

property viscosity

Viscosity of the gas at 0C [kg/m-s].