Grout Material

class pygld.GroutMaterial(kth=None, Cp=None)

The GroutMaterial class holds all the thermophysical properties relative to the grout that are required for the modeling of ground-loop heat exchanger systems.

A database of predefined grout materials is available and can be obtained or printed with the get_predefined_materials() and print_predefined_materials() methods. The GroutMaterial can be initialized directly from a predefined material with the init_as(), passing as argument the index of the material in the database.

An Example is available at the end of this section.

Thermal Properties

GroutMaterial.Cp

Volumetric heat capacity in J/m³·K.

Get or set the volumetric heat capacity of the material as a single positive float value.

GroutMaterial.kth

Thermal conductivity in W/m·K.

Get or set the thermal conductivity of the material as a single positive float value.

GroutMaterial.al

Thermal diffusivity in m²/s.

Return the thermal diffusivity of the material as a single positive float value calculated as:

where is the thermal conductivity in W/m·k and is the volumetric heat capacity of the material in J/m³·K.

Utilities

classmethod GroutMaterial.get_predefined_materials()

Return a dict containing the predefined GroutMaterial.

classmethod GroutMaterial.print_predefined_materials(end='\n')

Print all the predefined GroutMaterial.

classmethod GroutMaterial.init_as(material_index)

Initialize the thermal properties of the GroutMaterial based on the specified material index.

This is a convenience function; the member variables can also be initialized manually.

Example

Import and print the list of predefined GroutMaterial:

>>> from pygld import GroundMaterial
>>> GroundMaterial.print_predefined_materials()
Predefined materials for the 'Grout':
    0 - Bentonite 12% ........ kth=0.700 W/m·k, Cp=3900 J/m³·K
    1 - Bentonite/Sand 12%/15% kth=1.500 W/m·k, Cp=3400 J/m³·K
    2 - Water ................ kth=0.600 W/m·k, Cp=4200 J/m³·K

Initialize GroutMaterial from the predefined material at index #1 and print the results:

>>> grout = GroundMaterial.init_as(1)
>>> print(grout)
Grout material: Bentonite/Sand 12%/15%
Thermal conductivity: 1.500 W/m·k
Volumetric heat capacity: 3400 J/m³·K
Thermal diffusivity: 4.41e-04 m²/s

Change the thermal conductivity for another value and print the results:

>>> grout.kth = 1.75
>>> print(grout)
Grout material: User Defined
Thermal conductivity: 1.750 W/m·k
Volumetric heat capacity: 3400 J/m³·K
Thermal diffusivity: 5.15e-04 m²/s

Note that the grout material is now labeled as ‘User defined’.

It is also possible to initialize an empty GroutMaterial and set the value of the properties manually:

>>> grout = GroutMaterial()
>>> grout.kth = 2
>>> grout.Cp = 3500
>>> print(grout)
Grout material: User Defined
Thermal conductivity: 2.000 W/m·k
Volumetric heat capacity: 3500 J/m³·K
Thermal diffusivity: 5.71e-04 m²/s