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Class: ThermalResistance

The ThermalResistance class is a subclass of Variable designed to represent a material's resistance to heat flow. It simplifies calculations by internally storing all values in its base SI unit, Kelvin per Watt (K/W).

Supported Units

The following units are supported for initialization and conversion. Note that some units, like degrees Celsius per Watt (K/W), are numerically equivalent to the base SI unit.

Unit str Conversion Factor to Kelvin per Watt (K/W)
Kelvin per Watt K/W 1
Celsius per Watt C/W 1
hour-foot²-degree Fahrenheit per British Thermal Unit hft2F/BTU 0.1761
meter²-Kelvin per Watt m2K/W 1

Class Reference

class ThermalResistance(value, units='K/W')

A class for handling thermal resistance measurements with automatic unit conversion.

Parameters:

  • value : float or int
    The numeric value of the thermal resistance. Must be a positive number.
  • units : str, default='K/W'
    The unit of the provided value. Must be one of the supported units.

Raises:

  • ValueError : If value is not a positive number.
  • TypeError : If units is not a valid unit.

Examples: 

# Create a ThermalResistance object for a value of 0.5 K/W  
>>> r1 = ThermalResistance(0.5, "K/W")

# Create a ThermalResistance object of 2 C/W (numerically equivalent to 2 K/W)  
>>> r2 = ThermalResistance(2, "C/W")

Properties

Property Type Description
.value float The numeric value of the thermal resistance, always in Kelvin per Watt (K/W). This is the internal representation used for all calculations.
.original\value float The numeric value as provided during initialization.
.original\unit str The unit as provided during initialization.

Methods

to(target_unit)

Returns a new ThermalResistance object converted to the target_unit. The original object remains unchanged.

Parameters:

  • target_unit : str
    The unit to convert to. Must be one of the supported units.

Returns:

  • ThermalResistance
    A new ThermalResistance object with the same value, represented in the target unit.

Raises:

  • TypeError : If target_unit is not a valid unit.

Examples: 

# Initialize a thermal resistance of 2 K/W  
>>> r_K = ThermalResistance(2)

# Convert to hrft2F/BTU  
>>> r_BTU = r_K.to("hrft2F/BTU")

>>> print(r_BTU)  
11.353457 hrft2F/BTU

String Representation

  • __str__(self)
    Returns a human-readable string representation of the thermal resistance, rounded to six decimal places, using its original value and unit.
  • __repr__(self)
    Returns a string representation suitable for developers and debugging.