Data for ATS58 phase change material.

Reference: https://www.axiotherm.de/en/download/project/productdatasheet/file/19/

T_s = 56+273.15 (solidification temperature) T_l = 58+273.15 (liquid temperature) k_s = 1 (solid thermal conductivity) k_l = 0.6 (liquid thermal conductivity) h_f = 240000 (latent heat of fusion) cp = 3000 (specific heat capacity at constant pressure) rho_l = 1280 (liquid density) rho_s = 1280 (solid density) h_s = T_scp (mass specific enthalpy before phase change) h_l = T_scp+h_f (mass specific enthalpy at after phase change)

T(h, p=None)

Temperature as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant cp with phase change).

Parameters:

Name	Type	Description	Default
h	float	Specific enthalpy in J/kg	required
p	float	Pressure in Pa	None

Returns:

Type	Description
float	Temperature in kelvin

Source code in openterrace/bed_substances/ATS58.py

def T(h:float, p:float=None) -> float:
    """Temperature as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant cp with phase change).

    Args:
        h (float): Specific enthalpy in J/kg
        p (float): Pressure in Pa

    Returns:
        Temperature in kelvin
    """
    return np.piecewise(h, [h <= _h_s, (h > _h_s) & (h <= _h_l), h > _h_l], [lambda h: 1/_cp*h, lambda h: _T_s + (_T_l-_T_s)*(h-_h_s)/(_h_l-_h_s), lambda h: _T_l + 1/_cp*(h-_h_l)])

cp(h, p=None)

Specific heat capacity as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant cp with phase change).

Parameters:

Name	Type	Description	Default
h	float	Specific enthalpy in J/kg	required
p	float	Pressure in Pa	None

Returns:

Name	Type	Description
float	float	Specific heat capacity in J/(kg K)

Source code in openterrace/bed_substances/ATS58.py

def cp(h:float, p:float=None) -> float:
    """Specific heat capacity as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant cp with phase change).

    Args:
        h (float): Specific enthalpy in J/kg
        p (float): Pressure in Pa

    Returns:
        float: Specific heat capacity in J/(kg K)
    """
    return _cp*h**0

h(T)

Mass specific enthalpy as function of temperature at 1 atm (fit assumes piecewice constant cp with phase change).

Parameters:

Name	Type	Description	Default
T	float	Temperature in K	required

Returns:

Type	Description
float	Specific enthalpy in J/kg

Source code in openterrace/bed_substances/ATS58.py

def h(T:float) -> float:
    """Mass specific enthalpy as function of temperature at 1 atm (fit assumes piecewice constant cp with phase change).

    Args:
        T (float): Temperature in K

    Returns:
        Specific enthalpy in J/kg
    """
    return np.piecewise(T, [T <= _T_s, (T > _T_s) & (T <= _T_l), T > _T_l], [lambda T: _cp*T, lambda T: _h_s + (T-_T_s)/(_T_l-_T_s)*_h_f, lambda T: _h_l + _cp*(T-_T_l)])

k(h, p=None)

Thermal conductivity as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant k).

Parameters:

Name	Type	Description	Default
h	float	Specific enthalpy in J/kg	required
p	float	Pressure in Pa	None

Returns:

Name	Type	Description
float	float	Thermal conductivity in W/(m K)

Source code in openterrace/bed_substances/ATS58.py

def k(h:float, p:float=None) -> float:
    """Thermal conductivity as function of mass specific enthalpy at 1 atm (fit assumes piecewice constant k).

    Args:
        h (float): Specific enthalpy in J/kg
        p (float): Pressure in Pa

    Returns:
        float: Thermal conductivity in W/(m K)
    """
    return np.piecewise(h, [h <= _h_s, (h > _h_s) & (h <= _h_l), h > _h_l], [_k_s, lambda h: _k_s + (_k_l-_k_s)/(_h_l-_h_s)*(h-_h_s), _k_l])

rho(h, p=None)

Density as function of mass specific entahlpy at 1 atm (fit assumes constant density).

Parameters:

Name	Type	Description	Default
h	float	Specific enthalpy in J/kg	required
p	float	Pressure in Pa	None

Returns:

Name	Type	Description
float	float	Density in kg/m^3

Source code in openterrace/bed_substances/ATS58.py

def rho(h:float, p:float=None) -> float:
    """Density as function of mass specific entahlpy at 1 atm (fit assumes constant density).

    Args:
        h (float): Specific enthalpy in J/kg
        p (float): Pressure in Pa

    Returns:
        float: Density in kg/m^3
    """
    return _rho_l*h**0