Coaxial Grouted Borehole

class bhr.coaxial_borehole.Coaxial(borehole_diameter: float, outer_pipe_outer_diameter: float, outer_pipe_dimension_ratio: float, outer_pipe_conductivity: float, inner_pipe_outer_diameter: float, inner_pipe_dimension_ratio: float, inner_pipe_conductivity: float, length: float, grout_conductivity: float, soil_conductivity: float, fluid_type: str, fluid_concentration: float)

Bases: object

calc_cond_resist() → tuple[float, float]

Computes the pipe conduction resistance for the inner and outer pipes. :return: pipe conduction resistance, K/(W/m)

calc_conv_resist(m_dot, temp) → tuple[float, float]

Computes the convection resistance for the inner pipe and annular space between inner and outer pipes. :param m_dot: mass flow rate, kg/s :param temp: temperature, C :return: convection resistance, K/(W/m)

calc_conv_resist_annulus(m_dot, temp)

Grundmann, Rachel Marie. “Improved design methods for ground heat exchangers.” Master’s thesis, Oklahoma State University, 2016.

Eqns 4.4 - 4.11

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, C

Returns:

r_conv_outside_inner_pipe: convective resistances along the outer wall of the inner pipe, K/(W/m)

Returns:

r_conv_inside_outer_pipe: convective resistance along the inside wall of the outer pipe, K/(W/m)

calc_effective_bh_resistance_ubwt(m_dot, temp)

Grundmann, Rachel Marie. “Improved design methods for ground heat exchangers.” Master’s thesis, Oklahoma State University, 2016.

Eqns 4.28 & 4.29

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, C

Returns:

effective_bhr_ubwt: effective borehole resistance for uniform borehole wall temperature boundary condition, K/(W/m)

calc_effective_bh_resistance_uhf(m_dot, temp)

Grundmann, Rachel Marie. “Improved design methods for ground heat exchangers.” Master’s thesis, Oklahoma State University, 2016.

Eqn 4.33

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, C

Returns:

effective_bhr_uhf: effective borehole resistance for uniform heat flux boundary condition, K/(W/m)

calc_fluid_pipe_resist(m_dot, temp)

Calculates the combined convection resistance of the annular space and the conduction resistance of the outer pipe. :param m_dot: mass flow rate, kg/s :param temp: temperature, C :return: annular convection resistance and outer pipe conduction resistance, K/(W/m)

calc_local_bh_resistance(m_dot, temp)

Grundmann, Rachel Marie. “Improved design methods for ground heat exchangers.” Master’s thesis, Oklahoma State University, 2016.

Eqns 4.4 and 4.5

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, C

Returns:

local_bh_resist: total local borehole resistance K /(W/m)

Returns:

r_internal_resist: local internal borehole resistance K /(W/m)

Returns:

r_borehole_resist: local borehole resistance K /(W/m)

laminar_nusselt_annulus()

Laminar Nusselt numbers for annulus flow

Hellström, G. 1991. Ground Heat Storage: Thermal Analyses of Duct Storage Systems. Department of Mathematical Physics, University of Lund, Sweden. pp 67-71

Returns:

nu_ii: Laminar Nusselt number for inner surface of annulus pipe

Returns:

nu_oo: Laminar Nusselt number for outer annulus pipe surface

re_annulus(m_dot, temp)

Reynolds number for annulus flow

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, C

Returns:

Reynolds number

turbulent_nusselt_annulus(re, temp)

Turbulent Nusselt numbers for annulus flow

Grundmann, Rachel Marie. “Improved design methods for ground heat exchangers.” Master’s thesis, Oklahoma State University, 2016.

Eqns 4.10 and 4.11 based on the Dittus-Boelter equation

Parameters:

• re – Reynolds number

• temp – temperature, C

Returns:

nu_ii: Turbulent Nusselt number for inner surface of annulus pipe

Returns:

nu_oo: Turbulent Nusselt number for outer annulus pipe surface