Double U-tube Grouted Borehole

class bhr.double_u_borehole.DoubleUTube(borehole_diameter: float, pipe_outer_diameter: float, pipe_dimension_ratio: float, length: float, shank_space: float, pipe_conductivity: float, pipe_inlet_arrangement: str, grout_conductivity: float, soil_conductivity: float, fluid_type: str, fluid_concentration: float = 0)

Bases: UTube

calc_bh_resist_local(m_dot_per_u_tube: float, temperature: float) → float

Calculates tube-to-borehole resistance (aka local borehole resistance).

Claesson, Johan, and Saqib Javed. 2019. “Explicit Multipole Formulas and Thermal Network Models for Calculating Thermal Resistances of Double U-Pipe Borehole Heat Exchangers.” Science and Technology for the Built Environment 25 (8): 980-92. doi:10.1080/23744731.2019.1620565.

Eq: 13 & 14

Parameters:

• m_dot_per_u_tube – mass flow rate in each u-tube, kg/s

• temperature – temperature, Celsius

Returns:

borehole_resist_local: local borehole resistance, K/(W/m)

calc_effective_bh_resistance_ubwt(m_dot: float, temp: float) → float

Calculates effective borehole resistance for uniform borehole wall temperature.

Claesson, Johan, and Saqib Javed. 2019. “Explicit Multipole Formulas and Thermal Network Models for Calculating Thermal Resistances of Double U-Pipe Borehole Heat Exchangers.” Science and Technology for the Built Environment 25 (8): 980-92. doi:10.1080/23744731.2019.1620565.

Eq: 46

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, Celsius

Returns:

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

calc_effective_bh_resistance_uhf(m_dot: float, temp: float) → float

Calculates effective borehole resistance for uniform heat flux along the borehole.

Claesson, Johan, and Saqib Javed. 2019. “Explicit Multipole Formulas and Thermal Network Models for Calculating Thermal Resistances of Double U-Pipe Borehole Heat Exchangers.” Science and Technology for the Built Environment 25 (8): 980-92. doi:10.1080/23744731.2019.1620565.

Eq: 44

Parameters:

• m_dot – mass flow rate, kg/s

• temp – temperature, Celsius

Returns:

effective_bhr_uhf: effective borehole resistance under uniform heat flux boundary conditions [K/(W/m)]

calc_internal_resist(m_dot_per_u_tube: float, temperature: float) → float

Calculates tube-to-tube resistance (aka internal resistance).

Claesson, Johan, and Saqib Javed. 2019. “Explicit Multipole Formulas and Thermal Network Models for Calculating Thermal Resistances of Double U-Pipe Borehole Heat Exchangers.” Science and Technology for the Built Environment 25 (8): 980-92. doi:10.1080/23744731.2019.1620565.

Eq: 18, 19, 22, 23

Parameters:

• m_dot_per_u_tube – mass flow rate in each u-tube, kg/s

• temperature – temperature, Celsius

Returns:

internal_resist: local internal resistance, K/(W/m)

update_b1(m_dot_per_u_tube: float, temperature: float) → float

Updates b1 coefficient.

Javed, S. & Spitler, J.D. Calculation of Borehole Thermal Resistance. In ‘Advances in Ground-Source Heat Pump Systems,’ pp. 84. Rees, S.J. ed. Cambridge, MA. Elsevier Ltd. 2016.

Eq: 3-47

Javed, S. & Spitler, J.D. 2017. ‘Accuracy of Borehole Thermal Resistance Calculation Methods for Grouted Single U-tube Ground Heat Exchangers.’ Applied Energy.187:790-806.

Eq: 14

Parameters:

• m_dot_per_u_tube – mass flow rate in each u-tube, kg/s

• temperature – temperature, Celsius

Returns:

b1: a ratio of (1-beta)/(1+beta), dependent on pipe resistance & grout conductivity, dimensionless