Science – Society – Technology
Table 2 Parameters used in the model
From: Optimization of the utilization of deep borehole heat exchangers
Parameter | Symbol | Amount | Unit |
|---|---|---|---|
Borehole diameter | db | 0.2 | m |
Inner pipe outer diameter | dpo | 0.09 | m |
Inner pipe wall thickness | ti | 0.00734 | m |
Outer pipe outer diameter | deo | 0.177 | m |
Outer pipe wall thickness | te | 0.00587 | m |
Flow rate | w | 11.6 | L s−1 |
Pipe wall thermal conductivity | \(k_{\text{pp}} , k_{\text{ep}}\) | 0.5 | W m−1 K−1 |
Grout thermal conductivity | \(k_{g}\) | 0.73 | W m−1 K−1 |
Grout volumetric heat capacity | \(c_{g}\) | 3.8 × 106 | J m−3 K−1 |
Water density | \(\rho\) | 1000 | kg m−3 |
Water volumetric heat capacity | \(c_{f}\) | 4.19 × 106 | J m−3 K−1 |
Water thermal conductivity | \(k_{f}\) | 0.59 | W m−1 K−1 |
Water viscosity | \(\mu_{f}\) | 1.14 × 10−3 | kg m−1 s−1 |
Water Prandtl number | Pr | 8.09 | – |
Average ground temperature | Ts | 15 | °C |
Borehole depth | D | 2000 | m |