Skip to main content

Science – Society – Technology

Geothermal Energy Cover Image

Table 2 Parameters used in the model

From: Optimization of the utilization of deep borehole heat exchangers

ParameterSymbolAmountUnit
Borehole diameterdb0.2m
Inner pipe outer diameterdpo0.09m
Inner pipe wall thicknessti0.00734m
Outer pipe outer diameterdeo0.177m
Outer pipe wall thicknesste0.00587m
Flow ratew11.6L s−1
Pipe wall thermal conductivity\(k_{\text{pp}} , k_{\text{ep}}\)0.5W m−1 K−1
Grout thermal conductivity\(k_{g}\)0.73W m−1 K−1
Grout volumetric heat capacity\(c_{g}\)3.8 × 106J m−3 K−1
Water density\(\rho\)1000kg m−3
Water volumetric heat capacity\(c_{f}\)4.19 × 106J m−3 K−1
Water thermal conductivity\(k_{f}\)0.59W m−1 K−1
Water viscosity\(\mu_{f}\)1.14 × 10−3kg m−1 s−1
Water Prandtl numberPr8.09
Average ground temperatureTs15°C
Borehole depthD2000m