Table 3 Input parameters for the estimation of the heat supply rate

Hydrogeology

 Darcy velocity^a

\(v_{\text{fUA}}\)

3.5 × 10⁻⁶ m/s

\(v_{\text{fLA}}\)

3.3 × 10⁻⁷ m/s

\(v_{{\text{fUA}}+{\text{LA}}}\)

1.76 × 10⁻⁶ m/s

 Groundwater velocity^a

\(v_{\text{aUA}}\)

1.17 × 10⁻⁵ m/s

\(v_{\text{aLA}}\)

1.65 × 10⁻⁶ m/s

\(v_{{\text{aUA}}+{\text{LA}}}\)

8.78 × 10⁻⁶ m/s

 Porosity^b

\(p_{\text{UA}}\)

0.2

\(p_{\text{LA}}\)

0.1

\(p_{{\text{UA}}+{\text{LA}}}\)

0.14

 Hydraulic conductivity^c

\(K_{\text{UA}}\)

3.5 × 10⁻³ m/s

\(K_{\text{LA}}\)

3.3 × 10⁻⁴ m/s

\(K_{{\text{UA}}+{\text{LA}}}\)

1.66 × 10⁻³ m/s

 Hydraulic gradient^d

i

0.001

 Aquifer thickness^e

\(m_{\text{UA}}\)

13 m

\(m_{\text{LA}}\)

18 m

\(m_{{\text{UA}}+{\text{LA}}}\)

31 m

 Longitudinal thermal dispersivity^f

\( a_{\text{L}}\)

3.4 m

 Transversal thermal dispersivity^g

\(a_{\text{T}}\)

0.34 m

 Retardation factor^h

R

2

 Volumetric heat capacity of waterⁱ

\(c_{\text{pw}}\)

4.16 × 10⁶ J/m³K

Geothermal system

 Relative annual operation period (heating + DHW)^j

\(t_{\text{h}}\)

1700 h

 Heat extraction rate hGSHP^k

\(q_{\text{hGSHP}}\)

33 W/m²

 BHE length

\(l_{\text{vGSHP}}\) ^m

17 m

\(l_{\text{vGSHP}} \) ^l

100 m

 Heat extraction rate vGSHP

\(q_{\text{vGSHP}}\) ^j

60 W/m

\(q_{\text{vGSHP}}\) ⁱ

100 W/m

 Hours per year

\( t_{\text{y}}\)

8760 h

 Temperature difference^g

\(\Delta \)T

6 K

 Time after reinjection^g

t

1000 d

 Coefficient of performance^g,n

COP

4

Rintheimer Feld^j

 Number of refurbished buildings

31

 Area RF

\(A_{\text{RF}}\)

0.13 km²

 Average space heating demand: before refurbishment

\(h_{\text{b}}\)

136 kWh/m²

 Average space heating demand: after refurbishment

\(h_{\text{a}}\)

50 kWh/m²

 Total thermal energy demand: before refurbishment

\(H_{\text{b}}\)

10.12 GWh

 Total thermal energy demand: after refurbishment

\(H_{\text{a}}\)

4.79 GWh