Skip to main content

Science – Society – Technology

Geothermal Energy Cover Image

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

From: Meeting the demand: geothermal heat supply rates for an urban quarter in Germany

Parameter Symbol Value
Hydrogeology
 Darcy velocitya \(v_{\text{fUA}}\) 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 velocitya \(v_{\text{aUA}}\) 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
 Porosityb \(p_{\text{UA}}\) 0.2
\(p_{\text{LA}}\) 0.1
\(p_{{\text{UA}}+{\text{LA}}}\) 0.14
 Hydraulic conductivityc \(K_{\text{UA}}\) 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 gradientd i 0.001
 Aquifer thicknesse \(m_{\text{UA}}\) 13 m
\(m_{\text{LA}}\) 18 m
\(m_{{\text{UA}}+{\text{LA}}}\) 31 m
 Longitudinal thermal dispersivityf \( a_{\text{L}}\) 3.4 m
 Transversal thermal dispersivityg \(a_{\text{T}}\) 0.34 m
 Retardation factorh 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 hGSHPk \(q_{\text{hGSHP}}\) 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 differenceg \(\Delta \)T 6 K
 Time after reinjectiong t 1000 d
 Coefficient of performanceg,n COP 4
Rintheimer Feldj
 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
  1. UA Upper Aquifer, LA Lower Aquifer
  2. aCalculated based on Hölting and Coldewey (2013)
  3. bBusch et al. (1974)
  4. cWirsing and Luz (2007)
  5. dTiefbauamt, City of Karlsruhe
  6. eLGRB (2005)
  7. fBeims (1983)
  8. gBaden-Württemberg (2009a)
  9. hMolina-Giraldo (2011)
  10. iVDI 4640, part 2 (2001)
  11. jJank and Kuklinski (2015)
  12. kRamming (2007)
  13. lBBergG (1980)
  14. mLGRB (2017)
  15. nMiglani et al. (2018)