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| Titel |
Comparison of local and regional heat transport processes into the subsurface urban heat island of Karlsruhe, Germany |
| VerfasserIn |
Susanne Benz, Peter Bayer, Kathrin Menberg, Philipp Blum |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094850
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| Publikation (Nr.) |
 EGU/EGU2014-11252.pdf |
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| Zusammenfassung |
| Temperatures in shallow urban ground are typically elevated. They manifest as subsurface
urban heat islands, which are observed worldwide in different metropolitan areas and which
have a site-specific areal extent and intensity. As of right now the governing heat transport
processes accumulating heat in the subsurface of cities are insufficiently understood. Based
on a spatial assessment of groundwater temperatures, six individual heat flux processes could
be identified: (1) heat flux from elevated ground surface temperatures (GST), (2) heat flux
from basements of buildings, (3) reinjection of thermal waste water, (4) sewage drains, (5)
sewage leakage, and (6) district heating. In this study, the contributions of these processes
are quantified on local and regional scales for the city of Karlsruhe in Germany.
For the regional scale, the Regionalized Monte Carlo (RMC) method is used. This
method applies a single Monte Carlo (MC) simulation for the entire study area.
At relatively low data demand, the RMC method provides basic insights into the
heat contribution for the entire city. For the local scale, the Local Monte Carlo
(LMC) method was developed and applied. This method analyzes all dominant
heat fluxes spatially dependent by performing an MC simulation for each arbitrary
sized pixel of the study area (here 10 x 10 m). This more intricate approach allows
for a spatial representation of all heat flux processes, which is necessary for the
local planning of geothermal energy use. In order to evaluate the heat transport
processes on a regional scale, we compared the mean annual thermal energies that result
from the individual heat flux processes. Both methods identify the heat flux from
elevated GST and the heat flux from buildings as the dominant regional processes.
However, reinjection of thermal wastewater is by far the most dominant local heat
flux processes with an average heat flux of 16 ± 2 W/m2 in the affected areas.
Although being dominant on the regional scale, fluxes from elevated GST and buildings
only contribute with minor heat fluxes of 0.1 ± 0.3 W/m2 and 0.7 ± 0.8 W/m2,
respectively, which clearly shows that such differences in heat fluxes should be
carefully considered for the site specific and local planning of geothermal installations. |
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