In Brief
Urban Heat Islands as Heating Sources
Climate change and the heat island effect have caused not only a rise in surface temperature in large cities. The ground water likewise has warmed up. In a project coordinated at the KIT, scientists investigated the geothermal potential of ground water reservoirs close to the surface in conurbation areas. The result: Enormous heating sources lay dormant underneath cities.
Measurements conducted by scientists both in Cologne and in Winnipeg, Canada have revealed an increase of ground water temperatures of up to five degrees compared to the rural hinterland. Using geothermal heat pumps, for example, this energy could be used to efficiently heat houses in winter and cool them in summer. The researchers calculated that if in Cologne the water in an approximately 20 metre thick underground reservoir was tapped and cooled down by only two degrees, the annual heating demand of all residential buildings in the city could be covered for from at least two and a half to a maximum of 20 years. In mega-cities such as Shanghai and Tokyo the ground water could even provide heating warmth for several decades.
