Study finds that geothermal energy could be harnessed from underground car parks

A study published earlier this year at the Science of the Total Environment journal deducted that heat trapped in underground car parks can be retrieved in the form of geothermal energy.

Furthermore, the study investigated the thermal impact of 31 underground car parks in six cities, and then expanded the analysis to 5,040 underground car parks in Berlin.

It was found that heat produced by car engines stays trapped in underground car parks, creating heat islands, and raising the temperature of groundwater.

Several factors were found to play a part in how temperatures vary in underground car parks. Namely, top floors directly under the ground were found to have lower temperatures compared to floors below them.

In addition to this, higher temperatures were observed in public underground car parks, compared to private ones, with the reason behind it being that public ones generally experience more traffic and hence, more warm engines that transfer heat to them.

Calculations showed that the yearly average thermal energy that is emitted into Berlin’s groundwater is equal to 652.6 TJ.

The study suggests that shallow geothermal methods, as well as heat pumps integrated into existing ventilation systems could harness this thermal energy and provide for the average heating demand of 14,660 German households, or 26,639 people.