When Cooling Heats the City: Heat Pumps, Urban Heat Islands, and 5th Generation District Cooling

As buildings electrify and cooling demand increases, sustainable cooling becomes more than a building-energy problem. This presentation examines how cooling interacts with urban heat in the Brussels European Quarter, focusing on the heat that buildings remove and where that heat is ultimately rejected, reused, or stored. It shows how urban morphology influences heat exposure, how renovation and electrification can increase the importance of cooling loads, and why heat-pump performance depends strongly on the available heat sink. The presentation then explores a district-scale approach in which buildings, neighboring thermal demands, shallow geothermal resources, seasonal storage, and residual environmental heat rejection are considered together. Drawing on Brussels-specific evidence and fifth-generation district heating and cooling principles, it argues for expanding the control boundary from the individual building to the district. The central message is that sustainable cooling is not only about producing cooling efficiently, but about managing the destination of the heat that cooling moves.