Up to 50% of energy used today is lost to waste heat. This makes industrial waste heat recovery one of the most effective ways to improve energy efficiency and reduce global carbon emissions. The Aurubis group has taken this very approach in one of their smelters. Waste heat that before was lost to the river Elbe, now has the potential to heat 20 000 homes through the district heating network in Hamburg's Hafencity. An ambitious and challenging project. One challenge was that the hot water used in district heating needed a temperature of at least 90 degrees celsius. To achieve this, Aurubis had to redesign the heating source, increasing the process temperature of the sulfuric acid to approximately 120 degrees celsius. However this added further complications since higher process temperature substantially increased the corrosiveness of the acid. To cope with the corrosive nature of the fluid. Each of the sulfuric acid lines has three heat exchangers using unique Alfa Laval plates made of Hastelloy D-205 material. This nickel based alloy is resistant to concentrated sulfuric acid at high temperatures. A tried and tested solution with more than three hundred units installed worldwide and decades of operation. The recovered heat has a carbon footprint of zero. And when the project has reached its full potential. It could result in a 100 000 tonne per year reduction in CO2 emissions. Equivalent to the energy consumption of 20 000 four person households. Almost every city has untapped heat sources like Aurubis. And Alfa Laval's heat transfer solutions make it possible to harness that energy and reduce carbon emissions. Join us in our hunt for waste energy.