Freiburg, a city located at the western foot of the Black Forest, has an average annual temperature of betweenBetween 7 ℃ and 15 ℃, it may drop to below zero at night, with an average of about 30 days of snow accumulation per year,Residents have a strong demand for centralized heating.

In the era of traditional heating, cities mainly relied on gas boilers and waste incineration waste heat, with low thermal efficiency and limited emission control technology，Exacerbating air pollution and greenhouse effect; Distributed heat sources are difficult to achieve economies of scale and have insufficient energy utilization efficiency40%, a large amount of low-grade waste heat is directly discharged, and the coverage of the heating network is limited, which can only meet the needs of a few communities.To make up for itTraditional heatingShortcoming, Freiburg can only handle a large quantityRelying on imported energy has high economic costs and a heavy burden on residents' heating expenses. These issues prompted Freiburg to explore cleaner and more efficient energy utilization paths, laying the groundwork for the birth of industrial waste heat recovery systems later on.

Freiburg once had steel smelting and salt trade as its core industries，fifteenth centuryafterGradually becoming an important industrial and commercial hub in the Upper Rhine region.TREA garbage treatment station in 2005ofEngineers discovered that incineration producesThe waste heat from the 400 ℃ high-temperature flue gas has not been fully utilized, and a four stage heat exchange system has been developed to classify the waste heat for power generation, process heating, and other purposessmallRegional heating. This successful practice has verified the multi-level utilization value of industrial process waste heat，And letFreiburg CityThe government recognizesIndustrial waste heat asThe 'neglected treasure' contains enormous potential，Therefore, the governmentIncorporate waste heat recovery into the systematic engineering of urban governance.

2001，FreiburgThe launch of the Climate Protection Plan requires new buildings to be connected to regional heating networks, forcing the expansion of industrial waste heat supply systems. ButThe environmentally friendly football field, which was put into use in 2019, has become a landmark demonstration project. Through the collaborative power supply mode of a 15000 square meter photovoltaic ceiling and an industrial waste heat pipe network, it intuitively demonstratesMulti energy complementary systemThe feasibility has accelerated public recognition of waste heat utilization. These practices form a positive cycle, driving industrial waste heat from passive treatment to active planning, ultimately evolving into city level energy solutions.

After more than 30 years of exploration, the utilization of waste heat in Freiburg has developed from a technical pilot to a mature model. The current Freiburg industrial waste heat network has formedThe Three VerticalsonehorizontalThe three-dimensional architecture of the system consists of three major industries: waste incineration, biopharmaceuticals, and food processing as the main heat sources vertically, and two energy storage centers in the south and north of the city horizontally connected by intelligent heating networks. The phase change heat storage tank group located in the old port area can store the excess heat energy of the filter factory during low electricity consumption periods and release it during heating peaks. The aquifer heat storage system located 30 meters underground in the exhibition center cleverly utilizes geological structures to achieve cross seasonal energy storage, retaining industrial waste heat collected in summer for use in winter. The core breakthrough of this system lies in dynamically adjusting the flow and temperature of 2400 thermal nodes through machine learning algorithms, making the volatile industrial waste heat output as stable and reliable as municipal heating.

Looking towards the future, Freiburg is promoting the upgrading of waste heat recovery towards intelligence and regionalization，Explore the joint construction of cross-border waste heat exchange networks with Switzerland and France border areas, and expand energy cooperation to the European scale. For the world, Freiburg has validated the use of industrial waste heatThe feasibility of upgrading "waste by-products" into strategic resources provides a reusable solution for other industrial cities to break energy dependence and reduce carbon emissions. It also reshapes the relationship between industry and cities, transforming high energy consuming industries into clean energy providers, and providing a practical paradigm for global cities to explore sustainable development that balances economic, environmental, and social resilience.