Technical and Economic Assessment of Supermarket and Power Substation Waste Heat Integration into Existing District Heating Systems

District heating systems are almost always located in densely populated urban areas where various heat sources are available, such as cooling and refrigeration systems in supermarkets, shopping malls, and power transformers. These urban sources often have a large share of waste heat, which is usually emitted into the environment. This waste heat could be used to partially cover the thermal load in district heating systems. The biggest challenge for their integration is the spatial distribution of urban heat sources in relation to the existing heat network and the temporal distribution of the availability of waste heat energy throughout the year. In this paper, we have developed an economic assessment model for the integration of urban heat sources into existing district heating systems. By the hourly merit order of waste heat utilization technologies based on pinch analysis, we have defined the most suitable integration of urban heat sources into existing district heating systems. Different temperature regimes of the urban source and the existing heat network have been considered. Finally, the method was tested on the case study of a supermarket and power substation located in Zagreb, while the sensitivity analysis was carried out with a focus on various technical and economic boundary conditions.