Flexibility framework for production-related waste heat and internal gains valorization in building energy supply at facility and district scales

The recovery of waste heat from the manufacturing industry for building heating and cooling has a high decarbonization potential. Flexibility measures such as demand response can further enhance energy savings. However, there is a lack of case studies on the utilization of production-related excess heat for building energy supply. Both waste heat availability and production-related internal gains as demand response signals remain unexplored. We present an analysis framework for three scenario types for on-site and off-site industrial excess heat utilization: (I) on-site waste heat demand response for building heating, (II) on-site production-related internal gains demand response, and (III) waste heat utilization for district heating. For (I) and (II), load shifting and peak shaving are compared using EnergyPlus Ideal Loads-based simulations. At the district scale (III), the demand of buildings surrounding the production facility is determined through archetype-based energy simulations. The framework was applied to two industrial use cases - one in Spain and one in Norway. Results show that on-site thermal energy storage provides the highest reduction potential under the idealized modeling assumptions: auxiliary heating demand reductions reach up to 98.65 % in the Spanish case and up to 9.02 % in the Norwegian case. At the district scale, targeting building subgroups enables technically feasible waste heat utilization, with adjacent educational buildings in Spain achieving 15.13 % demand coverage and residential buildings in Norway reaching 3.84 %. The proposed framework demonstrates the potential of waste heat utilization across facility and district scales, offering industrial plants a systematic approach to assess the potential reduction in building energy demand.