In this paper, typical process chains of metal processing/gear manufacturing are examined according to the pinch method with regard to their potential for heat recovery and their suitability for heat pump applications. The focus is on machine tools and parts washing machines as fluctuating heat sources and sinks. Heat sources at a low temperature level, such as the cooling of machine tools, are becoming increasingly important in contrast to conventional fossil waste heat sources due to the electrification of energy and production systems. Based on energy monitoring data from a real production system, this paper uses a simple example production line to illustrate the extent to which both the interdependencies in a material flow and a varying system size increase the energy efficiency of the overall system and how they influence the dimensioning of heat-pump-storage-solutions. Finally, the inclusion of statistical fluctuations and their significance for thermal crosslinking of production machines is discussed.