Approximately 22 % of the total German energy consumption is used to provide thermal energy in the industrial sector. Therefore, energy efficiency measures in this area offer a major lever for decarbonizing the energy system. Central heating networks can achieve high energy efficiency levels through economies of scale, the coupling of efficient technologies, or the integration of waste heat. Although energy efficiency of an industrial heating network is a key aspect to minimize operating cost, heating networks are mostly planned and realized with fixed control parameters (e.g., pressure, flow rate or flow temperature). An adjustment of control parameters especially in changing production systems and the integration of renewable energies or waste heat often holds immense energy efficiency potential. This potential can only be harnessed by achieving transparency in the operation of heating networks outlining inefficient behavior.
This paper presents a method to continuously evaluate heat flows in industrial heating networks by deriving key performance indicators. The method focuses on linking heat demands as well as flow and return temperatures of production processes or building services to the CO2 emissions and energy efficiency of the heating network. The indicators include network and converter specific parameters such as part load behavior and temperature dependencies. To understand the effects on network efficiency in case of parameter changes (control parameters or network topology), both the generation and the demand side are included in the analysis. By that, operating behavior of an industrial heating network can be improved, e.g., by the integration of waste heat or the linkage to a district heating network. The method is conducted on real data of a complex heating network in an industrial site. An application for the reduction of return temperatures of a consumer showed that potentially 7.6 % of the total CO2 emissions could be reduced by the integration of waste heat.