A simultaneous approach for integration of thermal energy storages in industrial processes using multiperiod heat integration

Abstract

In times of increasing global warming, enormous efforts are required to rapidly reduce greenhouse gas (GHG) emissions. Due to the EU’s target of climate neutrality by 2050 and the even more ambitious goal of becoming climate-neutral in Germany by 2045, it is necessary to systematically increase energy efficiency and decarbonize the industrial heat sector. The methods of heat integration can be used to exploit existing potentials for waste heat utilization and to integrate renewable technologies for heating and cooling. By using a non-stationary, multiperiod approach, additional energy savings can be achieved by integrating a thermal energy storage (TES) that enables heat transportation over time. This paper presents a simultaneous approach for thermal energy storage integration into multiperiod heat integration problems. The approach can be used to minimize energy demand, costs and CO2 emissions and is demonstrated in two case studies. In case study 1, it is shown that the presented approach is capable of integrating a TES properly into a simple multiperiod heat integration problem with two periods. In case study 2, a simplified example from a cosmetics manufactory is investigated. The total utility demand can be reduced by up to 44.3% due to TES integration and the energetic optimal storage size can be determined as 125 m³. The savings are strongly dependent on the constellation of heat flows between the periods, on the temperature levels and on the storage size. Significant reductions of energy demand, costs and CO2 emissions can be achieved with TES being properly integrated into a suitable operating environment.