Simulation and assessment of an integrated thermal processes and Organic Rankine Cycle (ORC) system with Modelica

Abstract

Waste heat recovery (WHR) has been regarded as a viable method to improve energy efficiency and promote sustainability in industry. The operation of high energy consuming thermal processes in industry generates high quantities of thermal losses, thus being associated to a great waste heat potential. In this sequence, several technologies have emerged to reuse this industrial waste heat. The implementation of these technologies within the operation of plants results in the project of different WHR strategies. This work presents a simulation model developed in Modelica language for an industrial waste heat recovery (WHR) installation. Such installation involves several industrial processes, which integrate system of thermal processes and an Organic Rankine Cycle (ORC). Based on the specific data from a case-study of a ceramic industry plant, namely two tunnel kilns, a WHR strategy is conceptualised,​ simulated and assessed in terms of economic viability and environmental impacts. The simulation results demonstrated the validity of the developed model (deviation values for key variables were calculated with a maximal value of 0.94% having been obtained for one of the variables, which is a considerably negligible deviation). The economic and environmental assessment revealed that the WHR project is overall viable, considering a 1.1 years payback period and 2.36 kton CO2,eq reduction (corresponding to 32.8% of natural gas savings and 11.3% of electric energy savings).