Prediction of power and energy demand for hybrid furnaces to optimize the use of fluctuating green energy sources

Hellwig Martin - Ipsen International GmbH (Germany)

Energy-intensive industries are encountering new challenges due to rising energy prices and upcoming environmental regulations related to CO2 emissions. As the energy transition progresses, the proportion of renewable energy sources is growing, offering cost and emissions benefits. However, their availability remains inconsistent. A hybrid furnace, introduced by Ipsen, addresses these issues by using multiple energy sources, yet strategic planning of processes and related energy demands is crucial to maximize this flexibility.

The first step toward intelligent energy management is accurately forecasting the system’s power consumption during scheduled hardening processes. To achieve this, a digital twin is employed to simulate system behaviour before the actual process begins. This allows for energy flow analysis, power demand forecasting, process optimization and process planning for an entire hardening shop with optimal energy resource utilization.

This article explores the design of the digital twin for a sealed quench furnace used for tempering and hardening steel in a gas atmosphere. Accurate modelling of thermal transitions and heat flows within the heating chamber is essential to predict the power demand over time. The article explains how energy exchange through convection and radiation is calculated between the furnace components, atmosphere and batch and identifies factors affecting the energy demand. Additionally, the simulation can determine certain state variables that are not measurable in the actual furnace but can be used to optimize process workflows.

To validate the results, the digital twin’s performance is compared to data from various batches. The article further demonstrates how power profiles generated by the digital twin can optimize process and system controls in a hardening shop, focusing on peak power requirements or CO2 emissions. An estimation of the energy and CO2 savings potential for a typical hardening shop is also provided.