Decarbonization through Intelligent Heat Recovery: airinotec Optimizes Hall Ventilation for Model Group
The modernization of paper production at the Eilenburg site posed a special challenge for Model Sachsen Papier GmbH. The conversion from graphic papers to corrugated base paper not only required adapting the hall ventilation system, but also finding a solution to meet the significantly increased energy demand in a climate-friendly way. Together with airinotec, a concept was implemented that—through intelligent heat recovery, optimized control strategies, and modern automation technology—drastically reduces primary energy consumption and thus makes an important contribution to decarbonization.
Model Sachsen Papier: Sustainable Production in the Heart of Europe
Since August 2021, Model Sachsen Papier GmbH has been part of the internationally operating Model Group. The Eilenburg plant, built from scratch in 1993/94, is one of the most modern paper production sites in Europe. Following the conversion, the facility will produce around 625,000 tonnes of corrugated base paper per year, using 100% recycled paper. The focus on grammages of 70 to 120 grams per square meter supports the sustainable trend toward lighter packaging solutions.
Challenge: Increased Humidity and Heat Load after Machine Conversion
Switching the paper machine to the production of corrugated base paper brought significant changes to the hall climate. This type of production releases more moisture into the hall—along with a higher heat load. As a result, the supply air volume for the paper machine hall had to be increased by 560,000 cubic meters per hour, which raised the heating demand by more than 50 percent. Additionally, a finished goods warehouse and a microflotation system each required ventilation of 80,000 cubic meters per hour. In total, the volume of air to be heated grew to around 1.5 million cubic meters per hour. Without an efficient concept, this would have meant a considerably higher consumption of primary energy—clearly contradicting Model’s ambitious sustainability goals.
The Task for airinotec: Efficiency and Decarbonization through Heat Recovery
airinotec was commissioned to adapt the hall ventilation to the increased requirements while reducing primary energy consumption as much as possible. The solution was not to rely on additional fossil energy but to make optimal use of the existing waste heat from production. This required a comprehensive adaptation and optimization of the existing process hot water system (PWW) and the heat recovery units. In addition, an intelligent control strategy had to be developed and implemented to optimize the interaction between the heat recovery systems, the supply air units, and the PWW system throughout the year.
Implementation: Expansion, Modernization, and Intelligent Control
airinotec assumed full responsibility for engineering, delivery, installation, and commissioning. The paper machine hall received four additional supply air units, each with 100,000 cubic meters per hour, as well as a new exhaust air unit with 80,000 cubic meters per hour. For the finished goods warehouse, one supply air unit with 80,000 cubic meters per hour and four exhaust fans of 20,000 cubic meters per hour each were installed. The microflotation system was also equipped with supply and exhaust air units, each with 80,000 cubic meters per hour. At the same time, the heat recovery system was modified to recover more waste heat from the process. The EnergyOpt control strategy ensures that the efficiency of heat recovery is maximized year-round. This not only makes more waste heat usable but also reduces the electrical energy demand of the pumps.
With this project, we have demonstrated how intelligent control strategies and optimized heat recovery can drastically reduce energy consumption. Together with Model Group, we are making an important contribution to decarbonizing the paper industry.
Customer Benefit: 73 Percent Less Primary Energy and Massive CO₂ Reduction
The results of the project are impressive. Despite increasing the air volumes by 50 percent, the primary energy requirement was reduced from 27,500 megawatt hours to just 7,500 megawatt hours. This means that heat recovery now covers 90 percent of the heating demand. This not only significantly reduces CO₂ emissions but also provides considerable cost advantages in ongoing operations. In addition, the customer benefits from continued use of existing systems, saving investment costs and resources.
Conclusion and Outlook: A Flagship Project for Sustainable Paper Production
With the successful modernization of the hall ventilation and the associated heat recovery system, Model Sachsen Papier GmbH has consistently implemented its sustainability strategy and taken an important step toward climate-friendly production and decarbonization. The project shows how technological innovation and environmental responsibility can go hand in hand. airinotec will remain a reliable partner in the future for energy-efficient solutions that sustainably reduce the CO₂ footprint.
