Process Cooling in LDPE Regranulation  Cold for the Circulatory System 

When processing film waste, temperature control determines the quality of the LDPE regranulate. That is why Rymoplast Deutschland relies on a 1.5-megawatt container cooling system from Technotrans to support its extrusion lines in Markranstädt. Practical application demonstrates how the system combines process stability with significant energy savings. 

The Morssinkhof-Rymoplast Group has invested approximately 30 million euros in its plant in Markranstädt, Saxony, to process approximately 30,000 metric tons of film waste into LDPE regranulate annually. In this process, the film bales are shredded, washed, dried, and extruded. The subsequent granulation step, in particular, requires precise thermal management, as insufficient cooling causes the material to stick together and drastically reduces its quality.

“Compressed air, water, and a reliable supply of refrigeration are the three pillars on which our process stability rests,” explains Mark Langenhof, Business Development & Application Engineer at Rymoplast Deutschland. To avoid temperature-related production downtime, the company relies on a centralized cooling solution from Technotrans. 

A closed-loop system protects against contamination

To conserve space inside the facility and protect the equipment from production dust, Technotrans installed the entire 1.5-megawatt system in a weatherproof container assembly located outdoors. The enclosed system eliminates the vulnerabilities of conventional, open cooling towers.

“Open systems are susceptible to contamination and carry the risk of Legionella growth, which results in strict regulatory requirements,” explains Roger Schmidt, Sales Manager for Cooling Solutions at Technotrans Solutions. The system continuously supplies the production line with a flow temperature of 15 °C. Frequency-controlled dual pump sets ensure redundancy and optimize power consumption during partial-load operation. 

Smart Free Cooling Reduces Electricity Consumption

Since closed-loop systems require a different cooling method than evaporative systems, the plant combines highly efficient chillers with a free-cooling unit mounted on the container roof. When outdoor temperatures are high, adiabatic cooling maximizes efficiency by using sprayed water to cool the intake air. During the colder months, a feature known as “winter load relief” ensures that cooling is generated passively using the outside air, keeping the compressors shut down. “In our part of the world, we can shut down the chillers completely for many months of the year—or at least significantly reduce their load,” says Schmidt.

Compared to conventional compression refrigeration systems, the system saves approximately 650 MWh of electricity annually. This corresponds to a reduction in CO₂ emissions of nearly 40%, or approximately 480,000 kg per year, which is why the investment was subsidized by the Federal Office for Economic Affairs and Export Control (BAFA). 

Modular scalability for growing capacity

For the operators, the long-term flexibility of the system design was just as crucial as energy efficiency. The refrigeration system was designed to be modular from the outset: While it initially supplied two extrusion lines at the start of 2022, the planned expansion to include a third Erema line was implemented smoothly in May 2025. “The connections and the control system were already in place,” Langenhof emphasizes.

To ensure continuous operation, the system is also connected to a digital monitoring system. Maintenance personnel monitor pressures, temperatures, and flow rates in real time via an HMI touch panel, while Technotrans can access the control system directly via a remote maintenance interface as needed.