Process Line for Waste Heat Recovery in the Production of Stretch Film Based on Compressor Heat Pumps with Environmentally Friendly Refrigerants

The production technology for stretch film is highly energy-intensive. Electrical energy is used not only to power individual components of the technological line but also to change the physical state of the raw material (granules) from solid to liquid, which is poured onto the first calender roller. The calender roller must be cooled to solidify the liquid raw material, and the low-temperature heat generated in this process has been treated so far as waste heat and dispersed into the atmosphere. A low-temperature process heat recovery line has been developed, enabling its transformation into high-temperature heat. High-temperature process heat can be utilized in the technological process for the preliminary preparation of raw material when recycled material (regranulate) with highly variable parameters is added to the base material (granules) with strict specifications. The regranulate content can be as high as 80%. The waste heat recovery system is based on two compressor heat pumps powered by eco-friendly refrigerants. This innovative solution facilitates a circular economy, reduces the carbon footprint, and aligns with the European Green Deal.