Chris Ferriday, Business Line Manager at Atlas Copco Compressors UK, explores the critical importance of thermal management in plastics manufacturing and considers the different cooling technologies now available to help improve operational efficiency and product quality.
Atlas Copco Compressors
Cooling is a vital part of the plastics production process because it helps to solidify the plastic material after it has been shaped. Without proper cooling, the plastic may not solidify correctly or stick to the mould, leading to defects and inconsistencies in the final product. By optimising the cooling process, manufacturers can reduce cycle times, which increases throughput and productivity.
Proper cooling also supports product integrity because it ensures that the plastic parts do not warp, shrink, or develop internal stresses that could compromise their structural integrity
Types of process cooling
Process cooling methods include the following:
- Air chillers work on the principle of evaporative cooling. A pump circulates water from a tank onto a series of cooling pads. A fan or blower draws warm air through these wet pads, which absorb the heat and reduce the temperature. Air coolers are more energy efficient than air conditioners, making them more cost-effective. They do not use refrigerants, which makes them more environmentally friendly, and with few moving parts, they have modest maintenance requirements.
- Water chillers use water and a refrigerant to absorb heat from the manufacturing process. They comprise four essential components: an evaporator, a compressor, a condenser, and an expansion unit. The water absorbs process heat, circulates to a cooling tower where the heat is evaporated away, and is then recirculated back to the chiller. They're more energy-efficient and can handle larger cooling loads. However, they can be more expensive to buy, require more space and have more complex installation and maintenance requirements.
- Hybrid chillers combine the principles of both air-cooled and water-cooled systems. The chiller absorbs heat from the process using a refrigerant, which transfers the absorbed heat to a heat exchanger. The heat exchanger is cooled by air through fans and is sprayed with water to enhance the cooling effect through evaporation. The cooled refrigerant is then recirculated.
Latest cooling technology developments
Process cooling technology is constantly evolving to improve reliability, energy efficiency, and drive down lifecycle costs. The development of more advanced materials with improved heat transfer properties has enabled free cooling methods, which use natural changes in air pressure caused by volume expansion to regulate temperature. For example, the AXpro from Eurochiller is a versatile process water chiller that can integrate multiple energy-saving technologies in a single solution to optimise efficiency and energy consumption in both winter and summer seasons.
Selecting the right cooler
With so much cooling technology to choose from, the selection process can seem daunting. While CAPEX is always important, OPEX should also be taken into account to achieve the best return on investment (ROI). What seems like a good initial price can quickly undermine any initial saving if the chiller proves to be power-hungry, unreliable, or if spare parts are difficult or expensive to source.
Build quality, reliability, and service support are related factors in assessing the total cost of ownership (TCO). Resource use not only impacts running costs but also has implications for plastics manufacturers wishing to reduce environmental impacts. Cooling equipment requires power, water and, in some cases, a refrigerant. Chillers offering high energy efficiency, low water loss and the use of eco-friendly refrigerant can improve sustainability credentials. Check whether the investment offers the ability to alter cooling capacity to match current variations in production demands and how easy it would be to extend in the future. A full survey and technical analysis by your preferred supplier is recommended to establish cooling load requirements.
Conclusion
Effective process cooling is vital for the plastics industry to maintain high standards of product quality and operational efficiency. Working with cooling experts, plastics manufacturers can achieve significant benefits in terms of energy savings, reliability, and environmental impact. Innovative cooling solutions can also enhance sustainability efforts by reducing energy consumption and using more environmentally friendly refrigerants. Investing in high-quality cooling solutions is a strategic decision that can drive long-term success and sustainability.