Chillers or Free Cooling: Sizing Industrial Cooling for a Molding Plant

Cooling in a molding plant is invisible — while it works. A mold cooling slower than designed stretches the cycle; water warmer than specified causes warpage and longer cooling times; an oversized chiller burns electricity idling. Here is how cooling is sized properly, and where the biggest savings hide.

Where the Heat Comes From

Every kilogram of molten plastic brings heat into the mold that the water must carry away. The exact amount depends on the polymer, melt temperature and ejection temperature — higher throughput and higher process temperatures mean a larger required cooling capacity. On top of that comes hydraulic heat (on hydraulic machines), dryer heat and conveying blowers.

That is why sizing is done from a heat balance, not by eye: the machine list and capacities, materials processed, mold temperatures and operating regime. From that follow the required cooling capacity, flow rate and water temperature regime.

Central Chiller or Machine-Side Units

Smaller plants often start with one small chiller per machine. As the plant grows, a central system becomes more economical: one larger chiller with distribution, better control and capacity reserve. A central system also enables two temperature circuits — colder for molds, warmer for hydraulics and periphery — saving further energy.

Free Cooling: the Cheapest Kilowatt Is the One a Compressor Never Produces

A free cooling module uses cold outside air to cool the process water: whenever it is colder outside than the return water, fans take over and compressors idle. In Serbia's continental climate, with long periods below 15°C, that means a significant part of the year the plant cools on fan power alone.

For plants running around the clock — which is nearly all molders — free cooling is typically the fastest-payback investment in the whole cooling system.

What Makes a Chiller Efficient

An efficient chiller is defined by its technology, not its brand: self-adapting compressors that track the real load, electronic expansion valves, low-consumption EC (brushless) fans and a small charge of low-GWP refrigerant. Solutions like these also meet EU energy-efficiency requirements for cooling equipment (Ecodesign/ErP). For the plant that means lower consumption at every load point, not just nominal.

Perotec Systems supplies and services industrial chillers and cooling systems tailored to process requirements — browse the chiller range or send us your machine list, sizing is free of charge.