Stacked exchangers in series improve cooling while lowering maintenance costs.
A Chicago liquid-foods packager found themselves in a make-or-break moment. A major customer was ready to hand them a lucrative soup-packaging contract—but only if they could guarantee one thing: every batch had to be cooled from 198°F (92°C) to exactly 77°F (25°C) before it hit the packaging line.
That precise temperature wasn’t the only challenge. The packager needed a system that could handle different soup recipes, meet strict food-grade sanitation rules, and fit into a footprint about the size of a walk-in closet—14 feet by 6 feet, under a 12-foot ceiling. Oh, and it had to keep utility costs in check by using cooling tower water whenever possible.
No pressure, right?
The Challenge: Cooling, Cleanability, and a Tight Fit
Different soups meant different thermal properties, so the system had to be flexible. It also needed to be easy to clean between batches. If any leftovers lingered, flavors could mix or bacteria could grow. Accuracy mattered, too. If the soup was too warm, it could spoil. Too cool, and the containers could sweat, causing labels to slide off. Not exactly ideal for a product on shelves.
The space issue made everything trickier. The heat exchangers had to meet strict 3-A sanitary standards while also staying compact, cleanable, and efficient.
First Attempt: Two Large Exchangers, One Big Problem
The packager’s engineering partner first proposed a simple setup: two large, straight-tube shell-and-tube exchangers in series. The first would knock down the temperature using cooling tower water. The second would finish the job using a 45°F (7°C) glycol/water mix from a chiller. Both were inclined for draining and built with davit swing arms for easier inspection.
On paper, it looked clean and straightforward. In practice, two issues popped up quickly.
1. The Temperature Cross Problem
Because cooling tower water entered at around 70°F (21°C), it warmed up to about 120°F (49°C) inside the shell. That meant the soup couldn’t get any cooler than that in the first stage. The second exchanger—and the chiller—would have to do nearly all the heavy lifting. That meant higher energy use and a bigger, pricier chiller.
2. Cleaning Bottlenecks
The exchangers could be backflushed, but hitting the recommended 5 ft/sec cleaning velocity wasn’t possible with the packager’s 200-gallon-per-minute CIP system. Achieving proper cleaning would have required a system nearly eight times larger. Not exactly realistic.
These limitations pushed the team back to the drawing board.
Rethinking the System: Smaller Exchangers, Bigger Benefits
To solve the cleaning issue, the team took a different approach: reduce the tube field size. That meant shrinking the exchanger diameter from 24 inches to 6 inches. With less area in each unit, more units were needed overall—six exchangers for the cooling-tower stage and two for the glycol/chiller stage.
This redesign fixed more than just cleaning.
Better Heat Transfer: Fewer tubes meant higher product velocity, which boosted cooling performance.
No More Temperature Cross: Each small exchanger got its own stream of fresh cooling tower water. That prevented the warm-up effect that stopped the first system from reaching lower temperatures. In winter, when cooling tower water dropped below 70°F, the packager could skip the chiller altogether and cool the soup with ambient water alone.
Easier Cleaning and Sanitation: The smaller units reached the needed CIP velocity and were easier to polish to 3-A standards. The lighter bonnets also made teardown and inspection much simpler.
The Final Layout: A Stacked, Flexible, Space-Saving System
The eight exchangers were mounted on a custom rack, with room left to add two more if future recipes or batch sizes required extra cooling power. All units were pitched for draining and connected with easy-to-reach utilities and jumpers.
Standardizing on smaller exchangers had bonus benefits:
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Lower-cost spare parts
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Readily available gaskets and clamps
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Interchangeable components across all eight units
Most importantly, the entire stacked system fit inside the tight footprint and stayed within the project budget.
Results: A Cooler Process and a Hot Contract Win
The redesigned cooling system delivered consistent, precise temperatures across multiple soup types. It checked every box: sanitary design, easy cleaning, lower utility costs, space efficiency, and room for future growth.
With the cooling challenge solved, the packager secured the contract—and gained a more efficient process for years to come.
If you’re facing tight specs, tight space, or a tight deadline, you don’t have to tackle it alone. Reach out to Enerquip, and let’s build the right solution together.