Cryogenic vs. mechanical freezers: The best uses for each method

Part two: Process freezing series.


Cryogenic vs. mechanical freezers: The best uses for each method. Courtesy: Stellar Food for ThoughtMany food plants rely on freezers and refrigerators to store and ship their products. In last week's post, I outlined four variables food processors must understand during process freezing. I want to take a look at freezing methods and equipment, and the applications they're best suited for. Depending on the type and quantity of food, certain freezers are more useful than others.

Two main freezing methods

1. Cryogenic freezing. This method involves spraying or immersing the food directly with liquid nitrogen or carbon dioxide. The product is frozen almost instantly, while the refrigerant is lost to the atmosphere. Cryogenic freezing equipment generally requires lower up-front capital costs than mechanical freezing equipment of the same capacity. However, cryogenic equipment requires significant volumes of refrigerant, which creates high ongoing costs for the producer. Also, cryogenic vapors are colorless and odorless, so care must be taken to ensure adequate ventilation is provided to protect workers from oxygen displacement.

  • Cryogenic freezing is most often used for individual quick frozen (IQF) products, such as individual chicken wings, frozen peas, or other bulk packaged food items where it is important to maintain individual pieces.
  • It is sometimes chosen where space is limited or as a lower-cost means of getting a new product to market quickly.

2. Mechanical freezing. This method involves a standard mechanical refrigeration cycle, using one of the common refrigerants like ammonia or carbon dioxide. Mechanical process freezing systems usually have higher capital costs than cryogenic systems because they require supporting refrigeration systems. But, they're usually the more efficient and cost-effective option from a long-term standpoint.

  • Mechanical freezing is most often used for high-volume production of both raw and finished goods.

Freezer types and their applications

Cryogenic systems are often used for individual food pieces, like frozen peas. Courtesy: Stellar Food for Thought

Some freezers are better suited for certain applications than others depending on product type, process conditions or quantity. To ensure the best quality product, it's important to choose the freezing equipment that creates the most efficient freezing process for your specific product. Below are several types of freezers and their typical applications:

  • Process freezer—These freezers are typically incorporated into the manufacturing line, usually situated just before the end-of-line packaging equipment.
  • Individual quick freeze freezer—IQF freezers can be mechanical, but are most often cryogenic systems. They're ideal for protein served in small pieces such as diced ham, wings, meatballs or shrimp. They can also be used for fruits and vegetables and prepared foods like pizza or pasta.
  • Spiral freezer—The freezers can be either mechanical or cryogenic, and move the product around a spiral conveyor inside an insulated enclosure for a certain amount of time.
  • Tunnel freezer—Working in the same fashion as spiral freezers, these freezers move the product linearly, rather than in a spiral pattern.
  • Plate freezer—This type of freezer is a special hollow plate that has liquid refrigerant flowing through it. Products are placed between two plates and evenly cooled to freezing temperatures. These freezers are ideal for flat products or brick-shaped packaged products, such as frozen meals.
  • Blast freezer—These are mechanical systems are generally used to freeze products in bulk on pallets. Blast cells are not part of the manufacturing line like process freezers. The food is sealed in a blast cell and remains there for multiple days as cold air is continuously circulated throughout the room.

When selecting the proper freezing equipment, it's helpful to work with a refrigeration equipment provider to determine which system is best suited for the specific product. Often times, food plant owners can work with providers to create a custom-designed system to fit their needs perfectly.

—Randy Peterson is a senior project developer at Stellar Refrigeration Contracting. This article originally appeared on Stellar Food for Thought. Stellar is a CFE Media content partner. Edited by Erin Dunne, production coordinator, CFE Media,

Stellar is a CSIA member as of 11/30/2015.

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Safety for 18 years, warehouse maintenance tips, Ethernet and the IIoT, GAMS 2016 recap
2016 Engineering Leaders Under 40; Future vision: Where is manufacturing headed?; Electrical distribution, redefined
Strategic outsourcing delivers efficiency; Sleeve bearing clearance; Causes of water hammer; Improve air quality; Maintenance safety; GAMS preview
SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Safety at every angle, Big Data's impact on operations, bridging the skills gap
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
Applying network redundancy; Overcoming loop tuning challenges; PID control and networks
Driving motor efficiency; Preventing arc flash in mission critical facilities; Integrating alternative power and existing electrical systems
Package boilers; Natural gas infrared heating; Thermal treasure; Standby generation; Natural gas supports green efforts

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role of plant safety and offers advice on best practices.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me