Mechanical & Cryogenic Refrigeration

Recent reports within the food processing industry indicate that the average cost of food freezing is up to 12 cents more per pound with the use of Cryogenic systems than with a similar Mechanical system.  This dramatic discrepancy is the result of costly, non-renewable Liquid Nitrogen (LN) consumption.

According to conservative estimates, LN costs approximately 3 cents per pound.  Depending upon the product, cryogenic freezing can consume between 0.5 and 1.5 pounds of gas for every pound of product.  Therefore, a production system that runs 40 hours per week at 5,000 pounds per hour will incur an operating cost of $27,000 per month.  Cryogenic/Mechanical Cost A similar mechanical, air-blast system will use 35 kilowatt-hours of electricity, resulting in a monthly energy bill around $630 (assuming 10 cent per kilowatt-hour rates).

Still, many food processors continue to turn to cryogenic solutions for the relatively low initial capital investment.  In spite of the rapid pay-back period for  mechanical systems, some sources maintain that cryogenic systems are feasible for start-up operations, but should be replaced with mechanical solutions as soon as the investment can be made.

According to Process Engineering & Fabrication president, Bob Amacker, “When testing the market  for your product, it may be savvy to keep capital expenditures low.   However, once you have gained a clearer picture of the  demand for your product and increased confidence in your ability to fill that demand, it is best to switch to the lowest long-term cost option.”  With a pay-back period under 2 years, mechanical freezing is that option. Given that a cryogenic system could incur variable costs in excess of $2 million over a 10-year period, the initial price of a similar spiral system is negligible.

Food processors still face important considerations in the mechanical/cryogenic debate.  Cryogenic tunnels do not have a clear advantage in factory footprint over conventional spiral freezers, but cryogenic spiral freezers are clearly the most compact option.   Issues of factory footprint, crust freezing, and freeze-rate favor cryogenic spirals, whereas spirals with mechanical freezing reduce operation costs significantly, and are the best choice for the long-term.