So you save only 20 hp in your quest to reduce energy consumption. What is that worth? A lot. If you are now paying 5 cents /kW for electricity and operate the equipment for 4000 hours per year you would save $3243 this year. However, if the cost of energy continues to escalate at 10% per year, in 20 years you will have saved $186,058 or an average of $9302/year. This type of projection is well within the escalation predicted for energy sources by many experts.

While comparing cryogenics with mechanical freezing systems we will compare liquid carbon dioxide and liquid nitrogen with a typical mechanical system that was designed for the same type duty.

Freon freezants have been considered as "cryogenics" in some circles. However, due to the fluorocarbon/ ozone controversy and the probability of restriction being placed on the use of certain halocarbonsj freon freezants (F-12) comparisons have not been made. Over the last 10 years freon freezing has found very limited applications and has mainly been used in the freezing of peeled and deveined shrimp, cob corn, and certain specialty items.

To keep energy costs in perspective, A basic cost analysis between liquid nitrogen, liquid carbon dioxide, and mechanical refrigeration is shown in Table 2. Mechanical refrigeration is by far the "miser" in energy usage. Liquid carbon dioxide energy costs are 4.5 times mechanical and liquid nitrogen energy costs are 17.5 times mechanical. Because of liquid nitrogen's high energy usage, most cryogenic freezant suppliers started to switch their liquid nitrogen customers to liquid carbon dioxide as early as 1975.