Virtis, a company that makes equipment for freeze-drying technology, is planning to use a new HFC refrigerant designed to work with mineral oils. The refrigerant has an ASHRAE designation of R-417A and consists of 50% 134a, 46.6% 125, and 3.4% 600 (butane). It is being produced and packaged by ICOR International of Indianapolis, IN, under the name NU-22.

The company said the refrigerant is rated A1 in terms of toxicity and flammability safety. The use of 125 and 134a allow for the refrigerant to be used “with wide temperature ranges,” said ICOR’s Gordon McKinney. The butane provides “for adequate oil return” when used with mineral, alkylbenzene, or POE oils, he said.

According to Ted Sutherland, Virtis vice president, “NU-22 provides us with a practical, environmentally safe solution to the replacement of R-22.

“The majority of freeze dryers sold call for cascade refrigeration systems,” he explained. “We have previously used R-22 as the high-stage refrigerant. In Europe, R-22 is no longer acceptable in new equipment. By switching to NU-22, we can stay with a single refrigerant for all areas of the world. We have found we can maintain our capillary sizes, greatly simplifying the changeover process.”

McKinney noted, “ICOR is reporting a major increase in sales of NU-22 in the service industry. There has been a large and somewhat unexpected response to this product from the commercial ACR service industry. NU-22 is now being successfully used in a variety of refrigeration systems within the commercial food industry.”

Publication date: 04/01/2002