With the well-known global warming potential and destructive effects of hydrofluorocarbons and HFC/HCFC refrigerants on our planet’s ozone layer, natural refrigerants-such as hydrocarbon refrigerants-offer a sustainable alternative that has been advocated through corporate initiatives such as Refrigerants, Naturally!, and is seeing increasing adoption in many parts of the world.  However, no freezer for sale in the United States was able to offer 100% natural refrigerants until 2014, when Stirling Ultracold received U.S. EPA and UL approval to introduce an all hydrocarbon-based, low global warming potential refrigerant cooling system in the SU780UE ultra-low freezer. Our natural hydrocarbon refrigerants have a much lower destructive effect on the environment than HFC refrigerants and will slow the pace of global warming.

But this major milestone certainly didn’t happen overnight!

A 3-Year Process

We started our U.S. hydrocarbon refrigerant approval process in August 2012 by presenting an initial submission through the EPA’s Significant New Alternatives Policy (SNAP) program for the “proposed use of ethane in ultra-low freezers non-mechanical heat transfer applications.”  This was followed by final submission a year later, a completeness letter, a public posting of the “proposed rule inviting comment” in 2014 and a final publication in April of 2015.

This process also involved compliance with the UL 471 Standard, as one of the EPA’s conditions for use of ethane in very low-temperature refrigeration equipment for hydrocarbon refrigerants used as a heat transfer medium.

Questions to Ask About Hydrocarbon Refrigerant ULTs

We welcome announcements that other ultra-low freezer manufacturers are now be offering natural refrigerants for refrigerators and freezers, including ULTs sold in the U.S. Having already navigated through the rigorous U.S. approval process, we do suggest asking some questions about each manufacturer’s specific application of natural refrigerants and their expected time to market:

• What refrigerant is used in the upper and lower stages?
• What is the mass of the refrigerant in each stage?
• Is the total mass of refrigerant less than 150 grams?
• Has the freezer been submitted to UL for listing?
• Has the application been submitted to SNAP? If so, what stage is the submission in the SNAP process?

Been There, Done That

At Stirling Ultracold, we’re pleased to see the industry moving toward natural refrigerants and are proud to have led the way in providing a 100% hydrocarbon refrigerant alternative in the U.S.   If you’re interested in a natural refrigerant ULT solution for the U.S., there’s no reason to wait.  Just contact us at [email protected] or 740-274-7900.