Stirling Ultracold Supplies Island of Puerto Rico and U.S. Embassy Locations with Ultra-Low Temperature (ULT) Freezers to Help Facilitate Global COVID-19 Vaccination Efforts

Stirling Ultracold’s ULT units are the only commercially available freezers capable of storing and protecting both Pfizer and Moderna’s approved COVID-19 vaccines during the last mile delivery.

Athens, Ohio — Stirling Ultracold, innovative developer and manufacturer of ultra-low temperature (ULT) freezers for life science and biopharma research, today announced it will be the exclusive ULT freezer provider for the entire island of Puerto Rico, as well as all U.S. embassy locations around the world. The Puerto Rico National Guard has partnered with Select Gases of Atlanta and Bionuclear of Puerto Rico to purchase and distribute four of Stirling Ultracold’s SU780XLE upright freezers, 20 SU105UE undercounter freezers and 20 ULT25NEU portable freezers to vaccinate the island of Puerto Rico. Additionally, the State Department has purchased and already received a shipment of 210 Stirling Ultracold ULT25NEU portable freezers to thermally protect and move vaccines to all U.S. embassy locations in order to safely vaccinate government employees and officials around the world. 

One of the biggest challenges in the safe distribution of the COVID-19 vaccine lies in the last mile – or the last hand off in the supply chain before it gets administered to the patient. Once a vaccine shipment makes it through the supply chain in Pfizer-BioNTech’s specialty-made pizza boxes, it needs to be stored between ‑80ºC to ‑60ºC (‑112ºF to ‑76ºF) at all health service locations, pharmacies and central repositories in order to ensure safe distribution to patients. Similarly, Moderna’s approved vaccine needs to be stored between -25°C and -15°C (-13°F and 5°F). Stirling Ultracold freezers are the only commercially available freezers to run the ULT gamut from -20°C to -86°C in a single system and are proving to be an integral asset in safely storing and administering Pfizer’s COVID-19 vaccine. Traditional methods for ULT storage, like dry ice and liquid nitrogen, are both currently in short supply and require specialty personal protective equipment (PPE) and training for proper handling, making them an unreliable and risky source for transporting and storing a COVID-19 vaccine. Stirling Ultracold’s portable unit is also the only ULT freezer that can be plugged into universal power sources, like wall plugs or any vehicle outlet, in order to maintain efficacy while in transit. Each portable ULT freezer can hold up to seven of Pfizer’s pizza boxes, and nearly 7,000 vaccine doses overall. Both the Puerto Rico National Guard and the State Department recognize this challenge and have armed themselves with the ULT assets needed to safely deliver the COVID-19 vaccine.

National Guard with freezer
Sgt. Jorge Chévere prepares to inspect the contents of Stirling Ultracold Freezers at Fort Buchanan, Puerto Rico. The Puerto Rico National Guard works around the clock to maintain a high standard in the handling of the COVID-19 vaccines. (U.S. Army National Guard photo by Spc. Jonathan Vázquez García)

“The approval of Pfizer’s COVID-19 vaccine has given everyone a glimpse of hope that relief is on the way,” said Major General Jose J. Reyes at the Puerto Rico National Guard. “We are about to reach the final hour for this vaccination and are doing everything in our power to get the vaccine to communities around the world. We are very aware of the challenges associated with last mile delivery and can rest easy knowing we have the ULT infrastructure in place to support the historic global COVID-19 vaccination.”

The Puerto Rico National Guard plans to use Stirling Ultracold’s upright freezers as a central repository, or hub, on the island, while its undercounter will be for the vaccination centers, and portable freezers will be used to transport vaccines around the island for local vaccine administration. The drive across Puerto Rico is approximately six hours and the community cannot afford to lose even one shipment of vaccines. Stirling Ultracold’s portable ULT freezers serve as the perfect solution for safely transporting vaccines to more rural communities and locations around the island. Similarly, The State Department plans to load vaccines into Stirling Ultracold’s portable freezer units state side, power them onboard aircraft, and deliver them directly to the embassy doorstep where they will then be plugged into power and ready for vaccine administration. Universal power sources, batteries and vehicle outlets will be used all along these delivery routes to keep the freezer powered, ensure thermal stability, and limit any exposure the vaccines may have to ambient conditions.

“There are so many pieces to the vaccine delivery puzzle that need to go right in order for it to arrive to the patient as safely and effectively as possible, regardless of location,” said Dusty Tenney, CEO, Stirling Ultracold. “Stirling Ultracold understands these distribution challenges and has been working around the clock to ensure ULT vaccine storage is accessible to both metropolitan areas, as well as more rural locations that may be harder to reach. Global relief is coming soon, and we are honored to be a part of the solution.”

About Stirling Ultracold

Stirling Ultracold, a division of Global Cooling, Inc., manufactures and sells environmentally sustainable ultra-low temperature (ULT) freezers for the global market from its headquarters in Athens, Ohio. Powered by the free-piston Stirling engine, and the first in the U.S. to use 100 percent natural refrigerants, these upright and undercounter ULT freezers use less than one-third the electric power of standard compressor-based ULT freezers, as validated by the industry’s first ENERGY STAR® partnership for ULT freezers. The company also produces the industry’s only portable ULT solution available for remote clinical trials and biologic drug delivery. For more information, please call (740) 274-7900, or visit the company’s website,

Stirling Ultracold Media Contact:
Meghan Witthaus
10Fold for Stirling Ultracold

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