Tips on Selecting a ULT Freezer for Your Lab

In 2020, people around the world thought more about ultra-cold storage than ever before. That started when BioNTech and Pfizer reported that their vaccine against SARS-CoV-2, the virus that causes COVID-19, requires temperatures of –60 to –80° C to safely store it for six months. Although this example really grabbed the attention of people outside of science labs, research personnel often work with samples that require that kind of cold storage to stay viable over time. Creating such conditions depends on an ultra-low temperature freezer, often known as a ULT.

Storing samples at –70 to –80° C slows down biological processes, says David Lewandowski, director of business development for cell and gene therapy at Brooks Life Sciences, but stopping those processes will sometimes require even colder temperatures, such as the –190°C of cryogenic storage.

This selection guide walks readers through the key features to keep in mind when shopping for a new ULT.

Tips from the top

To get started in looking for a new ULT, Gordon Shields—global senior commercial marketing manager, ultra low temperature freezers, Thermo Fisher Scientific—recommends researching several things about the manufacturer, including:

• Does the manufacturer have the capacity to supply units on a timely basis?
• What regulatory standards does the manufacturer meet?
• Does the manufacturer have a focus on sustainability?

For the product itself, Shields makes many suggestions. For one thing, he asks: “Have the interiors been designed to maximize storage in the smallest possible footprint?” He also encourages buyers to consider the insulation used. “Vacuum panel insulation combined with water blown—green—foam insulation provides the best R-value coupled with space savings and regulatory compliance,” he says.

Despite the fundamental value of the method and materials used to insulate a ULT, other aspects of construction matter as well. For instance, Shields mentions the door designs and gaskets. “Units require heavy-duty hinges to minimize the opportunity of deflection over years of use,” Shields says. “Door seals and gaskets need to not only seal well but be able to withstand years of door openings, and they need to be field-replaceable.”

It’s also worth looking for some features in and around the doors. As an example, Shields mentions an “ergonomic door handle for ease of use” and “door/perimeter heaters to minimize frost build-up.”

In addition to keeping samples safe and stored at the desired temperature, today’s ULTs can communicate with scientists. “We live in a connected world, and today’s ULTs are no different,” says Ryan White—senior product manager, ultra low temperature freezers, Thermo Fisher Scientific. “The latest advances in cloud services provide real-time status notifications, performance data tracking, telemetry data monitoring, and proactive predictive maintenance recommendations.”

Require rigor

In purchasing any cold-storage platform, Lewandowski encourages scientists to consider risk management. “If a –80 freezer fails, you’ll have four to six hours to get your material in another freezer,” he says. In larger facilities, he adds, there might be one backup freezer for every 10, and smaller facilities might not be able to afford backup and just ignore this important risk-mitigation consideration. Alternatively, others are choosing a liquid nitrogen-based ULT, which includes a better risk profile, including 96 hours of temperature hold time protection in an emergency, according to Lewandowski.

“Research shows that the average value of products stored in a single ULT is over $750,000,” Shields says. “Many users indicate the value of their samples to actually be priceless as they are irreplaceable human, animal, or plant samples.”

In addition to rigor in a product, a lab manager must train staff to be just as rigorous in using a ULT. “Most people don’t realize it could take up to an hour for a freezer to cool back to its intended temperature after a door opening,” Lewandowski says. “The problem can be compounded in a highly utilized freezer.”

Some freezers include mechanisms to keep track of users and use. The security mechanisms can require a log-in to access the cold-storage device. Plus, requirements from regulators for cold storage can be handled by platform software. Lewandowski adds that “automation makes it easier to scale up.”

Go green

In a world in a climate emergency, scientists should keep energy efficiency in mind when it comes to existing and new ULTs. “Like much of the world, ULTs are evolving towardsmore sustainable solutions,” White says. “Modern ULT designs consume substantially less energy than their predecessors, resulting in reduced operational costs and carbon footprint.”

Organizations and labs can actively improve the energy efficiency of their cold storage by participating in My Green Lab’s Freezer Challenge. Sometimes, it just takes time—not money—to improve the perform of ULTs. Also, simply setting a ULT at –70° instead of –80° can save 30–40% in energy.

Overall, a lab can think of cold storage as an ecosystem composed of existing and new ULTs. The energy use of existing ULTs can be improved, and energy use should be considered when buying a new one.

For example, Shields notes: “Hydrocarbon refrigerants provide low energy, low global-warming potential, and greater reliability.” So, it’s worth thinking about how a ULT creates the cold.

Keeping the inside of a ULT cold usually adds heat to the room. So the overall cost of maintaining sample temperature should include the costs of air conditioning based on regionality and seasonality. Lewandowski points out that “a ULT-temperature freezer using liquid nitrogen vapor as the coolant will provide a zero heat load alternative to upright freezers.”

Certainly, COVID-19 created an emergency that required ULTs and rising world temperatures create an ongoing reason to get and stay energy conscious. Picking super-efficient cold storage is a great place to begin to reduce the energy required to run science and health care.