Greener freezers for a greener future

Program replaces 43 of the campus’s least-efficient units

Ultra-low temperature (ULT) freezers are the unsung heroes of biomedicine, storing materials that are vital for discovery and diagnosis. In the age of the coronavirus, they are also key to storing tens of thousands of COVID-19 vaccine doses. But this critical cold storage comes at a steep cost.

“There are 1,200 ultra-low temp freezers on campus, and everyone depends on them,” said Dean Shehu, research commodities manager in UCSF’s Supply Chain Management. “These freezers go down to −80°C (−112°F), almost as cold as the lowest temperature ever recorded in Antarctica, but just one old freezer can use the same amount of electricity as two homes.”

In the last two years, Shehu, with backing from UCSF School of Pharmacy Dean B. Joseph Guglielmo, PharmD, the Office of Sustainability, and Executive Vice Chancellor and Provost Dan Lowenstein, MD, replaced 43 of UCSF’s oldest ULT freezers with modern, EnergyStar models that halve each machine’s carbon footprint.

The new freezers are also less likely to fail, and they make the university more resilient in the face of power outages, according to Shehu.

“Dean [Shehu]’s freezer replacement program is a shining example of using a scientific approach to improve how we do research and patient care here at UCSF,” said Guglielmo. “We’re now using measurably less energy, but we cannot rest when it comes to becoming more sustainable over time.”

Building a case for sustainable cold storage

Shehu arrived at UCSF in 2017 to serve as “lab manager” for the entire university. Backed by years of experience as a research lab manager and product line manager at industry-leading life sciences companies, he was tasked with overseeing supply chain concerns that individual UCSF labs couldn’t handle on their own.

One of his first assignments was to take a closer look at UCSF’s ULT freezer situation. Shehu quickly realized that these freezers made up a huge portion of the university’s electricity budget.

Shehu proposed 10 projects to improve how ULT freezers were used, ranging from encouraging labs to throw away expired or unusable samples, to adopting newer ultra-low temperature storage systems, to replacing the oldest, least-efficient freezers.

For each proposed idea, he crunched some numbers to provide a ballpark estimate of their costs and benefits. In late 2018, he presented his findings to a handful of university leaders, including Guglielmo.

Soon after, Guglielmo contacted Shehu, asking about the impact that just the freezer replacements could make both on the School of Pharmacy’s budget and its carbon footprint.

“Joe seized on that one project idea, so I pivoted my research on the freezers to account for the School of Pharmacy and sent him my business case,” said Shehu. “I told him, you would save millions of dollars in electricity per year, and even if the School or campus paid up front for the freezers, no cost to the labs, you’d get that money back in savings in six years.”

Guglielmo was convinced. He threw his weight behind Shehu’s idea, rallying approval from UCSF leadership to direct financial resources to the budding project. The Office of Sustainability and Executive Vice Chancellor Dan Lowenstein soon joined the cause, with Guglielmo and Shehu leading the charge to keep the project moving forward.

“This was a systems-level problem and we needed a systems-level solution for it,” said Guglielmo. “But to carry out such a bold plan, Dean needed our support early on.”

Shehu began assembling a team that included UCSF Facilities and Sustainability staff members to draft, fund, and execute a plan for replacing some of the campus’s older freezers—a test run for an idea that he hoped could inspire the entire university to action.

Upgrading freezers with care

The first order of business for Shehu was to survey UCSF research groups about their freezer use. He wanted to know how many freezers each lab depended on, the age of those freezers, the nature of their contents, and how each lab felt about the prospect of replacing its freezers. Also, the replacement would require work and planning from the lab itself, so he held a series of focus groups and invited lab managers to participate.

“I couldn’t think about replacing a piece of equipment that in many cases holds people’s life’s work without hearing their concerns,” said Shehu. “These focus groups were essential for putting people at ease with different aspects of the program.”

Shehu focused on two of the primary research buildings at UCSF, Byers and Genentech Halls, to create a pilot project with a defined scope. He received further, critical help from Nevan Krogan, PhD, director of the Quantitative Biosciences Institute, and David Morgan, PhD, Vice Dean for Research in the School of Medicine, who served as the project’s respective liaisons to the labs in each of these buildings.

Some labs were excited to finally replace their aging freezers, many of which were at high risk of failure. Others had questions about the new freezers that they’d receive, or the logistics of keeping freezer contents cold during the swap and properly disposing of the old freezers.

Just as these focus groups were occurring, in early 2020, the COVID-19 pandemic imposed a new normal for all business at UCSF. But Shehu and his team moved forward, abiding by new pandemic restrictions as they came in.

Abueg standing in front of freezer

Robinson Abueg, UCSF Pharmacy Receiving Manager, poses after placing the first Pfizer COVID-19 vaccine into a new ultra-low temperature freezer (left) at UCSF. This freezer was one of two installed by Dean Shehu and his team in the fall of 2020 in support of the vaccination effort.

Ultimately, with buy-in from 13 labs, Shehu selected Stirling Ultracold, a freezer manufacturer, to place a bulk order for 43 modern ULT freezers. Each freezer cost $12,460 up front plus another $130 for transportation to and installation in labs.

The first energy-efficient ULT freezers began arriving at UCSF in the late summer and fall of 2020—just as Pfizer’s and Moderna’s COVID-19 vaccines received approval from the U.S. FDA. Understandably, Stirling put the remaining replacement freezer orders on hold to ensure that there were enough freezers nationally to support the vaccine effort.

Shehu quickly found himself balancing the competing but synergistic needs of both research and public health, negotiating over individual freezers with the manufacturer.

“We then installed two freezers from our order at UCSF specifically for the vaccines, just weeks before the vaccines arrived [in late November 2020],” Shehu said. “It was a kind of nutty time in my life, but we learned a lot in a very short amount of time about how to set up optimal vaccine cold storage.”

The backlog on the ULT freezer supply began to clear in February 2021 and the team got back to work replacing freezers in research labs.

A model for the university

Handfuls of modern, efficient ULT freezers arrived each month in the first half of 2021, at a pace that matched the ability of Shehu’s team to replace the older freezers. Each replacement took a small village to carry out, with UCSF Logistics receiving the large machines and delivering them at the Mission Bay campus, to ferrying them to the proper lab and safely swapping freezer contents without letting them thaw.

The process took a few days per freezer, and the team hit its stride as spring gave way to summer. By August, 41 new freezers had been installed and outfitted with free meters provided by UCSF Facilities to monitor their temperature stability. (Two of the project’s ULT freezers remain in use for UCSF’s COVID vaccine program).

Shehu recently received Executive Vice Chancellor support to replace the oldest freezers across the university. He envisions a program that relies on the predictive algorithm developed by the pilot program team, which quickly and accurately flags the freezers with the highest energy use for replacement, based solely on each unit’s storage volume and age.

Patient samples on a freezer shelf
Susan Merrell

Blood samples from COVID-positive patients are stored in an ultra-low temperature freezer in the Chin-Hong Lab at UCSF Medical Center, part of a study of the anti-viral drug remdesivir.

The team found an additional incentive for replacing these freezers—40% of the target freezers in the pilot were on the brink of failure.

“There’s no need to replace all the freezers at once—just the ones at risk of failure, the oldest ones,” Shehu said. “If we are strategic, we can still make a big impact on UCSF’s energy needs. We’ll also be better off when PG&E curtails power during fire season. And our scientists won’t need to worry about their life’s work disappearing due to freezer failure.”

Shehu expects to publish a white paper on the project in the coming months. It will detail the exact benefits the program has already reaped for energy and financial savings on ULT storage, as well as the strategies that earned the acceptance of UCSF’s research community and leadership.

“The School of Pharmacy, and UCSF at large, is a world leader in so many areas, but we can’t take our position for granted,” said Guglielmo. “Shehu’s vision and success have paved the way for our community to ensure the quality of its science and health care in a world where energy rightfully comes at a cost.” And for Shehu, that sort of support from up high will continue to be welcome and necessary.

“I’m not on a sustainability team, and Dean Guglielmo certainly isn’t either,” said Shehu. “But in the context of UCSF and our goal for carbon neutrality, it’s pretty much everybody’s job.”


Freezers for a Sustainable Future (UCSF Office of Research)

No Catch: Your Lab Can Save Money and Reduce CO2 Emissions (UCSF Office of Sustainability)


School of Pharmacy, Department of Pharmaceutical Chemistry, Department of Bioengineering and Therapeutic Sciences, Department of Clinical Pharmacy, PharmD Degree Program

About the School: The UCSF School of Pharmacy aims to solve the most pressing health care problems and strives to ensure that each patient receives the safest, most effective treatments. Our discoveries seed the development of novel therapies, and our researchers consistently lead the nation in NIH funding. The School’s doctor of pharmacy (PharmD) degree program, with its unique emphasis on scientific thinking, prepares students to be critical thinkers and leaders in their field.