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Freezer Challenge spurs labs to Store Smart (and save electricity)

May 5, 2011

This month, like every other, graduate students, lab managers and faculty will open up any of 1,000 ultra-low temperature freezers at UC Davis and retrieve some very, very cold research samples of biological materials.

So, how is this May unlike any other? This May marks the debut of the Freezer Challenge, a national contest pitting UC Davis against other universities in a race to save energy and improve sample management. Expect to see some freezer "spring cleaning" underway in labs as contestants vie for cash awards, rebates, and, of course, bragging rights. The challenge organizers have even created a Facebook page where participants can post before and after photos of the "gnarliest" (frostiest and messiest) freezer. The contest runs from May 3 through June 3, and contestants must record their participation through online surveys.

UC Davis’ energy and maintenance costs for ultra-low temperature freezers, not counting refrigerators and standard (minus 20 degrees Celsius) freezers, are estimated to be over $1,000,000 a year. The ultra-low freezers reach temperatures as low as minus 86 degrees Celsius (about minus 123 degrees Fahrenheit) to preserve biological samples, and at those low temperatures each of those 1,000 ultra-low temperature freezers uses the same amount of electricity as a large household (around 20 kilowatt-hours a day).

Allen Doyle, sustainability manager at UC Davis, conceived of the Freezer Challenge as a way to introduce a variety of laboratory cold storage techniques, ranging from cleaning out and defrosting freezers to creating inventories of frozen samples to adjusting freezer temperatures and retiring old, less efficient freezers. He convinced colleagues at six other universities, including Harvard and CU Boulder, to partner with him and bring the challenge to their campuses. Their goals for the Freezer Challenge are to save energy, reduce the volume of freezer space, retire as many freezers as possible by June 3, and improve sample access and security, through encouraging researchers to adopt a variety of sample management techniques and practices.

Doyle notes that many of the lab managers he's talked with estimate that 10 percent to 30 percent of freezer samples could be discarded or stored elsewhere, allowing for freezers to be used more efficiently or retired, and thus save energy and money. "In future years we hope to save up to $100,000 annually while making sample access better for researchers, if we get smart about how we use freezers," said Doyle.

Doyle and his student assistants – who call themselves the Energy Team – are using the Freezer Challenge to roll out Store Smart, an innovative and comprehensive campaign of strategies to improve cold storage management. In conjunction with five UC Davis researchers, the Energy Team has developed an integrated approach that improves sample access and security.

The team created educational materials that explain how to clean out and care for an ultra-low temperature freezer, both to save energy and to prolong freezer life. They explain how a good sample inventory helps researchers find valuable research materials (one example they cite is of a UC San Diego lab that rediscovered several thousand dollars of needed reagents during a freezer cleanout); how to inventory a sample collection with management software; and how to safely dispose of old, unneeded samples.

With their freezers cleaned out, researchers may find they can consolidate or share with another lab group, and be able to retire a freezer altogether and receive a cash rebate. For those lab groups that decide to replace an old freezer with a new, more energy efficient model, rebates are also available through the existing, successful Freezer/Refrigerator Replacement Program.

Another technique is "temperature tuning," which involves setting ultra-low temperature freezers to higher temperatures than -80˚C for bio-molecules and microbial cultures that can be kept at temperatures as high as -60˚C and -70˚C. The Energy Team learned that ultra-low temperature freezers used to be called "minus seventies," then the industry developed refrigerants and compressors that could achieve lower temperatures and researchers started setting their freezers 10 degrees lower. Recent data from one manufacturer shows that energy use rises dramatically for those lower settings: electricity use doubles going from -60˚C to -86˚C. Doyle also notes that most DNA can be safely stored at -20˚C in standard freezers, an energy savings of about 75 percent over ultra-low temperature storage.

The team also addresses scientists' concerns about deviating from standard storage procedures for fear of compromising their data. And, because freezers risk failure and are energy intensive, the team highlights other storage options, including freeze-drying, air-drying and even room temperature sample storage, which uses chemical solutes to store genetic molecules indefinitely. "This is an opportunity that is gaining attention across the country, and it has the potential for huge savings. Samples sometimes linger in freezers 30 years or more, and retiring professors would like their life’s work protected," remarked Doyle.

The Energy Team has received positive feedback about the Store Smart program from researchers, administrators and facilities managers. To get the word out about the Freezer Challenge and the Store Smart program, the team is giving lunchtime talks in May, bringing pizza and educational materials to five different parts of campus with the aim to reach as many labs as possible. "We hope that researchers will see that with a little effort, they can improve sample access and save energy at the same time," stated Samantha Ip, Cold Storage Coordinator on the Energy Team. Added team member Kate Lin: "All we need for change is researchers' motivation and involvement, and the Energy Team will provide resources and tools."

Register to participate in the Freezer Challenge and see the lunchtime presentation schedule at Store Smart. To request a presentation, contact Allen Doyle at apdoyle@ucdavis.edu.