Sustainable Labs

Best practices in ULT freezer maintenance

Ultra Low Temperature (ULT) freezers arecommonly used in research facilities. However,ULT freezers have significant operating costs andenergy usage, often using more than 5% of alaboratory’s total electricity consumption.Important steps can be taken to optimize ULTfreezer effectiveness and energy consumption.

Switch TO -70ºC

-80ºC has only become the industry standard for ULT freezers in recent years. Thefirst ULT freezers operated at -60ºC, and -70ºC, and the switch to storing samples at-80ºC is the result of industry marketing rather than scientific need.

Benefits of using -70° C:

  • Reduces energy use up to 30-40% and saves up to 10-15% of electricity costs
  • Prolongs freezer life

Can be stored at -20ºC or -70ºC depending on required length of storage. DNA samples stored at up to -20ºC are stable to multiple freeze-thaw cycles and do not degrade. In the short term, genomic DNA can be stored at 4ºC or room temperature, but must be monitored for changes inconcentration and evaporation.

 

Microorganisms (including fungal strains) can safely be stored at -20ºC and -70C. Of note, liquid nitrogen is another alternative option for storing living cell samples that is cheaper and often more convenient.

Studies have demonstrated that protein samples can be stably stored at -70ºC for at least 1 year.

Check if any reagents stored in your freezers are required to be stored at these temperatures.

Preventative maintenance

  • REGULAR CLEAN-OUTS
    Implement a lab-wide freezer cleaning/maintenanceschedule as suggested by the vendor.
  • MINIMIZE FROST
    Minimize frost formation on freezer doors and shelves.Regularly clean refrigerator and freezer coils. Checkdoor seals and gaskets for leaks.Harvard provides de-icing kits for all labs with ULT freezers!
    The CDC has saved more than
    350,000 kWh/yr
    across the board and the NIHhas saved an average of
    25,000 kWh/yr
    per freezer
    by implementing thesebest practices.
    TURN IT OFF
    Turn
    off empty freezers and decommission old freezers(and other equipment).

 

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