ULTs at -70° C: Existing Data and a Current Research Study

Amorette Getty, UCSB
Cameron Guiliano-Puzi, UCSB

Ultra Low Temperature (ULT) freezers draw a significant amount of power, causing them to be a key research appliance of focus when looking for ways to save energy costs. Typically, ULTs are run at a setpoint of -80 C to reduce risks to sample integrity, and to widen the buffer zone for sample rescue in case of a power outage. Anecdotal data has been collected on researchers storing material at warmer setpoints, such as -70C, which leads to energy savings and decreased stress on instrument compressors, however no peer-reviewed studies to date addressing ULT sample storage temperatures for the research environment have been published. Such data may be critical to verify that warmer setpoints are a reasonable modification to sample storage protocols and to encourage behavior-change among data-driven research scientists making decisions about setpoints for their sample storage.

UC Santa Barbara is conducting such a study with the intention of peer-reviewed publication, on the effects of increased sample storage temperature from the research cultural norm. Several labs have been enrolled to contribute identical sets of samples of various biological types typically stored in ultra-cold conditions, to be stored for a period of one year in two identical, newly-purchased ULT freezers. These were set to average internal temperatures of -70 C, and -80 C. After six months and one year of storage, the samples stored under the two conditions will be tested to quantify sample viability and look for indicators of degredation, with testing methodologies based on each type of stored sample.

In addition, a pre-cursor study was conducted prior to experimental sample storage, comparing time for loaded freezers beginning at the two setpoints to reach critical, sample-endangering temperatures in the event of a power outage, and to map out temperature variation within the freezer compartment, both during operation and during a power-outage event.

While the yearlong experimental timeline is not complete in time for I2SL, the 6 month trials for multiple samples will be complete, and these early results as well as discussion of the experimental design will provide preview results prior to the publication of the peer-reviewed study. In addition, we will review existing repositories of anecdotal data on this subject, and discuss plans for future phases of this research effort.

Learning Objectives

  • know how to access existing public repositories of anecdotal data on sample storage temperatures for the research environment, and be aware of other relevant studies underway in this subject area;
  • understand the diversity of temperature ranges which can occur in cold storage interiors;
  • know the conditions being tested in a currently-underway research study on sample storage temperatures; and
  • understand the energy-saving opportunities and sample security concerns related to biological sample storage at increased setpoints.


Amorette Getty is Co-Adviser for UCSB's LabRATS program, and chairs the UCSB Campus' Laboratory Ventilation Working Group. LabRATS strives to help scientific labs use every resource they have with expanded efficiency: electrical energy, human energy, water, material waste, researcher time, experience, and attention, and grant funding dollars.

Cameron Guiliano-Puzi is a third year Environmental Science major who has worked with LabRATS for two years. He primarily works with laboratories to achieve sustainability among researchers. His experience in LEAN manufacturing as well as lab experience at UC Davis led him to want to apply sustainability practices learned in commercial manufacturing to the laboratory setting. He has spoken at two CHESC conferences, and upon the completion of his degree he hopes to continue his work in laboratory


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