Greener, Cleaner Laboratory – I: ULT Freezers

It’s no secret that scientific research laboratories around the world aren’t exactly the most eco-friendly institutions. Among high energy consumption, one-time use products, and the need to dispose used chemicals, there are many ways that routine work in a laboratory can hurt the environment. However, we can proactively address improper laboratory practices to lessen their adverse impact on the environment.

Ultra-low temperature (ULT) freezers are one of the biggest culprits for energy consumption in research laboratories given their requirement of 16–25 kWh per day per freezer, on an average. At NorthEast BioLab, we currently have 10+ ULT freezers in use. If handled improperly, these freezers could meter up a large energy bill and an even larger carbon footprint. Consequentially, we have taken multiple steps to lessen our freezers’ energy consumption and negative impact on the environment.

Set up for success

  • Raise the set temperature from -80oC to -70oC

Raising the temperature to -70oC will not affect sample integrity, but it will lower the energy consumption of the freezer by 1-2 kWh per day while also lengthening the life-span of the freezer by putting less stress on the compressor going onwards.

  • Do not set up freezers in small rooms/hallways

If ULT freezers are operating in small spaces, they can raise the temperature of the room by 10-15oC, resulting in extra stress on the lab’s HVAC system. Additionally, more work will be required from the compressors to keep the freezer at the set temperature.

  • Ensure that all freezers have at least eight inches of surrounding space

ULT freezers produce plenty of heat. If that heat has nowhere to go, it will cycle back into the freezer motor. This will cause the motor to work harder, using more energy in the process.

  • Install a two-way ventilation system

At NorthEast BioLab, we have an exhaust system set up behind all our freezers. During summers, the hot air produced by the freezers is expelled outside through the exhaust fan. During winters, the outdoor line is plugged, and the fans push the hot air away from the freezers and throughout the lab to assist in heating.

Stay on the course

  • Do not let ice/frost buildup occur in the freezer

Ice/frost lining of the seal gasket on the door happens over time. This allows cold air to seep out and warm air to seep in. Thus, it is important to regularly check for frost and ice buildup, once a month at a minimum.

  • Regularly clean air filters and motor coils

Dust and grime accumulate on air filter and motor coils over time and make the freezer motor work harder than necessary. Regular cleaning of these components can reduce freezer energy consumption up to 25%. While it is important to check on this item every few months, it generally only needs to be taken care of once per year.

  • Replace Old ULT Freezers

The average life-span of a ULT freezer is 7-10 years when operating at -80oC and 10-12 years while operating at -70oC. However, when freezers reach the end of their lifespan, they can begin to use 2 to 4 times as much energy as when they were brand new. Even though new ULT freezers are expensive (generally around $12,000-15,000) the savings from a reduction of energy usage can easily be over $1,000 annually.

  • Monitor Temperature 24×7

Temperature monitoring is not only important to ensure sample integrity, it can provide actionable datapoints regarding the energy usage and efficiency of the freezer. At NorthEast BioLab, we check the temperature chart of each freezer once per week at a minimum.

Telltale signs of an inefficient freezer include:

  • Average temperature observed below the set temperature
  • Significant rising and falling temperatures when the freezer doors have remained closed
  • Gradual increase / decline in average temperature over any period

All these signs can point to an aging compressor that will soon fail and is likely using more energy than needed, or there’s a leak somewhere in the freezer allowing warm air in.

Even as the energy consumed by ULT freezers will likely always be quite significant, it’s noteworthy that their energy consumption can be greatly decreased by following a few simple steps during setup, monitoring, and maintenance. While many of the eco-friendly practices implemented at laboratories come with significant cost, lessening the energy consumption of ULT freezers is the one that can simultaneously help both the environment and your wallet.