Set up for success
Raise the set temperature from -80oC to -70oC
This practice will not affect sample integrity, but will lower the energy consumption of the freezer by 1-2 kWh per day. It will also raise the life-span of the freezer by lowering the stress on compressor going onward.
Do not set up freezers in small rooms/hallways
ULT freezers in small spaces work the compressors harder to maintain the set temperature. Moreover, this can increase the room temperature by 10-15oC and put extra stress on the lab’s HVAC system.
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 adjustable exhaust system set up behind all our freezers. The generated hot air is expelled outdoor during summers and circulated throughout the lab to assist in heating during winters.
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 over the air filter and motor coils over time, making the freezer motor work harder than needed. Regular cleaning of these components can reduce freezer energy consumption up to 25%. While it’s important to check this every few months, the cleaning generally is only required 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 2-4 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 not only ensures sample integrity, but also provides actionable data regarding the freezer’s energy usage and efficiency. 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.