How to Make Your Laboratory Freezer More Sustainable

Learn more about sustainable practices

Achieving sustainability in the lab is an ongoing process, and best practices around equipment use can make a significant difference to your lab’s carbon footprint. This is particularly relevant when it comes to ultra-low-temperature (ULT) freezers – being more sustainable may start with choosing a greener, more energy efficient ULT freezer, but it doesn’t end there. How you utilise sample storage space and maintain the freezer will have an impact to its performance and energy usage.

Maximise sample storage density to improve your footprint

The first step after choosing a sustainable ULT freezer is to maximise your storage density. This means you are storing more of your samples in the space that you have available.

Historically, it has been standard for researchers and lab professionals to use 2mL tubes to store their samples. But today’s machines are more sensitive and don’t necessarily require as much sample volume as they have in the past.

Considering this, if you are looking to make a sustainable change, ask yourself the following:

How much sample do I need to store?
Am I using the appropriate tube or vessel size?
Is my inventory adequate to keep track of my samples?

Does changing the amount of sample stored really make much of a difference?

Yes, to illustrate the difference sample density can make, consider the capacity of the ULT Thermo Scientific TSX400 freezer, which can fit 16 racks for boxes of standard tubes. With 2mL tubes, there is capacity for 40,000 samples. Yet with half a microlitre (0. 5mL) tubes, there is capacity for 86,016 samples - you can double the number of samples you have in the same freezer by using smaller sample volumes and slimmer tubes.

Did you know that a full freezer performs better?

You can improve the sustainability of your freezer by being more efficient in your storage. Did you know that a full freezer performs better? Having mass or thermal load within the chamber keeps it cold and reduces air displacement when the door is opened.

Maintain your cool with inventory management

The other key point to make about managing freezer sample storage is inventory. Having an inventory management system – such as the utilisation of barcodes for racks and tubes – will help keep you keep track of what samples are inside and where they are located. You may also want to consider putting an inventory map or list of what is inside the freezer on the outside of the door. This can reduce the number of times the freezer door is opened and the length in which the door stays open.

Care and maintenance of ULT freezers

The care and maintenance you perform on your ULT freezer will impact how efficiently it works.

One of the key features of a ULT freezer is the door gasket which serves to seal the unit. These should be checked regularly for leaks and tears to ensure there is a good seal between the door and cabinet. This can be done at the same time as wiping them with a soft cloth. Any gaskets with ice build-up should be replaced.

The condenser should also be inspected and cleaned regularly. This plays a vital role in airflow, allowing heat to escape from the freezer unit. To perform maintenance, open the grill door, vacuum the condenser, and check the filter cleanliness. The filter should be cleaned every 2-3 months.

“Ice will act as an insulator and make the unit work harder than it should, so it’s important to regularly wipe frost off from sealing surfaces to prevent the formation of ice.”

One of the main issues faced with freezer units if they are not cared for or maintained, is the build-up of ice. Ice will act as an insulator and make the unit work harder than it should, so it’s important to regularly wipe frost off from sealing surfaces to prevent the formation of ice. Likewise, a defrosting of the unit is recommended once a year.

We suggest writing a preventative maintenance programme with a checklist to ensure your ULT freezer is functioning correctly and efficiently.

A maintenance checklist should include:

Inspect door gaskets for ice build-up
Inspect door latches for latch loosening
Check inner doors for good functioning
Check battery for full charge and voltage
Check filter/ condenser cleanliness
Check firmware version for updates

To learn more about maintenance best practices regarding a ULT freezer unit, you can access an on-demand webinar presented by Thermo Scientific cold storage experts.