Find out how to save energy in cold storage. Image ULT freezers (“minus 80s”) consume the most energy of all cold storage systems. Below are listed ways to improve sustainability of ULT freezers. Some of these tips will also improve the energy efficiency of other cold storage. ULT freezers (“minus 80s”) can use £1,000 of energy annually Less energy waste means more money for research According to SRS at University of Edinburgh -70 C uses 25% less energy than -80 C Adrian Bird’s lab saved almost 50% energy by changing ULT temperature from -80 to -70 C Other Benefits: less strain on freezer components, reduced maintenance costs for repairs reduced risk of damage or destruction of valuable samples (the contents of a ULT freezer could have a value over £1m) less UoE staff time spent arranging for freezer maintenance team call-outs and transferring contents to a hotel freezer during a freezer failure less UoE staff time spent attending freezer alarms out-of-hours more productive staff due to less room overheating (less heat output from the ULT freezers) - staff working in spaces which are too hot are less productive Tips on saving energy in cold storage 1. Raise temperature of freezers from -80 to -70 C Most materials do not require storage at -80C. Consider raising temp of your ULT. See the following link to information on storage of biological samples at higher temperatures than -80 C, obtained from SRS. Cold storage data As an example in our building, EPPF stores the following reagents in -70C: Competent cells, Cell pellets from expression cultures, Purified proteins (note not all proteins remain active/folded at -70oC and conditions need to determined empirically). If storage at -80oC is essential consider having a communal freezer at -80oC. Image C Finlayson enjoying the warmth produced by fully operating -80 C freezers 2. Orchestrate the increase of temperature with other owners of ULT freezers in the same room. - 80 freezers produce heat, which puts an additional demand on neighbouring freezers to keep the temperature low and on air conditioning of the room. 3. Avoid frequent and prolonged opening of the freezer 4. Defrost: Ice build-up poses a risk to samples by stopping the door from closing properly, and increasing energy demand Image P Heun succeeding to excavate a precious sample from ice 5. Label all freezer contents clearly Your name, materials, and expiry date; Use labels which will last. Good organization helps quicker finding and reduces time of door opened. 6. Clear out: Remove samples which are no longer needed and avoid further purchases of reagents you already have. 7. Avoid storing -80 in poorly ventilated, overcrowded room and in the vicinity of waterbaths. Warm humid air will condense on the freezer. Remove water baths from the room if possible. Image Clean filter 8. Clean up: Air filters and heat dissipation fins accumulate dust, which makes them less effective and uses more energy. Dusty filters are also a frequent reason for alarm setting of. Image Damaged or non-existent seals 9. Inspect all rubber seals around door and handles. If damaged they may cause warm air entering the freezer. 10. For a fridge and freezer to work efficiently keep 15 cm space around sides and at the back and do not store items on top. 11. Fill in the unoccupied space inside with material such as empty boxes and cold packs to minimize warm air entering and for keeping your samples at more stable temperature. 12. Replace old units at the end of their life with energy efficient ones 13. Under-bench fridges and freezers use the most energy. When replacing consider having a tall unit instead. Advice on cleaning and checking on -80 every 2 weeks Day 1: de-ice the door moving from outside to the inside of the freezer (leave the shelving for the next day to avoid excessive increase of temperature). Dry wipe the de-iced surfaces. Day 1: Check and clean the filters Day 2: clean the shelving: scrape and make sure shelves work easily Day 2: check the rubber seals Report any mulfunctions or problems Other days: remove unnecessary items, organize the content for easy and quick access, fill empty spaces with marked empty boxes This article was published on 2024-06-17
