Currently we use in our Biobank an upright -80 freezer to store all our samples. We are planning to buy a fully automated bio-repository storage that will do the picking of samples under restricted conditions. But in the meantime I foresee that we have to pick the samples manually. The disadvantage of upright freezers is the fall out of cold air and the warming up of the samples. A chest freezer does perform better on cooling the samples in my opinion, though it has some disadvantages; space, heavy towers etc. But I haven’t done measurements and my question is:
– Do you have measurements available where you compare the both freezer types?
– What is the main choice in freezer type?
– Do you have time access restricted protocols to prevent warming of samples in upright freezers?
1 Comment
Sylvain Riendeau
August 22, 2012You are correct, a chest freezer will perform much better than an upright. However, this comes as a cost: The foot print (size) becomes an issue unless you have a large facility.
o There seems to be 10 upright freezers for every chest freezer sold.
o Temperature uniformity is better in a -80C chest
o Temperature recovery is better in a -80C chest
o Life cycle of a chest freezer is more than a upright freezer ( since the compressors cycle time is much less on a chest freezer).
o Electrical usage: An upright freezer compressor cycle time is approx.
70% to 80% “ON” ( depending on ambient temp., door opening, product added to freezer). Keep in mind the compressor housing on a upright freezer is located under the freezer. Therefore adding heat to the freezer cabinet when compressors are operating, thus adding time to the recovery run cycle. Using chest freezers will also reduce your air conditioning cost, since cycle duty is less on a chest freezer.
o Ergonomic: It is easier to pull/slide a rack horizontally from an upright freezer than lift a rack from a chest freezer
o Time access: This is difficult to manage, since no two people can retrieve samples from a freezer at the same rate/ time. Most lab grade freezer do have a door open warning system i.e. ( 30 sec), therefore user is notified of door opening ( visual/ audible) to reduce/prevent temperature rise.
o Sample Storage: For upright freezer rule of thumb, only store long term storage at the bottom of the freezer ( bottom two shelves) and use the top two shelves as short term storage, therefore reducing the cold air from falling out of the freezer each time the door is opened.
Again, if you have a large facility and can afford the large foot print of a chest freezer, then a chest freezer would be best.