Conventional ULT freezers are used for freezing and storage of biopharmaceutical bulk DS, but they are not always the optimal solution. ULT freezers are designed for storing frozen material and have limited capacity for freezing liquid DS.
For freezing bulk DS, forced air convection freezers that are designed for the application provide much faster freezing rates, much more consistent freezing rates, and greater mechanical reliability.
For storage of bulk DS, there are now three options available – conventional ULT freezers, large custom freezers, and a newer option of midsize ULC freezers. There are pros and cons to each option, and one tool to find the optimal solution is an economic evaluation. The results of an example evaluation show the optimum solution varies with the amount of freezer capacity required. For a small freezer capacity requirement (around five ULT freezers or fewer), ULT freezers provide the lowest overall cost. For very large applications where more than 100 ULT freezers would be required, the large custom freezers are optimal. And when freezer capacity of between five and 100 ULT freezers is required, the ULC freezer option gives the lowest overall cost.
Key Words: Design, Strategies, Blast