Over the next 20-30 years, the air-blast freezer became universal in the New Zealand frozen food industry. Several variations were developed, including cross flow and vertical air flow systems and there was a move from batch to continuous production for larger through puts and reduced labour costs. By the 1980’s, energy efficiency became an important design parameter. Many potential energy saving initiatives were investigated in terms of both the refrigeration system and the system as a whole. Such energy saving initiatives included: improved air flow design by altering the product stacking arrangement and the use of baffles and turning vanes, varying the air velocities at different times throughout the freezing process and the effect of product packaging on freezing times. The easiest and most advantageous energy saving device today is the use of variable speed drives (VSD’s) on evaporator fans. 3. Why blast freeze?