This paper presented a snapshot of the use of blast freezers in
the food industry, including historical background, modelling
features, issues and recent advances that have enabled air blast
freezers to play a significant role in the meat industry due to their
versatility and low capital cost. There seems to be a great potential
to achieve energy savings in blast freezer industry by employing
VSD’s on fans that could result in with energy savings of up to 44%.
Other, cheaper and simpler energy saving measures include air
baffles, air turning vanes, fan inlet cone and outlet diffuser, and
improved user operating procedures.
When determining the heat load during the design process it is
insufficient to use the mean product load. The “peaky” nature of
meat, particularly hot boned meat, must be taken into account to
ensure adequate freezing times are achieved. Evaporators should
be sized 50% higher for 24 h freezers and hot boned meat. Also, the
design capacity of the freezer will deteriorate with time. It is
imperative the product is stacked with adequate spacing to enable
air to pass through; failure to do so will result in localised regions of
long freezing times.