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View Full Version : Hey guys, how does a blast chiller work compared to a fridge?







Steffus
19-04-2016, 12:37 PM
What is the difference between the two of them?
Is it a more powerful compressor or the fans or someting else?
And I know it is possible to combine a blast chiller with a blast freezer but how does it work in particular? Do they use a magnet valve when they only have one compressor?

Thanks for every response :)

Magoo
20-04-2016, 05:58 AM
generally the difference is high velocity air flow to gain advantage of wind chill factor, and rapid chilling or freezing.
Search " wind chill factor " and see the difference. Dependent on air velocity as in lineal m/ s . Roughly -40' C air at high air velocity has a wind chill factor of around -60' C .
Basically the difference of snow outside no wind , then walk out into a blizzard and feel the difference.
magoo

Steffus
26-04-2016, 10:10 AM
Ok I get the point with the air flow thank you :)
but if I but some high end fans in an ordinary fridge it wont turn to a blast chiller, will it?
So there has to be something in addition like a "better" evaporator / compressor or am I wrong?^^

Tycho
26-04-2016, 05:34 PM
Ok I get the point with the air flow thank you :)
but if I but some high end fans in an ordinary fridge it wont turn to a blast chiller, will it?
So there has to be something in addition like a "better" evaporator / compressor or am I wrong?^^

it's all about airflow, but of course you will need a refrigeration plant that can handle the higher heat transfer, and you also need to calculate the heat added by the fan motors.

Glenn Moore
27-04-2016, 12:06 AM
Steffus
Blast freezers/chillers are different in design to cold stores for several reasons.
Cold stores are built to store pre cooled products, so the plant capacity has only maybe 10-15% extra capacity for temperature pulldown to allow for any temperature rise during transportation, say from slaughterhouse to the butchers shop. The cold store typically has a design running time of 14-16 Hours per day .
Blast Chillers or Freezers are designed to pull the product temperature down very quickly from 60-70degrees down to minus 20 Deg C in a 2 hour cycle. This entering temperature will depend if the entering product has just come out of an oven or cooker, or is a newly slaughtered carcase of meat etc . So we call this a process chiller or freezer because it will do several batches of product per day , and so the plant has to have the capacity to remove the product heat load from its entering temperature down to its storage temperature in its blast cycle time.
Cold room equipment is normally off the shelf products ie Condensing units ,Evaporators and expansion valves.
Blast equipment is a little different.
The evaporators are normally designed to fill one complete wall of the cold room from floor to ceiling with the inlet face of the evaporator drawing air through the product at high speed. As the air passes through the evaporator it is then drawn through the fans and then blasted back across the ceiling of the room and the cold air is then percolated back to the cooler through the product .
So the system capacity is a lot higher due to the high volume air circulating around the room and so the equipment would also be bigger in capacity to do the job.
You can get bespoke built units which are designed so that specific sized trolleys or pallets fit in the blast area made to measure
You will need a fully qualified refrigeration guy to install and gas the system thanks to EU legislation

Steffus
28-04-2016, 10:06 AM
Well a big thank you for all your answers, never expected such help :)

Something else: does a blast chiller / freezer generally work with 230V or 400V? Because I heard, that u definitely need a 400 V compressor, is this right?

chemi-cool
28-04-2016, 10:24 AM
It depends on capacity but 3 phase always better and also the evaporator's fans should be 3 phase as you need the highest speed.