Defrost Room Design

[homerphish]

Has anyone ever designed a defrost room before? I have 96000 lbs of beef that I have to defrost from 0 to 28F over 24 hours. I know what the required Btu's are for the latent heat and the overall warming, but is the room setup similar to a chilling room with a pull down load, or is there a specific way for doing defrost rooms?

 

[imok2]

homerphish
so what are you gonna do about a defrost method... I,m curious?

 

[homerphish]

I was thinking about using hot gas, like I would in a Hot Gas Defrost for the coil, only I would leave the fans on to distribute the heat.

 

[sterl]

This is often called a tempering room. Assume the application is preparation for a production conditioning step such as saw or blade cutting or shredding, yes? Those of my past involvement have either had to be operated with some insight (which is to say uncontrolled and reliant on presumed insight of the user) or have to be designed carefully, with intensive and addressable controls...The released moisture and drainage scenario is a sizeable consideration too. With the variances of product and desired conditions in a given plant, most of the former "normal" applications are now serviced by microwaves incorped right into the line.

The temperatures of a "normal" hot gas reheat are just about right but the airflows you would employ in something like a carton freezer are much higher than you want for tempering...may best recall is that you don't want anything more than about 40 fpm over a Cryobagged type of product, somewhat higher over something in a paperboard container.

The packaging and single block or particle size will have a lot to do with the "intensity" of the heat application rate but you will need a fairly intense period of heating followed by an equilabration period, and the "target" for the actual finish condition has to be established...Most represent a friable but still crystalline condition, that is only partially defrosted.

 

[imok2]

A recommended way to defrost is by using chilled water where the defrost time is about 1/8 the required time of room temp defrost but the product should be wrapped. This method is faster than refrigerator thawing but requires more attention. The food must be in a leak-proof package or plastic bag. If the bag leaks, bacteria from the air or surrounding environment could be introduced into the food. Also, meat tissue can also absorb water like a sponge, resulting in a watery product. This is just FYI...not a personal recommendation!