Cooling Liquid product in plastic pouches via Liquid medium in pool

[NNNNNN]

Dear All,

We are looking to cool liquid product in plastic pouches (Diff. Viscosities in each patch). Please if you can help with formulas to calculate load estimation, capacity to cool for example from 30 Deg C to 4 Deg. C. each pouch has around half Kg. (may be in the future more than half Kg or less in each pouch will be used) 900 pouch in each minute. We can assume the liquid in the pouch is water (or any other liquid product with such viscosity and the cooling medium can be glycol (it is new design) the liquid product in pouches is food.

if you can help also with some sketchs.

Thanks in advance

[mad fridgie]

The very first question is how long is the product to be cooled for, or do want it chiller in 1 minute.

[mad fridgie]

815Kw at production rate
900*.5
450/60
7.5*4.182*26= 815Kw

[NNNNNN]

Yes, it is one minute to be chilled, and it is inside the plastic pouch

[NNNNNN]

Hi mad fridgie,

What about the liquid density (cooling effect, heat transfer) and what about the cooling time to penetrate the cooling from the cooling medium (in the pool) through the plastic pouch then into the center of the liquid inside the pouches (plastic bags) besides any other effect which is the quantity of the cooling liquid in the pool, flow rate and spaces between pouches and quantity of pouches each time in the pool.

Thanks.

[michaelm]

B”H
It is a huge load. I would ask you if it is 24 hrs. operation, if not you should look at using thermal energy ice storage maybe with a slurry ice.

[mad fridgie]

One minute, "well" I think not, but it does depend upon the shape of the pouch and how cold the cooling medium.
Leaving the cooling medium alone for a second, it is the products own thermal resistance will will limit the cooling period. "core temp" If is long wide and very skinny like apiece of paper then yes, but as it becomes thicker then the rate slows and/or the cooling medium becomes colder.
You could use something like a spin chiller (used for fresh killed chickens and the like) basically a long skinny bath with a slow moving auger (speed controlled). Normally a one pass water system, but in this case you circulate.
Do a simple test, dangle a pouch in a bucket of ice and water (not to much ice) stir it slowly. Measure core temp during the process. Time?. calculate the length of your spin chiller based upon this time and the production rate for width. (If the test is way to long add some salt to drop the temp and do again) and so on.
Nothing better than doing a practical test, when this sort of money is involved.
Yes thermal storage is great option if only short term production (many spin chllers do use ice/water mix)

You could also look at sprayed conveyor or shallow bath with air agitation (either with mechanical product movement or water flow)

[Magoo]

Why not chill the milk before packaging.

[mad fridgie]

I thought it was soup!

[michaelm]

B”H
Probably it was cooked in pouches and by the regulations need to be cooled to 4C

[adrian88]

Blast chillers are commonly used for this purpose in the seafood industry however they are used for snap freezing products. Maybe contact a manufaturer of these types of cooling systems and see if one can be modified to suit, my guess is they will suggest some form of cascade system to provide fast cooling and make the physical size of the system smaller. Either way she is going to be one fancy cooler to do what need.

[Magoo]

Hi MF.
my mistake, milk soup what ever, but pre chilling before packaging with a swept surface HX for continuos production and high volumes

[NNNNNN]

One minute, "well" I think not, but it does depend upon the shape of the pouch and how cold the cooling medium.
Leaving the cooling medium alone for a second, it is the products own thermal resistance will will limit the cooling period. "core temp" If is long wide and very skinny like apiece of paper then yes, but as it becomes thicker then the rate slows and/or the cooling medium becomes colder.
You could use something like a spin chiller (used for fresh killed chickens and the like) basically a long skinny bath with a slow moving auger (speed controlled). Normally a one pass water system, but in this case you circulate.
Do a simple test, dangle a pouch in a bucket of ice and water (not to much ice) stir it slowly. Measure core temp during the process. Time?. calculate the length of your spin chiller based upon this time and the production rate for width. (If the test is way to long add some salt to drop the temp and do again) and so on.
Nothing better than doing a practical test, when this sort of money is involved.
Yes thermal storage is great option if only short term production (many spin chllers do use ice/water mix)

You could also look at sprayed conveyor or shallow bath with air agitation (either with mechanical product movement or water flow)

Hi mad fridgie

I agree with you. But let?s take the worst case that the bag shape has a depth to the core center about 4 cm. and the product liquid inside the bag has such density. Besides, not water agitating and the bags are still. The cooling medium has certain flow rate and inlet temperature and we can assume that cooling liquid out temperature. Would there be formulas to calculate the cooling load required to cool that product from such temperature to the objective temperature and the time to reach cooling required to the core of the bag.

Thanks.
________
Laguna Bay Condominium Prathumnak (http://pattayaluxurycondos.com)

[michaelm]

B”H
I was involved in the project with the meat application. We used two tanks: “buffer tank” with the slurry ice (thermal energy storage) and “product tank” with a very low concentration of ice (we allowed the buildup of a small layer of ice on the top, just before the product went in) just to eliminate the initial “thermal shock” of the hot cooked product and the rack.
Product load ~ 1ton of the cooked meat was going into the tank to chill; 10 loads per day/tank. We are able to reduce the chilling time by 75% in compared to chilled water. Good agitation is very important. We could chill the product to -2C (8% salt solution) and they may not need to place the product in the blast freezer running @-18C, which would go in to storage afterwards @-35C. I would not advice to use glycol but salt solution. You can use final element analysis for calculation but a real testing is the way to proceed.

[Magoo]

There is no way you are going to chill a 0.50 kg pouch of product in 1 minute with blast chill or bath immersion, chill the product with a swept surface HX before packaging, alfa laval do them, similar to an ice cream churn

[NNNNNN]

What about if we increase the 1 minute to 15 minutes or even 30 minutes, Still there should be formula to calculate, as the product is liquid with such density and in bags that has some thickness (needs some time to cool the core – such distance between the plastic wall and the core). As well the chilled water flow need to be calculated.

[Magoo]

Hi NNNNN,
as MF stated earlier, you need to establish the specific heat value of your particular product. Themometers and a bucket iced water, then things will become clearer. Extending chill time will certainly help.