Will additional fans chill faster?

[kengineering]

Our Air screen bottle cooler works great with 2- fans. It is for maintaining the temperature of pre chilled drinks. I'm trying to make a quick cool case where a store could fill it with room temp product, close an insulated door an quickly cool the product. By simply closing the door product pulls down from 70 *f to 38*f in a little over an hour.
My boss says that adding another evap fan will improve this. Wouldn't that be like Wind Chill ? It would seem that it would feel colder but the temp would still be the same. In fact I think the addtional fan would raise the temp of the coil. I asked for an explanation of this theory but he can't seem to explain it. But after all he is the boss.
Your thoughts please, Ken

[lowcool]

sack your boss and move onto blast chiller principles

[coolhibby1875]

it would do quite the oposite and add heat!!

[sherif.bakir]

Dear All
As it seems your are experts in the field of refrigeration!

Iam the owner of one of the Frozen Vegetables producers in egypt, and I need professional help in the following, as no one here In Egypt has the experience nor the understanding of our needs!

We need to implement a Blast Freezer to Freeze Blanched Vegetables with an infeed temperature of +15C and out feed -20C.
We need to freeze 2 tons per 2 hours in a Room with the following dimensions : 5mW 6mL 2.5mH.

We've managed to conclude the systems as follow , Kindly advise which is better and if shall be any other better Options:

A. 2 Copeland 25 hp 2 stage compressors with a Friga bohn 60 KW 6 fans Coil.

B. 2 Bitzer 25 hp 2 stage compressors with a goedhart TN.P 60 KW 4 Fans Coil.

Please advise which will be better the bitzer comp or the copeland , and if these systems will do the Job, and if they will have a long life in production.

[coolhibby1875]

Dear All
As it seems your are experts in the field of refrigeration!

Iam the owner of one of the Frozen Vegetables producers in egypt, and I need professional help in the following, as no one here In Egypt has the experience nor the understanding of our needs!

We need to implement a Blast Freezer to Freeze Blanched Vegetables with an infeed temperature of +15C and out feed -20C.
We need to freeze 2 tons per 2 hours in a Room with the following dimensions : 5mW 6mL 2.5mH.

We've managed to conclude the systems as follow , Kindly advise which is better and if shall be any other better Options:

A. 2 Copeland 25 hp 2 stage compressors with a Friga bohn 60 KW 6 fans Coil.

B. 2 Bitzer 25 hp 2 stage compressors with a goedhart TN.P 60 KW 4 Fans Coil.

Please advise which will be better the bitzer comp or the copeland , and if these systems will do the Job, and if they will have a long life in production.

bitzer over copeland any time

[kengineering]

it would do quite the oposite and add heat!!

Exactly what I thought

sack your boss and move onto blast chiller principles

Ok Where might I find blast chiller princples?

[mad fridgie]

Dear All
As it seems your are experts in the field of refrigeration!

Iam the owner of one of the Frozen Vegetables producers in egypt, and I need professional help in the following, as no one here In Egypt has the experience nor the understanding of our needs!

We need to implement a Blast Freezer to Freeze Blanched Vegetables with an infeed temperature of +15C and out feed -20C.
We need to freeze 2 tons per 2 hours in a Room with the following dimensions : 5mW 6mL 2.5mH.

We've managed to conclude the systems as follow , Kindly advise which is better and if shall be any other better Options:

A. 2 Copeland 25 hp 2 stage compressors with a Friga bohn 60 KW 6 fans Coil.

B. 2 Bitzer 25 hp 2 stage compressors with a goedhart TN.P 60 KW 4 Fans Coil.

Please advise which will be better the bitzer comp or the copeland , and if these systems will do the Job, and if they will have a long life in production.

rapid blast freezing is more about the product than the refrigeration. Your vegies are they loose, how are they stacked, trays, bins etc. This is a 100% batch cooling, product in/product out.(no storeage)
Does the 2 hours include loading unloading and defrost!
Are you controlling the air flow (do you have a false ceiling in the room) You need a product stack air velocity of a least 5

[Magoo]

Hi sherif.
blast freezing blanched veges, you need to operate temp at -40 'C to snap freeze, too slow and the product will lose weight. I would suggest a line freezer tunnel, for 1 tonne per hour retention time 45 minutes and approx 120 Kw refrig capacity.
magoo

[kengineering]

So if the additional fan is not the answer what is.

[glenn1340]

With all the hassle of fitting a larger evaporator and increased refrigeration capacity it would be far easier to look out for a used blast chiller. Chill the drinks down then put them in the cabinet. Last one I got cost just under £500. put a crate of beer in, press the button and ice cold lager in 30 mins...lovely stuff.

[Magoo]

Kengineering.
by upping the airflow you will effectively reduce the evap design TD, but reduce the latent cooling factor, so more sensible cooling. Plus improve compressor performance at a slightly higher suction condition. Make sure the condensing unit can handle the load. The fan input increase would be marginally higher. The higher air flow would effectively reduce pull down time of product. Your boss is not totally stupid.

[coolhibby1875]

Kengineering.
by upping the airflow you will effectively reduce the evap design TD, but reduce the latent cooling factor, so more sensible cooling. Plus improve compressor performance at a slightly higher suction condition. Make sure the condensing unit can handle the load. The fan input increase would be marginally higher. The higher air flow would effectively reduce pull down time of product. Your boss is not totally stupid.

his boss isn't to clever either if he thinks adding a fan will help!!

[RANGER1]

kengineering ,
Have you ever seen those mini glycol chillers for wine .

You buy a warm bottle of wine & put it in & in minutes its pretty cold due to it being in direct contact of product .

An extra fan will help only if there isn't enough air circulation already .

[kengineering]

As you can see by my 1st post here that our standard unit with the insulated doors down we can get the temps quite chilly. In fact we pull down to 21*f . I think he feels at that temp the additional fan will just move the load to the chill that much faster.

[kengineering]

An extra fan will help only if there isn't enough air circulation already .

Two fans are fine with the self select case, door open. Close the door and maybe the additional fan brings temps and pressures up a bit and its ok too. I'm not ready to call it uncleaver just yet.

[coolstuf]

Hi Ken,

An extra fan will help to cool the product faster, remember the moving air is your cooling medium, so more air, more cooling, but in the end your limit is your condenser capacity.

Cheers

[lowcool]

my avatar has a 7/8 hp unit.grossly oversized for a two door fridge.hot beer cans in the airflow chilled to drinkable in 1/2 an hour down to -1.5 deg c in an hour.air flow and unit sizing are required to achieve what you want as in a blast chiller.all of your extra airflow will only load up the unit causing a higher evaporator temp.maybe your boss was clever enough to oversize the unit for the original application and has jagged it.

[sherif.bakir]

rapid blast freezing is more about the product than the refrigeration. Your vegies are they loose, how are they stacked, trays, bins etc. This is a 100% batch cooling, product in/product out.(no storeage)
Does the 2 hours include loading unloading and defrost!
Are you controlling the air flow (do you have a false ceiling in the room) You need a product stack air velocity of a least 5

Actually the vegies are put on plastic crates 30cm w 30cm L 7cm H, as to help the product freeze faster.

We made a false ceiling as to control the air flow.

we need to freeze the 2 tons in 2 hours not including Defrost and unloading.

The thing is will the capacity of the Two 2 stage compressors will be able to do the job and also will the 2 stage compressors have a long life ?