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w.l.ong
14-12-2006, 06:22 PM
Hello,
anyone out there have any infomation for blast freezer using R410?
a customer is look for a blast freezer capacity: 30KW@ -60C........ET=-60C / CT=40C using R410
air temp request is -50C.

it is posible to use R410 in low temp? from what i know R410 high pressure is very high.

Thank.

US Iceman
14-12-2006, 07:19 PM
This is certainly an interesting application.

At -60C, R-410a is in a vacuum. That is not a terrible thing, but you would have to use a purger to remove non-condensable gases if the compressors have shaft seals.

You would not be able to provide this system with a single stage of compression. You would need at least two stages and even possible three stages of compression. It would be a slightly complex system.

In these temperature ranges (-60C) this is very close to where you might also consider using a cascade system, but this also has some complexity.

Why are they wanting to use -60C for blast freezing?

old gas bottle
14-12-2006, 09:43 PM
odd but interesting, sure they dont mean R404A but even then you may need a second stage refrigerant, is all the information correct,you know what customers are like!

US Iceman
14-12-2006, 10:29 PM
is all the information correct,


Well, I was doing something I really hate to do... I assumed so.



...you know what customers are like!


Yes sir, and that's why I refer back to the above comment. Customers have a habit of only telling you part of the story. When you try to help answer questions, they remember the parts they like, which may not have any effect on the final outcome.:D

winfred.dela
15-12-2006, 06:26 AM
Hello,
anyone out there have any infomation for blast freezer using R410?
a customer is look for a blast freezer capacity: 30KW@ -60C........ET=-60C / CT=40C using R410
air temp request is -50C.

it is posible to use R410 in low temp? from what i know R410 high pressure is very high.
Thank.

I have participated in following projects:
note: R410a & R507 almost have same performance except R507's glide=0

Year 1999: Start-up a Seattle (USA) assembled blast freezer with Open type 2 stage recip compressor/90KW motor, R507.
The US maker insisted (with warranty) that we can operate the freezer up to -70C box temp. It runs for a couple of months (of course at vacuum) before the compressor needs overhauling.
The local processor now used it for -45C room temperature

Year 2001: Made a blast freezer using a Bitzer 2-stage semi hermetic recip compressor (30KW), R507, Room temp can go as low as -50C. Now, we operate the unit at -45C blast freezer room temperature.

Last year, i visited another client's blast freezer (Cascade) and it operates at -65C room temperature.
We have done studies and evaluation if the fish blast frozen at -45C room and -65 room temperature has really some difference in the quality. I believe, it is minimal.

If I may ask:
Why do you need a -50C air temperature?
For what product?

. . . :)

w.l.ong
15-12-2006, 12:10 PM
Hello,
this -50C blast freezer is use for blast procesed fish (vacuum pack to sizes)
i told them to use cascade system but thier said to hard to take care of the system,
i will ask them to use R507 for this job,

Thank

winfred.dela
15-12-2006, 12:22 PM
this -50C blast freezer is use for blast procesed fish (vacuum pack to sizes)
Thank


If its vacuum pack frozen fish, it will be kept at -20C to -25C storage freezer and then transport via a container van -20C to -25C holding temperature.

The blast freezing at -60C Tevap will only be useful if the cold chain from processing plant up to retailers are all using the -60C freezers as follows:

(1) Fish processor cold storage - (2) Transport container van - (3) wholesaler - (4) retailer (with -60C chest type freezer).

This have been the problem for the last 5 years of some group based down here.

I hope you can also pose the same problem/question to your prospective customer.

. . . :)

NH3LVR
15-12-2006, 04:10 PM
The blast freezing at -60C Tevap will only be useful if the cold chain from processing plant up to retailers are all using the -60C freezers as follows:

(1) Fish processor cold storage - (2) Transport container van - (3) wholesaler - (4) retailer (with -60C chest type freezer).:)

Winfred;
I did not understand what you meant here. Blast freezing temperatures are always lower than the storage temperatures, in order to minimize quality loss due to slow freezing. Do I misunderstand?

Was the Freezer you referred to as made in Seattle made by Seattle Refrigeration? I have worked on their units before and they are a excellent company, with a Engineering staff who was not afraid to be a bit innovative. Of course innovation has it's risks, as we all know.

US Iceman
15-12-2006, 04:24 PM
I think what Winfred is talking about is the entire food storage process must be kept under consistent temperature control.

Blast freezing helps to control the cell quality of the product, but it is also important to maintain consistent temperatures too.

Variable temperatures can have an effect on some of this as the product tends to undergo cell changes when the temperatures change (cold to warm, and then warm to colder).

Winfred... I thought R-410a did not have any glide also. I would have also thought the R-410a might have been a better selection since it's pressure would be higher in the low temperatures (less vacuum). Of course the pressures would also be much higher at the condenser too.

winfred.dela
15-12-2006, 07:20 PM
I did not understand what you meant here. Blast freezing temperatures are always lower than the storage temperatures, in order to minimize quality loss due to slow freezing. Do I misunderstand?


For the -20C/-25C cold chain infrastructure, the Blast Freezer could be just at -45C Te.
Using the -60C Te would be OK but somewhat overkill and its too expensive for the product.
The processor will just incur unnecessary cost.

Of course, if the customer needs a better quality sashimi, the -60C cold chain system should be developed.
For the last few years, the west starts to developed the same taste buds as the Japanese so -60C has some future.
But until the chest type freezer @ -60C or maybe -45C box temperature will become a little cheaper this system will not really take off as expected by some frozen fish processor.




Was the Freezer you referred to as made in Seattle made by Seattle Refrigeration?


No, its made by another company.

. . . :)

winfred.dela
15-12-2006, 07:29 PM
Winfred... I thought R-410a did not have any glide also. I would have also thought the R-410a might have been a better selection since it's pressure would be higher in the low temperatures (less vacuum).


The glide is not much @ <0.2K and it could have a lower temperature before vacuum.

My main reason for not using is the supply here in my part of South East Asia where R410a is not yet found in all refrigeration stores.

. . . :)

Peter_1
15-12-2006, 09:43 PM
Joined a litlle bit late this thread.
My thoughts.
Going that low seems for me a waste of energy. Especially because I think you don't need to go that low for a freezing tunnel.
Better make then a longer tunnel to increase holding time in the tunnel.

If it's necessary to go that low, then use a cascade system with the proper gasses so that you don't have to run in vacuum because this will give you some special expected problems which can be avoided.
Especially when you have a leak in the low side.

USiceman, what about the purger you mentioned, will it not release any gass to the atmosphere? I always have some feelings that it does sometimes more bad then good.

It's not because your client is asking you solutions for his problems that you must provide him a solution for all his questions. It's your responsibility to point him on possible problems and give better options, more economical, less energy consuming, and warn him at least what problems can be expected when he persists in his specs.
Hope I explained this enough in my school English.

US Iceman
15-12-2006, 10:33 PM
USiceman, what about the purger you mentioned, will it not release any gass to the atmosphere? I always have some feelings that it does sometimes more bad then good.


That is true Peter. The purger would have a tendency to also purge refrigerant. This is probably the reason why a cascade system should be used, so that no vacuum is necassary.

winfred.dela
15-12-2006, 10:55 PM
Going that low seems for me a waste of energy.


In the 80s up to early 90s,
(1) blast freezer with -30C room temperature using single stage compressor is acceptable.
Then, in late 90s most wanted
(2) blast freezer with -45C room temp. Now, some wanted
(3) blast freezer with -60C room temp.

The frozen fish quality is a lot better using (2) than (1). The increase in quality is minimal from (2) to (3)

However, the shelf life at -60C cold storage is said to be double than the -25C cold storage.




If it's necessary to go that low, then use a cascade system with the proper gasses so that you don't have to run in vacuum


Cascade is the right one but the price difference is more than double for the same size (total compressor HP) equipment.
Also, the refrigerant for the low side is very expensive.
Thus, running at vacuum is being used by some.

. . . :)

Peter_1
15-12-2006, 11:15 PM
The shelf life at -60C is double as that with -25C storage is said
Well, I shouldn't believe this if this hasn't been proved by an official organism.
I don't say it's not true.
What has been proved is that the molecular structure remains more intact the faster your freeze the product so that ice crystals can't deform the structure.
And you loose less water out of the product if you freeze faster.
Really need to go that low in temperature , I should choose then for a cryogenic tunnel.

The refrigerant on the second stage is indeed expensive but that's in my opinion a short vision of the problem: what about operating costs calculated over all the years?
One stage on R410a gives a COP of +/- 0.7 with all the additional problems.

A cascade will run at a COP of +/- 2 so almost triple efficiency.

And must this cost really double because it's a cascade system? Most components remains the same whatever system you use.
But I haven't calculated it.

winfred.dela
16-12-2006, 12:50 AM
Really need to go that low in temperature , I should choose then for a cryogenic tunnel.


Cryogenic will be the future.
Have done some experiment on the Liquid Nitro freezing and its really impressive.

The equipment though is a lot lot more expensive especially if investment includes a Liquid Nitrogen Generating Plant.




The refrigerant on the second stage is indeed expensive but that's in my opinion a short vision of the problem: what about operating costs calculated over all the years?
One stage on R410a gives a COP of +/- 0.7 with all the additional problems.

A cascade will run at a COP of +/- 2 so almost triple efficiency.


If the plan push through to have a cascade blast freezer in one my client's fish processing facility, i can have all that data.

I hope its in the near future.
There are still some pieces missing in the cold chain especially in the retailer's side.




And must this cost really double because it's a cascade system? Most components remains the same whatever system you use.
But I haven't calculated it.

Am only using the price quoted by suppliers for the complete system.
Of course, we know its not double in the COST side but suppliers usually make the SELLING PRICE of equipment like this much more than the usual prices. They have to consider warranty side.
A leak of R23 or R508 will cost a lot plus the technicians that will service the equipment.

. . . :)

Peter_1
16-12-2006, 08:47 AM
.... Have done some experiment on the Liquid Nitro freezing and its really impressive.
The equipment though is a lot lot more expensive especially if investment includes a Liquid Nitrogen Generating Plant.

Here in Belgium, they allways bring the liquid nitrogen with big trucks to a special isolated container.


If the plan push through to have a cascade blast freezer in one my client's fish processing facility, i can have all that data.

I'm really interested in this and I think with me, many others.

winfred.dela
16-12-2006, 11:34 AM
Here in Belgium, they allways bring the liquid nitrogen with big trucks to a special isolated container.


Six years ago (year 2000), a Japanese firm installed mini Liquid Nitrogen Plants in 3 places here in Mindanao. Its the set-up am thinking of.




I'm really interested in this and I think with me, many others.


We have already made some test (2 years ago) and its OK but very few data were gathered. I will share if the project push through.

It's a pity that there are no Japanese Refrigeration Engineers that are active in this forum.
For so many years, they have been into this -60C blast freezer, cold storage and chest type freezers.
I have seen it done (year 2001) for large Tuna (50kgs+ fish) in Indonesia.

Also, the Cell Alive System (CAS) has been developed to served the same Sashimi fillet and other fish processing plants.

. . . :)