Air Infiltration with internal dimension of Tunnel freezer.

[nuntachai]

Hi. Refrigeration mans.
Now, I'm working with the tunnel freezer and we get a lot of moisture in evaporator fin space it cause of poor efficiency for freezing , we found that the high rate of outside air infiltrate to the freezer by evaporator fans.

Please help me to know or suggestions about How we calculation or else to define the internal dimension of the tunnel freezer in order to relate with number and cfm of evaporator fans ?
Thank you.
Nuntachai (Thailand)

[smpsmp45]

Your question is not very clear. I am unable to understand how do you get the outside air into the enclosure.
If you can explain the system, some more details can be worked out

[nuntachai]

smpsmp45...
2 way that outside air infiltrated into the tunnel
1) during of product loading to belt conveyer.
2) suction by evaporator fans.

Thank you.
Nuntachai S.
2504

[smpsmp45]

With the Belts this is always a problem. But generally due to high airflow inside, we have seen that the inside air comes out of the opening & the outside air getting inside is very rare. Infact we had done few modifications work on such systems to minimise the loss of cold air through such openings. We had provided a insulated enclosure around the belts outside the freezer room. That has saved lots of energy & the issues what you are describing.

I think trying that could be simple & effective.

[nike123]

But generally due to high airflow inside, we have seen that the inside air comes out of the opening & the outside air getting inside is very rare.
Isn't that a fact, if we having the amount of air coming out, than that also same amount is getting in?;)

[nike123]

Hi. Refrigeration mans.
Now, I'm working with the tunnel freezer and we get a lot of moisture in evaporator fin space it cause of poor efficiency for freezing , we found that the high rate of outside air infiltrate to the freezer by evaporator fans.

Check this description! (http://www.blastfreezer.com/iqf_tunnel.htm)
Also, consider use of some form of “Air Curtain”.

[nuntachai]

Thank you all of your suggestions.... , Anyway I want to know about ... How do we balancing or calculation of between Air flow(cfm) by all fan and internal volume space of tunnel(ft3) ? I found that ,we will get a lot of moisture when we applied high flow of fans( high cfm) and the moisture can reduce while we reduce rpm of fans.

Best regards.
Nuntachai S.

[nike123]

Thank you all of your suggestions.... , Anyway I want to know about ... How do we balancing or calculation of between Air flow(cfm) by all fan and internal volume space of tunnel(ft3) ? I found that ,we will get a lot of moisture when we applied high flow of fans( high cfm) and the moisture can reduce while we reduce rpm of fans.

Best regards.
Nuntachai S.

What moisture you thinking about here! That of air infiltration, or that of processing product is carrying inside or on self.

[nuntachai]

Thank you nike123 .
I think of both , but I concentrate about how to matching air flow rate (cfm) from fans and internal volume(ft3)?
For example
Tunnel have internal volum 425 ft3(wxLxH) and install 4 unit of fan evap. coil @ 15,000 cfm ,that meaning we will get air infilltration from outside right? or else.
Best Regards.
Nuntachai S.

[nike123]

Thank you nike123 .
I think of both , but I concentrate about how to matching air flow rate (cfm) from fans and internal volume(ft3)?
For example
Tunnel have internal volum 425 ft3(wxLxH) and install 4 unit of fan evap. coil @ 15,000 cfm ,that meaning we will get air infilltration from outside right? or else.
Best Regards.
Nuntachai S.


I think that air flow rate is determined by evaporator capacity, dT, required air speed for product freezing and not by internal volume.
Infiltration of outdoor air depends on size of openings and design of air flow thru tunnel (and conveyor belt), and I think that, in well designed tunnel, it is minimal.
I think that most of moisture comes from products who are freezing.

Is that tunnel new design?

[nuntachai]

Thank a lot nike123
Yes , Now I am working with 16 m tunnel freezer ( 2.4 x 16 x 2.1 m dimension) .... any way when we compare with the other competitor , we found that they biger dimension but the same of cooling cap. So.. I think that have effect.

I will discussion with you again when I get some result for my freezer.

Best regards.
Nuntachai S.