First, I am sorry if this is a redundant post, I've searched through all the posts and online but I want to make sure I haven't made a horrible miscalculation. Secondly, I'm sorry if this is in the wrong topic.

So Now the part that's got my brain overworking.

I am in the process of redesigning a freeze tunnel for individual hash brown patties to get rid of our current spiral freezer. More headaches than its worth, belt is constantly breaking, limiting us to about a max of 5.7 ton/hr production, having to defrost a coil every hour (4 coils). I would like to suggest replacing it with a linear tunnel freezer, depending on cost is the biggest factor if it gets approved or not. I would like tol take the current time of freezing from 1 hr to about 10-15 minutes depending on production and how long the tunnel has run. We are a continuous 24/7 two week run facility, so we only shut down for a day every two weeks for major maintenance and heavy cleaning. I will be using a water defrost for the coil defrost method as that is what we currently have available and plumbed in.

I am basing the design off our other main line freeze tunnel that we run 54 ton/hr through without any problem until a defrost is needed about every 48-60 hours depending on what product we are running.

Design parameters:

Max design tonnage 15 ton
max running tonnage 12 ton (if you tell production they can only run 12 ton / hr they will try and push 14-15 ton / hr)

The freeze tunnel will be in two sections, a precool section to take the initial heat of the patties from ~190 degF to ~32 degF. This ideally will be accomplished in about 60% of the total time the patties are in the tunnel. The second section will be the main freeze section of the tunnel that takes the patties down to a core temperature of ~14 degF +/- 5 degF.

I used the basic calculation of
Q=M*Cp*∆T
Q = BTU / hr
M = lbs / hr
Cp = Specific heat, above and below freezing
dT = temp change
L = latent heat

M = 30000 lbs / hr
Cp1 = 0.81 above freezing
Cp2 = 0.42 below freezing
T1 = 190 degF
T2 = 40 degF
T3 = 14 degF
L = 113.5 BTU/lbF

Q1 = 2460000 btu above freezing
Q2 = 934800 btu below freezing
L = 3405000 btu latent
Btu precool = Q1 + L = 5865000 btu / hr
Tons precool = 488.75 tr
Btu freeze = Q2 + L = 4339800 btu / hr
Tons freeze = 361.65 tr
tons total = tons precool + tons freeze = 850.4 tr


I know I am probably headed in the right direction but those numbers don't seem too accurate when compared to our current need of ~200 TR when running 5 ton/hr currently in a spiral freezer with the full capacity in it with no precool section.

Thank you for your help!
Brian