shrimp boat refrigeration

[licensed to chill]

I have a guy that approached me about some refer work on a shrimp boat he is building. he bought a used brine tank(no condensing unit included)and would like me to install a condensing unit for him. The tank is to be filled with a brine solution and kept a -6 degrees. When the shrimp are caught they are put in brine tank and froze before they are put in a holding freezer at -10 degrees. My question is

The brine tank has a 6 circuit evaporator with 6 Danfoss txv's (TX2 bodies and #04 orfices R-22 refrigerant)

If i am correct, these valves are rated for 2.25 tons each.
That would equal 162,000 btu =13.5 tons of refrigeration.
I want to switch to R-404a valves and condensing unit.
If i installed 6 2 ton valves and sized the condensing unit for a -10 degree evap. temp. the unit would have to be around 30 hp? Damn that is alot of refrigeration for 1 tank??? Has anybody worked on these brine tanks before? Are my calculations correct?

Any advice would be appreciated!!

[icemeister]

From what I can find on these systems, the brine tank is used to quick freeze freshly caught and cleaned shrimp in an agitated 0 to +5ºF salt brine solution from warm to fully frozen in 20 minutes or less. After the brine tank they store the shrimp in a holding freezer at around -10ºF.

One example I found said a 5 HP system on a 450 gallon brine tank should freeze 60 lbs of shrimp in 20 minutes. Here's a link to that: http://www.seagrantfish.lsu.edu/pdfs/TAAWildShrimp.pdf
Look way down about page 65 or so. There's a lot of helpful background info in there too.

Your 30 HP guesstimate probably isn't that far off. I would consider possibly two units for the brine tank because the freezing load is much higher than the holding load. You might end up with two 15 HP units for the brine tank, one 15 HP for the holding freezer and another as a standby or swing machine that could be valved into either system.

The units I've seen while surfing about have been primarily Bitzer direct drives and Carlyle 5H40's with marine condensers, oil separators, etc. The open compressors are obviously preferred.

[Edited by icemeister on 03-02-2006 at 07:43 PM]

[hvac wiz 79]

Bubba Gump shrimp rocks !!!!!

[licensed to chill]

thanks for the info icemeister

[bennytec]

Mmmmmmmm shrimp

[ccao850]

I am interested in learning about this type of refrigeration system. Know how I can get started?? thanx

[ccao850]

how do i learn about this type of system??

[Capz]

Installed a liquid co2 tank on a fishing boat out of Atlantic City years ago. Liquid co2 will spray out of the nozzle/gun at about -5F--0F. The whole experiment never really took off but likely due to lack of money on the boat owners part. But it was sort of cool to install a tank on a commercial fishing boat. The co2 tank used low temp refrigeration to hold the co2 at 290psi or -5F.

Good luck with your shrimp project. Brought back memories.

[Bobbycold]

The shrimp boats that I did work for on the side out of Vinton, LA didn't maintain any ice machines on board the vessels. What they did was keep a bunch of large ice machines shoreside and when they get underway they take large amounts of ice from the machines. Most of these boats were underway as long as 3 days at a time, but usually about 36 hours underway. For the longer voages they would have their wives meet them with up to 4 boxes (5 ft x 5ft x 5ft each) of ice at peirs. The ice machines were the same large machines used by most industries, except they were some of the oldest ones being used. I have worked on lots of R-12 units. I have had to almost completely rebuild 2 of these after Hurricane Ike. It is such a labor intensive job, that the only reason the owner wanted it done instead of just replacing the machine was because I gave him an extremely low price, provided he help alongside me, since he was also my landlord. I really don't recall anyone with an ice machine actually on the boat.

[K_Neil]

It's a bit different up here but the ice supply for commercial fishing up here in northern manitoba works the same. The fishermen pick up tubs of ice and take them to the lakes where they fish. The most primitive one I know of is summer time ice supply from The Pas MB. to Pukatawagan MB. The ice is on the train for 10 hours with no refrigeration to hold it. They have 2 Howes at the fish plant that I have been called in on that work great.

[coolerik]

Ive done a fare bit of marine refrigeration in the past, i no longer work for the, and am not a big fan of the owner, but they build some really skookum stuff. Worked there for 3 years, all custom built, I have know doubt that they will be able to help
http://www.pacificwestrefrigeration.com