Sea water cooler advice

[mangonui]

Hi Gents
I would like some advice as to how i can build a system which maintains a water temperature of 3 degrees on 2 ton of sea water. This is system would be used to keep lobsters live but dormant. Lobsters will go into a relaxed mode with the correct water temperature and aeration. I have been told that a beer cooling unit does the job? All advice on this subject will be appreciated.
Cheers Len

[mad fridgie]

You need a titanium heat exchanger.
Hi water flows through the heat exchanger to ensure freezing does not occur (actual freezing point will depend upon salt concentration)
Size wise you need to calculate you tank losses, but normally your biggest duty is the filtration pump. Add these to you loses,and the chiller pump. Do not grossly over size (short cycling occurs)

[lowcool]

gday mangonui
im thinking the beer cooler your talking about may be equivalent to what we call a temprite.the beer coils inside are made from stainless steel.i have yet to see a stainless system for holding lobster.when dealing with lobster etc titanium is a good option if not the only viable one.anything less is liable to kill them .your cheapest option is maybe to bend up a few lengths and dump it in your water circuit.probably pay to research correct pvc piping and tank materials also.
good luck

[Magoo]

Mangonui,
definitly titanium, I am thinking you are in NZ. Crayfish, Mongonui etc., I will be up there sometime next month, so contact me.

[lowcool]

Magoo.dont forget the thermidore recipe!!

[charlie n]

you also need to change about 4 to 5% of the water per hour.

[lice to chill]

I've been running 15 tanks approx 650 ltrs using 316 stainless for 8 years.15kw per 3 tanks with solenoid but no capacity control.all good till any contaminatants/electrolosis.good while it lasted.titanium/intercooler if you can or be very vigilant. foreign bodies in pine shavings to flush crays has contaminated my coils in the past.keep the oxy levels up and the filters happy good luck.

[tmm]

Mangonui, the advice on titanium evap is sound but do not use plate formats. As I'm sure you are aware all aquatics give debris to the water and this will eventually block the plate-liquid back onto the compressor & failed unit.
I designed tanks for mussels/clams and oysters on the South coast using a heat exchanger from a now defunct company called 'Aquanetics'. I have heard that spares are available so a web search would be a good idea.
Currently I use APV Baker for a helical exchanger to good affect so again this may be another avenue to consider.
Finally if you can pump seawater direct this would obviously be the ideral case although the Environmental Agency typically need convincing in that they consider the returning water to be 'dirty' & may require filtration!

TMM

[Magoo]

Low Cool.
send details for cray saurce. Yumbo

[Magoo]

mangonui,
I could possibly find some titanium spiral coils if you are interested, ex a smaller cray plant.

[Snowflake]

Hi Mangonui

I did a chiller a few years back for the co i worked for then, it was for crayfish, sea water was pumped from the sea into tanks, the water in turn was pumped through a titanium heat exchanger, the evap temp was controlled so as not to freeze the water, the water temp was taken down slowly over certain periods to out the crafish "to sleep" the water flow controlled by a 3 way valve when reached close to setpoint, this was all controlled via a controller which adjusted temp at differnt times etc, are you in NZ i can contact the co that used to own the unit and see if its still around as they were not using it.

Cheers

Snowflake