Help calculating required capacity for our brine chiller system

[VITALINE69]

Hi everybody,

We are currently planning to re-commission our Vitaline popsicle line and are just trying to get our heads around some of the numbers. Being that New Zealand only has a handful of these machines we could do with all the help we can get and although we have a few people looking into this for us I figure asking here couldn't hurt either.

Sorry if we are missing some key specs but please ask for what you see if missing and I will post it up.

Temps required: The old specs sheets reads "Cooler must have the capacity to cools brine from -28 f to -32 f at 250GPM

Our Vitaline is programmed to run at two speeds:

* 8 cycles (8 x 6 mold strips) per minute
* 16 cycles (16 x 6 mold strips) per minute

Each mold strip will contain a total of 432ml of fluid product at a filling temp 4 degrees Celsius

* 8 cycles - ~ 3.5 liters per minute
* 16 cycles - ~7 liters per minute

There is constantly ~130 molds in the brine with a new one going in every 7.5 / 3.75 seconds respectively.

The molds travel along the conveyor for ~18 minutes (8 cycles p/m) or ~9 minutes 16 cycles p/m)

Brine flow has been recommended 250 GPM or ~1000 litres

Working time for the Vitaline is expected to be in the range of 3 - 6 hours per production day.

For compressors we currently have 2 x 32 Hp compressors - Copeland low temperature units at our disposal.

Our current recommendation is to set up our skid using the Copeland's equipped with braised plate heat exchangers and air cooled condensers with the brine (Calcium or Glycol) running through an insulated 1000 liter holding tank on one side of the Vitaline to offer a buffer.

This should be a good start and I can fill in the gaps and you ask.

[piewie]

What is the specific heat content of the fluid product?

[sterl]

Unless you are mixing something that has a water content less than 90% you are going to be brick hard with 9-minutes duration.

Your steady state load for the 16-index rate is only about 13 TR or about 46 KW refrigeration. You will need to maintain the brine flow rate so your actual temperature difference is going to be more like 1.5 deg. with a 5-Hp recirc pump.

The compressors sound large enough though without knowing the refrigerant, the model and the capabilities of the braze plates as well as your nominal condensing peak condensing temperatures we can't be specific about that. One thing: you will want a lot of extra condenser capacity and some pull down arrangement that will prevent the compressors overloading....Otherwise starting these things up takes a good long time.

[VITALINE69]

What is the specific heat content of the fluid product?

We pump our juice product in at ~4c .

[mad fridgie]

Roughly speaking you need 20Kw for product cooling (depending upon SHC and final temp) plus you need to include heat gains and pump power.
If your Copeland's are Discus, then at -40Csst and 40Csct R404a, each is rated at approx 15Kw.
All seems to balance.
Which part of NZ

[VITALINE69]

Thanks, we're in Auckland

[mad fridgie]

Thanks, we're in Auckland
Will be up there in a few weeks to see Lenny Henry.
Best you contact Magoo, knowledgeable young fellow in your neck of the woods (not so young though)
http://www.refrigeration-engineer.com/forums/member.php?11526-Magoo

[Magoo]

Hi
we need to know the glycol solution, temper solution or what ever. You posted two parts of the resolve 1/ required temp of solution and 2/ the flow rate.
magoo