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bezar
26-02-2012, 10:59 PM
Hi

I should be building a ice water system with DX R404A

The plan is to build a copper piping system inside the water basin, like a standard ice building system. Anyway, my customer will have a three shaft production and there will be not time for ice buidling, so I need to have full demand of 300 kW in ice water at the same time.

Anyone have a tip on how long my piping system should be? I thought to use 18 mm pipe to build the evaporator. One evaporator should have 7x6 matrix of pipes that will be 4 meters long. On matris will be on top of the other. If anyone have similar experiance please comment

Thnaks

Magoo
27-02-2012, 02:14 AM
You would better to look at a falling film chiller for zero degree water, example Chester Jenson.

michaelm
27-02-2012, 04:50 AM
B"H

If it is 24 hrs operation, why do you need ice. Could it be brine instead of water.

bezar
27-02-2012, 09:16 AM
This was my first proposal, but customer needs to have water. From time to time, process will be wasting some amount of coolant, and therefore, it has to be water on such low temepratures.

Falling film is one of the options but they prefer standard water basin with copper coil inside.

If there would be some ratio regarding pipe lenght, diameter, evaporation temp, water agitation, it would be more then useful.

Magoo
27-02-2012, 08:25 PM
Ice forming on bare pipes, 2'C water and -14'C refrgerant the U factor 0.051 Watts/ square meter of pipe per K rise. [ quoted from Table R3 Principles Refrig R Dossat.] non agitated.

Magoo
27-02-2012, 09:29 PM
Hi Bezar.
Alot depends on the production/ process time and temp rise from process. Then you can build ice on coils during non process periods. Larger the pipe diameter the less lineal pipe length required and the greater the ice build thickness, agitators improve U factor.

mad fridgie
27-02-2012, 09:46 PM
I think you best understand your application.
I understand that you want close to 0C supply water. What is your return water temperature! This then determines the design criteria.
Do you understand that a single "tube in a bath" water chilling system, heat transfer is based upon your required outlet temperature.

bezar
03-03-2012, 07:43 AM
Thanks for comments

I have managed to instruct my customer to go for falling film. It would be more safe solution for both of us, and is really the best for such conditions.

If I would have time to build ice, I would go for another solution, but for 24h operation, falling film is the only option.

Magoo
04-03-2012, 01:01 AM
Hi Bezar.
thank you for coming back to us all with an obvious wise decision/advise to client.
Several years ago I did a system with 4.2 kilometers of 25 mm stainless pipe, ice building 8 hours a day, the rest as an on line chiller system. The water bath /tank was the size of of a large house. Meggar bucks $ envolved. Client was determined to take advantage of off peak power cost reductions, pay back was in region of 10 years.