Sizing the Supply and return tanks for chilled water system

[shaheryarbhatti]

Well i am currently working as a project engineer for utilities at my factory .This is my first installation of chilled water system.So would be requiring some help in sizing the Chilled water supply and return tanks.I am attaching the picture along so that the system is easily understandable.

 

[turbo]

I have done a lot of heat and mass balance studies for mills, but none of them have been based on such a bare-bones snapshot.

If you want to size your system, you need to need (at a minimum) to identify the seasonal high and low temps of the input water (then over-design by a margin), identify the capacity of your plant to cool the input water to suitable temperatures (with margins, of course), and identify the expected exit temperatures (again with margins) and see if you can size a system that might meet these requirements.

It would also be a really good idea to talk to senior engineers/management, etc to see if there are any plant expansions or process modifications over the horizon that might tip your project into unworkable/uneconomic territory. In an industrial environment, the bean-counters can ruin your career pretty quickly, even if you gave them conservative parameters initially and they changed the rules after the fact or during implementation.

Good luck.

 

[shaheryarbhatti]

Well sorry for the bare diagram because i just wanted to make it simple.I tried to size it but have few issues .Let em first define my systems parameters.

Water in Chilled water tank is at temperature of 5-6 C
Temperature of Water in Return Tank is aroudn 18 C in Summer and around 14-15 C in winter

Chilled water generated is at 1228 m3/h i.e. 307m3/h by each chiller.

System requirement of chilled water is 856m3/h

I designed the Forward tank(140m3/h) with 10 minutes of buffer time that is the case if chillers go on shutdown due to power failure we would have 10 minutes to get system back online.



I calculated that all the time 131 m3 of water is inside the lines.


Now my concern is the Return Tank .How do i size it and on what basis.SHoudl i just keep it 140m3/h or need to size it and on what basis .