Hi

I am providing chilled waetr to a 100L process vessel jacket where by purified water is manually poured into the vessel at 70 deg C. A coil surrounding the vessel within the jacket is linked to the chilled water system and is requireed to reduce the purified water in the vessel from 70 deg C to 40 deg C over a period of time ( say 10 minutes). The chilled water design conditions for the factory at 6/12 degc.
I dont have any design figures for the coil in the jacket surrounding the vessel. How can I ensure I dont send back water over 12deg C to the main chiller plant, do I need a heat exchanger to seperate the CHW system from the vessel jacket coil.? How do I size the pipework , kW cooling load for this?? Even an approximnate method would do fine, i understand the thermodynamics of the vessel are changing constantly as the water cools down and makes it a complex calculation plus I have no design info on the coil.

Any ideas>>>??

Can you provide a diagram of your setup? Are you saying you already have a heat exchanger and unsure of correct sizing for the application? You need to determine the performance parameters of the coil as well as its physical sizing.

Rough estimation based on given states, I get a cooling load of ~20.4 kW.

The cooling load for the vessel and heating load for the coolant are essentially mirror imaged. Assuming ideal conduction, etc., 20kW for water with only 5°C temperature rise would require at least 15.8gpm.

Do you care if the vessel gets below 40°C? Is the time limit fixed?

TTFN
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One option is to use a blending station on the chilled water loop near the jacket connection.Blending station is basically a three way diverting valve with one leg going into the jacket coil and the other leg going directly into the return leg.The diverting valve is to be modulated to hold the return temperature at 12 C in this instance.This scheme would not have any control over the purified water temperature it may go below 40.

A mixing tank with hot and cold well is the other option.You would need to use a CHW loop out of this tank to cool the vessel and you can have much higher temperature rise in this loop and you can control the purified water temperature as well.Spill from cold well to hot well will ensure 12 C return back to the chiller.

SAK9

I like that idea of the mixing valve, it ensures my CHW retun temp is not any more than the design return so I will not upset the chillers. Any idea how i could get an estimation on cooling time if I sued say a 1 inch supply/reutn pipe?