What is the function of pressurization unit in chilled water system?

[AliNaseem2]

What is the function of pressurization unit in chilled water system? i have a Primary , secondary pumping chiller system ,

Why we need a Pressurization unit with makeup water in a closed loop chilled water system , what should be the location of PU in a Complete Closed loop

 

[LittleInch]

Function is to make sure that there is no vapour at the highest point and prevent the pump from cavitating. Also means you find any leaks....

Location can be anywhere, but usually on the inlet to the pump.

There is a lot of opinion and past posts on this subject if you search for it.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[lilliput1]

Are you referring to expansion tanks? Water expands when heated and is not compressible. So the expanded water is held in the expansion tank which can have a bladder separating the water from air or not. If it has no bladder the water and air level would be monitored on a gauge glass column.

 

[lilliput1]

See Amtrol Expansion Tank for formulas involved to determine required expansion tank acceptance volume, sizes and configuration of available expansion tanks. They are location at suction side of the pump. The compressed air fill pressure must be adequate to support the pressure exerted by the column of water equal to height of the highest piping above it plus minimum 6 ft to insure there will be no air in the piping system after it has been properly vented. The total volume of water in the system at its minimum operating temperature and the increase in volume at the highest possible operating temperature must be calculated to determine required acceptance volume. The water makeup line is typically connected to the [piping to the expansion tank and it is provided with a pressure regulating valve and a safety relief valve. The pressure regulating valve is set to control water makeup as required to maintain the design pressure at that point. The safety relief valve is set to relief at a pressure at its location such the with the pumps operating no part of the piping will see the max design pressure of the piping and equipment (max 150 psig for steel piping but say set 130 psig). This protects piping and equipment if the makeup pressure regulating valve fails.
The expansion tank is the point of no pressure change. If system volume change additional expansion tank must be added at the same location, not elsewhere.
All high points of piping must have vent valves. All low point must have drain valve. All strainer must have blow off valve.

 

[BronYrAur]

I think you might be referring to a glycol fill system with a break tank and an pump. Is there glycol in the system?

 

[lilliput1]

All closed water/glycol system require expansion tank and water makeup system. Water/glycol expands with temperature but is incompressible so the expanded volume need to go somewhere. You need makeup for fill and to offset drain/leak losses.