How do I increase the capacity of a refrigeration unit?

[Pluto68]

I was wondering if I change the head pressure control valve (210 psi), located before the roof condensing unit, for another one with a lower pressure setting (180 psi), I would notice a difference in the capacity of a Liebert refrigeration unit, used to chill a server room?

Right now, the unit has two compressors working full time.

[icecube51]

welcome Pluto, can you give some more details on the complete plant please.

thnx, Ice

[chemi-cool]

You cant,

Lowering the head pressure will affect everything else, from frozen evaporator to oil return problems.

The only way I know to increase a unit capacity is replacing it with a bigger one or adding another unit .

[icecube51]

[quote=chemi-cool;121498]

Lowering the head pressure will affect everything else, from frozen evaporator to oil return problems.[quote]

this is wright,

Ice

[icecube51]

You cant,

this is so wrong,

Ice

[powell]

I was wondering if I change the head pressure control valve (210 psi), located before the roof condensing unit, for another one with a lower pressure setting (180 psi), I would notice a difference in the capacity of a Liebert refrigeration unit, used to chill a server room?

Right now, the unit has two compressors working full time.

Increasing the subcooling might give you about 1/2% in capacity for every 1 degree, depending on the system.

You could also verify that the system is running at its highest designed capacity by eliminating any low suction pressure symptons.

That's about it without changing the equipment.

[Pluto68]

The plant I have is a Liebert FH125A-B00 which I believe has 10 tons of refrigeration. The user has added a computer rack in the server room and the 2 compressors are loaded. I thought that there was a way to subcool before returning to the evaporator and therefore, increase the capacity.

From the comments above, it seems that I will have a oil return problem. That would not help me at all.

[Pluto68]

Also, the ***** is *****-22

[chemi-cool]

With all the respect to my distinguish friends,

By playing with head pressure, sub cooling and anything else you can think of, a few % is the limit.

Increasing as I see it, starts at 10% at least.

So icecube51, I'm not that wrong but if you can show me a way to really increase system output, I wold be more than happy to get wiser.

[icecube51]

i can, but not if you don't want to modify the system. than you're wright,you don't mess whit something thats working fine. thats why i asked about the plant design.

Ice

[Willem V]

in the summer when you needed most, ther would not be effect anymore I think