Chiller factory testing 1

[cme]

What type testing should I specify regarding centrifugal water cooled chiller factory testing?

Full load operation only with tonnage calculation?

Verification of chiller operation throughout its entire range without shutdown due to nuisance trips?

Measurement of current draw at max operation? How about draw at turndown at 75, 50, 25% of max?

What about penalty ($) to the manufacturer for tonnage below capacity and current draw beyond spec? ..... OR ..... On what grounds is chiller deemed unacceptable?

How long (time period of testing) should these tests be performed prior to acceptance of units?

I plan on the owner's and Engineer witness with the std lodging and travel expenses paid.

 

[MintJulep]

What do you want to know when the testing is over?

 

[imok2]

This is a typical factory test specifacation

http://www.facilities.upenn.edu/uop/2_mechanical/Section_15600_doc.pdf

 

[cme]

I want to know actual capacity, actual current draw and satisfactory operation throughout its range without nuisance trips.

There should be a penalty based on the capacity in dollars/ton defeciency.

What tonnage is usually the cutoff point in witnesses chiller factory testing?

 

[HVAC68]

Chillers are generally tested as per ARI standards and there are tolerances for both power consumption and tonnage (capacity).

As long as the results are within the tolerances, it's generally accepted, unless, you have specified otherwise.

If the chiller does not deliver the specified results within tolerances, then you should reject the chiller and not look at penalty.

HVAC68

 

[MintJulep]

...operation throughout its range

Where there is the challange. Unless this is a very special, and very tightly controlled application, the operating range is composed of an infinite number of permutations of all possible conditions at each of the machine's interfaces to the outside world.

The UPenn document seems extremely weak to me. I would make the engineer and supplier responsible for understanding the application and requirements, and for providing a chiller that works. As currenlty written, you just need to pass the (undefined) field performance test once.

 

[Drazen]

Yes, chiller meets capacity or not, no penalties.

If manufacturer is not at his best form, maybe it can happen that tests show capacity lower then specified (this couldn't be expected with "world class manufactuter").

In that case maybe you could judge that lower capacity still meets needs of your system - so you accept the chiller, but go in negotiations about price decrese.

Such situation hardly can be agreed in advance, because if you put such kind of price penalty in contract, that would imply that you expect lower quality than specified.

Many good specs are available even on the net, but imoc pulls one out of pocket in a second - that's why i give him a star.

Looking at that spec I recall one other important testing - noise acceptance. That will be very important anywhere except in the middle of heavy industry plant.

 

[KiwiMace]

You can download the complete ARI standard (550/590:2003) from here:

http://www.ari.org/std/standards.html

One thing to note is the significant widening of tolerances at part load. Can be quite surprising. A large chiller manufacturer should provide a full report. In the unlikely event that the chiller doesn't perform to spec, they'll probably want to retrofit the chiller to suit; add tubes etc. I agree with HVAC68, get them to make good rather than try and estimate the life cycle cost of them missing the mark.

We normally wouldn't witness factory tests less than say 300RT, but this depends on your convenience to the test facility. We also witness only one out of the batch for multiple chiller orders.