Over capacity chiller
Over capacity chiller
(OP)
Hi,
We have a 500 Tons capacity centrifugal water cooled chiller serving air conditioning to a special function auditorium. This building is rarely used and if use it is used for a short period of time, say 3-5 hours for exams and seminars. In addition to this during winter the chiller loads to merely 10 % of the capacity. In Both the above mentioned cases, chiller recycles frequently or Too many ON /OFF's are needed to maintain the comfort condition in the building. My question is what can be done to avoid this problem?
Please note: 1. Hot Gas Bypass is always ON, though it is not a good practice considering the energy conservation.
2.For sure, this is an over designed case.
Thanks...
We have a 500 Tons capacity centrifugal water cooled chiller serving air conditioning to a special function auditorium. This building is rarely used and if use it is used for a short period of time, say 3-5 hours for exams and seminars. In addition to this during winter the chiller loads to merely 10 % of the capacity. In Both the above mentioned cases, chiller recycles frequently or Too many ON /OFF's are needed to maintain the comfort condition in the building. My question is what can be done to avoid this problem?
Please note: 1. Hot Gas Bypass is always ON, though it is not a good practice considering the energy conservation.
2.For sure, this is an over designed case.
Thanks...





RE: Over capacity chiller
RE: Over capacity chiller
But this solution is not cost effective.
The best option for this kind of application is a very small chiller(say 50 tons) with a thermal storage tank.So take MFI 2000's advice and sell it off!
RE: Over capacity chiller
Most chillers can only turn down so far (maybe 40 to 50% on a centrifugal). Once you are turned down to the minimum capcity, you will need to go on hot gas or some form of capacity reduction. If energy reduction is the controlling factor, you may need to look at a smaller chiller to parallel the current machine and just run it in the low load conditions.
Ken
TXiceman
www.rae-corp.com
RE: Over capacity chiller
Thanks
RE: Over capacity chiller
RE: Over capacity chiller
Is this auditorium a stand-alone building, or part of a larger building or campus?
You could use your big chiller for other spaces, and decomission a bunch of smaller units.
RE: Over capacity chiller
I love chilled water storage tanks, but I believe you have to get into 10,000 ton-hours or more before you quit wasting money.
BTW, no offense to the suggestions, I agree in principle. However, retrofitting an existing 500 ton centrifugal with a VFD would be problemmatic. I agree that's the direction for the future, but its something that you'd want the mfr to build-in, unless you're into fabricating your own component process systems, compressors, heat exchangers, controls, etc. Guide vanes are most likely already in there. Nothing will help at 10% or below. If you're getting that, you're already doing great.
RE: Over capacity chiller
Or follow mintjulep's suggestion.