Shopping for a 130T Commerical Chiller

[motoguy128]

We currently have a 1993 300T RTAA that's on it's last leg, literally. Circuit 1 has been abaondoned with multiple small innacessible leaks (right by the frame supports) on the condenser coils that would have to be fixed 100% sinec as lcuk woudl ahve it, the EXV's failed closed some time last year and it blew it's charge out the PRV's. Thanks to new R22 rules, cannot put back in service until 100% fixed even though to loss of refrigerant was mostly unrelated to the leaks. The unit has not had proper service over the years. I don't think the comrpessors have every been rebuiolt sand are well past their service life. So we're down to 1 circuit and abotu 35-40% capacity, which based on the current installed capacity in the building, is plenty. W're at the point where we're robbing condenser fans out of circuit 2 to limp it along.

The application is comfort cooling with one large rooftop air handler (~50-70T), one smaller air handler indoors ~20T, and a handfull of fan coils thate are around 20-30T. We also have a LOT of chilled water piping since it's a old hospital, and much of it now has individual RTU's for each area and an area that's unfinished. The alrge Rooftop unit is probably only at 40-50% capacity sicne we never finished a large part of the building and never will in the near future (just moved a lot of personel to a new building in Chicago)

Our primary vendor locally is Trane. I don't even have any contacts for York or McQuay/Daikin sales people. We do have 3 York Water cooled chiller in our industrial operations. They tend to be a little more problematic, expecially the controls, than the Trane units we have... and of course they scream like a banshee. The other units are 2 Trane screw machines and 4 centrifugals.

I've been looking at a 130T CGAM. I even took a look at one at a Brewery in St. Louis. It looked nice, way very compact and quiet. My lunch and the fresh case of beer I purchased was still better.

Shold I consider some other brand? Anyone have sales office contacts other than what I can look-up online. I do have a comemrical mechainical contractor that we use for our HVAC that can work with most any distributor.

The building currently has Tracer Summit and communicates with the chiller. I'd like to retain this functionality. Nice to remotely see what's going on, saves a trip acorss town most of the time.

Any feedback on CGAM's? What I've heard of McQuay is that they are common in some local schools because they have great efficeincy ratings on paper, and cost less, but are mostly just trouble. For Yor, I think I have to contact someone 4 hours away in Des Moines. Probably the same with Carrier.

I'd like to look as scroll based chiller for the low noise levels, cost simplicity, repair costs, redundancy and size.

Will I have any issues with the existing circulation pump? My Trane rep says no. That the pipe size reduciton alone should reduce flow enough. I figure I might need to cut down the existing impeller or add a VFD.

[R123]

The CGAM is a nice chiller and will easily interface with the Tracer Summit. You can also get a Trane RTAC which is a screw chiller but will be louder. The RTAC's start at 140 tons. If I had my choice, I'd go with the RTAC.

As far as the pump goes, you need to make sure your water flow is proper with the smaller chiller.

[jayguy]

the CGAM only goes to 120 tons. the york YLAA goes to 170 tons. i agree with 123...a screw chiller would control better and work better overall than a scroll. what was your old water flow rate?

[motoguy128]

My Trane rep and Trane's site shows a 130T CGAM FWIM. Not sure what the flow rate is. I'd have to get the pump specs and check pressure drop (if there are gauges). Enough for a 300T chiller. We probably will have to either change or modify the impeller and/or bypass or dramatically pinch back on the flow. Any suggestions on what works best versus most cost effective?

I might go ahead and price the screw, but I think they really really want to put as little money into the facility as possible. We tend to just shut the chiller down in winter and we actually have hte economizers working properly, so I think low load control might not be too critical.

Looks like they may push off the purchase unitl 2013 at this point. I'd like to at least buy the equipment in 2012, then install it in 2013.

[Dallas Duster]

Carrier has 2 different scroll chillers in the 130 ton range.

[Southern Mech]

That size I would go back with a screw, I would stay slightly larger than what you say is full capacity so you have back up. Say a 200 ton, youd have 2-100 ton circuits

[supertek65]

I service a few 180 ton carrier 30rb scroll chillers.
They have been pretty good!

[motoguy128]

That size I would go back with a screw, I would stay slightly larger than what you say is full capacity so you have back up. Say a 200 ton, youd have 2-100 ton circuits

Good point. 130T would still give me about 25% reserve. 50% reserve except when it's really humid out late afternoon.

[flange]

Other than your request to maintain tracer, there are lots of options in that range. If you only do start/stop and temp monitoring with tracer, it doesnt matter. It does though if you are pulling everything out. Anyway, there are a few brands that use turbocore compressors that would be very quiet, there are a few that use copeland screws, which to me, are almost bulletproof, then you have the big three. To me, I would think that support matters more than brand. Who works with you guys well, go from there.