Smardt Compressor operation

[freerider]

We recently installed a 280 ton aircooled Smardt Turbocore. It is a very nice chiller and we are very happy with it. I am wondering why all 3 compressors run 24/7? As low as 30% load. Just wondering because the efficiency drops off at lower loads. .8 kw/ton at 30% vs .5 kw/ton at 60%.

[flange]

call them. maybe not setup right smardt.com

[freerider]

I wish I could. The RULES say only the boss can and he's uninterested. Like to hear from someone who has been involved with these(Kiltech) and doesn't mind sharing.

[flange]

can you email them? I can give you an address for that

[freerider]

I suppose I can without bruising any egos. Thanks- Sorry for the delayed reply. I went fishing for a few days.

[Dallas Duster]

The rules say that a free-rider can't call and ask a question about a sequence of operation? WTF

[freerider]

It is what it is.

[SubCoolWasTaken]

We recently installed a 280 ton aircooled Smardt Turbocore. It is a very nice chiller and we are very happy with it. I am wondering why all 3 compressors run 24/7? As low as 30% load. Just wondering because the efficiency drops off at lower loads. .8 kw/ton at 30% vs .5 kw/ton at 60%.

Wait... you're all very happy with 3 compressors running at the same time at .8kW/ton? What am I missing?

I'm sure you're happy that you have some really neat technology, but I wouldn't be smiling about that. The compressors are married to VFDs. Unlike other centrifugals that have 23-year lives (ASHRAE's number, not mine), I'd expect a VFD running 24/7/365 to last for about 11 years (assuming (100,000 hour MTBF) / (8760hours/year)). And that's a pretty good MTBF for a new technology like magnetic bearings.

Just my $0.02...

[bunglebear]

We recently installed a 280 ton aircooled Smardt Turbocore. It is a very nice chiller and we are very happy with it. I am wondering why all 3 compressors run 24/7? As low as 30% load. Just wondering because the efficiency drops off at lower loads. .8 kw/ton at 30% vs .5 kw/ton at 60%.

The efficiency's higher at part load. The VFD should slow the compressor and the vanes will stay at 110% to keep refrigerant in contact with the impeller for longer (produces more head). Tiy might find that the way the machine has been set up to control would benefit from changing though. We are quite heavily involved with these maches, I just got back from the factory. Your 3 compressors should be designed for 66% each of the load to enable them to all run at about half capacity each or just over.

[hvac_superman]

How many evaporators are on the unit? Maybe if it has multiple evaps the water would be mixing after leaving the chiller and it then couldn't keep the discharge water temp if a compressor was off.

[chiller is me]

From what i have heard, the VFD on the compressors should last the life of the chillers.

[softtail]

We recently installed a 280 ton aircooled Smardt Turbocore. It is a very nice chiller and we are very happy with it. I am wondering why all 3 compressors run 24/7? As low as 30% load. Just wondering because the efficiency drops off at lower loads. .8 kw/ton at 30% vs .5 kw/ton at 60%.

We had the same issue. Check the setup parameters, there's a parameter setting which allows all 3 compressors to start and stop at the same time if set to 3. Change to 1, if you want each compressor to start individually and cycle off separately from each other.

[freerider]

Thanks-I did find that and set it. You're exactly right. The thing still cycles the compressors more than I'd like.
It's one nice chiller. Average around .58 kw/ton. It's off for the summer now. But we have two new Carriers w/vfd's that run .50 kw/ton including the towers and pumps. Saving bookoo bucks on the power bill.