Trane Chiller and Ungrounded system

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Hi,

Hope someone can help me here. I am looking to install a Trane air cooled chiller 300ton in an industrial plant that have ungrounded power system. Just wonder if anyone has an opinion as to the reliability of refrigeration equipment on ungrounded system. It is quite cost prohibitive and disruptive to the operation if we have to have POCO install a neutral at the transformer. Would this not create some additional hazards if the new neutral not pulled to each panels.?

Have anyone run into situation like this with Trane where the ungrounded system would create a warranty issue with the vendor?


Thank you in advance.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
why would it matter any? what does Trane say about it?

there is a lot of stuff on ungrounded systems.

as long as the install is otherwise safe and to code I just don't see any issues.

IMO, unless the neutral is being used there is no reason to waste wire bringing it to every panel.

are you sure the system is ungrounded? it may be that it is grounded but that no one ran the neutral past the service point.
 
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kwired

Electron manager
Location
NE Nebraska
First make sure you have an ungrounded system, and not a corner grounded system, or as mentioned you maybe do have a neutral at the service, but no neutrals run after that point.

There could be warranty issues if you don't supply the unit with a specific voltage system. You could separately derive the system you need if that is the case. And if you do truly have an ungrounded system at your facility - there is probably a reason so you wouldn't want to mess with existing equipment by making the system grounded.

That said I believe most POCO will not supply an ungrounded system, though there may be some existing installations out there though that they kind of "grandfather" in. Usually if you want an ungrounded system you need to separately derive it.
 

StarCat

Industrial Engineering Tech
Location
Moab, UT USA
Occupation
Imdustrial Engineering Technician - HVACR Electrical and Mechanical Systems
On Board Control Scheme

On Board Control Scheme

A good many HVACR machines absolutely require grounding by the factory engineering.
Some in fact will not operate without it, due to the nature of modern solid state controls.
Any of the big guys like Trane and Carrier can custom configure machines for a price.
Some of those custom rigs work well and so do not.
The whys and limits can be answered by Trane Engineering.
Chiller installation should involve HVAC Techs from the start as they can tell you very quickly what will and will not work with regards to the total installation.
I have in the past had to debug the automation control scheme on a 3500 ton plant that was inadequate due to the startup having been done without all hands on board looking seriously at what is not working out with day to day running of the machines. Chillers by nature can and will develop dangerous ground faults when motors, compressors, some controls, and heaters fail. Having never been around a purposely ungrounded installation, I do not know how that matter is dealt with but I would expect it has to be approached very carefully.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Would well be worth a discussion with Trane. I have seen chiller systems work fine with a delta ungrounded system and have seem them be a PIA. As I recall, one of the problems arises from varible-frequency or soft start drives that didn't seem to care for ungrounded supplies.
 

kwired

Electron manager
Location
NE Nebraska
A good many HVACR machines absolutely require grounding by the factory engineering.
Some in fact will not operate without it, due to the nature of modern solid state controls.
Any of the big guys like Trane and Carrier can custom configure machines for a price.
Some of those custom rigs work well and so do not.
The whys and limits can be answered by Trane Engineering.
Chiller installation should involve HVAC Techs from the start as they can tell you very quickly what will and will not work with regards to the total installation.
I have in the past had to debug the automation control scheme on a 3500 ton plant that was inadequate due to the startup having been done without all hands on board looking seriously at what is not working out with day to day running of the machines. Chillers by nature can and will develop dangerous ground faults when motors, compressors, some controls, and heaters fail. Having never been around a purposely ungrounded installation, I do not know how that matter is dealt with but I would expect it has to be approached very carefully.
The reason ungrounded systems are used is for processes that can introduce more hazards if a component should happen to suddenly shut down as in the case of a ground fault on a grounded system. They do have monitoring system that will indicate when there is a fault, but all that happens when there is a fault is the system becomes grounded - with the faulted phase being the grounded conductor - things will continue to run just like they would with a corner grounded system. This will allow time to shut down the process in an orderly fashion instead of sudden shutdown that could introduce more troubles from the process itself.

One problem with this is you need to shut down as soon as possible and determine the reason for the fault, if you don't and a fault in a second phase should develop - you are going to have sudden shutdown anyway.


As Gus mentioned one big reason a chiller may not like an ungrounded system or even a corner grounded system is that many VFD's don't play well on such systems unless specifically designed to run on those systems. Otherwise the motors themselves won't care, and control circuits are typically separately derived and won't matter much there either.
 

priyankasethi

Member
Location
New Delhi
Occupation
Student
Which chiller type is best for server farms: air cooled, or water cooled? There's no single answer. Water-cooled chillers require cooling towers, which have basic support requests: water treatment, chiller condenser-tube cleaning, tower mechanical upkeep, and freeze insurance. Energy productivity: Water-cooled chillers are commonly more energy proficient than air-cooled chillers. By and large, air-cooled chillers last 15 to 20 years while water-cooled chillers last 20 to 30 years. Halfway, this is on the grounds that water-cooled chillers are regularly introduced inside and work at lower condenser liquid weight, while air-cooled chillers work outside, at higher condenser pressure. Since air-cooled chiller don't need water, they are frequently a favored decision particularly in areas where there is a water deficiency, or the water is pricey. As the report brings up, unquestionably more water is utilized to produce power that powers server farms than to cool them so chiller effectiveness again returns into thought.
 
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