3 phase UPS with air conditioning

[five.five-six]

My customer is doing a major remodel and will have 2 server rooms, each with a small ductless AC systems serving it. The customer wants a 3 phase UPS for a dedicated panel for his computers and servers. he also wants a transfer switch so that he can connect one of his portable generators (if on site) in the case of a prolonged power outage. He also wants his ductles ACs on that protected panel. The problem is that the AC units will dramatically increase the size of UPS needed and dramaticly decrease the backup time. I am trying to think of a way to disconnect the ACs from the UPS until the generator is connected.

I have 2 ideas:

1) have the transfer switch serve a panel for the ACs and serve the UPS which serves the panel for the computers and servers

2) Connect the ACs to contractors with coils fed from the primary side of the UPS


Any other ideas?

 

[zbang]

Go with #1, that's pretty standard in my experience (generator/transfer switch -> protected loads panel feeding A/C and UPS, UPS output feeds another panel).

I hope he plans has over-temp shutdowns so if the generator doesn't start something will shut down the computers before they melt.

 

[iwire]

Connect the ACs to contactors with coils fed from the primary side of the UPS

Or relays to break the HVAC control circuit instead of the power circuit.

 

[mgookin]

My customer is doing a major remodel and will have 2 server rooms, each with a small ductless AC systems serving it. The customer wants a 3 phase UPS for a dedicated panel for his computers and servers. he also wants a transfer switch so that he can connect one of his portable generators (if on site) in the case of a prolonged power outage. He also wants his ductles ACs on that protected panel. The problem is that the AC units will dramatically increase the size of UPS needed and dramaticly decrease the backup time. I am trying to think of a way to disconnect the ACs from the UPS until the generator is connected.

I have 2 ideas:

1) have the transfer switch serve a panel for the ACs and serve the UPS which serves the panel for the computers and servers

2) Connect the ACs to contractors with coils fed from the primary side of the UPS


Any other ideas?

The a/c may be as important as the servers. I hope you have run this by the customer. I'd hate to see him spend all this money and end up not having what he thought he was going to have. He may choose to upsize the UPS.

 

[iwire]

The a/c may be as important as the servers. I hope you have run this by the customer. I'd hate to see him spend all this money and end up not having what he thought he was going to have. He may choose to upsize the UPS.

By the same token speaking with the UPS vendor would be prudent as I don't believe UPSs are very good starting motor loads.

It might have to be a surprising oversized UPS to do it.

 

[KundaliniZero]

I have never seen an UPS with air conditioning.

When a sistem is big and you need to provide a lot of energy you should put a bank of batteries. We use that in the subway of my country. Also on tv i have saw a room 10 m x 10 m whole of batteries to provide energy to a town of my country).

Another option is to put a hidrogen fuel. Maybe i am spelling incorrectly, but they can provide to much KVA for a long time like 8 hour or more and the space is small like 2m x 2m 2 m. I only know the german product. In EEUU are using it in Node B (stations for telecomunication)

I really don't believe a ups can provide energy for enought time to air conditioning and computers (you need to calculate if it is posible). Put a big bank of batteries or the innovation solution of hidrogen containers. Both are expensives



Enviado desde mi GT-I9195 mediante Tapatalk

 

[__dan]

UPS outside of the server room to isolate its heat production from the servers and A/C.

A/C on generator / xfer switch but not loaded on UPS. Add on delay timers to the control circuit for the compressors so they don't start at the same time. UPS goes on generator first, it ramps load, fans next, compressors next one at a time. There is significant thermal ride through in the mass of the room while waiting for the A/C. Couple minutes at least. Servers can tolerate high ambient, but as noted earlier, some type of temp monitoring, equipment monitoring, with alarm reporting is advised.

If 480 is available, 480 volt UPS line and load side with a separate delta to Y step down transformer at the server room.

 

[topgone]

UPS outside of the server room to isolate its heat production from the servers and A/C.

A/C on generator / xfer switch but not loaded on UPS. Add on delay timers to the control circuit for the compressors so they don't start at the same time. UPS goes on generator first, it ramps load, fans next, compressors next one at a time. There is significant thermal ride through in the mass of the room while waiting for the A/C. Couple minutes at least. Servers can tolerate high ambient, but as noted earlier, some type of temp monitoring, equipment monitoring, with alarm reporting is advised.

If 480 is available, 480 volt UPS line and load side with a separate delta to Y step down transformer at the server room.

You are making very complicated scenarios just to power up two very different types of loads!

I think it is more doable to run all servers/computers on UPS and run those A/C's using the backup generator. ATS on both load types:

ATS1 for servers: normal-->mains; emergency-->UPS and
ATS2 for A/Cs: normal-->mains; emergency source--> backup generator​

 

[__dan]

You are making very complicated scenarios just to power up two very different types of loads!

I think it is more doable to run all servers/computers on UPS and run those A/C's using the backup generator. ATS on both load types:

ATS1 for servers: normal-->mains; emergency-->UPS and
ATS2 for A/Cs: normal-->mains; emergency source--> backup generator​

Yes. The servers are on the UPS, the A/C is not. The A/C is an interruptible load. Stopping it and starting it three or so minutes later probably will not hurt anything. Servers are always on the load side of the UPS, which may have normal and alternate source power.

Fans and A/C unit control power on UPS or not is probably discretionary. Some small minisplits power the fan unit from the compressor power, so it may be better to leave it that way. Compressor is utility or generator power only with on delay timers to stage the restart.

I don't see the complication.

 

[Jraef]

I did a bunch of systems for remote mobile air traffic control radar units for the Air Force during the first Iraq war, the A/C systems were an absolute to be on the UPS units because the radar systems put out a LOT of heat into the trailer and would cook themselves in the few minutes it took to connect a backup generator if the primary went down. Mind you, they had to cover the contingency of having the primary generator fail just as a plane was approaching and losing track of it, so expense was not as important. We ended up with a 25kVA on-line UPS for a 12 kVA load, including the A/C unit, because of the potential starting current of the A/C. In reality though, the A/C units never shut down.

The point is, I don't think it is up to the electrician to decide what is or is not supposed to be on the UPS. If they say they want it, you size the UPS to do what they want.

 

[topgone]

I did a bunch of systems for remote mobile air traffic control radar units for the Air Force during the first Iraq war, the A/C systems were an absolute to be on the UPS units because the radar systems put out a LOT of heat into the trailer and would cook themselves in the few minutes it took to connect a backup generator if the primary went down. Mind you, they had to cover the contingency of having the primary generator fail just as a plane was approaching and losing track of it, so expense was not as important. We ended up with a 25kVA on-line UPS for a 12 kVA load, including the A/C unit, because of the potential starting current of the A/C. In reality though, the A/C units never shut down.

The point is, I don't think it is up to the electrician to decide what is or is not supposed to be on the UPS. If they say they want it, you size the UPS to do what they want.

Really, it's a different thing designing for life safety compared to normal electric service. That design you did up there was based on the idea that "money is not a problem". Down here, while we strive to "install and forget" equipment, we are also keeping an eye on the figures that impact the wallet of the person paying for things we install. Bluntly, if the customer agrees, why not?