New chiller

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Urko

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Florida
I work on a project and I need to power new chiller (MCA - 611A, MOCP -700A at 208V, 3ph) selected by mechanical engineer on the roof of a high rise building. There is existing Power Company Transformer on the roof but without sufficient capacity to handle the new chiller.
I spoke to Power Company and they will provide a new transformer for the chiller.
I have some questions: :-?
1. How and what is best way (reliable, cheapest) to power the new chiller?
2. I propose to require from mechanical engineer to reselect the new chiller at 480V, 3ph to reduce the inrush current.
3. I can provide a new VFD for the new chiller but life expectancy of VFD is only 5-6 years. (I have read that in the forum).

Thank you
 
Yeah, you really want your largest loads to run off the highest voltage available at the site. The a/c is normally the largest load in resi high rise.
 
bigger is better in this case

bigger is better in this case

I agree, if you are going to have to change the transformer and no other loads are supplied other than the chiller go for the 480 volt, the cost difference should be minimal and you'll save on your end with smaller wire and conduit. I would go for the VFD if you explain the savings on the electric bill it pays for itself in no time, you should get plenty of years of service out of it, even if its 10 years the cost of all those inrushes will be much greater. Just remember if the landlord is paying for the install and the tenant is paying utilities the landlord may not want to spend any more than they have to.
 
LLSolutions said:
I agree, if you are going to have to change the transformer and no other loads are supplied other than the chiller go for the 480 volt, the cost difference should be minimal and you'll save on your end with smaller wire and conduit. I would go for the VFD if you explain the savings on the electric bill it pays for itself in no time, you should get plenty of years of service out of it, even if its 10 years the cost of all those inrushes will be much greater. Just remember if the landlord is paying for the install and the tenant is paying utilities the landlord may not want to spend any more than they have to.


That is a good point...goes back to communication. Communicate with all parties involved first...make less mistakes later. :wink:
 
Thank you for your assistance!

Thank you for your assistance!

Thank you for your assistance!
The landlord will pay for all upgrading. I will require to provide a VFD for the new chiller.
One more question.
What is the average life expectancy of a VFD? 5 or 10 years or more?
 
Urko said:
Thank you for your assistance!
The landlord will pay for all upgrading. I will require to provide a VFD for the new chiller.
One more question.
What is the average life expectancy of a VFD? 5 or 10 years or more?
What are you using the VFD for? Capacity control? Loop pumps? Cooling tower pumps? I think you're just requiring something you think sounds cool, without any real idea about what it does or what duty it will be put to. I've got a VFD on a hotel lobby fountain pump I know is going on 15 years old, but I'm sure there's much older one's out there.
 
Mark,
Thank you for your opinion. I agree with you.
I did not mention that existing chiller is controlled by a existing VFD.
I had researched and read about the Chillers, VFD and pumps because it is my first projects with that scope of work. :-?
I will discuss those suggestions and issues with our HVAC engineers /MFR.
 
Urko said:
Mark,
Thank you for your opinion. I agree with you.
I did not mention that existing chiller is controlled by a existing VFD.
I had researched and read about the Chillers, VFD and pumps because it is my first projects with that scope of work. :-?
I will discuss those suggestions and issues with our HVAC engineers /MFR.
Yes, chiller applications with VFDs are not something to be attempted by the novice. They are used with varying degrees of success, but can lead to real serious problems if you don't know what you are doing. "Surging" is the most common problem and can destroy the chiller. Companies who provide VFDs for chillers have specific control systems designed to prevent it. They also guard their secrets on how it is done very closely as it takes a lot of trial, error and correction over a long time to get it right. If you specify a VFD, specify it in a way that places the burden of a complete and safely functioning system on the heads of the bidders.
 
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