[158699] in North American Network Operators' Group
RE: Online/double-conversion UPS economy/high efficiency modes?
daemon@ATHENA.MIT.EDU (Alex Rubenstein)
Thu Dec 6 16:48:30 2012
From: Alex Rubenstein <alex@corp.nac.net>
To: "nanog@nanog.org" <nanog@nanog.org>
Date: Thu, 6 Dec 2012 16:46:22 -0500
In-Reply-To: <50C10B45.20400@tiedyenetworks.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> > I'm looking at several brands of rackmount 3kva double-conversion
> > UPSes, such as Tripp Lite and Eaton Powerware. I'm specifically
> > looking for something that will work as a line-interactive UPS until
> > the power starts to misbehave and will then switch to
> > double-conversion mode until a while after the last power bump.
Not entirely the topic asked, but we have good experience doing this at the=
500 kva module level. We are using the 'eBoost' method from GE, which is m=
ore or less what you ask for. It keeps the inverter and rectifier alive and=
energized, but current flow is via the bypass static switch.=20
We have used this for about a year or so now, and even including hurricane =
sandy craziness, have seen in excess of 98% usage of eBoost. When in that m=
ode, system efficiency jumps from about 92% to 99.8% efficient. A huge savi=
ngs per 500 kva / 450 kw.=20
450 kw * 24h * 30d * 7.8% increase in efficiency is 25,272 kw-hrs saved per=
month, or at $0.12/kw-hr is $3,032/month/450 kw of load.=20
The point is that it works, works well, and is green.=20
http://www.gedigitalenergy.com/products/brochures/PowerQuality/brochure-eBo=
ost-GEA-D1050-GB.pdf
To this point:
> even if it can switch - you are still taking that risk of power issues th=
at will
> jump your ups and hit your connected equipment anyways.
If the overall power system is designed correctly, this should never be an =
issue. We did pretty extensive testing on this.
I don't know if anyone does this at the very-small level. I know GE's small=
est unit is 300 kva for eBoost.
"Question everything, assume nothing, discuss all, and resolve quickly."
-- Alex Rubenstein, AR97, K2AHR, alex@nac.net, latency, Al Reuben --
-- Net Access Corporation, 800-NET-ME-36, http://www.nac.net --
