Hello. Can anyone give me a maximum estimate as to the BTU rating of a 200
Watt power supply (there are two) that is contained within the RSM 219 disk
tray system that Sun makes? I could not find anywhere on Sun's site what
the BTU rating is; I could find everything else about the 219 system but the
BTU. Thank you in advance.

Mark

"Mark" <toey9932@hotmail.com> wrote in message news:<vPPUa.3939$R43.976@fe01.atl2.webusenet.com>. ..
> Hello. Can anyone give me a maximum estimate as to the BTU rating of a 200
> Watt power supply (there are two) that is contained within the RSM 219 disk
> tray system that Sun makes? I could not find anywhere on Sun's site what
> the BTU rating is; I could find everything else about the 219 system but the
> BTU. Thank you in advance.

Unlikely you'll find a thermal spec for this old power supply
anywhere, so you'll have to make one up. You'll be quite conservative,
but if you're using Sun's thermal numbers elsewhere, you're
already being quite conservative.

You know that when you say "BTU" in this context, you really mean
"BTU/hr". BTU is a unit of energy, not power.

1 BTU/hr = 0.2931 Watts

BTU/hr = Watts/0.2931

Efficiency of an old switching supply could be as low as 65%.
More likely it's up around 70-75%, but we're being conservative.
So if the supply is running at it's 200W nominal spec (unlikely,
but we're being conservative), it could be consuming as much as:

200W*(1-0.65) = 70W, which is 70/0.2931 = 239 BTU/hr.

If these are dual redundant supplies, don't double-count,
right?

Or, if you know these are the only power supplies in your system,
just take the rest of your BTU budget and multiply by 1.35.

-Jay-

"Jay Lessert" <jayl-news@accelerant.net> wrote in message
news:7109f92b.0307301604.77edde95@posting.google.c om...
> "Mark" <toey9932@hotmail.com> wrote in message
news:<vPPUa.3939$R43.976@fe01.atl2.webusenet.com>. ..
> > Hello. Can anyone give me a maximum estimate as to the BTU rating of a
200
> > Watt power supply (there are two) that is contained within the RSM 219
disk
> > tray system that Sun makes? I could not find anywhere on Sun's site
what
> > the BTU rating is; I could find everything else about the 219 system but
the
> > BTU. Thank you in advance.
>
> Unlikely you'll find a thermal spec for this old power supply
> anywhere, so you'll have to make one up. You'll be quite conservative,
> but if you're using Sun's thermal numbers elsewhere, you're
> already being quite conservative.
>
> You know that when you say "BTU" in this context, you really mean
> "BTU/hr". BTU is a unit of energy, not power.
>
> 1 BTU/hr = 0.2931 Watts
>
> BTU/hr = Watts/0.2931
>
> Efficiency of an old switching supply could be as low as 65%.
> More likely it's up around 70-75%, but we're being conservative.
> So if the supply is running at it's 200W nominal spec (unlikely,
> but we're being conservative), it could be consuming as much as:
>
> 200W*(1-0.65) = 70W, which is 70/0.2931 = 239 BTU/hr.
>
> If these are dual redundant supplies, don't double-count,
> right?
>
> Or, if you know these are the only power supplies in your system,
> just take the rest of your BTU budget and multiply by 1.35.
>
> -Jay-




Hey Jay Lessert. Thank you so very much for the valuable information. I'm
really new to all of this BTU/hr stuff, and in general, admin stuff.
Basically, I have to give a rough estimate as to the total (max
conservative) BTU/hr produced of all of our equipment so that we can get
appropriate air cooling stuff. Thanks again!

Mark