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BTU question geoman 07-15-2006
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Posted by ftwhd on July 19, 2006, 6:35 pm

>I know its a 'pet' Mike. Just rattling you up a little so you won't fall
>asleep on the job and get killed and end up in hell, thats all :-)))
>
>Rich
>

Dont try and interfere with my nap time OTJ! Im union and its in my
contract! :)

AppliancePartsPros.com, Inc.
Posted by Abby Normal on July 16, 2006, 10:28 am
Geo, it sounds more like a commercial load you are running so manual j,
not the best approach.

Offices with flourescent lights, I think 1.5 per sqaure foot is pretty
good, they start with the fancy low voltage stuff , dimmable
incandescent then it could be higher. Maybe there is a lighting plan
you could look at.

For work stations now with the LCD monitors I allow 100W to 150W and it
seems to be conservative, copiers and high volume laser printers etc
need to be looked at specially

geoman wrote:
> Lights for Manual J. I'm not confident with the old stand by 2 watss per ft2
> since the new electronic fixtures. And computors have changed a great deal.
> What is everyone using for these BTU gains in J?
>
> The new style floresents four bulb suspended ceiling fixtures, what is
> appropriate to use for BTU gain?
>
> Computors. Changing all the time.
>
> Desktop BTU with CTR btu output?
>
> Desktop BTU with LCD Screen output?
>
> Laptop BTU output?
>
>
> Thanks
>
> Rich


Posted by geoman on July 16, 2006, 6:10 pm

> Geo, it sounds more like a commercial load you are running so manual j,
> not the best approach.
>
> Offices with flourescent lights, I think 1.5 per sqaure foot is pretty
> good, they start with the fancy low voltage stuff , dimmable
> incandescent then it could be higher. Maybe there is a lighting plan
> you could look at.
>
> For work stations now with the LCD monitors I allow 100W to 150W and it
> seems to be conservative, copiers and high volume laser printers etc
> need to be looked at specially
>
> geoman wrote:
>> Lights for Manual J. I'm not confident with the old stand by 2 watss per
>> ft2
>> since the new electronic fixtures. And computors have changed a great
>> deal.
>> What is everyone using for these BTU gains in J?
>>
>> The new style floresents four bulb suspended ceiling fixtures, what is
>> appropriate to use for BTU gain?
>>
>> Computors. Changing all the time.
>>
>> Desktop BTU with CTR btu output?
>>
>> Desktop BTU with LCD Screen output?
>>
>> Laptop BTU output?
>>
>>
>> Thanks
>>
>> Rich

Thanks Abby, finally thats something I can work with. I have been looking
for a copy of ASRAE project RP-822 for days now and can't find a copy
anywhere. My one contractor friend is on vacation and his workers don't know
where he has it

Lights, computors and copiers can be a pita for sure. So many people reply
and say to take the total watts x 3.413 and that is the BTU, which is wrong.

Thanks again, and if anyone has ASHRAE manual N numbers please post them.

Rich




Posted by geoman on July 16, 2006, 6:49 pm

>
>> Geo, it sounds more like a commercial load you are running so manual j,
>> not the best approach.
>>
>> Offices with flourescent lights, I think 1.5 per sqaure foot is pretty
>> good, they start with the fancy low voltage stuff , dimmable
>> incandescent then it could be higher. Maybe there is a lighting plan
>> you could look at.
>>
>> For work stations now with the LCD monitors I allow 100W to 150W and it
>> seems to be conservative, copiers and high volume laser printers etc
>> need to be looked at specially
>>
>> geoman wrote:
>>> Lights for Manual J. I'm not confident with the old stand by 2 watss per
>>> ft2
>>> since the new electronic fixtures. And computors have changed a great
>>> deal.
>>> What is everyone using for these BTU gains in J?
>>>
>>> The new style floresents four bulb suspended ceiling fixtures, what is
>>> appropriate to use for BTU gain?
>>>
>>> Computors. Changing all the time.
>>>
>>> Desktop BTU with CTR btu output?
>>>
>>> Desktop BTU with LCD Screen output?
>>>
>>> Laptop BTU output?
>>>
>>>
>>> Thanks
>>>
>>> Rich
>
> Thanks Abby, finally thats something I can work with. I have been looking
> for a copy of ASRAE project RP-822 for days now and can't find a copy
> anywhere. My one contractor friend is on vacation and his workers don't
> know where he has it
>
> Lights, computors and copiers can be a pita for sure. So many people reply
> and say to take the total watts x 3.413 and that is the BTU, which is
> wrong.
>
> Thanks again, and if anyone has ASHRAE manual N numbers please post them.
>
> Rich

Just recieved an email and it was facinating, your fiquires are more
realistic than mine.

To the emailer, thanks!!!

Rich



Posted by Jake on July 16, 2006, 6:46 pm
geoman wrote:
> Lights for Manual J. I'm not confident with the old stand by 2 watss per ft2
> since the new electronic fixtures. And computors have changed a great deal.
> What is everyone using for these BTU gains in J?
>
> The new style floresents four bulb suspended ceiling fixtures, what is
> appropriate to use for BTU gain?
>
> Computors. Changing all the time.
>
> Desktop BTU with CTR btu output?
>
> Desktop BTU with LCD Screen output?
>
> Laptop BTU output?
>
>
> Thanks
>
> Rich
>
>

Rich,

The manufacturers of lighting all publish the BTU output these days, as
I remember. We're using Cooper lighting in our new building and I know
they were able to provide the data.

We've seen severe disproportional heat loading in office environments
directly related to copiers and laser printers. Abby was right... these
need a real close look. Lexmark has some data out there on lasers... I
don't know if I've ever seen any on copiers.

AMD has some pretty good data on CPU cooling, as I remember. AMD's run
hot so their info would be conservative for Intel machines (I'm told).

My gut feeling is that in a one-person-per-office scenario, standard
LCD's and workstations don't present a huge problem. Start stacking them
together and it's a nightmare. I've seen it.

No one likes to deliberately oversize systems... but it would be nice if
just a little planning was done prior to installation. You're doing the
customer right by asking these questions.

Case-in-point: We recently were working a controls project at a major
order-taking/distribution site in the Indianapolis area. The building
had a huge open area that was the 'order-taking' bull-pen... so to
speak. A consultant decided that 'associates' could be more 'productive'
if printers were placed in numerous strategic locations throughout the
maze of cube workstations. That way... they didn't have to run half-way
across the building to get print-outs (which they need only occasionally).

They didn't ask anyone but their network people if this was a problem.
For the network... it was not. But going from 2 to 16 laser printers
took it's toll on the HVAC system in a 100 x 40 zoned space. The cooling
couldn't keep up. There was no 'magic' controls fix.

They had to upgrade the system.. which was expensive post-construction.

I know we're all very focused on energy savings these days.. which is
what VS and multi-stage systems are all about. It is my own opinion that
designing for a 20% (or more) increase in load is not a bad idea these
the way things change so quickly.

After all, the systems can be somewhat 'scalable' to demand.

Jake

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