Re: [EnergyPlus_Support] about the intrnal heat gain from computers

["Michael J. Witte" <mjwitte@xxxxxxxx>]

For nearly all electric equipment, 100% of the electricity consumed becomes 
heat in the space (radiant, visible (lights), latent, or convective).  The only 
cases where some of the power in would leave the zone without becoming heat 
would be equipment with some type of exhaust system such as large copiers or 
blueprint machines or equipment which heats a liquid that then goes down a 
drain.  I suppose one could argue that a portion of the energy consumed by the  
coffee-maker in the break room leaves that space as cups of hot coffee are 
carried out to other parts of the building. :-)

For standard desktop computers, all of the power in will become heat in the 
space.  I do not know what the proper split is between convective and radiant, 
but I would presume is it nearly all convective.

Mike




On 7 Jan 2005, at 18:33, Khizir Mahmud wrote:

> 
> Hi 
> 
> I also have faced the same kind of problem of calculating building
> internal heat sources specially for computers and monitors.
> Electricity Consumtions of computers and monitors varies from model to
> model. In ASHRAE Handbook , the range is given only but difficult to
> take the appropriate one for the use.
> 
> For my experiment, i tested one pentium-4 computer and a monitor by
> KWh meter. And i got around 120W has been consumed by the KWh meter.
> But i am  not sure about the ratio of electricity consumtion and the
> heat generation.
> 
> Thanks
> 
> 
> 
> On Fri, 7 Jan 2005 15:37:35 -0800 (PST), zhen tian <tianzhen9@xxxxxxxxx> wrote:
> > > Hi, All: > > I almost finish my simulation and very appreciate the help from
> Mike and many other expers in EnergyPlus group. > > Now I am checking the input
> in my model.  I have a question about the internal heat gain from "Electric
> Equipment". I know that typical office work and the inpin the Occupancy heat
> gain is about 100-130W/person for ut for "lighting design level" can be the
> calculation of lighting fixtures.  But I am not sure about the Electric
> Equipment. > > Although referring to some standard, I can use 10W/m2 for the
> office space. But right now I want to use the actual value for this.  Some days
> ago, there are some poster for discussing the computer heat production.  If the
> enegy consumption for a PC (including monitor)  is  about 300W, and there are
> only 2 computers in a zone. So the input value for this zone is 600W in the
> Electric Equipment Design Level. Is this method correct? > > Although this may
> be correct for calculation of electrity use of a space, is it correct for the
> actual heat production?  If all the 600W electricity consumed will be turned
> into heat production in the space?  If not, what ratio will become heat?   And
> if a PC is in a standby conidtion, what will be the reasonable range for energy
> consumption and heat production? Could sombody give me some reference or data? >
> > Thanks a lot. > > Regards, > > Zhen > > --------------------------------- > Do
> you Yahoo!? > The all-new My Yahoo! â?? What will yours do? > > [Non-text
> portions of this message have been removed] > > The primary EnergyPlus web site
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> 
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> 
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> 
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> 
> 
> 
> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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