[EnergyPlus_Support] Re: Zone Height

["craigburtno" <craigburton@xxxxxxxxx>]

Dear Mike

I understand that geometry in energy+ does not have thicknesses that affect building height, width or length but are only attributed to heat transfer.  What I am unclear about is how you can accurately model the geometry of a multi-storey building (I am looking at tall commercial buildings) which takes into account all fabric losses and gains, while accurately modelling the internal volume of air that requires heating/cooling.  For my current project, we have an intersticial MEP and Structural zone which will account for 25% of the external building fabric.  How is heat gain/loss accounted for in this intersticial zone which is given heat transfer properties but no external geometric features?

I apologize if this answer is straightforward, I am a relatively new user of energy+ and if there is a section of the manual which explains this in detail then I would be grateful if you could point this out.

Kind Regards
Craig

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" <mjwitte@...> wrote:
>
> In EnergyPlus, surfaces have thickness for heat transfer, but they do not have 
> thickness for geometry.  In most cases, the difference between inside and 
> outside dimensions is small, so use whatever dimension is most convenient from 
> the plans.  The key is to end up with the correct amount of heat transfer area 
> from exterior to interior.   For most medium to lightweight buildings, a good 
> rule of thumb is to use exterior coordinates for exterior walls and roofs, 
> interior coordinates for foundation floors, and centerline coordinates for 
> interior walls and ceilings.  For a building with very thick massive walls, 
> then use centerline coordinates to achieve the correct amount of thermal mass.
> 
> Mike
> 
> 
> On 15 Nov 2006 at 13:40, Thiago Karashima wrote:
> 
> > When inserting a roof over a zone, the height of this surface (z 
> > coordinate) which I must insert is the external height (including 
> > the thickness of the construction of the roof) or the internal 
> > height (from the floor to the internal surface of layer #4)?
> > 
> > The roof construction is:
> > Material 1,  !-outside layer
> > Material 2,  !-layer #2
> > Air space,   !-layer #3
> > Material 3;  !-layer #4
> > 
> > The same question I do for the corresponding walls. Which height do 
> > I have to use for the walls surrounding this zone?
> > 
> > Thanks for your attention.
> > 
> > 
> > Thiago Karashima
> > Air-Conditioning and Refrigeration Laboratory - LaAR - 
> > www.laar.unb.br
> > University of Brasília - Brazil
> > 
> > 
> > 
> > 
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> > 
> > The group web site is:
> > http://groups.yahoo.com/group/EnergyPlus_Support/
> > 
> > Attachments are not allowed -- please post any files to the appropriate folder
> > in the Files area of the Support Web Site.
> > 
> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press the
> > "search" button.
> >  
> > Yahoo! Groups Links
> > 
> > 
> > 
> > 
> > 
> > 
> 
> 
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support      
> EnergyPlus-Support@...
>




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