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Re: [EnergyPlus_Support] Re: The question about the internal thermal m ass
For thermal (infrared) radiant exchange, internal mass exchanges with all other
surfaces in the zone, weighted by the product of area and thermal absorptance.
Diffuse solar entering a zone is distributed to all surfaces in the zone,
regardless of position, weighted by area and solar absorptance.
Direct solar is handled several ways depending on the option selected for
"Solar distribution" in the BUILDING object.
Mike
On 2 Feb 2007 at 2:36, eric_zhou1223 wrote:
> Mike,
>
> For the third question, if there is no geometric position in the
> zone, then how is the radiation with other surfaces able to be
> considered(and further the solar radiation)? I feel this calulation
> could be related to the object's place.
>
> Eric
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@...> wrote:
> >
> > 1. No, the air volume is not adjusted. If you want to reduce the
> capacitance
> > of the zone air, change the volume in the ZONE object. But the
> contribution of
> > air mass is very tiny compared to the thermal mass of surfaces, so
> this should
> > produce negligible changes in results.
> >
> > 2. The only limit on internal mass area is that the radiant heat
> transfer
> > calculations require that any one surface must have an area less
> than or equal
> > to the sum of all other surfaces in the same zone. You can have
> multiple
> > internal mass objects in the same zone.
> >
> > 3. In your intial post, you stated "I know this thermal mass only
> consider the
> > convection heat transfer with zone air." This is incorrect.
> Internal mass
> > surfaces participate fully in all zone heat transfer mechanisms,
> including
> > convection with the zone air, thermal radiant (receiving radiant
> internal gains
> > and exchanging with other surfaces), and solar gains (diffuse, and
> direct if
> > the solar distribution is set to MinimalShadowing). It is just
> like a regular
> > heat transfer surface except that is has no geometric position in
> the zone.
> >
> > Mike
> >
> >
> > On 30 Jan 2007 at 8:35, wanglei wrote:
> >
> > >
> > > Dear Linda
> > > Thank you very much for your reply.
> > > I have two question about the internal mass.
> > > 1. If I add a thermal mass in a zone , the volume of the air is
> subtract by this thermal mass
> > > 2. what is the maximum thermal mass area, which I can input to
> the area field.
> > > Thank you ,verymuch!
> > >
> > >
> > >
> > >
> > > From: "Linda Lawrie" <linda@...>
> > > To: energyplus_support@xxxxxxxxxxxxxxx
> > > Date: Mon, 29 Jan 2007 23:04:22 +0800 (CST)
> > > Subject: Re: [EnergyPlus_Support] The question about the
> internal thermal m ass
> > >
> > >
> > >
> > >
> > >
> > > Remember that the internal mass will absorb heat and retain that
> > > temperature. "when I increasing the area of thermal mass above
> 50, <BR>the average temperature is high than less thermal mass. I
> think there <BR>is some problem." -- I would be looking at the
> significance of area
> > > "50" is with the rest of your zone.
> > >
> > > A more definitive answer will come if you upload your input file
> to
> > > the support group area.
> > >
> > > Linda
> > >
> > > EnergyPlus WebSite: http://www.energyplus.gov
> > > Owner: EnergyPlus_Support list
> > > Member: EnergyPlus Development Team
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> > > 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@...
> >
>
>
>
>
> 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
>
>
>
>
>
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