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Re: [EnergyPlus_Support] Re: design load output questions
1. Probably, but it's difficult to say exactly, because there are so many
modes of heat transfer going on. You also need to allow for some energy to be
stored/released in the slab material if you're not at a steady-state condition
2. Not a good way. Certainly the internal latent gain represents a signficant
portion, the remaining portion is the latent gain/loss from infiltration and/or
ventilation air which you can compute by hand (flow rate * [outdoor humidity
ratio - desired zone humidity ratio]) or by modeling a full HVAC system.
Mike
On 20 Aug 2004, at 20:47, sm278424 wrote:
>
> Ahh, very helpful, thank you.
>
> P317 of the I/O reference talks about the sizing issue - I had
> specified the Design Flow Rate for the air system, so the program
> calculates a sizing factor.
>
> Your answer leads to two more questions:
>
> 1. In this case, can I assume that the loss to the back side of the
> radiant panel is: (4161.89 + 8105.6) - 11587.44 = 680.05 ? This
> would be to a plenum, in this instance.
>
> 2. Is there a way to get a handle on the peak latent load for the
> zone and the air system aside from 'Zone,Sum,Zone-Total Internal
> Latent Gain[J]'?
>
> Thanks again
>
> Shaun Martin
>
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@g...> wrote:
> > I am guessing that you have a zone which is served by both an air
> system and a
> > radiant hydronic system.
> >
> > 1. The sizing reported in the zsz file is before application of
> the sizing
> > factor, the eio sizing includes the sizing factor. If this is no
> 1.0 (in
> > either SIZING PARAMETERS or ZONE SIZING), then the values will not
> be the same.
> >
> > 2. No. None of the values shown below include latent cooling,
> they are all
> > sensible loads. Values a and b are simulation results, values c
> and d are
> > sizing results. With radiant systems, unlike air systems, not all
> of the
> > cooling input to the slab will end up in the space. Values c and d
> are zone
> > cooling requirements which are completely independent of the type
> of system
> > which will serve the zone. Value a is the cooling energy input to
> the radiant
> > system, and some will be lost out the back side of the surface.
> >
> > Mike
> >
> >
> > On 20 Aug 2004, at 15:52, sm278424 wrote:
> >
> > > Hi
> > >
> > > I wonder if someone can help me interpret some of the E+ output.
> I'm
> > > trying to do some design sizing. From one run, I have:
> > >
> > >
> > > a) file.CSV - Z1 RADIANT PANEL:Hydronic Low Temp Radiant Cooling
> Rate
> > > [W](Hourly) = 4161.89 W (autosized)
> > >
> > > b) file.CSV - ZN1:E PERIM SPC:Zone/Sys Sensible Cooling Rate[W]
> > > (Hourly) = 8105.6 (fixed 6 ACH)
> > >
> > > c) file.EIO - DesLoad {W} Cooling = 10277.00 W
> > >
> > > d) file.ZSZ - ZN1:E PERIM SPC:VANC_INTL CLG .4% DB=>MWB:Des Cool
> > > Load [W] = 11587.44 W
> > >
> > >
> > > my two questions are:
> > >
> > > 1. should c and d be the same? or, why not?
> > >
> > > 2. should (a + b + latent) = c or d?
> > >
> > > Thanks
> > >
> > > Shaun Martin
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > 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.
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support
> > EnergyPlus-Support@g...
>
>
>
>
> 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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
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