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Re: [EnergyPlus_Support] Re: The wierd results of cooling load rate.
For any hour that the indoor zone air temperature is different between the
setback and no-setback models, the heat gains (losses) will be different for
ventilation, infiltration, and windows. The differences are not large, because
they occur during evening hours when the temperature difference between indoors
and outdoors is not large.
Mike
On 26 Apr 2007 at 2:05, xjtu.guowei wrote:
> Dear Michael:
>
> Thank you very much for your reminding. I have found that it is the
> internal mass and the massive building envelope made the difference. I
> still have several questions.
>
> 1. The total internal heat gains are exactly the same for both of these
> two models. It should be so because they have the same occupancy,
> lighting and equipment schedule. What puzzled me is for these two
> models, they also have the same infiltration volume flow rate, but the
> Infiltration Sensible Heat Gain is not the same to each other. Even
> though the difference is not too big, it still doesn't make sense to me.
>
> 2. As for the Mechanical Ventilation Cooling Rate Increase, I also have
> the same question. The two models have the same Outside Air Volume Flow
> Rate, but the Mechanical Ventilation Cooling Rate Increase are different
> from each other ( More Increase with more Set forward degrees). The
> difference is kind of significant.
>
> 3. As for the Windows Heat Gains, I can not the slight difference
> between this two models.
>
> Thank you very much.
>
> Wei
>
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@...> wrote:
> >
> > Thermal mass effects could result in a higher cooling rate for the
> entire
> > occupied period. Compare the sum of the cooling load across the
> entire 24 hour
> > period. You should see that the 24-hr cooling load is less in the
> night
> > setback case.
> >
> > Other factors to consider in such a comparison: does the HVAC system
> have an
> > outside air inlet? If so, it the fan continuous or cycling? Are you
> comparing
> > "Zone/Sys Sensible Cooling . . ." or the coil load?
> >
> > If you are not able to explain this, please upload the two input files
> to the
> > files area in the yahoo group or send as a zipped attachment to
> energyplus-
> > support@...
> >
> > Mike
> >
> >
> > On 23 Apr 2007 at 22:15, xjtu.guowei wrote:
> >
> > > Dear All:
> > >
> > > I have run the simulation for two models. The only difference
> between
> > > them is the thermostat schedule.
> > > The first one is 75F(Cooling) for the all time during the day; the
> > > other one is 75F(6:00AM-5:00PM)and 80F (the rest time of the day),
> > > which is sort of like nightsetback. People is in the zone from
> 7AM-5PM.
> > > From my analysis, for the second model,the cooling load rate will be
> > > going up around 7Am and go back to almost the same values as the
> first
> > > model.
> > >
> > > But from the results I got, during the period of 7AM-5PM, the second
> > > model's cooling load rate is about 20%-15% highter than the first
> > > model, which didn't make any sense to me. I am wondering if there is
> > > anything wrong with E+ or my model? Please help me to figure it out.
> > > By the way, I checked the heating load rate which made sense to me.
> > >
> > > Thank you in advance.
> > >
> > > Wei
> > >
> > >
> > >
> > > 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.pdf
> under the
> > > Documentation link and press the "search" button.
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
> >
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support
> > EnergyPlus-Support@...
> >
>
>
>
> [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.pdf under the
> Documentation link and press the "search" button.
>
> Yahoo! Groups Links
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
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The group web site is:
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