Re: [EnergyPlus_Support] heat gains in E+

[Helen Xing <hxing@xxxxxxx>]

Hello, Mike,

Thanks a lot for this.  I have couple of related questions as below, and 
appreciate your taking time to help.  - Helen


At 01:05 PM 8/22/2003 -0500, you wrote:

>Surfaces interact with the zone air heat balance by convection.  So,
>the value of most interest is (SurfaceInsideTemperature - ZoneAir
>Temperature) * SurfaceArea * SurfaceInsideConvectionCoefficient
>
>The best way to calculate the contribution from the envelope is to
>take the total load and subtract off the gains from windows, internal
>loads, infiltration, and ventilation.  The remainder will be the
>impact of the envelope.


Does Energyplus have an output which gives the total load of a building?  I 
saw "zone/sys sensible load predicted" and "zone/sys moisture load rate 
predicted"   and a grand total would help if it is available.

Alternatively, can we get the total load using several E+ outputs as follows?
total load =
Window Heat Gain + Window Heat Loss (Loss has a negative sign)
+ SUMHAT - ZoneAirTemperature * SurfaceArea * 
SurfaceInsideConvectionCoefficient
+ People (Lights, Electric-Eq) - Total Heat Gain
+ Ventilation Heat Gain + Infiltration Heat Gain

My model seemed to have problems with this, though.



>"Plant Loop Cooling Demand" is the required load on the chillers
>to meet the chiller water loop setpoint.  In your energy balance, you
>would also need to add in fan power and chilled water pump heat to
>fluid.
>
>Mike


So this specific output "Plant Loop Cooling Demand" minus the fan power and 
chilled water pump heat to fluid is the effective cooling provided by the 
plant, which should equal the total cooling load we tried to compute above?



>On 20 Aug 2003, at 22:23, Helen Xing wrote:
>
> > Hello,
> >
> > To itemize the hourly heat gains through a buliding's envelope -
> >
> > Is there a zone output for "Zone Opaque Surface Inside Face Beam Solar
> > Absorbed"?  This output is available for single surfaces from the E+
> > results, but the zone sum doesn't seem so.
> >
> > For window heat transfer and opaque surface inside face conduction
> > (maybe something else as well), E+ gives both heat gain and loss.  Is
> > there a zone output for the net value to reduce the data volume?
> >
> > One step further, wonder if there is a direct output that gives the
> > total net heat gain for a zone through the envelope?
> >
> > Is there a manual or something that explains the available output
> > names in .RDD files?
> >
> > 
>     What is "Plant
> > Loop Cooling Demand"?  According to the input-output reference, it is
> > the demand provided by the plant equipment to meet the cooling setting
> > point.  So is it equal to the total cooling load (sum of Qenvelope +
> > Qwindows + Qinternal + Q infiltration&ventilation ) as a
> > plant-building balance check?  In two cases of mine, this "balance"
> > didn't hold though.  What gives the cooling capacity value provided by
> > the plant if Plant Loop Cooling Demand is not the one?
> >
> > Thanks a lot,
> > Helen Xing
> >
> >


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Buy Ink Cartridges or Refill Kits for Your HP, Epson, Canon or Lexmark
Printer at Myinks.com. Free s/h on orders $50 or more to the US & Canada. http://www.c1tracking.com/l.asp?cid=5511
http://us.click.yahoo.com/l.m7sD/LIdGAA/qnsNAA/dkFolB/TM
---------------------------------------------------------------------~->

To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

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 are of the Support Web Site.




 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/