[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [EnergyPlus_Support] Radiant heat exchange
Mike,
After some additional analysis and trial runs, we determined that
radiation works in the design day model we put together, but the results
may be better for over all energy use than for actual surface
temperature analysis. We found that it doesn't make much difference
where we put the radiant heat panel in our space or which way it faces.
Just having it somewhere in the model raises the surface temperatures
very uniformly for all surfaces in our relatively small (6m x 9m x 6m)
space. In one trial we used a very small interior wall facing toward
the west wall (the building is essentially a box with a notch in the
middle of one side)
+-------------------------+
| |
+-^^-+ |
| |
+----+ |
| |
+-------------------------+
and had an equal temperature rise on the east exterior wall behind the
hot surface. Of course there is no stratification so the real
effectiveness of warm surface position can not be evaluated.
I'm not faulting EnergyPlus or suggesting there is some error in the
current calculations. I know that a CFD simulation would probably give
me a better approximation of results that I am looking for (especially
stratification). My point is "user beware", surface temperatures and
condensation flags may not be as reliable in EnergyPlus as one would
like.
Ned Lyon, Senior Project Manager
Simpson Gumpertz & Heger Inc.
41 Seyon Street, Bldg 1 Suite 500
Waltham, Massachusetts 02453
781-907-9350 direct
________________________________
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Michael J.
Witte
Sent: Monday, May 09, 2005 13:41
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Radiant heat exchange
I am not sure what might be wrong. Check the azimuth and tilt of the
heated
surface and the window. If they are facing the same direction, they
don't
"see" each other, and they will only have a slight long wave thermal
exchange
via other surfaces.
There is no difference in the internal heat balance between the design
day
calculation and a weather file run period.
Mike
On 6 May 2005, at 16:19, Edward G. Lyon wrote:
> I am trying to study how radiant panel heat alters the surface
temperature of an
> adjacent glass wall using a design day calculation. EnergyPlus
calculations
> include radiant energy exchange. However, my hot panel does not
appear to do
> anything to my glass wall (subdivided into small sections for
temperature
> distribution analysis) unless I make it so big that it heats up the
room air
> above the themperature set point. Am I wrong about the program's
ability to
> perform a calculation like this? I previously had good results for a
solar
> heated surface temperature model, but I wasn't using the design day
simulation
> for that study.
>
> Ned Lyon, Senior Project Manager
>
> Simpson Gumpertz & Heger Inc.
> 41 Seyon Street, Bldg 1 Suite 500
> Waltham, Massachusetts 02453
>
> 781-907-9350 direct
>
>
>
>
>
> [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.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
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
* To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
* To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<mailto:EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx?subject=Unsubscri
be>
* Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service <http://docs.yahoo.com/info/terms/> .
[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.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/