[BLDG-SIM] Mysterious space heating load spikes

[Jeff Haberl]

Hello:
 
The system is cycling on-off. This may be due to low thermal mass, and/or precalculated ASHRAE weighting factors. Try layering your surfaces, set your floor weight = 0 to turn on custom weighting factors.
 
In your run, the average daily energy use is o.k....it is just having trouble with the low thermal mass from the precalculated weighting factors and system setpoints. See the paper by Haberl et al, 1988 in the ASHRAE transactions, which showed the same spikes.
 
Jeff
 
8=! 8=) :=) 8=) ;=) 8=) 8=( 8=) :=') 8=) 8=) 8=?
Jeff S. Haberl, Ph.D., P.E.............................jhaberl at esl.tamu.edu
Professor......................................................Office Ph: 979-845-6507
Department of Architecture.......................Lab Ph: 979-845-6065 
Energy Systems Laboratory.......................FAX: 979-862-2457 
Texas A&M University..............................77843-3581
College Station, Texas, USA.......................URL: www-esl.tamu.edu
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________________________________

From: BLDG-SIM at gard.com on behalf of Randy Wilkinson
Sent: Fri 2/9/2007 4:58 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Mysterious space heating load spikes


Hi All,

Our eQuest model has very strange looking spikes <http://www.lseng.com/%7Erandyw/stegasaurus.pdf>  in the space heating load profile.  We can't figure out why they would be there.  I put a PDF of the Monthly Electric Peak Load Profile on my web page <http://www.lseng.com/%7Erandyw/> .  The is also a PDF of the complete simulation output <http://www.lseng.com/%7Erandyw/simulationoutput.pdf>  if that helps.  We did a sanity check of inputs...it still looks insane.  This model was done all with DD wizard inputs.  Anybody got any ideas? TIA.

http://www.lseng.com/~randyw/ <http://www.lseng.com/%7Erandyw/> 
http://www.lseng.com/~randyw/stegasaurus.pdf <http://www.lseng.com/%7Erandyw/stegasaurus.pdf> 
http://www.lseng.com/~randyw/simulationoutput.pdf <http://www.lseng.com/%7Erandyw/simulationoutput.pdf> 

Randy

-- 
Randall C. Wilkinson 
L&S Engineering
Spokane, WA

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