Re: [EnergyPlus_Support] Heating occuring past the heating setpoint

["Michael J. Witte" <mjwitte@xxxxxxxx>]

I've looked at the "Big Lecture Theatre"  a bit and it appears that you are 
caught in one of the quirks of the SINGLE ZONE REHEAT set point manager.  When 
the zone is floating in the deadband, this set point manager requests supply 
air that is at the zone air temperature (attempting to deliver no heating or 
cooling to the zone).  If you report the node temperature and setpoint at the 
air loop outlet node, you can see this behavior.  I see you also have several 
MIXING objects which can contribute to some control difficulties.  For this 
particular system (constant volume terminal reheat), you may be able to achieve 
better control by using BASEBOARD HEATER:WATER:CONVECTIVE with DIRECT AIR 
instead of a reheat coil.  Give the air terminal unit priority 1 and then the 
baseboard as priority 2.  See the CVBbRh example file.

Mike


On 24 Mar 2005, at 18:09, Sam Roose wrote:

> 
> I have uploaded a file to Problem Submittals\Sam Roose named
> "29_base_model".  The building model should heat at 18 degrees C and cool at 24
> degrees C. However, when I look at a period in winter (say 1-7 August) and look
> at the zone temperatures and the thermal heating load of each zone, I see that
> two of the zones "Big Lecture Theatre" and "Small Lecture Theatre" show a
> heating load late in the day despite zone temperatures being well over 18
> degrees. It also seems the warmer zone temperatures are at this time of day, the
> higher thermal heating load is.
> 
> I am currently using an outside air controller which increases and decreases
> outside air depending on the number of people present in each zone. I thought
> the cause of my problem might be that the outside air brought in during winter
> is too cold and the node sensing room temperature is different to the node
> sensing heating requirement (if this makes sense). However, I can't find a node
> which might be out of place and there are no node errors present in the error
> file. Any idea why heating occurs in this file when the room temperature doesn't
> require it? Thanks in advance
> 
> Sam Roose
> Energy Analyst
> Energy Solutions Ltd.
> Wellington, New Zealand   
> 
> 
> 
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> 
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> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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