[bldg-sim] Out of Throttle Range.

[Albert Sitorus]

Hello everybody,
 
I am modeling a 3-story building mixed-used LEED building. The first floor
is used as classrooms and retails. The 2nd and 3rd floors are used for
residential units. Most of the systems on the first floor are air-cooled
condensing unit with electric heat-pump heating, and the rest are exhaust
fan systems. For the 2nd and 3rd floors, the apartment units use unit
heaters  without any cooling. Corridors on these floors are served by
make-up air units with gas-fired heating. There is not any warning or error
when I simulate the model. 
 
The problem is that I can't reduce the "percent of hours any system zone
outside of throttling range" to an acceptable value. I have tried adjusting
air flow, throttling range, etc w/o achieving the desired results. I looked
at SS-O report and the problem is there are too many hours when the cooling
isn't satisfied for 2nd and 3rd floor. In other words, for all zones on 2nd
and 3rd floors there are many hours when the units are over 80 - 85F or even
above 85F. I also tweaked the fans night control cycle, infiltration
schedule, set-point temperature, and zone entering max supple temp but the
out of throttling range is still exceptionally high. 
 
I have no idea how to fix this error. Without cooling in these units, should
I not expect such large out of throttling range issues? Has anyone
encountered this kind of problem before? Can anyone share their experience
or solution? Has anyone done LEED model w/o cooling? I would appreciate any
response, idea or hints that would help solve this problem. I have described
the problem as clear as I can but I am sure there are things that I may have
left out, please don't hesitate to ask me. Again, I am trying to get some
ideas, hints or methods so I will provide as much info as anyone want in
order to help me solve this.
 
Thank you very much in advance for your help. I appreciate any help, hints
or suggestions. Thank you again. 
 
Sincerely, 
 
Albert Sitorus. 
 


Albert T. Sitorus
Energy Analyst
 

 <http://www.glumac.com/>  
  _____  

320 SW Washington, Suite 200
Portland, OR 97204-2640
T.  503.227.5280  F. 503.274.7674

Thinking. Inside the building.
www.glumac.com <http://www.glumac.com/>  
 


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