Well for anyone interested, I’ll answer my own question.
The Reference building models autosize the mechanical system on the design files. This includes the sensible heat ratio of the cooling coils. For some areas
of the country, the max dehumidification load does not correspond to the summer design temperature. When EnergyPlus calculates the cooling coil output, it apparently can’t or doesn’t resolve air conditions that exceed the sensible hear ratio. All that was
necessary to fix the RH exceeding 100% errors was to round up the autosize sensible heat ratios to the next larger two digit value and enter them manually and then let E+ autosize the rest of the system.
Ned Lyon, P.E. (MA, WV)
Staff Consultant
SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Tuesday, August 26, 2014 12:11 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Relative humidity out of range
I’m trying to help a colleague with a version 7.2 PsyRhFnTdbWPb Relative Humidity out of range error. We are running a DOE Commercial Reference Building and modifying the envelope,
windows and locations. All the mechanical are autosized. When this building is run in Chicago, we have RH out of range errors. We do not have these errors in other locations. Can anyone suggest a way to mitigate these errors. Shorter time steps and more
HVAC iterations do not help. Oversizing cooling by 2.8 does work, but I’m not sure that is the best plan. Thanks in advance.
Ned Lyon, P.E. (MA, WV)
Staff Consultant
SIMPSON GUMPERTZ & HEGER
|
Engineering of Structures and Building Enclosures
41 Seyon Street, Bldg. 1, Suite 500
Waltham, MA 02453
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com
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Posted by: "Edward G. Lyon" <EGLyon@xxxxxxx>
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