[Bldg-sim] [Equest-users] an inadequate cooling capability warning

[Sheila]

Hi Kevin,

 

I see this kind of warning a lot.  The warning usually comes from the
design load calculations, not from the simulation of actual hourly
requirements.  As long as the thermal zone in question does not have any
(or minimal) unmet load hours (check your SS-R report), there is no
worry.  For code compliance, I would use the SS-R report showing the
lack of unmet load hours as a justification that the unit is in fact not
undersized.

 

I hope this helps.  Have a nice day.

 

Sheila Sagerer

Energy Engineer, EIT, LEED AP

Energy Opportunities, Inc, a 7group company

Phone: 717-880-9069

www.sevengroup.com

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Kevin
Kyte
Sent: Monday, August 02, 2010 3:09 PM
To: 'eQUEST Users List'
Cc: bldg-sim at lists.onebuilding.org
Subject: [Equest-users] an inadequate cooling capability warning

 

I have been struggling with this scenario.  A pump room does not need to
exceed 104F.  Lake water is used for cooling.  The room is expected to
contain internal loads requiring cooling at almost all times.  Below 55F
the OA and RA modulate to provide 55F supply air.  Above 55F, 100% OA
and the cooling coil turns on.  I have the cooling Tstat set to 90F and
cooling coil available at 55F.  I am unsure how to even model Below 55F
except for economizing which is not really exact but when I set the
economizing low limit to 55F I get 200F in the space.  I have set
economizing to 90F integrated with the coil and no low limit.  The
cooling coil is rarely used and not needed in its full capacity yet I am
getting inadequate cooling warnings.  

 

The Min-Supply-T is set to 55F because supply should not be less than
this and hourly reports show acceptable supply temperatures into the mid
70s (I don't know if this is acceptable to the program?)  I am not using
a lake water chiller because I am not trying to use the same coil
temperature.  I am using a simple packaged single zone with the
cool-control range set to max and EIR zero'd because there is enough
force off the main header to not need any pumping through the loop.

 

This is only for energy code compliance and I need an explanation on the
warnings.  Other than stating several obvious limitations I don't really
understand why this warning is occurring.  Does anyone have suggestions
on how I may model this system?

 

I understand that electronic files would help and I will work on that.

 

Thank you.

 

 

 

 

Kevin Kyte, LEED (r) AP

Watts Architecture & Engineering, P.C.

95 Perry Street, Suite 300

Buffalo, NY  14203

p:  716.206.5174

f.:  716.206.5199

e:   kkyte at watts-ae.com

http://www.watts-ae.com <http://www.watts-ae.com/> 

 

 

 

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