[Equest-users] eQuest unmet heating hours oddity

Busman, Michael R MBusman at chevron.com
Mon Feb 4 13:11:18 PST 2013


In addition to what others have suggested, take a look at your thermostats at the zone level of your HVAC equipment tab.  I noticed that several (maybe all) of the defined systems are VAV.  I looked at a few of the thermostats, and they were defined as proportional.

I encountered a similar problem in a different century when I was using VisualDOE and the fix was to change the thermostats to reverse acting.  If you define them as proportional, the VAV boxes will close to the minimum position and continue to overcool the zone.  If they are defined as reverse acting, the VAV boxes will begin to bring on reheat and open the damper when they have reached the min. CFM setting to maintain the thermostat setpoint.

I hope this helps you.

My best,

Mike Busman

Michael R. Busman, CEM
Lead Project Engineer II

Chevron Energy Solutions
A Division of Chevron U.S.A., Inc.
145 S. State College Blvd.
Brea, CA  92821
Direct  714-671-3561
Fax     714-671-3438
eFax   866-420-0335 (Include my Full Name followed by "CAI:MHTZ" on Cover Sheet)
Mobile 310-387-2083
mbusman at chevron.com<mailto:mbusman at chevron.com>

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Netty Nina
Sent: Monday, February 04, 2013 6:20 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] eQuest unmet heating hours oddity

Hi Everyone,

This questions is about unmet heating hours in a model. I've scoured the bldg-sim list but I haven't come across anything like the problem I'm having. I'm modeling a high school in New England. The unmet heating hours are 99.99%. I've checked the heating and cooling schedules, fan schedules, etc., adjusted the throttling range, and so on. The SS-O reports show that the majority of space temperatures are below 60F. The building is in New England, but I find it unlikely that during the majority of the summer the temperature will be below 60F in the building.  It's not really a sizing issue either as changing equipment sizes does not do anything and the loads (for the most part) do not exceed the equipment capacity. Any help would be greatly appreciated.



Netty Nina<mailto:nnina at ers-inc.com>, LEED(r) AP BD+C
Project Engineer
120 Water Street, Suite 350
North Andover, MA 01845

Ph: 978-521-2550 ext. 224
Fax: 978-521-4588
nnina at ers-inc.com<mailto:nnina at ers-inc.com>

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