[Equest-users] Hrs exceeding throttling range on T24 baseline

Sundharam, Premnath psundharam at DLRGROUP.com
Wed Feb 10 11:16:00 PST 2010


Hey Hwakong,

Thanks for the response.... I realized the hard way that the capacities
doesn't matter.... 

Our system does not have any preheat or reheat coils. The proposed is a
SZRH that is connected to CHW and HW Loop (This is in essence to
simulate a THREE Deck Multi Zone System). T24 Standard system for this
zone is PSZ.

There are both heating and cooling unmet load hrs, but on one zone the
heating unmet load hrs is 1300 and the rest of the zone are minor. This
single handedly is what is probably causing the problem.

 

This zone is similar to many other zones in use, geometry and so on and
except for this one every other zone of similar nature functions
perfectly well....

 

 

 

The same zone on the T24 Proposed appears perfectly normal.... See image
below....

 

 

 

So again, T24 standard uses a PSZ and the T24 Proposed uses a SZRH....
It is impossible for a zone to have a minimum temp at -57.8 F in May in
San Diego...... the T24 Standard is doing something wrong! I tried many
things, like increasing the Hot Water Entering Zone temp., deleting the
system for this zone and re-assigning to a new system.... Nothing seems
to solve the problem....

 

Any help would again be greatly appreciated....

Thanks

Prem

 

 

From: Hwakong Cheng [mailto:hwakong at hotmail.com] 
Sent: Wednesday, February 10, 2010 11:59 AM
To: Sundharam, Premnath
Subject: RE: [Equest-users] Hrs exceeding throttling range on T24
baseline

 

In my experience, insufficient capacity in primary equipment (chillers,
towers, fans, etc) is seldom the cause of hours out of throttling range.
I would look more at reheat capacities, presence/absence of preheat
coil, presence/absence of reheat coils, and other control issues. These
are not autosized by eQUEST - for example, sizing the reheat coil
capacity is done in DOE-2 by specifying the reheat delta T. Sometimes
there are different system types between the proposed and standard
models that can cause differences in unmet load hours between the two.
Are your hours out of throttling due to insufficient cooling,
insufficient heating, or both? Is it one zone or many? You probably need
to review the detailed and hourly reports for the standard model to
understand what's not working right in that run... and then figure out a
way to fix that in the original model. 
 
We always see low heating energy in our T-24 proposed runs. We think
it's an artifact of eQUEST rather than a reflection of reality. 
 

________________________________

Date: Wed, 10 Feb 2010 11:11:24 -0600
From: psundharam at DLRGROUP.com
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Hrs exceeding throttling range on T24 baseline

Hello All,

 

I am doing a Title 24 Compliance through eQuest and I am just trying to
do a reality check to see if the model is performing correct.

 

Based on the T24 proposed and standard output files, it appears that the
T24 standard building has 17.6% outside of throttling range, where as
the T24 proposed has only 0.4% outside of throttling range.

One thing I don't understand is, if the program calculates its own
capacities, then how could T24 standard have such a huge unmet load
hours.

Anyways, is there a way to fix the T24 standards unmet load hours even
though the model complies with T24?

 

Also another question.... How do I check the heating capacity of the
system designed in Btu per sf in the output files... we typically see
around 20 Btu per sf as the heating capacity required in Phoenix...
assuming similar condition in inland San Diego... I wanted to check the
heating consumption against capacity, the program is showing a really
low heating need in San Diego which I seriously doubt... see attached
compliance report...

 

 

 

 

 

Any help would be greatly appreciated.

Thanks

Prem

 

Premnath Sundharam, Assoc. AIA, LEED AP

Architectural Designer  |  Senior Associate

psundharam at dlrgroup.com

DLR Group

Architecture  Engineering  Planning  Interiors

o: 602/381-8580
6225 North 24th Street, Suite 250  Phoenix, AZ  85016-2020
dlrgroup.com <http://www.dlrgroup.com/>   |  listen.DESIGN.deliver
 
 

 

________________________________

Hotmail: Trusted email with powerful SPAM protection. Sign up now.
<http://clk.atdmt.com/GBL/go/201469227/direct/01/> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100210/44c223e9/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 85055 bytes
Desc: image007.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100210/44c223e9/attachment-0008.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 49661 bytes
Desc: image008.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100210/44c223e9/attachment-0009.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 48242 bytes
Desc: image001.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100210/44c223e9/attachment-0010.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 55064 bytes
Desc: image002.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100210/44c223e9/attachment-0011.jpeg>


More information about the Equest-users mailing list