[Equest-users] Unmet Load Hours Calc

[Tom Serra]

I'm sure most of us have stories about mis-understandings between the LEED
reviewer and energy modeler.  I must resist the urge to speak negatively
about them , but I have received many comments that show lack of
understanding of very basic modeling procedures.  Anyone reading this forum
will also note that many users have similar issues.  I would expect this
from beginners , but at the same time I would expect someone providing third
party review to be more knowledgeable about energy simulation.

These type of questions are probably at the root of USGBC's reasoning for
bringing the review process back in house.

Does anyone know of a list where we could post review comments and our
solutions to the more common questions?

I found an older post from Scott at DOE2.com  that explains everything.
Since this is a developers explanation you could use it in your response.  I
wish there was a way to distribute this to every LEED review team so we can
stop getting this question.

"

From: Scott Criswell [mailto:scott.criswell at doe2.com
<http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org>]
Sent: Tuesday, October 27, 2009 11:09 AM
To: Rosenberg, Michael I
Cc: ashu gupta; Nick Caton; Crockett, Jim; Kendra Tupper;
bldg-sim at lists.onebuilding.org
<http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org>
Subject: Re: [Bldg-sim] Ashrae 90.1 - Unmet hours



I can confirm Mike's understanding of the DOE-2/eQUEST results.  To get
the correct number of hours of unmet loads, people should MULTIPLY the
Percent hours outside throttling range from BEPS or BEPU by the total
annual "hours fans on" listed in report SS-E.

One other comment re: Ashu's write-up - I believe that (for
DOE-2/eQUEST) a zone temperature has to be more than one degree outside
the throttling range for that hour to be counted as an hour outside
throttling range.  So for a zone with a heating thermostat setpoint of
72 and a 2 degree throttling range (=> 71-73 degree "throttling range"),
the zone temperature would have to be LESS THAN 70 in order for that
hour to be counted.

related info -
We are contemplating a change to the Air-Side HVAC Summary view in the
eQUEST interface to report this total number of hours as opposed to just
the percent in the totals section at the bottom of the report.
We have also just in the past several days (thanks to the efforts of
Steve Gates) added precision to the percent hours outside throttling
range reported on BEPS & BEPU and ALSO added separate reporting of hours
any zone is either under cooled or under heated, intended for reporting
to LEED submission templates.  Assuming no further changes (which is
certainly not out of the question), future releases of DOE-2/eQUEST will
report the following in the BEPS & BEPU reports:
         PERCENT OF HOURS ANY SYSTEM ZONE OUTSIDE OF THROTTLING RANGE =
4.45
         PERCENT OF HOURS ANY PLANT LOAD NOT SATISFIED                =
0.00
         HOURS ANY ZONE ABOVE COOLING THROTTLING RANGE                =
98
         HOURS ANY ZONE BELOW HEATING THROTTLING RANGE                =
25

- Scott


Thomas Serra
Project Manager
EMO Energy Solutions, LLC
3141 Fairview Park Drive, Suite 450
Falls Church, VA 22042
voice 703-205-0445 ex-113
fax 703-205-0449
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