Dear all,
I have received the following LEED design review:
"Mechanical drawings with equipment schedules (M-04, M-05, and M-06)
with the heating and cooling pumps, boiler, chiller, and cooling tower
schedules have been provided. However, the scheduled flows and
capacities are inconsistent with those reported in the Table 1.4.3 in
the spreadsheet.
Please revise the Proposed model to reflect the design conditions
(including all capacities, flows, controls, and setpoints), revise the
form and spreadsheet as required to reflect any changes, and provide
reports or screen captures to confirm the changes made."
My impression was that we don't have to enter the capacities / flows (as
per the Mechanical design) in eQUEST, as the program automatically
calculates/sizes these.
The reviewer noticed an inconsistency between Table 1.4.3 (whereby I
filled in the equipment capacities & loop flows from the eQUEST
Simulation Output reports) and the Mechanical schedules.
Shall I rerun my simulations with whatever capacities/schedules provided
by the Mechanical Engineers?
Thanks,
Omar
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on Green Building & LEED GA Training in November.
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___________________________
Omar Katanani
Hi Omar,
The Proposed Case should be entered as designed in eQuest. The default
values of eQuest can be used if there is no specific design available.
However, if the design is available the values should match in all the
design documents and the model. Rerunning is a good choice, I guess.
Providing a narrative to explain any revisions is always a good call.
Cheers
Kushagra Juneja
Omar,
By extension, you'll want to watch for any changes in your proposed
model's underheated/undercooled hours. eQuest makes generally sensible
assumptions regarding occupancies, internal loads and scheduling - but
these do not always agree with the HVAC designer's calculations and can
result in fairly different heating/cooling requirements for some spaces.
For this and future LEED modeling, you should plan on incorporating some
degree of QC between the load calculations used for equipment sizing and
your model's inputs, to avoid excessive undercooled/heated hours.
If you reach this stage of QC at an early enough stage of design (i.e.
before 100% documents), eQuest models can serve as a QC check for the
HVAC design as well, bringing to light loads/ventilation
requirements/etc... that were not considered in earlier HVAC equipment
sizing.
Also, since your reviewer is definitely going to be looking for matching
airflows on your resubmittal - remember to pay close attention to the
effects of site elevation within eQuest and take that into account when
entering scheduled capacities. Plenty of discussion in the archives.
Good luck!
~Nick
NICK CATON, P.E.