Hrs exceeding throttling range on T24 baseline

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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

Premnath Sundharam, Assoc. AIA, LEED AP

Premnath Sundharam

DLRGroup_Phoenix's picture
Joined: 2011-09-30
Reputation: 0

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

Premnath Sundharam

DLRGroup_Phoenix's picture
Joined: 2011-09-30
Reputation: 0