Unmet Load Hours

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Hi,

I am doing an energy model for a LEED USGBC project. In this project I am
facing a problem which is described below:

In Proposed case the total unmet heating load hours (from the output report
of SS-R) are 36, and "PERCENT OF HOURS ANY SYSTEM ZONE OUTSIDE OF THROTTLING
RANGE = 0.2." as shown in the BEPU report. Please note that the 36 unmet
heat load hours are total of all conditioned zones (approx 30 zones)

In Baseline case the total unmet load hours (which coming from the output
report of SS-R) are 112 and "PERCENT OF HOURS ANY SYSTEM ZONE OUTSIDE OF
THROTTLING RANGE = 0.5" as shown in the BEPU report. Again the 112 unmet
heat load hours are total of all conditioned zones (approx 30 zones).

Per USGBC the unmet load hours may not be exceed 300 hours (which is OK in
our case) for either the Baseline or Proposed design. And the difference in
unmet load hours between the baseline and proposed design must be no greater
than 50. But in our model difference is greater than 50. So anyone please
guide me that how can I bring down this number?

Currently here is how I am trying to bring down the unmet load hours in the
baseline model. I am increasing maximum heating rate (window shown below) in
these unmet zone (from Zero as default) to a value which is the maximum heat
load for that zone (from SS-R in output file).

Note: That this is a LEED CS project and system are not designed. To keep
apples to apples I am then going back to the proposed model and adding the
same maximum heating rate to the same zones. Is this the right approach?

Can anyone else suggest a different approach?

Any help would be greatly appreciated!

Thanks

Ashu

ashu gupta's picture
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Joined: 2011-09-30
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ASHU:
?
Try increasing the throttling range on your thermostats.
?
John Aulbach

John Aulbach's picture
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Joined: 2011-09-30
Reputation: 1