Hi John,
I wasn't able to make any changes to the model to correct the difference
in fan power. However, I noticed a couple of things.
The Baseline Case "Pretend" doesn't include any pressure drop adjustments
from Table 6.5.3.1.1B. This will help increase the baseline fan power.
Note that credit for heat recovery devices may not be taken unless it is
required in the Baseline Case system (see note under Table G3.1.2.9).
The Proposed Case "Actual" fan power seems high. See attached pdf for a
range of BHPs for a sample TRANE AHU at 3,000 cfm. They range from 0.88 to
3.08 depending on the system total static pressure. The system in the
model has a nominal HP of 10 which is being modeled as 7.46 kW.
Hope that helps,
Alex Chapin
Date: Thu, 10 Apr 2014 18:01:15 +0000
From: "Eurek, John S NWO"
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Anybody,
I need a little help. The fan energy usage of the Actual/Purposed
building is 4.5X more than the Pretend building.
I've looked and looked and looked for something that is causing such a
huge difference.
One thing I tried that really confused me was to set the system for the
pretend building as 'same as Alternate 1' and the pretend building fan
energy usage went up.... So then I went tab-by-tab and matched
Alternative 1 to the setting that the Pretend building was using and the
fan energy for Alternate 1 was still over 2 times the Pretend building.
John
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