System sizing ratio-Table G3.1.2.2

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Folks,

I 'm trying to increase the equipment capacities in baseline model in order
to comply with G3.1.2.2. using below options;

System sizing ratio-Option 1

System sizing ratio-Option 2

Basic

Cooling

Heating

Basic

Cooling

Heating

1.15

1

1.08

1

1.15

1.25

Both options are looks similar, but it's giving two different results
though!

If I change the basic system sizing ratio to 1, I can see increase in
equipment capacity but not in airflow. So, I concluded to proceed
with "option 1", since I can see increase in both capacities and airflow.

Am I doing correct here? Appreciate your suggestions.

Thanks

Gopi

GK Pandian's picture
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Good morning,

Option 2 is the appropriate way to represent the oversizing requirements in
Section G3.1.2.2. Since the supply airflow must be determined based on a 20
degree F temperature difference between the supply and room design
temperature (Section G3.1.2.8) and using the system oversizing factor will
violate this requirement unless you also adjust the temperature differential
to compensate for the fan oversizing.

Hope this helps!

Cam Fitzgerald

Cam Fitzgerald's picture
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