Forum discussion
NC-2009 EAp2: Minimum Energy Performance
90.1 AppG G3.1.2.8 says the return/relief fan should be sized for max (SA-OA, 90%*SA) [cfm]. But in table 1.4. the allowable fan power is only based on the supply fan power. If I calculate the return/relief fan power based onG3.1.2.8, it will exceed the allowable fan power calculated by 1.4. So does anyone have a good approach how to deal with this?
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Anthony Hardman
Building Performance AnalystThe Green Engineer
16 thumbs up
February 23, 2015 - 2:40 pm
It sounds more complicated than it is. All it's really saying is that the baseline case needs to have the same fan configuration as the design and that the total fan power can't exceed the allowance. So if the design has supply, return and relief fans, then the baseline should also. The baseline power allowance should be allocated in the same proportion as it is in the design.
Haojie Wang
Energy ModelerKJWW Engineering
4 thumbs up
February 23, 2015 - 2:58 pm
Thanks. That what I was hoping to do. But is there a rule of saying that I should use the same ratio as proposed or I can just arbitrarily set the supply and return/relief as long as the total is below the allowable fan power.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
February 24, 2015 - 10:20 am
Making it proportional is a good practice. In the end it is not really required for LEED projects since it generally does not impact the baseline fan energy use.