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NC-v4 EAc2:Optimize energy performance

Question on Table 6.5.3.1.1B of ASHRAE 90.1-2010 - How is prssure drop of the Air Heat recovery system of the base calculated?

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Stephan Zweig
Civil Engineer
BLPTK Construction
LEEDuser Basic Member
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Please give me a feedback if I have calculated right the Fan Power of the baseline building. Note that my baseline building requires an air heat recovery system (based on ASHRAE 90.1-2010) and that I have system 8.

Also according paragraph G3.1.2.10 and Table G3.2.1.9 my goal is to calculate the “A” at the equation CFMs*0.0013+A.

Also according Table 6.5.31.1A  , “A” is related from Pressure Drop with derives from table 6.5.3.1.1B.

For the Pressure drop of the heat exchanger I choose from 6.5.3.1.1B  “Energy Recovery Device other than Coil Runaround Loop”  => (2.2x Energy Recovery Effectiveness) – 0.5 wc

In the given formula “(2.2x Energy Recovery Effectiveness) – 0.5” is meat by Energy Recovery Effectiveness the energy effectiveness of my building which is 70% or the energy effectiveness of the baseline building which is 50%?

 

I calculated with the Energy Recovery Effectiveness of MY building as following

Pressure drop = 2.2*0.7-0.5 =1.04 wc. Do you confirm this approach is right?

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Fri, 02/14/2020 - 13:38

For the Baseline fan power calculation you would use the Baseline energy recovery effectiveness (50%). So the pressure drop would always be 0.6 in. w.c.

Tue, 02/18/2020 - 07:33

Dear Tyler, are your sure that we choose Baseline energy recovery effectiveness (50%) and not the effectiveness of the proposed  building (70%)? I mean the baseline pressure drop selection  for the Filter is defined of the Filter type of the proposed building. Why to change this logic in the Heat Exchanger?  

Tue, 02/18/2020 - 14:53

Yes, in general the Baseline parameters (ex. airflows) are the values as applicable to the Baseline system. I believe the logic with the filters is to allow for similar levels of filtration to the design, thereby not penalizing the design fan power for including extra filtration which is not included in the Baseline fan power. 

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