[Bldg-sim] 90.1-2007, Fan BHp and Filter Pressure Drop

[Chris Yates]

How does the calc apply for a fan coil system with 100% oa? Or is it  
only pertinent to vav? We had some gbc comments back asking to see the  
same calc for the proposed.

Sent from my iPhone

On 23 Mar 2010, at 22:49, "Rosenberg, Michael I" <michael.rosenberg at pnl.gov 
 > wrote:

> My opinion is that if a designer “schedules” a fan bhp to meet a  
> certain static pressure requirement, and then knowing that it will a 
> ctually have to meet a higher static pressure (not as a safety facto 
> r but during normal operation) schedules a motor with a large enough 
>  nameplate hp to accommodate that, it is an attempt to get around th 
> e requirement in 90.1.
>
> __________________________
>
> Michael Rosenberg
> Senior Commercial Buildings Energy Analyst
> ENERGY & ENVIRONMENT DIRECTORATE
>
> Pacific Northwest National Laboratory
> 2032 Todd Street
> Eugene, OR 97405
> (541) 844-1960
> michael.rosenberg at pnl.gov
> www.pnl.gov
>
> From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim- 
> bounces at lists.onebuilding.org] On Behalf Of Ryan Hammond
> Sent: Tuesday, March 23, 2010 1:31 PM
> To: bldg-sim at lists.onebuilding.org
> Subject: [Bldg-sim] 90.1-2007, Fan BHp and Filter Pressure Drop
>
>
>
> All,
>
>
>
> A colleague brought up an interesting point about filters and fan BHp.
>
>
>
> Regarding 90.1-2007, Table 6.5.3.1.1A, Option 2, what is your  
> interpretation of “bhp = the maximum combined fan brake  
> horsepower” for an AHU?  And how does 90.1-2007 verify this?
>
>
>
> 90.1-2007 defines “fan system bhp” and “fan system design  
> conditions”; however there isn’t any clear mention of how exactly  
> fan BHp is defined with respect to filters (100% loaded filter delta 
> -p, 66% loaded filter delta-p, 33% loaded filter delta-p, etc.).  Th 
> e fan system would still meet capacity requirements, just at a reduc 
> ed filter pressure drop as scheduled.
>
>
>
> For example, a designer could define (and schedule) the fan BHp to  
> operate at a max of 66% of allowable filter pressure drop for  
> reduced fan energy, yet schedule a fan motor to be able to meet the  
> fully loaded filter pressure drop.
>
>
>
> The ramifications of scheduling a lower fan BHp against 90.1-2007 is  
> the proposed system will now be operating more “efficiently”,  
> compared to the baseline, assuming the filters are truly replaced at 
>  66% of allowable filter pressure drop (which likely would never hap 
> pen in the field!).
>
>
>
> Any thoughts on this?  Anyone on the 90.1-2007 committee that could  
> shed some insight?
>
>
>
> Thanks,
>
> Ryan
>
>
>
> <image001.jpg>
>
> R. Ryan Hammond   PE, HBDP, BEMP, LEED AP
>
> Engineer
>
> (P) 916.921.1956 x202
>
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>
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