[Equest-users] outside air flow during unoccupied/setback hours

[Patrick J. O'Leary, Jr.]

is this a leed 2.2 or 3.0 project?

i'm guessing, without looking in my leed manuals, this is a usgbc 
requirement for at least 2.2.  for leed 3, 90.1-2007, appendix g, table 
3.1, no. 4 schedules, specifically states the "hvac fans that provide 
outdoor air for ventilation shall run continuously whenever spaces are 
occupied and shall be cycled on and off to meet heating and cooling 
loads during unoccupied hours."  90.1-2004 doesn't specify fans 
specifically for outdoor air for ventilation, it just says hvac fans - 
which is the same as the system supply fan in a non-doas/economizer 
capable of completely closing the outdoor air damper system so the 
outdoor air can't be shut off.

so the comment is contrary to the 90.1-2007 (and/or 2004 depending on 
systems) simulation requirement.  the 90.1-2004 user's manual appendix g 
section doesn't address the scheduling for hvac fans during unoccupied 
modes.

On 4/24/12 9:54 AM, R B wrote:
> I normally have a min sch specified at the zone level - 0 for 
> unoccupied hours and -999 for other hours that takes care of this comment.
> There is an hourly report for fan coming on during night cycle flag 
> (or something similar). If you do not have the fan coming on or do not 
> have the night cycle control, you should be ok. You can also look at 
> the hourly report for OA ratio and whether fan is on/off during the 
> unoccupied time.
> -Rohini
>
>
> On Tue, Apr 24, 2012 at 11:23 AM, Ramana Koti <ramana.koti at gmail.com 
> <mailto:ramana.koti at gmail.com>> wrote:
>
>     Dear All,
>     One of the LEED review comments on a university building project
>     I'm working on suggests to verify that all systems in baseline and
>     proposed models contain zero outside air flow when fans are cycled
>     on to meet setback temperatures during unoccupied hours.
>     What is the best way to go about verifying this? In the 'Hourly
>     Report Block' options under a system, I find 'Hourly summed zone
>     OA CFM for DCV calculation (cfm)' and 'Hourly max zone OA/total
>     flow for DCV calculation (cfm/cf/). Is one or both of these
>     options under an hourly report, the way to go or is there a better
>     way of doing it?
>     Thanks,
>     Ramana.
>
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