[Equest-users] Unmet hours in residential building

[Julien Marrec]

Mike,

You have set a zonal exhaust with make up air defined as infiltration? And your space linked to the thermal zone has an infiltration defined as ACH with a higher value for design days? How much higher?
Your HVAC is autosized for the zone?
Do you still have unmet hours for the bathroom?

If this is not doing anything, your HVAC system might be already autosized to a greater value due to another parameter such as sizing factor so that the added infiltration does nothing.
Or maybe your zonal fan doesn't actually run? Try and request some hourly variables to understand what is going on.

Julien
Envoyé de mon iPhone

> Le 28 oct. 2015 à 20:27, Michael Campbell <mcamp1206 at gmail.com> a écrit :
> 
> Julien,
> 
> Regarding the infiltration method... I am currently trying to do this with a small bathroom with 50cfm exhaust.  This is a core zone.  Adjusting the design day values as described in the write-up does not appear to be doing anything.  Any thoughts?
> 
> Thanks,
> Mike
> 
>> On Thu, Oct 15, 2015 at 11:45 AM, Julien Marrec <julien.marrec at gmail.com> wrote:
>> Michael,
>> 
>> First, you're under 300 hours so indeed it's a minor problem.
>> 
>> I've only looked at your model very briefly but:
>> HW loop operation is set to "SNAP" at OA of 60°F. This is causing some minor underheating in shoulder season.
>> You have local exhaust fan with makeup = infiltration. Basically equest ignores this added infiltration during the sizing, so you have to trick it to take it into account by having a different schedule for sizing (heating AND cooling design days). I've put together my findings on the subject on Unmet Hours here in some kind of tutorial that I hope is helpful. 
>> 
>> 
>> Do the above and your unmet hours disappear.
>> 
>> 
>> 
>> Additionally:
>> 
>> Throttle range of 0.3°R seems pretty aggressive to me.
>> when you use baseboards and want to oversize, use the system's sizing ratio
>> 
>> Hope this helps,
>> Julien
>> 
>> 
>> --
>> Julien Marrec, EBCP, BPI MFBA
>> Energy&Sustainability Engineer
>> T: +33 6 95 14 42 13
>> 
>> LinkedIn (en) : www.linkedin.com/in/julienmarrec
>> LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
>> 
>> 2015-10-15 16:30 GMT+02:00 Michael Campbell <mcamp1206 at gmail.com>:
>>> I mistakenly attached the PRD file instead of PD2.  Correct files are attached.
>>> 
>>>> On Thu, Oct 15, 2015 at 10:16 AM, Michael Campbell <mcamp1206 at gmail.com> wrote:
>>>> Hello,
>>>> 
>>>> I'm having what appears to be a minor issue with unmet hours in a model that I've inherited.  My INP and PD2 files are attached.  I've tried adjusting the cool sizing ratio and and adjusted infiltration rates and equipment loads with no real effects.  Anybody have any ideas?
>>>> 
>>>> Thanks,
>>>> Mike Campbell
>>> 
>>> 
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