[Equest-users] Unmet hours in residential building

Thu Oct 29 05:54:49 PDT 2015

Ok, so I've been doing various iterations to see how adjusting the
infiltration schedules affects the auto-sized heating capacity.  When I
change the schedule for Heating Design Day, it appears to have no effect on
the autosized capacity.  But, if I change the actual infiltration in the
schedule, the capacity will change accordingly.

On Thu, Oct 29, 2015 at 8:30 AM, Julien Marrec <julien.marrec at gmail.com>
wrote:

> I think this may be your problem right there :)
>
>
>
> --
> 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
> <http://www.linkedin.com/in/julienmarrec>
>
> 2015-10-29 13:15 GMT+01:00 Michael Campbell <mcamp1206 at gmail.com>:
>
>> Hi Joe,
>>
>> I have and the SV-A report is giving me zero heating capacity for the
>> bathroom zones.
>>
>> On Wed, Oct 28, 2015 at 9:14 PM, Joe Huang <
>> yjhuang at whiteboxtechnologies.com> wrote:
>>
>>> Mike,
>>>
>>> Allow me to jump in here a bit.  Have you looked at the SV-A report to
>>> see what DOE-2.2 has sized for the HVAC system, particularly the supply-cfm
>>> and heating/cooling capacities for the bathroom ?
>>>
>>> Joe
>>>
>>> Joe Huang
>>> White Box Technologies, Inc.
>>> 346 Rheem Blvd., Suite 205A
>>> Moraga CA 94556yjhuang at whiteboxtechnologies.comhttp://weather.whiteboxtechnologies.com for simulation-ready weather data
>>> (o) (925)388-0265
>>> (c) (510)928-2683
>>> "building energy simulations at your fingertips"
>>>
>>> On 10/28/2015 1:17 PM, Michael Campbell wrote:
>>>
>>> I've tried different values for the degree day multipliers, into the
>>> hundreds.  I'm trying out different scenarios now to see what works, but
>>> I'm still getting unmet heating hours in the bathroom.
>>>
>>> On Wed, Oct 28, 2015 at 3:57 PM, Julien Marrec <julien.marrec at gmail.com>
>>> wrote:
>>>
>>>> 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>
>>>> 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>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
>>>>>    <https://unmethours.com/question/3102/how-do-you-model-exhaust-fans-in-equest/>
>>>>>    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 <%2B33%206%2095%2014%2042%2013>
>>>>>
>>>>> LinkedIn (en) : <http://www.linkedin.com/in/julienmarrec>
>>>>> www.linkedin.com/in/julienmarrec
>>>>> LinkedIn (fr) : <http://www.linkedin.com/in/julienmarrec/fr>
>>>>> www.linkedin.com/in/julienmarrec/fr
>>>>>
>>>>> 2015-10-15 16:30 GMT+02:00 Michael Campbell < <mcamp1206 at gmail.com>
>>>>> 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>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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>>>>>
>>>>
>>>
>>>
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