[Equest-users] mystery heating load
Joe Huang
yjhuang at whiteboxtechnologies.com
Thu Dec 20 13:44:31 PST 2018
OH! I'm so glad I asked, because from the thread I got the impression
that the mystery load was due to outside air introduced by the HVAC
system! So, your experience should be a warning to all eQUEST users
that the LS-B, LS-D, etc. reports give only the heat flows from outdoor
or indoor sources, and not heat flows from HVAC operations or the true
interzone heat transfer from adjacent spaces. The former is quite
understandable since the HVAC simulation has not taken place yet, but
latter needs a little bit of explanation. In DOE-2 (underlying engine
to eQUEST), the "Loads" loads are calculated based on the input
temperatures for each space. Since most runs are done using the same
space temperatures, the LS-X reports would show no interzone heat
transfer. The subsequent System simulation solves for the true zone
temperature, so that when zone temperatures are different between
adjacent zones, there would be interzone heat transfer. Unfortunately,
this interzone heat transfer does not appear in any summary reports,
although the hourly values can be obtained through the HOURLY-REPORT
generator.
Joe
On 12/20/2018 1:19 PM, Chris Hadlock wrote:
> right...although I had deleted all child components for my zone in
> question, there were interior walls (defined in adjacent zones) that
> were exchanging heat transfer with my zone. The adjacent zone just
> happened to be an unconditioned parking garage that was very
> cold...foolish that I missed it.
>
> On Thu, Dec 20, 2018 at 4:00 PM Joe Huang via Equest-users
> <equest-users at lists.onebuilding.org
> <mailto:equest-users at lists.onebuilding.org>> wrote:
>
> And the cause for the mystery load is ?? Don't just leave us hanging!
>
> Joe
>
> On 12/20/2018 12:47 PM, Chris Hadlock via Equest-users wrote:
>> Thanks to all who responded...the problem has now been solved. My
>> faith in eQuest remains.
>>
>> Chris
>>
>> On Thu, Dec 20, 2018 at 2:33 PM David Eldridge via Equest-users
>> <equest-users at lists.onebuilding.org
>> <mailto:equest-users at lists.onebuilding.org>> wrote:
>>
>> That last sentence is the issue – the system is providing
>> some amount of air including return and OA to the space,
>> without a heating coil, meanwhile the thermostat may be
>> expecting 70F all of the time.
>>
>> The issue could be resolved by “upgrading” the unit to heat,
>> removing/reducing the OA quantity, or by relaxing or removing
>> the thermostat schedules depending on what your goals are for
>> the project.
>>
>> David
>>
>> *David S. Eldridge, Jr.**, P**.**E**.**, LEED AP BD+C, BEMP,
>> BEAP, HBDP*
>>
>> Associate
>>
>> Direct: (847) 316-9224| Mobile: (773) 490-5038
>>
>> *Grumman/Butkus Associates*| 820 Davis Street, Suite 300 |
>> Evanston, IL 60201
>>
>> Energy Efficiency Consultants and Sustainable Design Engineers
>>
>> _grummanbutkus.com <http://grummanbutkus.com/>_| _Blog
>> <http://grummanbutkus.com/blog>_ | _Facebook
>> <https://www.facebook.com/pages/GrummanButkus-Associates/1385285015032526>_
>> | _Twitter <https://twitter.com/grummanbutkus>_
>>
>> *From:*Equest-users
>> [mailto:equest-users-bounces at lists.onebuilding.org
>> <mailto:equest-users-bounces at lists.onebuilding.org>] *On
>> Behalf Of *Chris Hadlock via Equest-users
>> *Sent:* Thursday, December 20, 2018 1:05 PM
>> *To:* equest-users at lists.onebuilding.org
>> <mailto:equest-users at lists.onebuilding.org>
>> *Subject:* Re: [Equest-users] mystery heating load
>>
>> I've had a few responses requesting the modeling files so
>> I've attached the INP and PD2 file (weather file is
>> CWEC\Toronto.bin). The zone in question is "L0 Elev Lobby S"
>> and I've already removed all exterior surfaces from this
>> space (i.e. there are no Child Components). I've assigned
>> this zone to it's own system (it's the last system on the
>> air-side tab) called "Test System". I've already created the
>> hourly reports where you'll see all of the underheated hours
>> (which only occur in the winter). The LS-B report shows no
>> (zero) htg load. I realize the system is not really providing
>> any heating to this zone the way it's setup.
>>
>> Thanks,
>>
>> Chris
>>
>> On Thu, Dec 20, 2018 at 1:26 PM Chris Hadlock
>> <cjhadlock at gmail.com <mailto:cjhadlock at gmail.com>> wrote:
>>
>> Hello,
>>
>> I've created a model using eQuest 3.65 (DOE 2.2) build
>> 7173 that is of a 20 storey multi-residential building
>> located in Toronto, Ontario (Canada). There is a basement
>> with a elevator lobby that is an interior space (no
>> exterior walls).
>>
>> My model keeps telling me I have underheated hours for
>> this lobby. I'm trying to figure out why there is a
>> heating load and I'm stumped. I have removed what I
>> believe to be all potential sources of heat loss. I've
>> deleted the underground floor (which was R-100 anyway),
>> I've deleted the interior walls (just to be thorough),
>> there is no infiltration, and I've set the ventilation to
>> zero. In my mind, there is no source of heat loss. I've
>> even added a significant (10 W/ft2) equipment load and
>> yet there are still underheated hours (I've even reduced
>> my Tstat setpoint to 60F).
>>
>> I've run an hourly report to help figure out the loads
>> for both the space ("Sum of all weighted loads except
>> infil and latent") and zone ("Load Calc'd SPACE Sensible
>> load at const temp (Btu/hr)"). These reports all indicate
>> a positive load (i.e. net heat gain) from my lights, plug
>> loads and occupants. However through this process I'm
>> also questioning these reports as the lighting, people
>> and equipment load being reported don't exactly align
>> with my modeled schedules for these loads....but I've put
>> a pin in that.
>>
>> Regardless, I have no idea how to figure out what may be
>> resulting in net heat loss for this zone. To be thorough,
>> I checked the elevator lobby on the ground level and the
>> same thing is happening. Has anybody seen this
>> before...any ideas what might be causing heat loss for a
>> zone with no ventilation and no walls and no
>> infiltration? It does seem to be seasonal (i.e no
>> underheated hours in the summer) so it has some
>> connection to weather file but does not correlate exactly.
>>
>> If you do take the time to read this, a big thank you. If
>> you provide the answer, you'll for sure be on Santa's
>> "nice" list.
>>
>> Chris
>>
>> _______________________________________________
>> Equest-users mailing list
>> http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
>> To unsubscribe from this mailing list send a blank message
>> to EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG
>> <mailto:EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG>
>>
>>
>> _______________________________________________
>> Equest-users mailing list
>> http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
>> To unsubscribe from this mailing list send a blank message toEQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG <mailto:EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG>
> _______________________________________________
> Equest-users mailing list
> http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org
> To unsubscribe from this mailing list send a blank message to
> EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG
> <mailto:EQUEST-USERS-UNSUBSCRIBE at ONEBUILDING.ORG>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20181220/887fbe03/attachment-0001.htm>
More information about the Equest-users
mailing list