[TRNSYS-users] Strange Opening Factor (OF) of Window
王洋
wanghongyang1767 at gmail.com
Mon Oct 3 07:07:10 PDT 2011
Dear Mr. Bradley
Many thanks for your patient reply!
1) Firstly, I only defined one Thermal Airnode in one zone, two
External nodes, two Large opening. So I guess the reason is not the first
you said. But I found the definition of Large opening, especially For Closed
Opening: flow coefficient Cs per m crack is 0.0001 kg/s/m at 1 Pa. Moreover,
I found indeed the hot air escapes from the zone about 2.42 kg/h after I set
the OF as 0 (from 6 pm to 8 am). But when I set Cs as 0 kg/s/m at 1 Pa,
moreover, I defined wind pressure coefficients Cp as 0 for 2 external nodes,
there is still a WEIRD thing: the CO2% still decreases, however, the hot air
escapes from the zone about 0.65 kg/h (which is almost the same from 6 pm to
8 am) after I set the OF as 0. I guess COMIS maybe still has an default
although OF is 0 and Cs is 0 kg/s/m. But I indeed need CO2% as a constant
after OF is 0.
2) For your second reason, I checked the COMIS documentation. I found Air
Flow calculation is a steady state simulation, however, the Pollutant
Transport is calculated with a dynamic model. Whether CO2% decreases due to
this reason i.e. COMIS is trying to predict CO2%, when OF is 0 (Air Flow
calculation), however, CO2% is still calculated by COMIS (after OF is 0
during this simulation step). But like 1), the hot air escapes from the zone
about 0.65 kg/h (which is almost the same from 6 pm to 8 am) after I set the
OF as 0. Hence, I think this reason 2) is still not reasonable. Moreover, I
found although TRNFlow ‘s engine is COMIS, for some issues, the manuals of
both of them COMIS and TRNFlow are still not clear and relative completely.
Could you introduce other references or COMIS (EMPA) guys to give me an
exact answer for this WEIRD thing? Because it troubles me for a long time. I
need find the stable PID parameters to control OF which can keep CO2% under
or at the set-point 1000 ppm. Until now, I found the stable PID parameters
for one day, but due to CO2% decreases after OF is 0 from 6 pm. Hence, the
stable PID parameters for one day don’t work for next day from 8 am. Please
see the ATTACHED. The stable PID parameters maybe are too large for next
day’s CO2%.
3) For your third reason, I only defined 2 Large opening not including fans
and ducts etc. by TRNFlow, maybe you think they two large opening are a true
Mechanical ventilation system?
Many thanks in advance!
Br.
wang
2011/9/30 David BRADLEY <d.bradley at tess-inc.com>
> Wang,
> I will preface this by mentioning that I am not an expert in the TRNFlow
> part of Type56.
>
> It is a little hard to know what is going on without knowing anything
> about the building. However, if you have multiple zones in the building, I
> imagine that there would be some air mixing going on between zones due to
> internal temperature and height differences and the CO2 concentration would
> decrease in one zone while increasing in another.
>
> I would also recommend looking at the COMIS documentation (COMIS is the
> engine that underlies TRNFlow) to see whether its algorithms are trying to
> predict CO2 concentration at a particular point in the space (like we do in
> Type56 for comfort calculations at a particular point in a zone) or whether
> it is assuming a fully mixed zone as far as the CO2 level is concerned. If
> COMIS is calculating concentration at a point and the air continues to mix
> after your opening factor has gone to zero then that might explain the
> decrease.
>
> Lastly, your mechanical ventilation system might have something to do with
> the decrease; If you are actively supplying air to the space after the
> opening factor is zero and if the mechanical ventilation system has some
> outdoor air associated with it then that also would explain the decrease in
> CO2 level.
>
> Regards,
> David
>
>
>
> On 9/30/2011 08:47, 王洋 wrote:
>
> Dear all,
>
> I simulated CO2 concentration changes using TRNFlow. But there is a
> STRANGE phenomenon. There are 2 occupants from 8am to 6 pm, CO2% is
> controlled by PID controller which controls Opening Factor (OF) of window at
> the set-point 1000 ppm. From 6 pm, there are no occupants, OF is 0, there is
> no infiltration in TRNBuild (Certainly, infiltration in TRNBuild indeed will
> inactivate when couping TRNFlow based on TRNFlow Manual). However, from 6
> pm, CO2% begins to decrease. It's extremely strange!
>
> Which relative expert can expain that? Or give me some advices for that?
> I am puzzled for a long time.
>
> Many thanks in advance!
>
> br
>
> wang
>
> 2011/9/30 <trnsys-users-request at cae.wisc.edu>
>
>> Send TRNSYS-users mailing list submissions to
>> trnsys-users at cae.wisc.edu
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> https://mailman.cae.wisc.edu/listinfo/trnsys-users
>> or, via email, send a message with subject or body 'help' to
>> trnsys-users-request at cae.wisc.edu
>>
>> You can reach the person managing the list at
>> trnsys-users-owner at cae.wisc.edu
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of TRNSYS-users digest..."
>>
>> Today's Topics:
>>
>> 1. Using Excel as Load Profile (Pei Ru Chao)
>> 2. TRNSYS error 300 (torres.carlos-moises at lte.ireq.ca)
>> 3. Direct expansion solar collector (Mohamad Azly Abd Aziz (Ir))
>> 4. simulation studio crash when updating project (Antoine Gautier)
>>
>>
>> ---------- 已转发邮件 ----------
>> From: Pei Ru Chao <simplica1 at hotmail.com>
>> To: TRNSYS <trnsys-users at cae.wisc.edu>
>> Date: Fri, 30 Sep 2011 16:31:53 +1000
>> Subject: [TRNSYS-users] Using Excel as Load Profile
>> Hi all,
>>
>> As a newbie I am wondering how to use Excel for load profile input. Can
>> anyone point me in the right direction as to how to use a Data Reader to do
>> this? For example, can the Data Reader read 10920 rows of data? In 9a for
>> example, Parameter 2 asks how many values of input to read and the maximum
>> is only 98?
>>
>> Thanks
>>
>> Pei
>>
>>
>>
>>
>> ---------- 已转发邮件 ----------
>> From: <torres.carlos-moises at lte.ireq.ca>
>> To: <trnsys-users at cae.wisc.edu>
>> Date: Thu, 29 Sep 2011 15:50:36 -0400
>> Subject: [TRNSYS-users] TRNSYS error 300
>> Dear all,
>>
>> Whenever I ry to run a type 56 simulation in TRNSED I am given the
>> following error even though the same program runned perfectly in TRNEdit
>>
>> ***** ERROR ***** TRNSYS ERROR # 300
>> UNABLE TO START PROGRAM IN CALLPROGRAM UTILITY
>> PLEASE CHECK PATH AND PROGRAM NAME, THIS MAY BE A PROBLEM IN TYPE 66
>>
>> *** Fatal Error at time : 0.000000
>> Generated by Unit : Not applicable or not available
>> Generated by Type : Not applicable or not available
>> TRNSYS Message 300 : The TRNSYS Program attempted to evaluate an
>> EQUATION that raised a negative number to a non-integer value. Please check
>> the EQUATION formulation and re-run the simulation
>> Reported information : Not available
>>
>> the message is not very helpfull and I don't even use Type 66 in my
>> simulation and I checked all my equations and nothing obvious comes to view.
>>
>> Is there any known solution to this problem? If need be I can send you the
>> files im using.
>>
>> Thank you
>>
>> Carlos Torres
>> Stagiaire universitaire
>> Laboratoire des technologies de l'énergie (LTE)
>>
>>
>>
>> ---------- 已转发邮件 ----------
>> From: "Mohamad Azly Abd Aziz (Ir)" <AZLY at jkr.gov.my>
>> To: "trnsys-users at cae.wisc.edu" <trnsys-users at cae.wisc.edu>
>> Date: Fri, 30 Sep 2011 04:36:25 -0700
>> Subject: [TRNSYS-users] Direct expansion solar collector
>>
>> Hi
>>
>>
>>
>> I wonder whether someone has come-out with heat pump type with direct
>> expansion solar collector/evaporator?.
>>
>>
>>
>> Regards
>>
>>
>>
>> Azly
>>
>>
>> ---------- 已转发邮件 ----------
>> From: "Antoine Gautier" <antoine.gautier at solamen.fr>
>> To: <trnsys-users at cae.wisc.edu>
>> Date: Fri, 30 Sep 2011 13:48:10 +0200
>> Subject: [TRNSYS-users] simulation studio crash when updating project
>>
>> Dear all
>>
>>
>>
>> I cannot update my project any more without crashing simulation studio
>> (*.tpf and *.b17 in attachment).
>>
>> Is there another way to update the input list for Type56 so that I can
>> keep on working?
>>
>>
>>
>> Thanks a lot for your help.
>>
>> Best regards
>>
>> --
>>
>> Antoine Gautier
>> Solamen
>> +33 6 98 78 56 46
>>
>> antoine.gautier at solamen.fr
>>
>>
>>
>> _______________________________________________
>> TRNSYS-users mailing list
>> TRNSYS-users at cae.wisc.edu
>> https://mailman.cae.wisc.edu/listinfo/trnsys-users
>>
>>
>
>
> _______________________________________________
> TRNSYS-users mailing listTRNSYS-users at cae.wisc.eduhttps://mailman.cae.wisc.edu/listinfo/trnsys-users
>
>
> --
> ***************************
> David BRADLEY
> Principal
> Thermal Energy Systems Specialists, LLC
> 22 North Carroll Street - suite 370
> Madison, WI 53703 USA
>
> P:+1.608.274.2577
> F:+1.608.278.1475d.bradley at tess-inc.com
> http://www.tess-inc.comhttp://www.trnsys.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20111003/b8c73e52/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: PI control OF_CO2.jpg
Type: image/jpeg
Size: 81818 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20111003/b8c73e52/attachment-0001.jpg>
More information about the TRNSYS-users
mailing list