[TRNSYS-users] discrete time step and the simulation time step

王洋 wanghongyang1767 at gmail.com
Tue Oct 19 08:00:13 PDT 2010


Dear all,

I have some questions to ask you:

To Type 22: The manual said this controller can be used to model a real
feedback controller (e.g. PID) that would adapt its control signal
continuously or use a discrete time step much shorter than the simulation
time step in TRNSYS.

What's meaning of  a discrete time step and  the simulation time step ?

Do you know how many minutes this Type 22's discrete time step is ?  And
what's the min. minutes this Type 22's discrete time step is ?

What's the min. simulation time step  in TRNSYS?

many thanks!

br.

wang

2010/10/19 <trnsys-users-request at cae.wisc.edu>

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> Today's Topics:
>
>   1. Re: Trigeneration simulation: printing or convergence problem
>      ? (David BRADLEY)
>   2. fresnel Collector (farah.gammoh at mirroxx.com)
>   3. UNSUSCRIBE (info at aacarchitecture.be)
>   4. Re: type 109 with 5 minutes time step (Dimas Firmanda Al Riza)
>
>
> ---------- 已转发邮件 ----------
> From: David BRADLEY <d.bradley at tess-inc.com>
> To: "wim.vansteenkiste at ugent.be" <Wim.Vansteenkiste at UGent.be>
> Date: Mon, 18 Oct 2010 12:45:26 -0500
> Subject: Re: [TRNSYS-users] Trigeneration simulation: printing or
> convergence problem ?
> Wim,
> asterisks in the output file are often an indication that the format
> statement for what was being printed was not correct. I am not sure what
> component you are using for your output device but if it is either Type25 or
> Type46 make sure that you are using an "unformatted" mode.
> Regards,
> David
>
>
> On 10/16/2010 12:45, wim.vansteenkiste at ugent.be wrote:
>
>> Dear TRNSYS-users,
>>
>> I'm only been using TRNSYS for 2 months, so I'm quite new at it.
>>
>> I'm simulating a trigeneration system: a custom made gas engine model
>> combined with an absorption chiller.
>>
>> TRNSYS doesn't indicate convergence problems after simulating.
>> Based on plotted values, the simulation seems satisfactory as well.
>>
>> I print the output values of every component. When I view these output
>> values, there seems to be a problem:
>>
>> A lot of values aren't printed. Instead of the value,
>> "***************" appears. This happens for almost every mass flow as
>> well as for the energy rates in the absorption chiller. The strange
>> thing is that the values can be plotted, only when I print them I get
>> this problem. Temperatures and other values are printed correctly.
>>
>> Do you have an idea of what could be the cause of this problem?
>>
>> Thanks in advance,
>>
>> Wim.
>>
>>
>> _______________________________________________
>> TRNSYS-users mailing list
>> TRNSYS-users at cae.wisc.edu
>> https://www-old.cae.wisc.edu/mailman/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:+1.608.278.1475
> d.bradley at tess-inc.com
>
> http://www.tess-inc.com
> http://www.trnsys.com
>
>
>
>
> ---------- 已转发邮件 ----------
> From: "farah.gammoh at mirroxx.com" <farah.gammoh at mirroxx.com>
> To: "TRNSYS-users at cae.wisc.edu" <TRNSYS-users at cae.wisc.edu>
> Date: Mon, 18 Oct 2010 17:58:59 +0200
> Subject: [TRNSYS-users] fresnel Collector
> Hello,
> is there a way to simulate a fresnel collector field using once of the STE
> models?
>
> thanks and best regards,
> Farah
>
>
>
> ---------- 已转发邮件 ----------
> From: "info at aacarchitecture.be" <info at aacarchitecture.be>
> To: TRNSYS-users at cae.wisc.edu
> Date: Mon, 18 Oct 2010 21:55:09 +0200
> Subject: [TRNSYS-users] UNSUSCRIBE
> Please Unsuscribe following adresses:
> aac at win.be
> info at aac-archi.be
> info at aacarchitecture.be
>
> Thanks
>
>
>
> Marc Vande Perre
> mv at aacarchitecture.be
>
> n.v. AAC Architecture s.a.
>
>
>
> ---------- 已转发邮件 ----------
> From: Dimas Firmanda Al Riza <dimasfirmanda at gmail.com>
> To: hotline <hotline at transsolar.com>
> Date: Tue, 19 Oct 2010 10:32:47 +0800
> Subject: Re: [TRNSYS-users] type 109 with 5 minutes time step
> Dear all,
>
> I have problem again with simulation time step,
>
> I use Type 9 data reader, with 5 minutes time step data,
> 1. How to write the simulation start time in (type 9) if I simulate it
> together with weather data in June (in type 109)?
> 2. I did a test with my data file, I connect type 9 with online plotter, I
> put data in type 9 like the note bellow,
>     and I set simulation start time 0 stop time is 120, when I set
> simulation time step to 5 minutes the simulation error,
>     but when simulation time step to 2.5 minutes, the simulation run,
>     Do I need to set simulation time step in control card below 5 minutes
> if the data is in 5 minutes interval?
> 3. I run my complete simulation, with type 9 and type 109, I set simulation
> time step to 2.5 minutes, i run simulation for a month,
>     but the simulation run only for several hour and then stopped, I got
> some warning:
>
> simulation log:
>  Radiation while sun is down found    1 times (What is this?)
>  only the first 10 warnings with data info are printed
>  check: - Time of first data line
>         - Longitude and Latitude
>  REMARK: these radiation values are set to ZERO !
>
>  ***** WARNING FROM UNIT   2 TYPE 109 DATA READER
>  RADIATION DATA READ IN FROM FILE ==>Weather UTP - June 1-30 (5 min).109
>  AT LINE #    2 ARE SET TO ZERO SINCE SUN IS DOWN, ORIGINAL VALUE:   28.91
> W/m²
>
>  ***** WARNING FROM UNIT   2 TYPE 109 DATA READER
>  RADIATION DATA READ IN FROM FILE ==>Weather UTP - June 1-30 (5 min).109
>  AT LINE #    3 ARE SET TO ZERO SINCE SUN IS DOWN, ORIGINAL VALUE:   28.91
> W/m²
>
>
> Simulation lst file:
>  *** Warning at time       :        61.416667
>     Generated by Unit     : Not applicable or not available
>     Generated by Type     : Not applicable or not available
>     TRNSYS Message    441 : The inputs to the listed units have not
> converged at this timestep. The values at the last iteration will be used
> and the simulation will proceed.
>     Reported information  : UNITS: 4  10  11  17
>
> *** Fatal Error at time   :        61.416667
>     Generated by Unit     : Not applicable or not available
>     Generated by Type     : Not applicable or not available
>     TRNSYS Message    450 : The maximum number of warnings allowed per
> simulation has been exceeded. Please fix these warnings or increase the
> limit on the number of warnings allowed per simulation (LIMITS command)
>     Reported information  : Not available
>
> *** Warning at time       :        61.416667
>     Generated by Unit     : Not applicable or not available
>     Generated by Type     : Not applicable or not available
>     TRNSYS Message    442 : The listed differential equations have not
> converged at this timestep. The values at the last iteration will be used
> and the simulation will proceed.
>     Reported information  : DIFFERENTIAL EQUATIONS: 1
>
>
> Please help me to solve this problem, thank you very much
>
> Best Regards,
>
> Dimas
>
>
> ______________________________________________________________________________________________________________
> Note:
> Data in .txt file for type 9 (time interval 5 minutes):
>
>  25.07
> 40.18
> 42.77
> 0.00
> 27.82
> 27.91
> 15.28
> 46.04
> 30.81
> 54.12
> 33.61
> 54.50
> 49.43
> 54.36
> 85.52
> 57.23
> 83.40
> 83.58
> 105.23
> 98.98
> 96.83
> 108.26
> 113.00
> 121.50
>
>
>
>
> On Mon, Oct 18, 2010 at 3:59 PM, Dimas Firmanda Al Riza <
> dimasfirmanda at gmail.com> wrote:
>
>> I have adjusted it by now, and it works! thanks a lot!
>> I adjust it like below
>>
>>  <interval> 0.08333   ! Data file time interval between consecutive lines
>> <firsttime> 0.08333       ! Time corresponding to first data line (hours)
>>
>> -dimas-
>>
>>
>> On Mon, Oct 18, 2010 at 3:28 PM, hotline <hotline at transsolar.com> wrote:
>>
>>>  Dimas,
>>>
>>> did you also adjust the "Time corresponding to first data line" ?
>>>
>>> <firsttime> 1          ! Time corresponding to first data line (hours)
>>> In addition, you need to set the simulation time step to 5 minutes.
>>>
>>> Marion
>>>
>>>
>>>
>>>  ------------------------------
>>>    *Von:* Dimas Firmanda Al Riza [mailto:dimasfirmanda at gmail.com]
>>> *Gesendet:* Montag, 18. Oktober 2010 02:33
>>> *An:* trnsys-users at cae.wisc.edu
>>> *Betreff:* [TRNSYS-users] type 109 with 5 minutes time step
>>>
>>>   Dear all,
>>>
>>> I have 5 minutes time step weather data,
>>> How to conduct simulation with 5 minutes time step using type 109,
>>> do I need to change something in the .109 data file?
>>> I've try to just change the data in .109 file from 1 hour time step with
>>> my 5 minutes time step data
>>> but when I run simulation with 5 minutes time step the results become
>>> weird,
>>> Thank you very much
>>>
>>> Regards,
>>>
>>> Dimas Firmanda A.
>>> MSc student
>>> Mechanical Engineering Department
>>> Universiti Teknologi PETRONAS
>>>
>>>
>>
>
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