I think you are confused by 3 different problems:
1) Values in an EPW file are instantaneous or averaged depending on the variable. There is some info on the EnergyPlys website(http://apps1.eere.energy.gov/buildings/energyplus/weatherdata_format.cfm). Unfortunately I haven’t found a completely up-to-date, easy to read format definition, which seems strange for a format that wants to be (and has become) a standard. I found better documentation for the TMY3
format, which I think would be useful to you: www.nrel.gov/docs/fy08osti/43156.pdf. In short, the value on a given line for temperature is the instantaneous value at that time (e.g. the 1st line has the temperature at 1 AM on January 1st). Radiation values are integrated over the previous hour, so that the 1st line gives the total radiation (in Wh/m²) over the hour between 0 AM and 1 AM on January 1st). Since the time step in these file is 1 h you can also understand radiation numbers as average values in W/m².
2) TRNSYS uses average values for ALL variables. “TIME” in TRNSYS always refers to the end of the time step and all variables are
averaged over that time step. So if Type 15 reads the temperature during an hourly simulation, the value it should output for other components is not the value that it reads but the average between the line that corresponds to the current time (end of time step) and the line before. In doing that TRNSYS is not really interpolating but rather calculating the average over the time step.
3) Solar radiation projections are typically performed with sun angle values corresponding to the middle of the time step. This is what TRNSYS does (unless sunrise/sunset takes place during the time step). So during an hourly simulation solar radiation is not interpolated
or shifted, but sun angles are calculated at the middle of the time step (and since TIME represents the end of the time step, the middle of the time step is half an hour before).
In the case of shorter time steps TRNSYS does interpolate weather data, and it does it differently for radiation than other variables. But this email is getting too long already…
Michaël Kummert
Polytechnique Montréal
From: trnsys-users-bounces@cae.wisc.edu [mailto:trnsys-users-bounces@cae.wisc.edu] On Behalf Of saleh saadi
Sent: Monday, October 22, 2012 18:34
To: trnsys-users@cae.wisc.edu
Subject: Re: [TRNSYS-users] Weather Data Reader Type15
For those of you who usesTYPE15 (for EPW weather data) in TRNSYS 16.
Does TYPE 15 shift the solar radiation to the middle of the hour when interpolation is performed? or uses the weather data by the end of an hour and linearly perform the interpolation?
It is not about a specific weather file.
I'm developing my own weather model reader and processor in Simulink. I have used results
from E+ to verify my model but seems to be off at some times . So, I used TRNSYS _16, TYPE 15 to determine the solar radiation on south vertical surface using Perez model and compared that to my Simulink and E+ results. I figured that TYPE 15 interpolates the weather file (even at 1 hour time step) and therefore can't use it for verification. I was expecting that TYPE15 will read the weather file without interpolation when time step is 1 hr. Is there a way with this type or others to get the values at the beginning (or end ) of each hour rather than interpolating values at the mid of the hour?
Dear saleh saadi,
Salam, Please let me know the weather file name ?
I'm trying to extract
some
weather data from TRNSYS -16 after reading and processing EPW file using Pereze model (time step 1 hr). I have noticed that this TYPE interpolates the variables including the air temperature. Is there a way to extract the data without interpolation using this type or others?
1) I use TRNSYS 16, there is no
TSGRD in TYPE 56.
Ok. Please always include the TRNSYS release number .
2) The height over sea level of Default is 0 m I used.
Default values NEED to be adapted
to your data!
3) You are right. I tried to use *.tm2 weather data, this Error disappeared!
As I mentioned previous, there must be an error in your data file. Link the outputs to the online/printer for
checking
4) Yes, The data reader Type 9 is placed after the building now for my simulation.,
For a successive method all input data types should be placed at the beginning.
Check the component order and rearrange it.
Dipl.-Ing. Marion Hiller
TRANSSOLAR: KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäude
Munich - New York - Stuttgart + 49.711.67976.0
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart
Amtsgericht Stuttgart - HRB 23347, Steuernummer 99073/00911, USt-IdNr.:
DE152272639
Geschäftsführer: Dipl.Ing. Matthias Schuler,
Dipl.Ing. Thomas Auer, Dipl.Phys. Stefan Holst, Prof. Dipl.-Ing. Bleicher
Von: 王洋 [mailto:wanghongyang1767@gmail.com]
Gesendet: Mittwoch, 10. Oktober 2012 13:37
An: hotline
Cc: trnsys-users
Betreff: Re: Fwd: Converging error Dear Marion,
Many thanks for your patient reply!
1) I use TRNSYS 16, there
is no TSGRD in TYPE 56.
2) The height over sea level of Default is 0 m I used.
3) You are right. I tried to use *.tm2 weather data, this Error disappeared! But my Userdefined weather data is TRN/TRY weather data. Why does it result in aforementioned Errors (Converging error by my past emails)?
If I must use our own TRN/TRY weather data, how to avoid this Converging error?
4) Yes, The data reader
Type 9 is placed after the building now for my simulation., Do you mean Type 9 should be placed before the Building Type 56? Is Better?
Many thanks in advance!
Br.
wang
there are several issues within your simulation concerning the outside longwave exchange of external surfaces
1.) You didn’t connect TSGRD such that it is set 0 => If you have no information set it Tamb
2.) For Sky temperature calculation with Type 69, you forgot to enter the height above sea level.
3.) You read the ambient temperature and the relative air humditiy from a userdefined file by type 9
instead of using the data from the weather
file.
This file wasn’t attached, but it might be an error source especially when interpolating incorrect data.
For testing, please use the ambient temperature and rel. humidity from the assigned weather file throughout your simulation.
Please check your userdefined data and the outputs of Type 9 WITHOUT connecting them to TYPE 56.
4.) In addition, please check the component order. The data reader Type 9 is placed after the
building.
Dear Marion and TRNSYS Users,
Thanks for your reply!
I checked all you mentioned, I can't find any special/abnormal settings. Furthermore, it
runs well when the time step is 1 hour. For other steps e.g. 0.1 h, 0.2 h or 0.5 h, it appears that ERROR.
Please help me have a look at the attached project if you are free.
Many thanks in advance!
br.
wang
This problem may occur from incorrect ambient condition settings:
Please check the following inputs of Type 56
In addition make sure that in the BUI file the surface
- outside emissitive is ≤ 1
- outside convective heat transfer coefficient ist set to reasonable value
If the error presits, we need the complete project to give further advice.
I noticed from your listing (*.lst) file that your working directory is located on your computer's desktop directory. This is not recommended due to the potential issues with the Windows OS system and write privleges. I would first try changing your working directory to the ".\MyProjects" directory or in a folder right on the "C:" drive. I am not certain that
this is the issue with the TRNEXE, but if the problem persists, please contact your distributor, techsupport@tess-inc.com. On 2012-09-27 03:46, Karol Bandurski wrote:
I try to simulate dwelling with natural ventilation. I set some algorithm for window opening and ideal heating for colder part of year for each zone with set temperature
depending on time of day.
When I run my yearly simulation it stop in one moment and TRNEXE is frozen... There is even no error! Then I can only turn off TRNEXE.
Only think what appear (many times) in .lst file is
Notice: More than 6 iterations for internal regulation HEATING/COOLING.
I will be grateful for any advice!
------------------------------------------------
Poznan University of Technology
In general the notice has nothing to do with a frozen TRNEXE.exe,
it is just an information.
The message indicates that the internal controller for turning on the
integrated heating/cooling has convergence problems and a deadband is applied to promote convergence.
This may be the case at the moment of turning ON or OFF something.
After 6 internal iterations a deadband is added to promote convergence.
If the convergence isn’t reached after 12 iterations a warning is written to the lst/log file.
Dipl.-Ing. Marion Hiller
TRANSSOLAR: KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäude
Munich - New York - Stuttgart
+ 49.711.67976.0
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart
Amtsgericht Stuttgart - HRB 23347, Steuernummer 99073/00911, USt-IdNr.: DE152272639
Geschäftsführer: Dipl.Ing. Matthias Schuler, Dipl.Ing. Thomas Auer, Dipl.Phys. Stefan Holst, Prof. Dipl.-Ing. Bleicher
I try to simulate
dwelling with natural ventilation. I set some algorithm for window opening and ideal heating for colder part of year for each zone with set temperature depending on time of day.
When I run my yearly simulation it stop in one moment and TRNEXE is frozen... There is even no error! Then I can only turn off TRNEXE.
Only think what appear (many times) in .lst file is
Notice: More than 6 iterations for internal regulation HEATING/COOLING.
I will be grateful for any advice!
------------------------------------------------
Poznan University of Technology
This problem may occur from incorrect ambient condition settings:
Please check the following inputs of Type 56
In addition make sure that in the BUI file the surface
- outside emissitive is ≤ 1
- outside convective heat transfer coefficient ist set to reasonable value
If the error presits, we need the complete project to give further advice.
Dear all,
I met a converging error when I changed simulation time step 1 hour into 0.1 hour or 0.2 hour or 0.01 hour as follows:
*** Fatal
Error at time : 3972.000000
Generated by Unit : 56
Generated by Type : 56
Message : outside temperature of 2(external) wall in zone 1at time 3972.00 not converged!
Please tell me some possible solutions for that if you know. The attached is its Listing File.
Many thanks in advance!
Br.
wang
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***********************************************
Dr. Ramkishore Singh
Department of Energy & Environment
TERI University
Tel: 91-11-26122222, Ext. 1302
Fax: 91-11-26122874
Web: www.teriuniversity.ac.in
***********************************************
---------- 已转发邮件 ----------
From: "Karol Bandurski" <karol.bandurski@put.poznan.pl>
To: <trnsys-users@cae.wisc.edu>
Cc:
Date: Thu, 27 Sep 2012 10:46:49 +0200
Subject: [TRNSYS-users] problem with iterations?? I try to simulate dwelling with natural ventilation. I set some algorithm for window opening and ideal heating for colder part of year for each zone with set temperature depending on time of day.
When I run my yearly simulation it stop in one moment and TRNEXE is
frozen... There is even no error! Then I can only turn off TRNEXE.
Only think what appear (many times) in .lst file is
Notice: More than 6 iterations for internal regulation HEATING/COOLING.
I will be grateful for any advice!
------------------------------------------------
Poznan University of Technology
--
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Energy Analyst
New Delhi 110025,India