[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: negative solar radiation
- Date: Tue, 15 Jun 2004 15:01:29 -0500
- From: Michaël Kummert <kummert@xxxxxxxxxxxxx>
- Subject: Re: negative solar radiation
Just 3 more comments:
The most frequent cause of "out of bounds pane temperature" is an
unrealistic incident solar radiation on a window, so your two errors
could be related. You could first double-check that the connections are
correct and then the component order (as recommended by Jeff). I don't
think you should have to reduce the time step to prevent a "pane
temperature" error when using a radiator, so there is definitely
something wrong. If that error is still there when you fix the solar
radiation problem, you should watch the output of your radiator closely.
The fact that the solar radiation error is related to the time step
could also indicate that your data file is not read correctly. Please
remember that the correct start time for a simulation that uses a hourly
weather file is always 1, no matter what timestep you use. Otherwise you
may end-up skipping an incorrect number of lines, which then causes a
time shift in the data read. It is often useful to plot the
extraterrestrial radiation computed by Type16 versus the horizontal
radiation form the data file to make sure the timing is OK.
Concerning the IISiBat error, I don't think it has been reported with
the latest version (dated from 2003-04-18). If you are not using that
version yet, you can download it from the website (as part of the patch).
Kind regards,
Michaël Kummert
on 2004-06-15 12:29, Jeff Thornton wrote:
At 02:50 PM 6/15/2004 +0200, you wrote:
That is no problem anymore if I lower the timestep to 0.1 hour and
less, and/or reduce the power of the radiation. However, with smaller
timesteps I get the error
***** ERROR ***** UNIT 20 TYP # 56
NEGATIVE VALUE OF SOLAR RADIATION FOR 5. ORIENTATION ENCOUNTERED.
SIMULATION STOPPED.
If I follow the radiation from the radiation processor, this doesn't
seem the case. It seems that the problem is in Type56.
This can happen sometimes if the component order in IISiBat isn't
ideal. We've noticed it a few times when we have Type 16 followed by
Type 56 followed by a Type 34 shading device. Type 56 gets the
incidence angle from Type 16 and an older value of radiation from Type
34 at the first iteration and errors out. Check for situations like this.
And to make it really frustrating, TRNSYS doesn't appear to like my
TPF-files and announces from time to time when I want to save the
project "save failed". Trying to save it on another disk or diskette
doesn't work and when I reboot my computer, the whole file seems to
have dissapeared from the hard disk. Not only the latest changes, the
whole thing.
If that happens, copy everything in the project and paste it to a new
project - then save the new project. Can you replicate the error so we
can forward it on to the IISiBat developers?
Jeff
*********************************************************************************
Thermal Energy System Specialists (TESS)
Jeff Thornton 2916 Marketplace Drive
Principal Suite 104
Phone: (608) 274-2577 Madison WI 53719
Fax: (608) 278-1475 USA
E-mail: thornton@xxxxxxxxxxxx
Web Page: www.tess-inc.com
"Providing software solutions for today's energy engineering projects"
*********************************************************************************
--
_________________________________________________________
Michaël Kummert
Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706
Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert@xxxxxxxxxxxxx
SEL Web Site: http://sel.me.wisc.edu
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys