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Re: negative solar radiation

I found something that works to avoid the radiation peaks at the beginning and/or end of the day. I put a maximum on the radiation when the sun is below 5°, so a kind of solar obstruction.
T1 is the total radiation on the surface, B1 the beam radiation.
Whit this my simulation runs the whole 8760 hours.

Michaël Kummert wrote:

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
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?



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