<div dir="ltr">Hi Ben<div><br></div><div>Thank you so much for your answer, it helped a lot</div><div><br></div><div>Best Regards,</div><div>Amir</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Jun 25, 2014 at 6:11 AM, <span dir="ltr"><<a href="mailto:trnsys-users-request@lists.onebuilding.org" target="_blank">trnsys-users-request@lists.onebuilding.org</a>></span> wrote:<br>
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<br>Today's Topics:<br>
<br>
1. Re: The necessity of using pipes in TRNSYS models (Ben Heymer)<br>
2. Question about windows properties.. (Arnaud Candaele)<br>
<br><br>---------- Forwarded message ----------<br>From: Ben Heymer <<a href="mailto:bheymer@gmail.com">bheymer@gmail.com</a>><br>To: "TRNSYS users mailing list at OneBuilding.org" <<a href="mailto:trnsys-users@lists.onebuilding.org">trnsys-users@lists.onebuilding.org</a>><br>
Cc: <br>Date: Tue, 24 Jun 2014 09:17:17 -0500<br>Subject: Re: [TRNSYS-users] The necessity of using pipes in TRNSYS models<br>Amir,<br>
<br>
Yes, you should include pipes in the loop with at least enough volume<br>
to handle the flow during one timestep. If you think this volume is<br>
unrealistically high, reduce your time step. You can set the thermal<br>
losses of the pipes to zero if you choose.<br>
<br>
I sometimes use an equation to define the minimum pipe length to avoid<br>
convergence errors as I explore a model. If you define your time step<br>
as a global parameter, you can use something like:<br>
<br>
minpipelength = 1.1 * pipeflow (m^3/hr) * timestep (hr) / pipearea (m2)<br>
pipelength = max(minpipelength, realpipelength)<br>
<br>
-Ben Heymer<br>
<br>
On Tue, Jun 24, 2014 at 8:50 AM, Amir Nashed <<a href="mailto:nashed.amir@gmail.com">nashed.amir@gmail.com</a>> wrote:<br>
> Dear TRNSYS users<br>
><br>
> I am currently trying to model an application using solar collectors to heat<br>
> water and i realized that when i put pipes in the solar collector loop, i<br>
> get strange output water temperatures (very low values).<br>
><br>
> So what i did is that i isolated the solar collector loop and modeled it by<br>
> itself and the same problem occurs unless i use very small pipes in terms of<br>
> size.<br>
><br>
> But if i used a small pipe size i sometimes get the warning that the flow<br>
> rate the pipe during at least one component was greater than the capacity of<br>
> the pipe.<br>
><br>
> has anyone faced trouble with the pipes before? And is using pipes in the<br>
> model needed from the first place in terms of the model stability?<br>
><br>
> Thank you<br>
><br>
><br>
><br>
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<br><br>---------- Forwarded message ----------<br>From: Arnaud Candaele <<a href="mailto:arnaud.candaele@gmail.com">arnaud.candaele@gmail.com</a>><br>To: <a href="mailto:trnsys-users@cae.wisc.edu">trnsys-users@cae.wisc.edu</a><br>
Cc: <br>Date: Tue, 24 Jun 2014 16:34:57 +0200<br>Subject: [TRNSYS-users] Question about windows properties..<br><div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div>Hi all,<br><br></div>I know this kind of question has already been asked, but I can't seem to find a complete answer, so here it is again, maybe someone can help :<br>
<br></div>I'm using a window type in a building simulation, and for this I choose a window from the library "/American/w4-lib", ID 2306. Thiw window type has 2 layers of glass separated by a layer of gas.<br>
<br></div>My question is regarding the Emissivity properties that can be read :<br><br></div>Emis F 0.840 0.060<br></div>Emis B 0.840 0.840<br><br></div>I just want to be sure of what that means : I guess "F" and "B" are for "front" and "back", but which of these sides is actually towards the interior of the building ?<br>
</div>Also, which window is on the interior side, and which one on the exterior side (1st or second column ?) ?<br><br></div><div>I think that for exterior walls, TRNSYS uses "back" to describe the "outer" face of the wall (outside). But I also read somewhere (..) that for instance "Rfsol" (so "front" reflectance) in the window description is also for the exterior facing side of the window.. In the end, I don't know if "front" is supposed to mean "interior facing side" or "exterior facing side".<br>
</div><div><br></div>Also, in the window description, there are dimensions (width, height). In the Window Type Manager, there are also dimensions taht you can enter ("For 1 glazing module", just below "slope of window"). Finally, in the different zones of my building where I actually use this type of window, there is an area which correspond to the area of the window I drew in sketchup.<br>
<br></div>==> which one of these area is actually used in TRNSYS computation?<br><br></div>Any help would be greatly appreciated ! I've been looking in WINDOW manual, as wel in the TRNSYS manuals, I can't find anything in there...<br>
<br></div><div>Thanks ,<br></div><div><br></div>Arnaud.<br></div>
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