Dear Benoit,<br><br>Thanks for your reply!<br><br>I did as you said, i.e. I changed the air U-value from 0.09252 W/m2K into 4.65 W/m2K. Then the min. timebase 2 hours can work. But I'd like to ask you why we should set this value 4.65 W/m2K? Could you please tell me which reference literature said? Because I checked the air conductivity as 0.09252 kJ/hmK from the literature.<br>
<br>Thanks!<br>Br.<br>yang wang<br><br><div class="gmail_quote">2012/11/20 Benoit Delcroix <span dir="ltr"><<a href="mailto:benoit.delcroix@polymtl.ca" target="_blank">benoit.delcroix@polymtl.ca</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>Hello,<br>
<br>
To me, I think you should set your air layer as a resistive layer
and set the air U-value to 4.55 - 4.65 W/(m²K) (if there is no
ventilation in the basement). And normally, afterwards, you should
be able to decrease the timebase value (normally 1 hour should be
possible). If you want less, split the heaviest walls with an
active layer (probably the roof and groundfloor walls).<br>
<br>
Best,<br>
<br>
Benoit <br>
<br>
Le 2012-11-19 04:31, 王洋 a écrit :<br>
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Dear Leen, Jean, Marion, Benoit and others,<br>
<br>
Many thanks for your reply!<br>
<br>
I checked my Wall's thickness and thermal property etc. again. Why
needs it 9 hours as the timebase? I think maybe it is due to my
Ground floor (it is the basement's floor of the building) which
includes about 0.99 m's Air Layer.<br>
When I changed it into 0.1 m, the min. timebase 2.5 hours can work
without the ERROR:Error creating the wall transfer function
coeffients.<br>
<br>
Therefore, I'd like to ask you, <br>
1) Is it normal for TRNBuild setting how large the timebase is
maximally? 5 hours or others?<br>
2) How to solve this problem of the ground floor with about 0.99
m's Air Layer? But our building project indeed has<br>
the ground floor with about 0.99 m's Air Layer. I can't reduce it
into 0.1m? Is the only way to <span style="color:rgb(51,51,255)">
try the active layer approach of The group of Michael Kummert in
Montreal</span>? <br>
<br>
Please see the Attached INF file.<br>
<br>
Thanks in advance!<br>
Br.<br>
<br>
wang<br>
<br>
<br>
<div class="gmail_quote">2012/11/17 Benoit Delcroix <span dir="ltr"><<a href="mailto:benoit.delcroix@polymtl.ca" target="_blank">benoit.delcroix@polymtl.ca</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Hello,<br>
<br>
I'm one of the students of Michaël Kummert working on a
new method to generate the tranfer functions. I thing I
can help you for your problem. As Leen said, TRNSYS is
unable to generate the transfer functions coefficients for
a heavy and insulated wall with a low timebase. In the
TRNBuild project, you can modify that value and increase
it to allow TRNSYS to generate the transfer functions.
Actually, TRNSYS is unable to generate the transfer
function as soon as the Fourier number of the wall
(thermal diffusivity * timebase / thhickness²) is lower
than 0.0005. To check that, TRNBuild make the sum of one
of the coefficients series (a, b or c). The 3 sums are
equal and means, according to TRNBuild (I don't personally
think so...but it's like this), the Fourier number. <br>
<br>
As Leen said, it exists a trick. You can use an active
layer to split the wall in 2 and then forcing TRNSYS to
generate 2 series of transfer functions coefficients for
the same wall. As the 2 parts are thinner, you could use a
better timebase value. When you insert the active layer in
the wall, try to split the layer with the lowest Fourier
number. And then to insert the active layer, use the
expert mode that allows you to insert an equivalent
conductivity. Insert the biggest value you can. Like that,
the active layer is negligible at the thermal point of
view. Actually, the active layer is acting as a mini-zone
to split the wall. It is a little tricky but it
works...before having better solution.<br>
<br>
Good luck for your project and have a nice week-end,<br>
<br>
Benoit <br>
<br>
Le 2012-11-17 14:43, <a href="mailto:trnsys-users-request@cae.wisc.edu" target="_blank">trnsys-users-request@cae.wisc.edu</a> a
écrit :<br>
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