<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Thomas,<br>
The value to which you refer in TRNBuild is called a time base and it
is not quite the same thing as a time step. TRNBuild takes the walls
that you define and it applies an algorithm to them that results in the
calculation of a series of coefficients. Each coefficient is really a
weighting factor that tells how important a given factor (such as the
temperature difference across the wall, or the energy transfer through
the wall) was at a given point in the history of the wall. Normally,
the first coefficient determines how important the factor is at the
current time, the second coefficient determines how important the
factor was one hour ago, the third one determines how important the
factor was two hours ago, etc. For walls that are very massive or very
lightweight, you can imagine that the method would break down - if the
entire response of the wall occurs within the past 15 minutes, it will
not be accurately modeled if there are coefficients only for each hour
back in history. The time base in TRNBuild allows you to adjust the
frequency of the coefficient calculation; if you indicate that the time
base is 2 hours instead of 1, you can simulate more massive walls
because the history covered by the coefficients will extend farther
back in time. The only rule is that the TRNSYS simulation time step
cannot be greater than the Type56 / TRNBuild time base.<br>
Kind regards,<br>
David<br>
<br>
<br>
Real Thomas wrote:
<blockquote
cite="mid:07B2ADD37174144CA88EF5F05FDF76C1C64527C8@srv-exchange.aldes.local"
type="cite">
<meta http-equiv="Content-Type" content="text/html; ">
<meta content="MSHTML 6.00.2900.3395" name="GENERATOR">
<div><font face="Arial" size="2">
<div>
<div><font face="Arial" size="2"><span class="201562107-01102008">Dear
TRNSYS Users</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">I
have just discovered there is a time step in TRNBUILD which is
different from the time step in the Studio (deck).</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008">I ha<span
class="745192409-01102008">d</span> run a lot of simulations <span
class="448235009-01102008"><font color="#0000ff"><font color="#000000">with
a </font></font></span>TRNBUILD <span class="448235009-01102008"><font
color="#000000">time step of</font></span> 1 hour and<span
class="448235009-01102008"><font color="#0000ff"> <font color="#000000">a</font></font></span> Studio <span
class="448235009-01102008"><font color="#0000ff"><font color="#000000">time
step</font> </font></span>really lower (30 seconds, 1 minute, 5 minutes<span
class="448235009-01102008"><font color="#0000ff"><font color="#000000"> )</font> </font></span>.
These simulations seemed quite good and worked well if we put an Input
Value Recall (Type 93) between the Building outputs and some other
components.</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">I
have now changed the time step in TRNBUILD (0.1 hour => I couldn't
go lower) and changed the Studio time step to 0.1 hour.</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008">I
can see differences, but they are not big : less than 2% for a total
consumption of the year.</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><span class="201562107-01102008"><font face="Arial"><font
size="2">The problem is that I am studying strategies of heating
regulations. So<span class="745192409-01102008">, I need short time
steps to see if my regulation strategy is good.</span></font></font></span></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font><font
face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">I
have 2 questions :</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><span class="201562107-01102008"><font face="Arial"><font
size="2">- Do you think my simulations already run with different time
steps between TRNBUILD and the Studio are wrong ?<span
class="745192409-01102008"> not realist ?</span></font></font></span></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">-
If the time steps of the Studio is lower than the TRNBUILD <span
class="745192409-01102008">time step</span>, what information /
instructions are given by the studio to TRNBUILD ? </span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008">For
exemple I have calculated <span class="745192409-01102008">with the
Studio </span>every minute the air temperature to blow into a room in
the Studio, the TRNBUILD time step is 1h : what is the air temperature
used in TRNBUILD : the mean of the temperatures calculated every
minutes ? only the temperature calculated at 60 minutes ? or an other
one ?</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">Thank
you for your help</span></font></div>
<div><font face="Arial" size="2"><span class="201562107-01102008"></span></font> </div>
<div><font face="Arial" size="2"><span class="201562107-01102008">Kind
regards,</span></font></div>
</div>
<div> </div>
<div align="left"><img alt=""
src="cid:part1.08040609.03040503@tess-inc.com" align="bottom"
border="0" hspace="0"></div>
<div align="left">
<div align="left"><strong><font color="#0000cc" face="Arial" size="2">REAL
Thomas</font></strong></div>
<div align="left"><font face="Arial" size="2">Ingénieur Recherche</font>
<div><font face="Arial" size="2">Research Engineer</font></div>
<div><font face="Arial" size="2"><a moz-do-not-send="true"
title="mailto:lefebvre-camille@aldes.com"
href="mailto:real-thomas@aldes.com">real-thomas@aldes.com</a></font><font
face="Arial" size="2"><br>
Tel : 05.61.24.95.65 - Fax : 05.61.24.95.69</font></div>
<div><font face="arial" size="1"><font size="2"><a
moz-do-not-send="true" title="http://www.aldes.com/"
href="http://www.aldes.com/">www.aldes.com</a></font></font></div>
<div><font face="arial" size="1"> </font></div>
</div>
<div align="left"><span
style="font-size: 18pt; color: rgb(0, 102, 0); font-family: Webdings;"><font
face="arial" size="1">P </font></span><font face="arial" size="1"><b><i><span
style="font-size: 7.5pt; color: rgb(0, 102, 0); font-family: 'Arial','sans-serif';">Afin
de contribuer au respect de l'environnement, merci de n'imprimer cet
e-mail que si nécessaire.</span></i></b><span
style="font-size: 12pt; color: rgb(0, 102, 0); font-family: 'Times New Roman','serif';">
<o:p></o:p></span></font></div>
</div>
</font></div>
<pre wrap=""><font face="Arial" size="2">
<hr size="4" width="90%">
_______________________________________________
TRNSYS-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:TRNSYS-users@cae.wisc.edu">TRNSYS-users@cae.wisc.edu</a>
<a class="moz-txt-link-freetext" href="https://www-old.cae.wisc.edu/mailman/listinfo/trnsys-users">https://www-old.cae.wisc.edu/mailman/listinfo/trnsys-users</a>
</font></pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
***********************************************************************
Thermal Energy System Specialists (TESS), LLC
David BRADLEY 2916 Marketplace Drive - Suite 104
Partner Madison, WI 53719
USA
P: +1.608.274.2577
F: +1.608.278.1475
E-mail: <a class="moz-txt-link-abbreviated" href="mailto:bradley@tess-inc.com">bradley@tess-inc.com</a>
Web Pages: <a class="moz-txt-link-freetext" href="http://www.tess-inc.com">http://www.tess-inc.com</a> and <a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a>
***********************************************************************</pre>
</body>
</html>