<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content="text/html; charset=us-ascii" http-equiv=Content-Type> <META name=GENERATOR content="MSHTML 8.00.6001.19046"></HEAD> <BODY bgColor=#ffffff text=#000000> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>Greetings from windy Ottawa!</FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>I'm the author of recent changes [r6485] to subsys.F that alter use of the PREC5N variables. In this revision, I modified MZVNT to allow more flexibility in specifying infiltration air flow. These changes permit switching from one air flow computation method to another (AIM-2, scheduled flow and air-flow network) mid-simulation depending on the operating conditions in the building. </FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>Prior to r6485, ESP-r held air infiltration and ventilation flow conductance in the CVIN and CVVN arrays, in common PREC5N.  By default, ESP-r assumes that the air flow rates are specified by hourly schedules in the .opr file. CVIN and CVVN thus contain up to 72 separate flow rates for each zone: one for each hour (1-24) in each of the three day types (weekday/Saturday/Sunday). The routine MZVENC establishes values CVIN and CVVN prior to commencing simulation using the static air change rates specified in the .opr file. </FONT></SPAN><SPAN class=179154319-28042011><FONT color=#0000ff> During the simulation, ESP-r reads the infiltration and ventilation data for the current hour and day type from these arrays.</FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>Rather than create a specific data structure, the air flow network exploited the same variables for imposing network-computed infiltration and ventilation flows on the building thermal model. There two deficiencies with this approach:</FONT></SPAN></DIV> <UL dir=ltr> <LI> <DIV align=left><SPAN class=179154319-28042011><FONT color=#0000ff>It's cumbersome. Because CVIN and CVVN are designed to hold hourly schedules, the air-flow network had to locate the correct array location (that is, the current day type and hour) to save the data in, even though these parameters had no relevance to the air-flow network computation. This not only requires extra code; it also obfuscates the purpose of the CVIN/CVVN arrays.</FONT></SPAN></DIV></LI> <LI> <DIV align=left><SPAN class=179154319-28042011><FONT color=#0000ff>It erases the original schedules held in CVIN and CVVN.  These arrays are populated prior to simulation by routine MZVENC. By repurposing them, the air flow network overwrites the original flow schedules with time-step computed values. This prevents re-imposing the .opr schedules mid-simulation—a key objective in our work. </FONT></SPAN></DIV></LI></UL> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>For these reasons, I elected to revise routines MZVENT and MFLW2B to use dedicated variables when imposing infiltration and ventilation on the building thermal domain.  I introduced a new common block AfnToBldData common for this purpose. </FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>Regarding your observations Sara, I'm not sure I understand your comments. When the opr schedule or AIM-2 models are in effect, ventilation is still governed by the hourly ventilation schedule—and therefore should be established via CVVN as per line 1769. I'm also unsure what you're suggesting regarding line 1897. The if statement has two clauses: bAFN = TRUE for air flow networks, and an else clause otherwise. Am I missing something?</FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>Thanks,</FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff>- Alex </FONT></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011> <P align=left><B><SPAN lang=en-us><FONT face="Times New Roman">Alex Ferguson</FONT></SPAN></B><SPAN lang=en-us><BR><FONT face="Times New Roman">Housing, Buildings and Communities Group<BR>CanmetENERGY<BR>Natural Resources Canada<BR>P:+1 613 995 3294<BR>F:+1 613 996 9909<BR><A href="mailto:Alex.Ferguson@NRCan-RNCan.gc.ca">Alex.Ferguson@NRCan-RNCan.gc.ca</A><BR></P></FONT></SPAN></SPAN></DIV> <DIV dir=ltr align=left><SPAN class=179154319-28042011><FONT color=#0000ff></FONT></SPAN> </DIV> <DIV><FONT color=#0000ff></FONT> </DIV> <DIV><FONT color=#0000ff></FONT> </DIV> <DIV><FONT color=#0000ff></FONT> </DIV> <DIV><BR></DIV> <DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left> <HR tabIndex=-1> <FONT size=2 face=Tahoma><B>From:</B> Joe Clarke [mailto:joe@esru.strath.ac.uk] <BR><B>Sent:</B> April 28, 2011 12:02<BR><B>To:</B> core_developers@espr.list.cvsdude.com<BR><B>Subject:</B> Re: AW: Some bugs in subsys.F ?<BR></FONT><BR></DIV> <DIV></DIV>Dear All<BR><BR>In relation to Sara's recent post below, I have made changes to ESP-r to enable the coupling of non-air flow networks to building models to allow the use of ESP-r's building-side features in plant modelling. I use the variables in common PREC5N extensively. The changes are at present resident in my branch and not yet integrated in development_branch.<BR><BR>Regards,<BR><BR>Joe<BR><BR> <BLOCKQUOTE cite=mid:28396844bd4817e53adb29e80dc75cf8@212.203.77.242 type="cite"><BR>I want to only give a heads up in a mistake occurred in development_branch which should be fixed. It reflected in commit log 6618. Since the fluid flow network solver no longer changes the PREC5N variables and data is stored in the dedicated AfnToBldData common variables, the calculation of CV1, CV2 and other related parameters there for AIM2 in subsys.F should be changed (line 1769 in development_branch). Using the current version cannot calculate CVVF in the mode of AIM2 or OPR, so they have to be changed (which you can see in commit log 6618). <BR><BR>Another issue is in CVVFM modification line 1902. The if statement which is in line 1897 is wrong, it doesn't account for other type of air flow network which should consider them. It is also reflected in commit log 6618.<BR !=""><BR>Best Regards,<BR><BR>Sara Nikoofard<BR>Room C254A, Department of Mechanical Engineering, <BR>Dalhousie University, Halifax, NS<BR>Phone: (902)494-3165<BR>email: <A class=autolink href="mailto:s.nikoofard@dal.ca" moz-do-not-send="true">s.nikoofard@dal.ca</A><BR></BLOCKQUOTE><BR><PRE class=moz-signature cols="500">-- Professor J A Clarke email: <A class=moz-txt-link-abbreviated href="mailto:joe@esru.strath.ac.uk">joe@esru.strath.ac.uk</A> ESRU, Dept. of Mechanical Eng. phone: +44 141 548 3986 University of Strathclyde fax: +44 141 552 5105 Glasgow G1 1XJ, UK <A class=moz-txt-link-freetext href="http://www.esru.strath.ac.uk/">http://www.esru.strath.ac.uk/</A> </PRE></BODY></HTML>