Re: [EnergyPlus_Support] condfd Vs ctf

["Michael J. Witte" <mjwitte@xxxxxxxx>]

This is a known issue (see #7236 in Known_Issues-V2-0-0.htm).  The problem does 
not occur in all models.  We are investigating why and when it happens.  One 
thing we do know is that Material:Regular-R can cause problems.  So, one thing 
to try is to replace all Material:Regular-R objects with equivalent 
Material:Regular.

Mike


On 6 Jun 2007 at 4:24, basill_xw wrote:

> I will simulate a building containing PCMs.So I would like to test 
> energy+ calculations using CondFD instead of CTF for a buliding without 
> PCMs.
> I created a buliding model(about 10 thermal zones) wihtout heating and 
> cooling equipments in 
> designbuilder V1.3. First I finished the simulation with CTF algorithm
> (time step in hour is 6).Sencond I finished the simulation with Condfd
> (time step in hour is 60). And both algorithms reach convergence during 
> the warmup days.
> Then I compared the two results,there is a big difference between the 
> two results. The amplitude of indoor temperature(from Condfd algorithm)
> is much smaller than the amplitue of indoor temperature(from CTF 
> algorithm).
> And I have done the same work in e+ v2.0. There is the same problem.
> 
> Does anybody know why ?
> thank for your help in advance!
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
> Documentation link and press the "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 


========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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