Re: [EnergyPlus_Support] ConFD vs CTF

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

For most constructions, the results should be the same, but the CTF method is 
faster.  The primary advantage of CondFD in the current implementation is the 
ability to model temperature dependent thermal conductivity and enthalpy 
(specific heat) by using MATERIALPROPERTY:TEMPERATUREDEP:CondFD. The primary 
application for this is phase change materials.

Mike


On 17 Apr 2007 at 10:04, Ian Doebber wrote:

> What is the benefit of using the Finite Difference solution over the CTF method?
>  Has it been shown to better account for transient behavior (ie thermal mass)?
> 
> 
> 
> ________________________________
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of dust_broom Sent:
> Tuesday, April 17, 2007 7:03 AM To: EnergyPlus_Support@xxxxxxxxxxxxxxx Subject:
> [EnergyPlus_Support] High thermal mass envelope
> 
> 
> 
> Dear all
> 
> I'm simulating a 80 cm thick granite wall building. This is obviously
> a high thermal mass envelope. I know that there are some problems
> regarding the simulation of high thermal mass envelopes. I'm also
> comparing my results with the results provided by TRNSYS for the same
> building. In fact they don't match at all! so I was wondering witch
> solution algorithm should I use. I'm currently using the CTF but maybe
> for high thermal mass, the ConFD is more accurate.
> Can anyone give me some insight about this issue?
> 
> Thank you in advance
> 
> Emanuel Sá
> 
> 
> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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