[EnergyPlus_Support] Comparison between E+ and TRNSYS

[skalogir@xxxxxxxxxxxxxxxx]

I managed to model my first building with EPlus and tried to compare the results with
those obtained by modelling the same building with TRNSYS. I found some large differences
between the two models which I think are due to the ground heat losses (by increasing the
ground temperature the difference decreases) and the TFC's estimated by E+. 

In TRNSYS the ground losses were calculated by considering the perimeter heat losses as
suggested in ASHRAE H/B of Fundamentals. How these losses are estimated in E+? 

The second difference concerns the TFC. In TRNSYS these were estimated with the routine
PREP and the TFC's max. values of 16.5 and 18.3 for the ext. wall and roof respectively
were obtained and used in the model. The factors given by E+ (eio file) are as follows:

Ext. Walls:
35.6, -143.4, 240.2, -217.7, 116.5, -37.7, 7.3, -0.787, -0.412, -0.702, 0.167

Roof:
49.8, -92, 52.4, -10.1, 0.577, -0.937, 0.398, -0.337, 0.183

These values are much different than those obtained with PREP and I wonder why, as the
same construction is used for both. 

Yours help would be greatly appreciated. 

Wishing you all Merry Christmas and Happy new year,

Soteris
Kalogirou
 


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get 128 Bit SSL Encryption!
http://us.click.yahoo.com/CBxunD/vN2EAA/xGHJAA/dkFolB/TM
---------------------------------------------------------------------~->

To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

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 are of the Support Web Site.




 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/