A question has been raised regarding which space area (GROSS or NET) should be considered into the simulation thermal blocks conception in order to result in the most accurate results. The project team came up with the following discussion:
•There is a concerning that if GROSS area is considered, the thermal blocks will not represent the real designed space volume, and therefore, this will result in extra fan energy consumption;
•On the other hand, if NET area is considered, the model will have a reduced gross external wall area if compared to the real designed building, and also effect on the energy consumption results accuracy.
In relation to LEED and ASHRAE 90.1-2007 Appendix G, which option described above would be the most appropriate to consider?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 8, 2012 - 9:26 am
It depends on the software you use and how that software models the walls. For example in eQUEST you can enter wall thickness and then gross makes sense or you can enter just the wall U-value and then net makes sense.
Fabiano Castro
CTE23 thumbs up
May 10, 2012 - 9:15 am
Thanks Marcus!
Would you know how Energy Plus works?
The model constructions surfaces include wall thickness, but I could not find yet at Energy Plus tutorials what should I consider.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 10, 2012 - 9:59 am
We have used Energy Plus. If you have EP software questions you can use the help desk - http://energyplus.helpserve.com/
Fabiano Castro
CTE23 thumbs up
May 10, 2012 - 12:56 pm
Thanks!
I have got tha answer for both IES and EnergyPlus, if anyone have the same question, it is available on the following links:
ENERGY PLUS
http://energyplus.helpserve.com/Knowledgebase/Article/View/65/13/wall-th...
IES-VE
http://www.iesve.com/support/knowledgebase
-Search for 'Inner volume' in VE-PRO/ModelIT