Hello,
I am currently modelling a laboratory building in which all spaces are ventilated through AHU's with 100% Fresh Air in combination with individual FCU's without connection to ducts (recirculation only).
My baseline is system 5 - VAV w/ reheat. I looked for any guideline regarding recirculation for the baseline system and could not find any. Since all my AHU's in the proposed case are FAHU (100% OA), should I also disable recirculation for the baseline system?
Moreover, how should I define the heating and cooling calculation sequence in order to meet the load for the proposed case (I dont have project info regarding this)? Should I define the FAHU with priority 1 and the individual terminal FCU's as second or vice versa? I already defined the minimum outdoor air flow rate for each zone according to ASHRAE 62.1-2010, so I believe I shoul give priority to the individual FCU's to meet to load. Then the minimum OA that is supplied by the FAHU as well as the rest of the load (if FCU is unable by itself only).
Thank you in advance.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5921 thumbs up
July 13, 2018 - 11:05 am
Addendum cn to 90.1-2010 adds exception d. to section G3.1.2.6 that allows lab spaces to use 100% OA systems in the baseline. Also note the other exceptions for lab spaces in G3.1.1 exception c, G3.1.2.9.1 and G3.1.3.13.
You must get the sequence of operations for the proposed systems so that you can model the system as designed. This is required in Table G3.1-1 Proposed (a).