Seems that some of my questions are not easy to answer.
Here is another question for the same lab project.
Fan system Power limitations are calculated according to Table 6.5.3.1.1A of ASHRAE 90.1-2007 Standard. Therefore credits are given for devices in the ducts of the HVAC system.
The designed lab building which we have to calculate for LEED C&S uses a diversity of devices in the ducts.
For the supply duct they use 2 filters, 6 air louvres for control, 2 cooling coils (cool+recool), 2 heating coils (heat+reheat), 1 energy recovery, and 2 sound attenuators.
For the return duct they use 1 Filter, 4 air louvres for control, 1 humidifier for adiabatic cooling, 1 energy recovery and 2 sound attenuators sections.
This results in a big fan power as documented from HVAC engineer of about 3.3 W/CFM for the supply and about 3.7 W/CFM for the Ventilators.
The question is:
Can we use the diversity of filters (2+1) and sound attenuation sections (2+2) in the design to calculate the fan power limitation of the baseline?
Regards Heinrich
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5900 thumbs up
October 19, 2011 - 1:07 pm
Yes the hard ones require research and the polling of colleagues. As a volunteer contributor I usually get to the easy ones fast and the hard ones as time allows. This is a relatively hard one to answer.
Neither the Standard nor the User’s Manual are clear about whether you can take pressure drop adjustments for more than one filter or sound attenuation section within the same duct. Example 6-AAA in the User’s Manual indicates that you can apply a pressure drop adjustment for heat recovery devices to both the supply and exhaust airflow, so by extension you could make the argument that multiple pressure drop adjustments should be allowed for filters and sound attenuators since they increase the static pressure (and therefore fan power) of the Proposed system. Your best bet would be to request an interpretation from GBCI for the specific project in question.