Hello,
I´m modeling the garage fans in Proposed building in the following manner: double speed drive (1st step:50% airflow; 2nd step: 100%) with CO sensors located arround the park. When CO levels are below 50ppm, parking fans are at the lowest speed, but when those levels reach 100ppm, parking fans operate ate full speed.
As per ASHRAE 90.1 - 2010, section 6.4.3.4.5, garage fans do not need to stage/modulate if the one of the exceptions are met (the building falls under exception a, as the garage has arround 800m2 and does not have mechanical cooling or heating).
Since garage fans in 90.1 - 2010 are not considered a process load (as they are regulated), there is not the need to have equal energy consumption in both baseline and proposed.
My question is, may I take credit here by modeling the Baseline's garage fans as constant speed (as they are excepted to stage/modulate)?
Thank you in advance!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5925 thumbs up
June 13, 2018 - 1:06 pm
Yes. The baseline should be according to Section 6.4.3.4.5 and if exception a applies then the baseline should not have those controls. Baseline should be based on the minimum required ASHRAE 62.1 parking ventilation rates of 0.75 cfm/square foot. Baseline system fan power shall be calculated at 0.3 watts per CFM. I would suggest you provide an explanation to the reviewer within the MEPC or as a separate narrative.