Attached you’ll find my building file.
My process – created the geometry for the building – calculated the loads – assigned airflows to mechanical zones based the loads report. At the system level, assigned my fan power to be 1.3 hp for each 1,500 CFM packaged RTU.
I’m doing a NR T24 Performance calc – My question, how is it that my standard building I’m comparing against is using about 1/3rd less fan power? Building is ~26,000 sqft so I’m not Constant Volume. I have VSD’s on my fans. I’m not pushing to much air to spaces – airflows are reflective of the loads and are consistent with what I would expect. I’m using a Packaged VAV system type, gas furnace. My envelope isn’t anything crazy and pretty much right in line with prescriptive T24 values. But for the standard design to be using a 1/3rd less energy I must be missing something right?
I’ve even dropped my fan power to 0.77 bhp, ~ 0.000512 kw/cfm and still was not even close to the standard design…?
Appreciate the help – My description is pretty light here and I’m not expecting a direct answer so feel free to ask questions and poke away
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