Hello everyone, I have a project with the following conditioned area categorization.
1st to 5h Floor are composed by:
Assembly areas: 59,232 sq ft (considering hotel service areas such as restaurant, bar, gym, and convention center)
Retail: 70,060 sq ft
Office area: 4,485.42 sq ft (hotel administrative areas)
5th to 24th floor is merely only guest rooms:
Hotel: 122,318 sq ft
For system designation, I was wondering... retail, assembly and office areas differ in operational schedules in a daily basis since, retail and assembly still function in sundays when offices are unoccupied. However they don't really differ from operation in weekly hours (50.50, 46.30, and 48.60 weekly hours respectively)
Could I add up this three zone areas for creating a system 6 for HVAC purposes, with assembly/retail schedule or should I exclude the office areas and create its corresponding system 4 for zone with office schedule?
Also, for lighting purposes, my intention is to use 4 space classification areas: Office 1.0 W/ft2, Convention center 1.2 w/ft2, Retail 1.5 w/ft2 and hotel 1.0 w/ft2, these 4 classification areas would be the same for plug load designation.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
March 15, 2019 - 1:47 pm
So the process for system selection would be to take the predominant condition and enter Table G3.1.1A. In this case the hotel is residential so you subtract that off the total area. You take the remaining area and then enter the table again. Sounds like you arrive at a system #6. You then apply any exceptions to your baseline system under G3.1.1. So this may lead you to do a system #4 for the office.
You can use different building area values for different parts of a building like this.
Waleed AlGhamdi
Sustainability EnablerEskew+Dumez+Ripple
20 thumbs up
March 15, 2019 - 2:28 pm
If you're trying to maximize the number of LEED points, it's in your benefit to use System 4 for the office space, since the fan control is CV. If the building load is dominated by heating, this might be the opposite, since System 6 uses electric resistance heating vs. HP for System 4. The office might fall under exception b. given the occupancy load is different, since it's less than 20,000 SF. My understanding is following the exceptions in Appendix G is not optional (i.e. it is a requirement), but I'm not 100% certain of that.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
March 15, 2019 - 2:30 pm
You are correct projects must apply the G3.1.1 exceptions that apply to their project.
Jorge Lopez de Obeso
Architect / Environmental advisereosis Consulting
20 thumbs up
March 19, 2019 - 3:20 pm
Yes, applying all exceptions you are correct. My question was because of the size of areas, giving past experiences revisors have suggested me to keep it simple in cases where efficiency is not determinant due to area proportion. Will stick to ASHRAE. Thanks!