Hi,
I am working on a large building which is part theater, part convention center and part exhibitions halls + ancillary spaces. The baseline system is system type 7. App G says "For systems 5,6,7 and 8 each floor shall be modeled with a separate HVAC system". The building has many different levels and lots of spaces which span over multiple floors (Such as exhibition halls). The most common sense approach seems to be to match the baseline HVAC system zoning as per the proposed however this is not compliant with the sentence in App G (unless it is intended to imply a minimum of one HVAC system per floor). Is this correct?
If it is the case that each floor has to have 1 HVAC system in the baseline how do you determine the pressure drop adjustment for each floor? Each floor will be served by many different AHU types (e.g if some AHU's have heat recovery and others don't etc) and therefore there would be multiple values.
Thanks
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
March 16, 2014 - 3:37 pm
Correct you must model a system per floor.
Very hard to say exactly how to apply the pressure drop adjustments without seeing the situation but in general you apply the ones that are part of the proposed systems serving that floor. If a proposed system covers a portion of a floor and a pressure drop adjustment only applies to a part of a floor you would proportion the adjustment based on the supply air flows. In the case of heat recovery you only apply the baseline pressure drop adjustment for it if the baseline system is required to have heat recovery according to G3.1.2.10. Also if you apply any of the G3.1.1 exceptions you may need to model a second system on a particular floor.
Victoria Watson
AECOM4 thumbs up
March 26, 2014 - 10:46 am
Thanks Marcus,
Couple of other clarifications:
- If I have floors at different heights across the buildings (E.g half the building is at 3m and the other half at 3.6m) would you split based on floor number, e.g this would all be 2nd floor so 1 baseline HVAC system for the floor or floor height so this would be 2 baseline HVAC systems to cover the 2nd floor.
- For spaces which spans several floors (e.g theaters, exhibition halls) should they be on baseline HVAC system for the floor they start on?
Thanks
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
March 26, 2014 - 4:45 pm
Again hard to say without seeing the whole situation but if I had a floor that was at a slightly different level I would probably still count it as all one floor.
Yep the area is based on floor space.