Overwrite space/zone floor area in OpenStudio

asked 2016-05-30 07:36:26 -0600

updated 2016-05-30 07:42:41 -0600

I've got a 2 story mall concourse with very large openings (short story: on the second floor you can only walk at the perimeter, but otherwise see here) and that is conditioned by the same HVAC system. I've ended up defining it as a single space and thermal zone.

Basically I want to end up calculating correctly everything that needs to be calculated, including people, plug loads, and design specification outdoor air. I have my occupancy defined at people/ft², my plug loads as W/ft² etc.

I'd like to override the space area so that I end up with something like 1.6 times what it should be, and I'm wondering if there's a way to do this in OpenStudio or I'm left having to calculate my plug loads, outside air CFM, etc as a side calc?

(Knowing that this will also require some proper explaining for the reviewing authority as to why the output reports mentions LPDs that are out of range etc...)

answered 2016-05-30 09:05:44 -0600

Julien Marrec

29706 ●94 ●76 http://www.effibem.com/

updated 2016-05-30 09:56:44 -0600

Turns out as long as your have properly defined everything as per floor area, it propagates to EnergyPlus, so you can just use an EnergyPlus measure to overwrite the zone area.

Here's an example of a Lights object:

Lights,
  189.1-2009 - Office - ClosedOffice - CZ1-3 Lights, !- Name
  90.1-2007 - Office - ClosedOffice,      !- Zone or ZoneList Name
  Office Bldg Light,                      !- Schedule Name
  Watts/Area,                             !- Design Level Calculation Method
  ,                                       !- Lighting Level {W}
  11.8403014583807,                       !- Watts per Zone Floor Area {W/m2}
  ,                                       !- Watts per Person {W/person}
  ,                                       !- Return Air Fraction
  0.7,                                    !- Fraction Radiant
  0.2;                                    !- Fraction Visible

I've uploaded a measure to the BCL called Overwrite Zone Floor Area